vvEPA
                   United States
                   Environmental Protection
                   Agency
                    Research and Development
PROJECT  REPORT
                                 Atmospheric Sciences
                                 Research Laboratory
                                 Research Triangle Park NC 27711
                                 October 1987
                    DEVELOPMENTS  IN NATIONAL WEATHER SERVICE

                    f'EIEOROLOGICAL DATA COLLECTION PROGR/V1S

                    AS RELATED TO EPA AIR POLLLTION MODELS

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    DEVELOPMENTS IN NATIONAL WEATHER SERVICE METEOROLOGICAL
DATA COLLECTION PROGRAMS AS RELATED TO EPA AIR POLLUTION MODELS
                              by
             Thomas E. Pierce and D. Bruce Turner
              Meteorology and Assessment Division
           Atmospheric Sciences Research Laboratory
               Research Triangle Park, NC  27711
           ATMOSPHERIC SCIENCES RESEARCH LABORATORY
              OFFICE OF RESEARCH AND DEVELOPMENT
             U.S. ENVIRONMENTAL PROTECTION AGENCY
                  RESEARCH TRIANGLE PARK, NC

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                               NOTICE
The information  in  this  document  has  been funded  by  the  United  States
Environmental Protection Agency.  It has been  subject  to  the  Agency's peer
and administrative review, and  it has  been approved for publication  as  an
EPA document.  Mention  of  trade names  or  commercial  products  does  not
constitute endorsement or recommendation for use.
                             AFFILIATION

     Mr. Thomas E.  Pierce and Mr. D. Bruce Turner are on assignment from the
National Oceanic and Atmospheric Administration.   Mr.  Pierce is a Meteoro-
logist in  the  Environmental  Operations Branch, Meteorology  and Assessment
Division, Environmental  Protection Agency,  Research  Triangle  Park,  NC.
Mr. Turner is Chief of the Environmental Operations Branch.
                                     ii

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                              ABSTRACT

     During the next decade, the National Weather Service (NWS) will be
upgrading its meteorological instrumentation and data dissemination proce-
dures.  Because these changes will affect the operation of the U.S. Environ-
mental Protection Agency's (EPA) air pollution models, this project has
been undertaken to report on proposed changes and to recommend how to make
optimal use of the new NWS data products.

     New instrumentation will include automated surface observation systems,
next generation radar, and remote profilers.  Data dissemination is being
upgraded with an automated weather interactive processing system, the
conversion of data tapes to an element format, and the introduction of data
formats that are compatible with personal computers.  Complete descriptions
of existing and new formats that are applicable to EPA air pollution models
are given in the Appendices.

     To maximize the usefulness of NWS meteorological data, the following
actions are recommended: (1) adapt the EPA meteorological processors to
read the new data formats and upgrade them to incorporate advances in dif-
fusion meteorology; (2) encourage the collection of meteorological data
specific to diffusion modeling and investigate the feasibility of collecting
some of these data at NWS sites; (3) improve the handling and formatting of
NWS data for regional-scale models; and (4) maintain active communication
with the National Climatic Data Center.
                                    iii

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                               CONTENTS

Abstract	iii
Figures	vi
Tables	vi
Acknowledgements  	 vii

     1.   Introduction  	   1
     2.   Current Requirements  	   3
               UNAMAP Models  	   3
               Regional models  	  10
     3.   Proposed NWS Renovations	11
               Instrumentation  	  11
               Data Dissemination	  17
     4.   Summary and Recommendations	21

References	23
Appendices

     A.   Description of the TD-1440 format	25
     B.   Description of the TD-3280 format	45
     C.   Description of the TD-5600 format	85
     D.   Description of the TD-6200 format	89
     E.   Description of the TD-9689 format	107
     F.   Description of the TD-9773 format	Ill

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                               FIGURES
Number

  1
  2
Determination of twice-daily mixing heights
Determination of hourly mixing heights .  .  .
Page

  7
  8
                               TABLES
Number
                                                               Page
        Meteorological requirements for UNAMAP .  .  .
          (Version 6)  models
        Meteorological data formats used with UNAMAP
          (Version 6)  models
        Variables used in the TD 1440 format ....
                                    vi

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                           ACKNOWLEDGEMENTS

     The authors would like to thank the many individuals within the National
Oceanic and Atmospheric Administration and  the U.S. Environmental Protection
Agency who provided  much  of  the information contained in  this  report.   In
particular, the following people are recognized:

     National Climatic Data Center  (NCDC) -
          Mr. Richard Heim  (Climatological Services)
          Mr. Alva Wallis  (Climatological Services)
          Mr. Richard Davis  (Data Base Administration)
          Mr. Robert Quayle  (Data Operations)
          Mr. Kenneth Davidson  (Systems Integration and Planning)
     National Weather Service  (NWS) -
          Ms. Mary Heffernan  (AWIPS-90/NOAAPORT)
          Mr. Paul Hexter  (NEXRAD)
          Dr. Joe Facundo  (Upper-Air)
          Dr. James Almazan  (Office of the Federal Coordinator)
          Mr. Jon Paerin  (ASOS)
          Mr. Steve Short  (ASOS)
          Mr. Newton Page  (NOAANET)
          Dr. Robert Strickler  (Instrument Systems; Test and
                                 Evaluation Division)
     Environmental Protection Agency  (EPA) -
          Mr. William Keith  (Office of the Federal Coordinator)

The authors  would also like  to thank  Mrs.  Sylvia  Coltrane for her word
processing expertise and  especially Mr.  John Irwin  for his encouragement
and review of this project.
                                    vii

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                               SECTION 1
                             INTRODUCTION

     One of the principal inputs to an air  pollution model is meteorological
data.  Collecting and archiving the data  poses a challenge to those involved
in diffusion  modeling.   The  Nuclear Regulatory  Commission (NRG)  and the
Environmental Protection Agency (EPA) have  addressed this problem of meteor-
ological data quite  differently.   The NRC  requires that  nuclear installa-
tions collect  comprehensive  meteorological  data,  including  temperature
differences, hourly  average  winds,  and  turbulence   fluctuations.   These
measurements are usually taken on masts at  heights ranging from 30 to 100 m.
In some  localities,  such as near  a  large  body  of water,  multiple meteoro-
logical masts are required.  In  contrast,  EPA regulates a  greater number
and many more types  of  sources than  the NRC.  Because  it is impractical for
every potential emitter of  air pollution to operate a  comprehensive on-site
meteorological monitoring program, EPA has  traditionally relied on meteoro-
logical data collected  by the National Weather Service (NWS).  EPA's models
use simplistic characterizations  of diffusion meteorology  using only a few
measured NWS meteorological variables.  For example, the rate of dispersion
is determined by a Pasquill stability class as estimated from routine obser-
vations of  wind  speed,  cloud cover,  and ceiling  height.   Hourly estimates
of plume  rise,  dilution,  and transport direction are based  on  a single
2-minute average wind value reported  by an  observer on the hour.

     During the past few years,  the NWS has started to  modernize its meteor-
ological instrumentation and data  dissemination systems,  and EPA has begun
efforts to  use  additional meteorological  information  to  characterize dif-
fusion (EPA, 1987; Paumier  et  al. , 1986).   Upgrades in new instrumentation
will include automated  surface observation  stations (ASOS), next generation
radar (NEXRAD),  and  remote  profilers.  Data dissemination  will  be improved

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with the operation of an automated weather interactive processing system
(AWIPS) and perhaps with a modern climatological data distribution system
(NOAANET).  The focus of this report is to assess how these changes in NWS
meteorological data will affect EPA air pollution models.   In particular,
this report is intended to inform model users and developers on likely
changes and to recommend upgrades in meteorological processors in order to
effectively accoraodate data from new instruments and in different formats.

     In Section 2 of  this report, current  meteorological data requirements
for EPA air pollution models  will be reviewed.   Proposed changes to NWS
instrumentation and data dissemination  will  be  discussed in Section 3,
especially as related to EPA  models.  A summary and recommendations are
given in Section 4.

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                              SECTION 2
                        CURRENT REQUIREMENTS

     Air pollution models  in EPA can be broken  down  into  two  basic areas:
UNAMAP models and  regional models.   In general, UNAMAP models  are  used by
the public  for  regulatory  modeling.   It is estimated that  several  hundred
organizations in  the United  States  use UNAMAP  models.   Regional  models
tend to be  larger and more  complicated than UNAMAP models.   They are either
used for research and development or  for  planning emission reduction strate-
gies across  several  states.  Models  such as  the  regional model for  acid
depostion (RADM)  and the  regional  oxidant  model  (ROM)  are  being  used in
making important  policy decisions.   Like UNAMAP models, their  successful
operation depends  on National  Weather  Service  (NWS) meteorological  data.

UNAMAP MODELS

     UNAMAP  stands for  the User's Network for the Applied Modeling of Air
Pollution.   It  began in 1973 to  provide the EPA modeling community  ready
access to models for estimating air quality impact from proposed and exist-
ing sources  of air pollution.  The latest version of UNAMAP,  version 6, was
released in  1986 and contains over 24 models and meteorological processors.
Version 6 contains both models  that  have regulatory status and models that
are to be tested and  evaluated.   Two UNAMAP models, PLUVUE-2 and MESOPUFF-2,
are regional-scale models.   Attributes  of  each model  are  summarized  in
Table 1.

     The models listed in Table 1  are either short-term or long-term models.
Short-term models use hourly meteorological  data to  estimate air pollution
concentrations for time periods ranging from  1 hour to  1  day.  Long-term
models use   climatological  frequency  distributions   of  wind  speed,  wind
direction, and  stability class  to estimate  air  pollutant  concentrations
for seasonal or  yearly  periods.  Both types  of models depend  on  National
Weather Service data for meteorological information.
                                     3

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   Table 1.  Meteorological  requirements  for
                                                                6)  models.
   Model
Averaging time    Meteorological
                                                   Format
BLP
RAM
ISCST
MPTER
CRSTER
MPTDS
COMPLEXI
CALINE-3
INPUFF
PEM-2
PLUVUE-2
HIWAY-2
PAL- 2
APRAC-3
PBM
MESOPUFF-2
TUPOS
SHORTZ
PTPLU-2
COM- 2
ISCLT
VALLEY**
LONGZ
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Hourly
Long-term
Long-term
Long-term
Long-term
LJ1-\J\—^'&*J*-'J-
RAMMET
RAMMET
RAMMET
RAMMET
RAMMET
RAMMET
RAMMET*
none
none
none
none
none
none
none
PBMMET
READS 6/ ME SOPAC
MPDA
METZ
none
none
none
none
none
TD-1440/9689
TD-1440/9689
TD-1440/9689
TD-1440/9689
TD-1440/9689
TD-1440/9689
TD-1440/9689
Unique
Unique
Unique
Unique
Unique
Unique
Unique
TD-1440/9689
TD-1440/5600
TD-1440/5600/onsite
TD-1440/9689/ onsite
none-required
STAR
STAR
STAR
STAR
  *RAMMET is a generic  name  for EPA short-term meteorological  processors.
 **Can also predict 24-hour average  concentrations.

     As shown in  Table  1,  many of  the UNAMAP  models use  meteorological
data in special  formats  as available  from the  National Climatic Data Center
(NCDC) in Asheville,  North Carolina.   The four currently-used  data formats
are summarized in  Table  2.  Descriptions of  these data formats are contained
in the Appendices.

Table 2.   Meteorological data formats used with UNAMAP (Version 6) models.
NCDC format
identifier
TD-1440
TD-5600
TD-9689
TD-9773


Description
Hourly surface observations
Twice-daily rawinsonde observations
Twice-daily mixing height estimates
STAR data — joint frequency distri-
butions of wind speed, wind direction,
stability class
Appendix
A
C
E
F



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     Most short-term models  require hourly surface  and  twice-daily  mixing
height data in  the  TD-1440  and TD-9689 data formats.  Before  these  models
can be operated, they depend on a meteorological program, called RAMMET,  to
process the data.

   The TD-1440  format  is  generated  from  surface observations  reported  on
WBAN forms.  Variables  included  in the TD-1440 format are listed  in Table
3.  Only a few  of these variables  are  currently used with the EPA meteoro-
logical processor as  noted  in  Table  3.    A  complete description of  the
TD-1440 format is given in Appendix A.
          Table 3. List of variables in the the TD-1440 format.
Variable name Column
SFCID
YR
MONTH
DAY
HOUR
CEILHT
SKY
VISE
WX
PRESS
TDEW
WD
WS
S TAP RE
TEMP
TWET
RH
CLDS
OBSCUR
1
6
8
10
12
14
17
21
24
32
36
39
41
43
47
50
53
56

- 5
- 7
- 9
- 11
- 13
- 16
- 20
- 23
- 31
- 35
- 38
- 40
- 42
- 46
- 49
- 52
- 55
- 78
79
Description
WBAN 5 digit station number
Last two digits of year
01 = January, 12 = December
Day of month
Local standard time (00 - 23)
Ceiling ht. (hundreds of feet)
Sky condition (NOT USED)
Visibility (NOT USED)
Weather type (NOT USED)
Sea-level pressure (NOT USED)
Dew point temperature (NOT USED)
Wind direction (tens of degrees)
Wind speed (knots)
Station pressure (NOT USED)
Dry bulb temperature (F)
Wet bulb temperature (NOT USED)
Relative humidity (NOT USED)
Cloud information (NOT USED)
Total opaque sky cover (tenths)

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     The TD-9689  format  resulted  from a  study conducted  by  the  EPA  in
collaboration with the National Climatic Center  (now  NCDC).   In the  study,
reported by Holzworth (1972), twice-daily mixing heights and  mean  boundary
layer wind  speeds  were  computed  for  a  five year period  for  62  stations
across the  United  States.   The  manner  in  which the  twice-daily  mixing
heights have been calculated is shown in  Figure  1.  Both mixing  heights  are
based on the  1200  GMT sounding.   The  morning mixing  height,  used only  in
urban short-term modeling,  is  computed as  being the height  at which  the
adiabat extending from the morning minimum  temperature plus 5 C intersects
the 1200 GMT  temperature  sounding.   The  afternoon mixing height is  deter-
mined by taking  the  afternoon  maximum  surface  temperature and  finding  the
height at which its adiabat intersects  the  1200  GMT sounding.

     The UNAMAP  models  shown in Table 1 use these  twice-daily  values  for
determining hourly  mixing heights.   The  manner in  which  hourly  mixing
heights are determined is shown in Figure 2.  For rural  applications, only
the afternoon value  is used  as  described  in EPA (1977).  For urban  appli-
cations, both the morning and urban mixing  heights are determined from both
the morning  and  afternoon  mixing heights  as   reported in  TD-9689.   The
National Climatic Data Center makes no  provision for missing data,  precipi-
tation, and  cold advection.  The  user is  therefore  required  to  fill  in
these data gaps before running a preprocessor such as  RAMMET.

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         Morning  sounding  (12  GMT)
         Afternoon  mixing height
         Morning  (urban) mixing
                   height
                T,
n
              Potential  temperature
Figure 1. Determination of  twice-daily mixing heights as  used for TD-9689.
        Tn is the morning  minimum temperature, Tn +5 is the morning minimum
        temperature plus 5 K, and Tx is the afternoon maximum temperature.

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       PREVIOUS DAY
   CURRENT DAY
                           FOLLOWING DAY
 e>
H
a
             Sunaet
Sunrise   1400   Sunset
             Sunset
Sunrise   1400   Sunset



      TIME
                                    1400
                                    1400
Figure 2. Determination of hourly mixing heights  as used in UNAMAP short-term models.

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     In recent years, models have  been  added to UNAMAP that use additional
information on the lower atmosphere in an attempt to simulate more accurate-
ly diffusion  in  the  boundary layer.  One  example is  the  TUPOS dispersion
model (Turner et  al. ,  1986).  TUPOS was  especially  designed to  be  compa-
tible with  the  new EPA Meteorological Processor  for Dispersion Analysis
(MPDA) (Paumier et al. ,  1986).   MPDA specifies  diffusion in greater  detail
than the existing meteorological processor,  RAMMET.   It  allows  for on-site
data, missing data,  and uses upper air,  wind, and temperature data from the
twice-daily NWS radiosondes  (as  given  in  the TD-5600 format).   The TD-5600
format consequently  consists of  more  data  than that  available  from the
TD-9689 format which  has been  traditionally used.    A description  of the
TD-5600 format is  given  in Appendix C.   Other models  that have  special
provisions for  on-site  data include  INPUFF,  HIWAY-2,  and SHORTZ.   The
meteorological processor  for SHORTZ handles  on-site  data but  does  not
handle missing data  periods.  These more advanced  meteorological prepro-
cessors which handle  missing data,  on-site data,  and  available  National
Weather Service data  apparently represent  future  trends in UNAMAP  models
and will be discussed in Sections 3 and 4.

     Another sophisticated meteorological processor  is included with MESO-
PUFF-2.  It  computes  gridded values of  meteorological information  while
using hourly  surface and  twice-daily radiosonde data.   Meteorological data
requirements for regional models such as  MESOPUFF-2 will  be discussed in
the next subsection.

     Long-term models such  as CDM-2 and ISCLT are used for making seasonal
and annual estimates  of air quality.  They rely  on joint frequency distri-
butions of  wind  speed, wind direction,  and  stability class.    These  data
are usually obtained  from NCDC  in a format  commonly known as  STAR data.
Recently, these data  were made  available  on PC  diskette  (Heira,  1987)  in
format TD-9773.   This format is  described  in Appendix F.

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REGIONAL MODELS

     As mentioned above,  two of the UNAMAP models,  MESOPUFF-2 and PLUVUE-2,
are regional models.  They require more data than  the  other UNAMAP models.
MESOPUFF-2 requires surface and  upper-air data from many  locations  within
an area.   Its  meteorological  preprocessor,  MESOPAC,  accepts data  in  the
TD-1440 and TD-9689 formats.   PLUVUE-2 has similar  data requirements except
it does not have a preprocessor for manipulating meteorological data into a
specific format.

     Other regional models used by EPA include  RELMAP,  ROM, and RADM.  Most
of these models are undergoing research and development,  and their meteoro-
logical processors  can be  updated as new and improved meteorological data
become available.  Their  data  needs currently are similar to MESOPUFF except
that RELMAP requires precipitation amounts  for  one degree  latitude  by  one
degree longitude areas.   RADM  estimates precipitaton amounts  using its  own
dynamic prognostic meteorological model because adequate  precipitation data
do not exist for objective analysis (NCAR, 1986).
                                     10

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                              SECTION 3
                        PROPOSED NWS REVISIONS

     The National  Weather Service  (NWS)  is modernizing  its  observational
systems and  data  dissemination procedures.   Existing NWS  instrumentation
has not been significantly modified for 25 years and is rapidly approaching
obsolescence.  Furthermore,  the  current  observational   process  is  quite
labor-intensive and  requires  a large  expenditure  of  funds.   Technology
now exists  for automated  measurements  of surface  and   upper-air  weather
variables.  In addition,  the advantages  of  Doppler  radar  have  been clearly
demonstrated, especially  for  severe weather application  (Durham  and  Wilk,
1987).  These new  systems will generate additional  data  that  will require
enhanced data  handling  capabilities.   The  current  AFOS   system uses  1970s
technology and is overburdened in its data handling and processing require-
ments.  Also,  the  National Climatic  Data  Center is  striving to  meet  the
needs of  new data formats  and  the  increased amount  of  data that  will  be
collected in the near future.

     This section examines  these  changes from the  perspective of air pol-
lution modeling.    First,  instrument programs  will be examined  to see  if
they offer any potential for air pollution model application.  Then, changes
in data dissemination and data formats will be discussed.

INSTRUMENTATION

     Advances are  taking  place in  surface observations, upper-air obser-
vations, and radar.  Current surface observation platforms will be replaced
by an Automated Surface Observation System  (ASOS).   The upper-air rawinsonde
system will be supplemented by remote profilers.  Radars  are being replaced
by Doppler radar  in the next generation radar (NEXRAD) project.  This section
examines the attributes of each of these systems.
                                     11

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Automated Surface Observation System (ASOS)

     The National Weather Service (NWS) plans  for ASOS to  be  in operation
by the early 1990s.  ASOS is the  product  of several years  of  research and
is a cooperative venture among several  federal  agencies.   Development of an
automated surface  observing  systems was  initiated by  the Departments  of
Commerce (DOC), Defense (DOD). and Transportation (DOT) in the early 1970s.
The promise of  such a  system became apparent in  1978 in a joint project by
the Federal Aviation Administration (FAA)  and  the NWS.   Since  1984,  the
ASOS project has been jointly  funded by DOD, NWS, and  FAA.  Management and
operation of ASOS is being assumed by the  NWS.

     ASOS will be implemented in one of two levels, basic or unmanned.   In
the unmanned level, ASOS systems will be installed at sites which currently
do not have a meteorological observation system.   This  includes many of the
general aviation facilities around the country.   ASOS will  therefore provide
extensive surface  meteorological  measurements  at  locations  where  very
little or no information has  been available.  In  the basic  level of service,
ASOS will be installed  at existing  weather  reporting stations.  Initially,
however, on-site observers will augment the system by  reporting additional
cloud information and special remarks.  At some locations, where an observer
is available less  than  24 hours a  day, ASOS will run  in  an  unmanned mode
when the  observer  is  not  available.   In all,  about  1500 ASOS  sites  are
planned for the next 10 years.

     To accomplish its  objectives,  ASOS  uses  recent  advances  in meteoro-
logical instrumentation.  A  laser  ceilometer will replace the  current  25
year old rotating beam  ceilometer.  The laser  ceilometer  can measure cloud
bases through precipitation  and can detect  cloud  layers up to 12,000 feet.
Visibility measurements will be taken with a forward-looking  visibility
meter.   Observers consequently will  not be required to  estimate visibility,
which often varies  from  observer to observer and is difficult to estimate at
                                     12

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night.  With the eventual automation of ASOS, a laser weather identifier is
being developed.  The current design employs a light-emitting diode weather
identifier (LEDWI).  It projects  a partially coherent light  source  over a
1 m baseline and  measures  the light's scintillation properties.   The LEDWI
can discriminate  between  rain,  snow,  and drizzle  and  can  estimate  their
intensities.  However,  it  can not  discriminate between hail and ice pellets.
Other instruments  being updated include the hygrothermometer and  the  wind
vane.  The hygrothermometer,  called HO-83,  is  based  on a  "cooled mirror"
approach.  The  wind vane  is  a  new  prop-vane  designed  by  R.  M.  Young.
However, in preliminary tests,  it has  experienced  problems  associated  with
icing and stalling, and design changes are pending.

     ASOS will have the capability of storing data on-site and will connect
with the existing data dissemination network.  Current plans are for hourly
data summaries  to  be stored  on-site  for 30 days  and 1 minute data to  be
stored up to 8 hours.  ASOS  will  be integrated  into the exisiting  NWS  net-
work, currently called AFOS.   Later in the 1990s, the  data will be dissemi-
nated via  the   automated  weather interactive  processing   system  (AWIPS).
Eventually, the data from ASOS will  be archived at the National  Climatic
Data Center.

     Despite its  advantages,  ASOS poses  potential  shortcomings  for  air
pollution models.  At unmanned  sites, cloud information will be  available
only to  12,000  feet.   Current EPA meteorological processors require  opaque
cloud cover  for  stability  estimates.   However,  the  ASOS  program  office
intends to maintain  observers at  primary locations so  that certain  infor-
mation such as the upper—level cloud cover can be reported.  Unfortunately,
current plans by  the NWS  state  that hourly  values of meteorological varia-
bles will be based  on  only  2 minute  data averages collected on  the hour.
Since data will be sampled every minute, true  hourly averages (especially
of winds)  could  be  obtained  at   little additional  cost.    However,  this
averaging and archival of hourly  data  requires  a  committment of funds that
                                     13

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currently does  not exist.   In  summary, ASOS  represents a major  change  in
surface observations.   Its  deployment  and  operation should be watched care-
fully by those concerned with  using surface observations  in air  pollution
models.

Rawinsondes

     Since World War  II,  rawinsondes have  been used to measure the vertical
structure of wind, temperature,  moisture,  and pressure in the  atmosphere.
Although the system is well established,  some  minor  improvements  are being
implemented.  Microprocessors  are being installed  at each  rawinsonde  site
which will automate data collection and perform many of the quality assurance
checks.  This  should  result  in greater  data  capture and improved  data
quality.  The microprocessors  coupled with  a redesign in the  rawinsonde
package will yield more frequent measurements.  Instead of every 60 seconds,
data will be archived every 30  seconds, thus  providing  improved  resolution
of vertical  measurements.   Also,  data measured every  six seconds will  be
archived at each site  for up to  six  months.  Special requests for six second
data, say  for  a field study,  can be  made  through the Upper Air Programs
Office of the NWS.

Profiler

     For years, rawinsondes have not provided  upper-air data  in  a temporal
and spatial  resolution  desired  by  numerical  weather  prediction and  air
pollution modelers.   Currently,  upper-air  data are  available every 12 hours
and only at  selected stations.  The profiler  system  is  designed  to fill in
these temporal and  spatial data gaps  for weather  forecasting  purposes.

     The profiler is  a  ground-based  remote  sensing  system designed  to
measure wind, temperature,  and moisture profiles above  a  given  site during
                                     14

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all weather conditions.  It consists of two subsystems: a wind profiler and
a thermodynamic profiler.  The wind profiler is  a UHF (frequency currently
established at 405 MHz)  clear-air radar which is  sensitive  to backscatter
from radio  refractive-index irregularities  caused  by turbulence.   Winds
with the profiler are  determined from Doppler shifts  of  the backscattered
signal.  The  thermodynamic profiler  used  for  measuring temperature  and
moisture consists of six channels of a radiometer which measures thermally
emitted electromagnetic  energy.    More details   on  the  profiler  can  be
obtained from Chadwick and Hassel (1987) and Hogg et al. (1983).

     The profilers are undergoing operational development.  The first oper-
ational profiler network is expected to begin operation in 1989.  Initial-
ly, 31 sites have been established in which it is hoped to demonstrate the
feasiblity of  the  profiler.   This  demonstration  network  is expected  to
operate until  1994, when the NWS hopes to implement a national  network of
profilers.  Currently,   it  is  anticipated  that  the  profilers  will  only
augment the  current  rawinsonde network.  Ultimately,  as  the technology is
improved and field-tested,  the profilers  would be expected  to replace the
labor-intensive rawinsonde system.

     Like the ASOS program,  the  profiler network does  pose  some potential
problems for air pollution modelers.   The  lower limit of measurement for the
405 MHz wind profiler  is 0.5 km.  This limitation would  be a detriment to
boundary layer models  which require  lower-level tropospheric winds.   The
National Weather Service has indicated that  it is considering to collocate
acoustic Doppler sounders  along  with  the wind  profilers  to provide lower
level winds.  However,  these plans require further investigation.  With the
thermodynamic profiler,  temperature  and moisture data will  be measured up
from the surface, but the accuracy of these measurements will decrease with
height.  Satellite sensing  data  is  expected to augment this  data at upper
levels. Preliminary tests of the  radiometric data measurements indicate that
                                     15

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while the temperature and moisture profiles are  averaged quite accurately,
the radiometer fails  to detect  rapid  changes in these parameters.   Research
is continuing on how to integrate information from the wind  profiler and
other data sources to the temperature  and moisture  readings.   Therefore,
while it will be beneficial to  have hourly vertical profiles of temperature
and winds, much work  remains  to be accomplished with the profiler to obtain
the data  in   sufficient  vertical  resolution  for  air pollution  modeling.
NEXRAD
     Another advanced system planned for  deployment in the 1990s is the Next
Generation of Weather Radars (NEXRAD).   Like ASOS,  it is the culmination of
years of research in an effort by the DOC, DOD,  and DOT to modernize instru-
ment systems.  The NEXRAD program will have Doppler  radars  which will pro-
vide increased range  and  resolution of  reflectivity  patterns.   The  radars
also can estimate wind velocities within precipitating clouds.   While their
primary purpose  is  for  severe  storm detection and  tracking,  their  output
should assist in regional  scale air pollution modeling.

     Acquisition of the NEXRAD system was initiated by the NWS in 1980.  In
September 1987,  the  NWS was scheduled  to have selected  a  final contractor
to assume  limited production  of  10 units.   These  prototypes  should  be
delivered during  1989  - 1991.   Full-scale  production and  installation of
NEXRAD at 165 sites is scheduled during 1990 - 1994.

     Of the more  than 25 meteorological products expected from NEXRAD, rain-
fall accumulation will probably most benefit air pollution modeling.  NEXRAD
will provide rainfall rates in 2 km x 2 km areas.   NCDC anticipates that it
will archive these  gridded  values  for  every  15  minutes.   However,  final
                                     16

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archival requirements have  not  been established.  Acid  deposition models,
such as RADM,  would  particularly benefit from the relatively high-resolution
rainfall data.

DATA DISSEMINATION

     Most users of EPA air pollution models rely  on historical  or  climatic
data.  These  data have traditionally  been obtained  through the  National
Climatic Data  Center  (NCDC)  in Asheville, North  Carolina.   Near-real-time
meteorological data and forecast  products are available from  the  National
Weather Service (NWS).  Although NWS  data  are not usually accessed directly,
it is  possible that users  may  begin to  use  real-time data for  emergency
response applications.

     This section primarily discusses changes  in data dissemination related
to NCDC, but  will also briefly review  a  new  data acquistion  system under
development by the NWS called AWIPS/NOAAPORT.

National Climatic Data Center

     Most modelers  of  air pollution depend on the National Climatic Data
Center (NCDC)  for meteorological  data.  Because of this reliance  on NCDC,
it is  important that  renovations  at NCDC  be  examined with  respect  to new
data formats and changes in operation.

     The center each day handles hundreds  of requests  for  data.   Six staff
meteorologists interact with users  to  determine the  data needs  for each
user.  The number of  data  requests and  the amount  of  data  continue to grow
at a staggering pace.   The center handles  over 20,000 requests  for data per
year.  It also has to maintain a tape library  of over 30,000 magnetic tapes
which grows weekly.   Because  of this huge amount  of  data,  NCDC has started
to modernize its operation.
                                     17

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     Modernization activites at NCDC  include  an increased use  of  Personal
Computers (PCs) and the introduction of the element format.   The use of PCs
was recently discussed by Heim (1987).   The primary motivation for going to
floppy diskettes as a means of transferring data was  because of the demand
by the air pollution modeling community.  Several data formats are available
on floppy  diskette.   These include TD-1440  surface data, TD-3280  surface
data, TD-9689 mixing height data,  and TD-9773  STAR data.   As  PCs gain favor
among the  air  pollution  modeling  community,  the  sale of  floppy diskettes
by NCDC will likely grow.

     Thus  far, the new element formats (TD-3280 and TD-6200)  have  not been
used in EPA air pollution modeling.  Although  they have been available since
1984, changes  in computer codes for EPA meteorological processors take time
and money.  However, discussions  with NCDC have revealed that obtaining the
same data  in  TD-3280 format instead of  TD-1440  reduces costs  by  about 40
percent.   NCDC  is  basically set  up on  a  cost reimbursable  basis  — they
charge what it costs them to generate the data.  Because data are stored in
the element format, it  is advantageous  to obtain the data in  the new format.
Besides,  the  new  format  is  fairly easy  to  run,   and  only   the  variables
needed for  modeling  need be ordered.   Descriptions of the new  formats are
given in Appendices B and D.

     The advent  of  new observational  systems  in the NWS present additional
challenges  to  NCDC.  NCDC  has made  some effort on  establishing  formats for
NEXRAD and  profilers.  Archiving data  for  NEXRAD will  be a problem because
of the  amount  of  gridded data.   The  amount   of  data consists  of  gridded
values (for 1  km by  2  km areas)  every 5-15 minutes for up to 25 variables.
Clearly, this is a large  amount of data and needs to be maintained in a logi-
cal manner.  Because profilers are  still undergoing development, their data
are being  stored by NOAA's  Environmental  Research Laboratory  in Boulder,
Colorado.   Eventually, the  profiler data need to be added to the national
archive, but  no  arrangements for  archiving  the data  have  yet  been made.
                                     18

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     As the size  of the data bank  continues  to grow and if  the  center  is
restricted to a small staff, a  greater  reliance will be  placed  on computer
technology to  faciliate data  transfer  and  processing  orders.   One  idea
which has  been discussed  is  establishing  a  modern climatological  data
transfer system to  be  called NOAANET.   The idea for  such a  system is that
it would allow the  user to  order  data  via terminals  (without  interacting
directly with  people) and  have  the order filled either  by electronic data
transfer or by software which  uses artificial intelligence to generate  a
magnetic tape  or  floppy diskette.   Because the  idea is preliminary,  people
requesting data for at  least the next five years will probably  continue  to
order data in the current manner.

AWIPS/NOAAPORT

     A major component  of  the NWS's modernization  is the development of  an
Automated Weather Interactive Processing System (AWIPS).   It  is  intended  as
"an advanced  data  processing,  display,  and  communications  system"  which
will replace  AFOS  (Boezi  et al. ,  1987).   Although AWIPS  will  emphasize
forecasting and  improved severe-weather  warning capability,  some  of  its
features may have  a bearing on future  air pollution modeling  activities.

     The design and installation of AWIPS  is  a  five phase program.   We are
currently nearing the  end of  the   first  phase  entitled  Requirements.   In
March 1988,  the NWS  will select  two  contractors   to  participate  in  the
second phase  System Definition.  The third phase will be  for Development,
and it is scheduled to  begin in  1989.  Deployment (Phase IV)  is  planned for
1991, and Full Operation (Phase V)  is set to  begin in early 1992.
                                     19

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     Major  components  of  AWIPS  will  include  the following:
     o Acquire  data and products from  conventional and advanced  observing
       systems.
     o Process  and display data and  guidance material for  the  forecaster.
     o Extract  and assimilate information and  help the forecaster  in  pre-
       paring warnings and forecasts.
     o Serve the  needs of  external users  by  interacting  with  NOAAPORT.

     NOAAPORT is expected to be of  interest  to air pollution model users.
When near-real-time meteorological  data  are  needed,  say  for  emergency
response models, NOAAPORT would  likely  provide  the  necessary meteorological
information.  Also, NOAAPORT may be  useful if information,  for example  from
NEXRAD or profilers,  are  not being archived into  the national  data base.
The specifications  for NOAAPORT  have   not   been  defined,   and   interested
parties should  monitor development  of  the AWIPS/NOAAPORT  system over  the
next few years.
                                     20

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                              SECTION 4
                     SUMMARY AND RECOMMENDATIONS

     This project began  as  an attempt to understand how  data formats from
the National Climatic Data Center (NCDC) were changing and how these changes
would impact  EPA's  meteorological  processors.   While  investigating  these
changes, we learned  of new advances  in meteorological  instrumentation and
data dissemination which potentially can benefit EPA's air pollution models.

     For EPA to best accomodate  the planned  changes  to  NWS observation and
data dissemination programs and the planned changes to NCDC's data formats,
we offer the following recommendations:

(1)  Recognizing that EPA's meteorological processors will need to be modi-
fied  to handle new  NCDC data formats, they should also be upgraded to in-
corporate our more advanced knowledge  of  diffusion meteorology.  This up-
grade could also serve  as a catalyst for incorporating more advanced modeling
techniques into air pollution models.  It should be noted that such efforts
have begun with the development  of the  Meteorological Processor  for Dif-
fusion Analysis  (MPDA)  (Paumier et  al. ,  1986) and  the Turbulence Profile
Sigmas (TUPOS) model (Turner et al., 1986).

(2)  EPA should encourage the collection of meteorological data specific to
diffusion  modeling  and should  investigate the  feasibility of collecting
some  of  these  data at  NWS  sites.  As  recommended  by  an expert panel
(Hoffnagle et al., 1981), additional meteorological variables such as hori-
zontal fluctuations of wind direction  (09),  harmonic mean wind speeds,low-
level temperature gradients, and total solar radiation  should be collected
for air pollution modeling.   It is  promising  to note that EPA  (1987) recent-
ly provided guidance for collecting some of these variables at on-site mea-
surement programs.   Not all air pollution modeling applicants, however, will
have access to an extensive meteorological monitoring program and will have
                                     21

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to depend  on  NWS  data.   Therefore,  EPA  should  actively  coordinate  NWS
meteorological data collection programs  through the  Office of  the Federal
Coordinator.   In particular,  it  is  advisable  that  EPA maintain  vigorous
participation in the  Working Groups  for  Automated  Surface  Observations,
Profiler Systems,  and Radar  Meteorological  Observations.   Perhaps  with
funding from  appropriate  organizations  and cooperation with the  NWS,  ad-
ditonal meteorological data for diffusion modeling can  be  collected at NWS
sites.

(3)  The formatting and handling  of meteorological data for regional-scale
models should be improved.  Regional-scale models  require  vast  amounts of
surface, upper-air,  and  satellite  data.   Because   these  models  operate
sequentially, data  must  be sorted  by hour.   Unfortunately,  NCDC  data are
sorted by  station  and not  by hour.  Consequently,  much effort goes into
generating a  data  set in the appropriate format.  Two  options  which could
be  investigated include the development  of a new NCDC  data format and direct
access and storage of NWS observations by EPA.

(4)   The Environmental Operations Branch  (BOB) should maintain active com-
munication with NCDC.  In performing this study,  it  became  quite  apparent
that NCDC is willing  to be responsive to  the needs  of  the air pollution mod-
eling community.  By  improving communication with NCDC, EOB can more effec-
tively inform users  about changes  in data formats.   One possibility is to
develop  a  users'  guide  describing  meteorological  data  requirements  for
UNAMAP models.   The  guide would also provide information  on how  to order
meteorological data  from NCDC, and it could  serve as a valuable reference
manual for  NCDC meteorologists  when dealing  with  air  pollution  modeling
clients.
                                     22

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                                REFERENCES

Boezi, L.J.,  H.L. Schmidt,  and W.L. Murray, (1987):  Advanced weather interac-
     tive processing system for  the 1990's (AWIPS-90).  Preprint, Third Inter-
     national Conference on  Interactive  Information  and Processing  Systems
     for Meteorology, Oceanography, and Hydrology,  January  12-16,  1987-   New
     Orleans, American Meteorological Society, pp. 6-7.

Chadwick, R.B.,  and N.  Hassel (1987):   Profiler:   the next generation surface-
     based atmospheric sounding  system.  Preprint, Third International Confer-
     ence on Interactive Information  and  Processing Systems for Meteorology,
     Oceanography, and Hydrology, January 12-16, 1987.   New Orleans, American
     Meteorological Society, pp. 15-21.

Durham, A.F., and  K.E.  Wilk  (1987):   NEXRAD  - the nation's next  generation
     radar.  Preprint, Third  International  Conference on  Interactive  Infor-
     mation & Processing Systems for Meteorology, Oceanography,  and Hydrology,
     January 12-16, 1987.   New  Orleans,  American Meteorological Society,  pp.
     11-14.

Heim, R.  (1987):   Climatological  data available on diskette.   Paper 87-109.6
     presented at the 80th Annual Meeting of the Air Pollution  Control Assoc-
     iaton, New York, June 20-26, 1987.  10 p.

Hoffnagle, G. , M. Smith,  T.  Crawford, and T. Lockhart (1981):  On-site meteoro-
     logical instrumentation requirements  to characterize diffusion from point
     sources - a workshop,  15-17, January  1980,  Raleigh, NC. Bull. Am.  Meteor.
     Soc. , (52, pp. 255-261.

Hogg, D.C.,  M.T. Decker,  P.O.  Guiraud,  K.B.  Earnshaw,  D.A.  Merritt,  K.P.
     Moran, W.B. Sweezy,  F.G.  Strauch,  E.R. Westwater, and G.G.  Little (1983):
     An automatic profiler  of temperature,  wind, and humidity  in  the  tropo-
     sphere.   J. Climate and Appl. Meteor, 22, pp. 807-831.

Holzworth, G.C.   (1972):  Mixing heights, wind speeds,  and potential for urban
     air pollution throughout the  continguous United States.   Office  of  Air
     Programs Pub. No.  AP-101.   United States Environmental Protection Agency,
     Research Triangle Park, NC.  118 p.

National Center  for  Atmospheric  Research  (1986):   Preliminary  evaluation
     studies with the  regional  acid  deposition  model  (RADM).   EPA/600/3-86/
     024, U.S.  Environmental  Protection Agency, Research Triangle  Park,  NC.
     198 p.

Paumier, J. ,  D.  Stinson,  T. Kelly,  C.  Bollinger, and I.  Irwin (1986):  MPDA-1:
     A meteorological  processor for  diffusion  analysis.   EPA/600/8-86/011,
     U.S. Environmental Protection Agency, Research Triangle Park, NC, 192 p.
     [Available   from NTIS as PB86-171-402/AS].
                                      23

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Turner,  D.  B. ,  T.  Chico,  and  J.  A.  Catalano,  1986:  TUPOS - A  multiple
     source Gaussian  dispersion  algorithm using  on-site  turbulence  data.
     EPA/600/8-86/010,  U.   S.   Environmental   Protection  Agency,   Research
     Triangle Park,   NC.   171   p.   [Available  only  from  NTIS,  accession
     number PB86-181-310/AS].

U.S. Environmental  Protection  Agency  (1977):  User's manual for single-source
     (CRSTER) model.   EPA/450/2-77/013,  Research Triangle Park, NC.  279 p.

U.S. Environmental  Protection  Agency (1987):  On-site meteorological program
     guideline  for  regulatory modeling  applications.    EPA/450/4-87/013,
     Research Triangle Park, NC, 192  p.
                                    24

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                                APPENDIX A
                    DESCRIPTION OF THE TD-1440 FORMAT

     This description is reproduced from documentation provided by  the National
Climatic Data Center (NCDC).
                                      25

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TAPE DECK
  1440
                                        AIRWAYS SURFACE OBSERVATIONS
                                                                                                    PAGE NO.
                                             INTRODUCTIOK





   SOURCE




   Weather observations, in support of aircraft operations, have been taken at airports since the earliest




   days of aviation.  The rapid growth of the industry during the 1940's made it evident that some mechanical




   means of summarizing the data must be developed.   Hov was a site to be selected or an airport designed




   without adequate statistical information on which to base decisions?  The first efforts toward this end




   caused the WEAN No. 1 card to come into being.   For archiving purposes these observations, mostly from




   military stations, were designated as Card Deck-141.  The period of record is generally 1941-1944.  A




   change of format necessitated a new card deck designation (Card Deck-142) to be instituted in 1945.




   This deck remained in force into 1948.  During 1948 additional major changes were made in observing and




   recording practises.  These led to the development of Card Deck-144.  Although the usual beginning




   data of digital  information in this form is June 1948 the changeover was made station by station on




   varying dates.   Then too, some stations have had observations back-punched in this format to much




   earlier dates.









   In  the early 1960's  the FAA undertook a major airport study.  To facilitate the handling of large




   masses of data necessary for this effort the Climatological Services of the Weather Bureau, Air Force




   and Navy along with  the FAA devised the tape format described in this manual.  This format was called




   Tape Data Family-14  (TDF-14) to retain some continuity with the card decks.  Within this family of




   similar observations there are several Tape Decks   each one uniquely identified at the beginning of




   each physical record on tape.









   Beginning January 1, 1965, for most National Weather Service stations and March 1, 1972, for most Naval




   Weather Service  stations the digitizing of the Airways Observations was reduced from 24 obs/day to




   8 obs/day.  These observations, at 3-hourly intervals, coincide with the normal GKT schedule of OOZ,




   03Z, 06Z etc.  This means, of course, that the observations, keyed in Local Standard Time (LST)




   differ according to time zone.
   Oct 1975	




                                                     26

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TAPE DECK
  1440
                                        AIRWAYS SURFACE OBSERVATIONS
                                                                                                    PAGE NO.
                                                                                                       ii
   QUALITY CONTROL AMD CONVERSIONS




   All observations have been subjected to some form of quality control.   During the earlier years this was




   almost entirely a manual effort.  As more sophisticated techniques of  processing were introduced the




   quality control procedures were also improved.  Today, the quality control effort is a blend of several




   computer programs and manual review.  Observations are checked for conformance to established observing and




   coding practises, for internal consistancy, for serial, or time oriented consistency, and against




   defined limits for various meteorological parameters.









   The archiving of long term climatological information presents an almost constant dilemma to the archivist,




   systems analyst and programmer.  Refinements of observational instruments, new techniques,  changes




   in user needs and other factors combine to keep the incoming data in an almost perpetual state of




   change.  In some instances the changes are of such significance that individual fields in the tape




   format must be redefined and the ultimate user must adapt this new information to his needs.









   At other times the changes may be of such a nature that they can be incorporated into the existing




   format by converting units or other measurements.  For example, wind speeds were recorded and punched




   in miles per hour through 1955 and in knots thereafter.  All wind speeds on the.tape file are in knots,




   the earlier period having been converted from mph.









   USE OF THE MANUAL




   This manual was designed so that recourse to additional reference material should be unnecessary.




   Occasionally, however, the researcher may wish to obtain a copy of the original Card Deck reference




   manual.  This may be done by writing to the Director, National Climatic Center, Federal Building,




   Asheville, NC  28801.









   Care should be taken to read carefully the general tape notations and  coding practises.
   Oct 1975	




                                                      27

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TAPE DECK
  1440
                                       AIRWAYS SURFACE OBSERVATIONS
                                                                                                       ill
                                    MANUAL AND TAPE NOTATIONS

   FORMAT

   Each physical  tape  record  contains  six observations and  is 495 bytes  long.   These records consist of

   15 bytes of  identification folloved by six logical records of 80  bytes  each.   Records always begin with

   the Local Standard  Time  hour  of  OOLST, 06LST, 12LST or 18LST.  Thus,  four physical records are needed to

   contain each day's  observations.


   Space is always retained on tape for  24 obs/day.  When no observation is  available the hour is Indicated

   (2 bytes) and all other  fields  are  coded blank.  Care in programing  should be taken to allow for this

   condition, particularly  with  most tapes from 1965 onward.


   The manual presents a graphical representation of the standard format indicating Tape Fields, Tape

   Positions and Element Definition followed by detailed information for each field.


   Also included as part of the  manual is a simple  FORTRAN  program that  may  be used to overcome the

   problems of alphanumeric characters.


   MANUAL AND TAPE

   The following notations  are used throughout  the  manual:

        x - any numeric or  alphanumeric  character

        i * same as x but used to  show that the character is an indicator  rather than part of the

            recorded element

          - an "11" or zone punch

        + - a "12" punch

            both the   and  the + may appear by  themselves or in combination  with a numeric digit to

            indicate an overpunch  or signed field

        A - blank

        * • an 11,8,4  punch
*  Currently, archive tapes are 9 track,  1600 bpi,  blocked four (495x4-1980 bytes) and can be

   furnished with this blocking factor if requested.   The advantage is that the entire period of

   record for one station can be provided on one reel of tape.
   Oct 197S	
                                                       28

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TAPE DECK
   1440
                                     AIRWAYS  SURFACE OBSERVATIONS
                                                                                                    PAGE NO.
                                                                                                       iv
                                              SPECIAL NOTE
      The  observations  described  in this manual  are  those  from Card Deck-144.  The Tape Deck number




      is 1440.   Elements  for  certain fields may  differ  in  other Decks within this Tape Data Family.




      Requesters of  data  other  than TD-1440 will be  furnished appropriate reference material.
     Oct 1975
                                                    29

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TAPE DECK
  1440
                                                                                                    PAGE NO.
                                      AIRWAYS  SURFACE  OBSERVATIONS
   Oct 1975
                                         CHARACTER  SET  TDF-14
HEXADECIMAL
1
2
3
4
5
6
7
8
9
0
A (blank)

*
4
A
B
C
D
E
F
G
E
I
J
K
L
M
N
0
P
Q
R



Fl
F2
F3
F4
F5
F6
F7
F8
F9
FO
40
60
5C
50
Cl
C2
C3
C4
C5
C6
C7
C8
C9
Dl
D2
D3
D4
D5
D6
D7
D8
D9
CO
DO
EO
OCTAL
01
02
03
04
05
06
07
10
11
12
20
40
54
60
61
62
63
64
65
66
67
70
71
41
42
43
44
45
46
47
50
51
72
52
32
                                                                 EQUIVILANT  CARD  PUNCH
                                                                     COMBINATION	

                                                                     1
                                                                     2
                                                                     3
                                                                     4
                                                                     5
                                                                     6
                                                                     7
                                                                     8
                                                                     9
                                                                     0
                                                                     blank
                                                                     11
                                                                     11,8,4
                                                                     12
                                                                     12,1
                                                                     12,2
                                                                     12.3
                                                                     12.4
                                                                     12,5
                                                                     12,6
                                                                     12,7
                                                                     12,8
                                                                     12,9
                                                                     11,1
                                                                     11,2
                                                                     11.3
                                                                     11.4
                                                                     11.5
                                                                     11,6
                                                                     11,7
                                                                     11,8
                                                                     11,9
                                                                     12,0
                                                                     11,0
                                                                     0,2,8 (record mark)
                                                    30

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TAPE DECK
  1440
                                      AIRWAYS  SURFACE OBSERVATIONS
                                                                                                    PAGE NO.
                                   FORTRAN  SUBROUTINE FOR  SIGNED  FIELDS

       SUBROUTINE  SIGNCK  (IFLD,ISGN)

 C  THIS SUBROUTINE WILL  TEST ANY  WIND  SPEED  OR PSYCHROMETRIC WITH A  SIGN OVER UNITS POSITION
 C READ AS Al, AND THE HIGH  ORDER  POSITIONS READ AS AN  I  SPEC OF PROPER WIDTH.
 C THE SIGN  SHOULD ENTER  THE PARAMETER  LIST AS  ISGN, THE  REMAINING PORTION AS
 C IFLD. UPON RETURN  FROM THIS  ROUTINE, THE VALUE OF THE  FIELD WILL BE  AN INTEGER
 C WITH PROPER SIGN.  IT WILL BE THE USER RESPONSIBILITY TO  CONVERT THIS TO REAL
 C FORM WITH PROPER DECIMAL  ALIGNMENT.  INVALID  CONDITION  CAUSES  IFLD  TO BE
 C SET TO 9999.

       DIMENSION IP(10),MIN(IO),NUM(10)
       DATA  IP/'A'.'B'.'C'.'D'.'E'.'F'.'G'.'H'.'I'.'oV
       DATA  MDi/'J'.'K'.'L'.'M'.'N'.'O'.'P'.'Q'.'R'.'o'/
       DATA  NUM/1,2,3,4,5,6,7,8,9,07,LAST/'*1 /

       IF (ISGN.EQ.LAST)  GO  TO  16
       DO 14 K-1,10
       IF (ISGN.EQ.IP(K)) GO TO 20
       IF (ISGN.EQ.MIN(K)) GO TO  22
  14   CONTINUE
  16   IFLD- 9999
       RETURN
  20   IFLD- IFLD*10  + NUM(K)
       RETURN
  22   IFLD- -(IFLD*10 +  NUM(K))
       RETURN
       END
  Oct 1975	

                                                    31

-------
TAPE DECK
  1440
                                        AIRWAYS  SURFACE OBSERVATIONS
                                                                                                     PAGE NO.
                                                                                                        vii
                                          TAPE  DECKS  WITHIN  TDF-14
             TAPE  DECK        NAME  OF  CARD  DECK

                1400         L'SWB  Form  1130-Aero  Hourly  Surface  Observations
                1410         USAF  Form  94-A Hourly  Surface  Observations
                1411         Hourly Ceiling-Visibility Observations (Card 1)
                1412         Canadian Hourly  Surface  Observations  (Type 141)
                1420         WEAK  Hourly Surface  Observations, 1945-1948
                1422         Canadian Hourly  Surface  Observations  (Type 142)
                1440         WBAN  Hourly Surface  Observations, 1945-
                1441         Hourly Ceiling-Visibility Observations (Card 2)
                1442         Canadian Hourly  Surface  Observations  (Type 144)
                1443         Canadian Hourly  Surface  Observations,  1950-
                1445         Metar Observations
                1480         Turkish  Hourly Observations
                1481         British  Hourly Observations
                1482         Azores Hourly Observations
                1483         Korean Hourly Observations  (ROK)
                1484         Taichung Hourly  Observations
                1485         German Hourly Observations  (GZMO)
                1486         Chinese  i  Formosan Hourly Observations
   Oct 1975
                                                   32

-------
TAPE DECK
  1440
                                        AIRWAYS SURFACE OBSERVATIONS
                                                                                                    PAGE NO.
FIELD
NUMBER

TAPE
DECK
14XX

STN
NUMB
xxxxx

YR

XX

MO

XX

DY

XX

HR

XX

CEIL

iXXX

VIS

iXXX
WIND
DR

XX
SPD

XXX

DRY
BLE
XXX

WET
BLB
XXX

DEW
FT
XXX

REL
HUM
iXXX

S.L.
PRESS
XXXXX

STA
PPES
XXXX

SKY
COND
iXXXX
T
0
T
X
0
p
Q
X
CLOUDS
LAYER 1
A
M
T
X
T
Y
P
X
HGT
XXX
LAYER 2
A
M
T
X
T
Y
P
X
HGT
XXX

S
U
H
X
LAYER 3
A
M
T
X
T
Y
P
X
HGT
XXX

S
U
M
X
LAYER 4
A
M
T
X
T
Y
P
X
HGT
XXX
WEATHER
T
D
K
X
L Q
P P

X

X
F R Z
P C P

X

X

X
0 B
V S

X

X
W D
D R
X X
BLK
AAA
R
M
+
HP.
XX
CEIL
iXXX
WEATHER
T
H
D
X
L Q
P P

X

X
F
P

X
R Z
C P

X

X
0 B
V S

X

X

WD
DR

XX

BLK


AAA

K
M

+
 FIELD
 NUMBER
      TAPE
  FIELD NUMBER

      001
      002
      003
      004
      005

      101
      102
      103
      104
      105
      106
      107
      108
      109
      110
      111
      112
      113
      114
      115
      116
      117
      118
      119
      120
      121
      122
      123
      124
      125
      126
      127
      128
      129
      130
      131
      132
      133
      134
      135
  TAPE
POSITIONS
001
005
010
012
014

016
018
022
026
028
031
034
037
040
044
049
053
058
059
060
061
062
065
066
067
070
071
072
073
076
077
078
079
082
083
084
085
086
087
088
  004
  009
  Oil
  013
  015

  017
  021
  025
  027
  030
  033
  036
  039
  043
  048
  052
  057
- 064
  069
  075
  081
                 ELEMENT

TAPE DECK NUMBER
STATION NUMBER
YEAR
MONTH
DAY

HOUR
CEILING HEIGHT AND INDICATOR
HORIZONTAL VISIBILITY AND INDICATOR
WIND DIRECTION - 16 POINTS
WIND SPEED
DRY BULB (AIR) TEMPERATURE
WET BULB TEMPERATURE
DEW POINT TEMPERATURE
RELATIVE HUMIDITY AND INDICATOR
SEA LEVEL PRESSURE
STATION PRESSURE
SKY CONDITION AND INDICATOR
TOTAL SKY COVER
TOTAL OPAQUE SKY COVER
AMOUNT OF LOWEST CLOUD LAYER
TYPE OF LOWEST CLOUD OR OBSCURING PHENOMENA
HEIGHT OF BASE OF LOWEST CLOUD LAYER OR OBSCURING PHENOMENA
AMOUNT OF SECOND CLOUD LAYER
TYPE OF CLOUD - SECOND LAYER
HEIGHT OF BASE OF SECOND CLOUD LAYER
SUMMATION AMOUNT OF FIRST TWO CLOUD LAYERS
AMOUNT OF THIRD CLOUD LAYER
TYPE OF CLOUD   THIRD LAYER
HEIGHT OF BASE OF THIRD CLOUD LAYER
SUMMATION AMOUNT OF FIRST THREE CLOUD LAYERS
AMOUNT OF FOURTH CLOUD LAYER
TYPE OF CLOUD - FOURTH LAYER
HEIGHT OF BASE OF FOURTH CLOUD LAYER
OCCURRENCE OF THUNDERSTORM, TORNADO OR SQUALL
OCCURRENCE OF RAIN, RAIN SHOWERS OR FREEZING RAIN
OCCURRENCE OF RAIN SQUALLS, DRIZZLE OR FREEZING DRIZZLE
OCCURRENCE OF SNOW, SNOW PELLETS OR ICE CRYSTALS
OCCURRENCE OF SNOW SHOWERS, SNOW SQUALLS OR SNOW GRAINS
OCCURRENCE OF SLEET, SLEET SHOWERS OR HAIL
OCCURRENCE OF FOG, BLOWING DUST, OR BLOWING SAND
   Oct 1975
                                                      33

-------
TAPE DECK
  1440
                                        AIRWAYS  SURFACE  OBSERVATIONS
                                                                                                    PAGE NO.
                                                                                                       2
      TAPE
  FIELD NUMBER

      136

      137
      138
      139

  201 - 239
  301   339
  401   439
  501   539
  601   639
  TAPE
POSITIONS

089

090 - 091
092   094
095

096   175
176 - 255
256 - 335
336 - 415
416 - 495
                 ELEMENT

OCCURRENCE OF SMOKE, HAZE,  SMOKE  AND HAZE,  DUST,  BLOWING SNOW,
BLOWING SPRAY
WIND DIRECTION - 36 POINTS
BLANK
RECORD MARK
SECOND OBSERVATION)
THIRD OBSERVATION )
FOURTH OBSERVATION)
FIFTH OBSERVATION )
SIXTH OBSERVATION )
THESE OBSERVATIONS FOLLOW
THE SAME FORMAT AS FIELDS
101-139 (TAPE POSITIONS
016-095).
 Oct 1975
                                                   34

-------
 TAPE DEPK
   1440
                                         AIRWAYS SURFACE OBSERVATIONS
                                                                                                     PAGE NO.
    TAPE         TAPE
FIELD NUMBER   POSITIONS
    001



    002




    003


    004


    005

    101



    1021
001 - 004



005   009




010   Oil


012 - 013


014 - 015

016   017



018
    102
               019 - 021
   ELEMENT

TAPE DECK NUMBER



STATION NUMBER




YEAR


MONTH


DAY

HOUR
                                CEILING HEIGHT
                                INDICATOR
                                CEILING HEIGHT
    1031
               022
                                VISIBILITY INDICATOR
    TAPE                 CODE DEFINITIONS
CONFIGURATION              AND REMARKS

 1400 - 1499    Used to distinguish different
                data sources.  See current list
                at beginning of manual.

01001 - 98999   Unique number used to identify
                each station.  Usually a WEAN
                number but occassionally a
                WHO number.

   00 - 99      Year of observation.
                00-99 - 1900-1999

   01 - 12      Month of observation.
                01-12 « Jan.  - Dec.

   01   31      Day of month.

   00   23      Hour of observation in local
                standard time.
                00-23 = 0000-2300 LST

   1,2,3,-      These codes indicate  various
   &,A,A        schemes used to convert  ceiling
                heights to hundreds of feet or
                to indicate special conditions
                of little or no meaning  to the
                general user.

  000 - 800     Ceiling in hundreds of feet.
  888, 999      Ceiling is defined as sky cover
  AAA, AA*      of .6 or greater.
                000-800 - 00000-80,000 feet
                888     - Ceiling of  cirroform
                          clouds at unknown
                          height.  Used  for the
                          period Sep. 1956-
                          March 1970.
                999     = Unlimited ceiling
                AAA     = Unknown
                AA*     = Original value invalid

    0-5       These codes indicate  various
    M, A        schemes used to convert
                visibilities into statute miles
                and have little or no meaning
                to the general user.
    Oct 1975
                                                      35

-------
 TAPE  DECK
                                        AIRWAYS SURFACE OBSERVATIONS
                                                                                                    PAGE
    TAPE
FIELD NUMBER

    103
  TAPE
POSITIONS

023   025
   ELEMENT
HORIZONTAL VISIBILITY
    TAPE
CONFIGURATION

 000-990
 999
 (Not all
 values used)
 AAA
 AA*
    104
               026   027
                                WIND DIRECTION    16 POINTS
                                                                  00-88
                                                                  AA, A*
         CODE DEFINITIONS
           AND REMARKS

Prevailing horizontal visibility
(usually at an elevation of 6
feet above the ground) in
statute miles.
                                                                                000
                                                                                001
                                                                                002
                                                                                003
                                                                                004
                                                                                005
                                                                                006
                                                                                007
                                                                                008
                                                                                009
                                                                                010
                                                                                012
                                                                                014
                                                                                016
                                                                                017
                                                                                018
                                                                                019
                                                                                020
                                                                                024
                                                                                027
                                                                      -  Zero  visibility
                                                                      •  1/16     Statute  miles
                                                                      -  1/8
                                                                      -  3/16
                                                                      -  1/4
                                                                      -  5/16
                                                                      -  3/8
                                                                      -  1/2
                                                                      -  5/8
                                                                      •  3/4-7/8
                                                                      •  1
                                                                      -  1 1/8
                                                                      -  1 1/4
                                                                          3/8
                                                                          1/2
                                                                          5/8
                                                                          3/4

                                                                          1/4
                                                                          1/2
                                                                  030-150 -  3-15  miles in
                                                                            increments of one mile
                                                                  200-950 -  20-95 miles in
                                                                            increments of five
                                                                            miles
                                                                  990     -  100 miles or greater
                                                                  999     •  Unlimited
                                                                  AAA     •  Unknown
                                                                  AA*     •  Original value invalid

                                                                  Direction  from  which the wind
                                                                  is blowing in special 16 point
                                                                  WBAN code.
                                                                                 11
                                                                                 12
                                                                                 22
                                                                                 32
                                                                                 33
                                                                                 34
                                                                                 44
                                                                                 54
                                                                                 55
                                                                                 56
                                                                                 66
                                                                                 76
                                                                                 77
                                                                                 78
                                                                                 88
                                                                                 18
                                                                                 00
                                                                                 AA
                                                                                 A*

                                                                                 Note:
                                                                       North
                                                                       North-Northeast
                                                                       Northeast
                                                                       East-Northeast
                                                                       East
                                                                       East-Southeast
                                                                       Southeast
                                                                       South-Southeast
                                                                       South
                                                                       South-Southwest
                                                                       Southwest
                                                                       West-Southwest
                                                                       West
                                                                       West-Northwest
                                                                       Northwest
                                                                       North-Northwest
                                                                       Calm
                                                                       Unknown
                                                                       Original value
                                                                         349°-011°
                                                                         012°-033°
                                                                         034°-056°
                                                                         057°-078°
                                                                         079°-101°
                                                                         102°-123°
                                                                         124°-146°
                                                                         147°-168°
                                                                         169°-191°
                                                                         192--213"
                                                                         214°-236°
                                                                         237°-258°
                                                                         259°-281"
                                                                         282°-303"
                                                                         304°-326°
                                                                         327°-348"
                                                                     invalid
    Oct 1975
                                                                                        Beginning Jan 1,  1964
                                                                                        wind  directions were
                                                                                        observed and coded to tens
                                                                                        of degrees (see field 137).
                                                                                        These values were converted
                                                                                        to the 16 point code.
                                                       36

-------
 TAPE DECK
   1440
                                         AIRWAYS SURFACE OBSERVATIONS
                                                                                                     PAGE NO.
    TAPE
FIELD NUMBER

    105
  TAPE
POSITIONS

028 - 030
   ELEMENT
                                WIND SPEED
    TAPE
CONFIGURATION
   +     +
 000   199
 AAA, AA*
    106
    107
    108
031   033
034   036
037   039
DRY BULB (AIR) TEMPERATURE
WET BULB TEMPERATURE
DEW POINT TEMPERATURE
001   130
00$   14$
AAA   AA*
    1091
               040
                                RELATIVE HUMIDITY INDICATOR
                                                                  4, A
    109
    110
               041   043
               044 - 048
                                RELATIVE HUMIDITY
                                SEA LEVEL PRESSURE
    111
               049   052
                                STATION PRESSURE
         CODE DEFINITIONS
           AND REMARKS

Wind speed in whole knots.

AAA " Unknown
AA* • Original value invalid

Note:  When this field is numeric
       it is always signed
       positive (12 over punch).

Specified temperature in whole
degrees fahrenheit.

OOl - 130 - -1°   -130°F
00$ - 14$   0" - +140°F
AAA       » Unknown
AA*       - Original value
            invalid

Note:  When these fields are
       numeric they are always
       signed to indicate negative
       (11 overpunch) or positive
       (12 overpunch) temperatures

& • Used to denote that dew point
    temperatures and relative
    humidities were originally
    coded with respect to ice
    when temperature was below
    32°F but were recomputed
    with respect to water.
A • No special conversions made.
                                                  001   100       Relative humidity in whole
                                                  AAA, AA*        percent.

                                                                  AAA • Unknown
                                                                  AA* • Original value invalid.

                                                09000 - 10999     Pressure, reduced to sea level,
                                                AAAAA,  AAAA*     in millibars and tenths.

                                                                  09000-10999 - 900.0 - 1099.9 mb
                                                                  AAAAA       • Unknown
                                                                  AAAA*       - Original value
                                                                                invalid.

                                                 1900   3999      Pressure at station level in
                                                 AAAA,  AAA*      inches and hundredths of Kg.

                                                                  1900-3999 - 19.00 - 39.99 in Hg.
                                                                  AAAA      " Unknown
                                                                  AAA*      • Original value
                                                                              invalid.
    Oct  1975
                                                       37

-------
 TAPE
   1440
                                        AIRWAYS SURFACE OBSERVATIONS
                                                                                                     PAGE NO.
    TAPE         TAPE
FIELD NUMBER   POSITIONS
    1121
               053
ELEMENT
                                SKY CONDITION INDICATOR
    112
               054
                     057
                                SKY  CONDITION
    TAPE                 CODE DEFINITIONS
CONFIGURATION              AND REMARKS

 -, A           Indicator of method of recording
                Bky condition or other phenomena.

                  • Sky condition   U.S. stations
                    prior to June 1951.
                A • Sky conditions - U.S. stations
                    June 1951 and later.

                Note:  Some other decks have
                       various configurations
                       in this position denoting
                       deviation from standard
                       coding.  Detailed Infor-
                       mation will be supplied
                       when applicable.

                A descriptive symbolic coding
                of the state of the sky,
                referring in general to the
                amount of the celestial dome
                covered by clouds or obscuring
                phenomena.  There was a major
                change in the method of recording
                this field in Jume 1951.

                When used to describe the amount
                of sky cover alphanumeric
                characters in this field have
                the following meaning:

                0 • Clear or less than .1 cover
                1 • Thin scattered clouds .1   .5
                2 - Scattered clouds .1   .5
                3 - Dark scattered clouds .1   .5
                4 • Thin broken clouds .6   ,9
                5 - Broken clouds .6   .9
                6 - Dark broken clouds .6   .9
                7 « Thin overcast clouds 1.0
                8 • Overcast clouds 1.0
                9 ™ Dark overcast clouds 1.0
                - • Obscuration
                A " Partial obscuration

                      PRIOR TO JUNE 1951

                During this period when scattered
                clouds were reported the two
                middle figures of the field
                represent the height, in hundreds
                of feet, of the lowest layer of
                scattered clouds.

                During this period only  two layers
                were recorded in this field.  The
                first digit always represents
                the higher layer and the last
                digit the lowest layer.

                The codes on page 7 describe  the
                Sky Condition configurations  that
                appear on tape prior to June
                1951.  Tape configurations  for  the
                period July 1951 onward  are
                explained on page 8.
    Oct 1975
                                                     38

-------
 TAPE PEEK
   1440
                                         AIRWAYS SURFACE OBSERVATIONS
                                                                                                     PAGE NO.
    TAPE
FIELD NUMBER

    112
  TAPE
POSITIONS

054   057
ELEMENT
                                SKY CONDITION
                                  TAPE
                              CONFIGURATION
CODE DEFINITIONS
  AND REMARKS
                                         0	 ™ Obscuration occurring alone
                                         0—0 = Clear or less than .1 cover
                                         0—A • Thin obscuration reported alone
                                 0—4 to 0—9 » One layer of broken or overcast
                                                clouds reported
                                 4	 to 9	 - Obscuration with higher layer
                                                of broken or overcast clouds
                                 4—A to 9—A • Thin obscuration with higher
                                                layer of broken or overcast
                                                clouds
                                 A—4 to A—9 - Layer of broken or overcast
                                                clouds with thin obscuration
                                                above
                                 4—4 to 9—9 = TWO layers of broken or
                                                overcast clouds
                                         	«• Two layers of obscuration
                                                phenomena
                                         	A » Thin obscuration with
                                                obscuration above
                                         £	* Obscuration with thin
                                                obscuration above
                                         A—A - Thin obscuration with thin
                                                obscuration above
                                 	4 to 	9 » Layer of broken or overcast
                                                clouds with obscuration above
                                 0001 to 0993 • Layer of scattered clouds
                                 1001 to 9993 " Layer of scattered clouds
                                                with scattered, broken or
                                                overcast layer above
                                 -001 to -993 - Layer of scattered clouds
                                                with obscuration above
                                 A001 to A993 • Layer of scattered clouds
                                                with thin obscuration above
                                         **** . Original value invalid
                                         AAAA = Unknown

                                                For the two middle digits:

                                      00 - 98 = Height of the lowest scattered
                                                layer in hundreds of feet
                                           99 = 10,000 feet or greater
                                           — = No low scattered clouds
                                           AA ~ Unknown
                                   *A, A*, ** • Original value invalid
    Cct 1975
                                                      39

-------
 TAPE  DECK
   1440
                                         AIEWAYS  SURFACE  OBSERVATIONS
                                                                                                     PAGE NO.
    TAPE
FIELD NUMBER
    112
  TAPE
POSITIONS

054   057
   ELEMENT
                                SKY  CONDITION
    TAPE
CONFIGURATION

 0000 - 9999
 ****
 AAAA
    113
    114
    115

    118

    122

    126
058
059
060

065

071

077
TOTAL SKY COVER
TOTAL OPAQUE SKY COVER
AMOUNT OF LOWEST
CLOUD LAYER
AMOUNT OF SECOND
CLOUD LAYER
AMOUNT OF THIRD
CLOUD LAYER
AMOUNT OF FOURTH
CLOUD LAYER
    116

    119
    123
    127
061

066
072
078
TYPE OF LOWEST CLOUD OR
OBSCURING PHENOMENA
TYPE OF CLOUD-SECOND LAYER
TYPE OF CLOUD-THIRD LAYER
TYPE OF CLOUD-FOURTH LAYER
 0-9,  -
 K,M,N,0
 P.R.A
          CODE  DEFINITIONS
           AND REMARKS

Beginning June 1951  sky  condition
was reported and  coded by layer
in ascending order.   This allows
four layers to be  described
because heights of scattered
clouds are no  longer entered.
Individual sky condition
characters have the  same meaning
(0-9, A,  -) as those  described
on page 6.  If less  than four
layers are present the remaining
positions are  coded  0.
Example:
2580 = Three layers  of clouds
       lower scattered, broken
       layer and higher overcast

AAAA = Unknown
**** = Original value invalid

Amount of the  celestial dome
covered by clouds or  obscuring
phenomena.  Opaque means clouds
or obscuration through which
the sky or higher cloud layers
cannot be seen.

0   « Clear or less  than .1
1-5 » .1  to .5  covered (scattered)
6-9 ™ .6  to .9 covered (broken)
    - > .9 covered (overcast)
A   - Unknown

Note:  When cloud amount for
       individual layers is less
       than one tenth, the height
       field may appear as the
       actual  height  of the
       fragment or as an invalid
       (AA*) configuration.

Generic cloud  type or obscuring
phenomena.

0 • None
1 - Fog
2 • Stratus
3 » Stratocumulus
4 • Cumulus
5 ~ Cumulonimbus
6 • Altostratus
7 " Altocumulus
8 - Cirrus
9 " Cirrostratus
K • Stratus Fractus
M • Cumulus Fractus
N » Cumulonimbus Mamma
0 • Nimbostratus
P • Altocumulus Castellanus
R ™ Cirrocumulus
  • Obscuring  phenomena  other
    than  fog
A • Unknown
    Oct  1975
                                                     40

-------
 TAPE DEfK
   1440
                                         AIRWAYS SURJACE OBSERVATIONS
                                                                                                     PAGE NO.
    TAPE         TAPE
FIELD NUMBER   POSITIONS
    117
               062 - 064
    120        067   069

    124        073 - 075

    128        079 - 081
                    ELEMENT

                 HEIGHT OF BASE OF LOWEST
                 CLOUD LAYER OR OBSCURING
                 PHENOMENA
                 HEIGHT OF BASE OF SECOND
                 CLOUD LAYER
                 HEIGHT OF BASE OF THIRD
                 CLOUD LAYER
                 HEIGHT OF BASE OF FOURTH
                 CLOUD LAYER
                                     TAPE
                                 CONFIGURATION

                                   000 - 800

                                   AAA
                                   AA*
    121

    125
    129
070

076
               082
SUMMATION AMOUNT OF FIRST
TWO CLOUD LAYERS
SUMMATION AMOUNT OF FIRST
THREE CLOUD LAYERS
                 OCCURRENCE OF THUNDERSTORM,
                 TORNADO OR SQUALL
0   9
-. A
                                  0-6
                                  A
                                  *
     130
               083
                 OCCURRENCE OF RAIN, RAIN
                 SHOWERS OR FREEZING RAIN
     Oct  1975
         CODE DEFINITIONS
           AND REMARKS

Height of base of clouds or
obscuring phenomena in hundreds
of feet.

000-800 • 0 - 80,000 feet
888     • Cirroform clouds of
          unknown height
	     • Partial obscuration
          when field 116 coded
          - or 1.   Otherwise
          indicates rone or no
          clouds for which height
          could be reported.
AAA     <• Unknown
AA*       Original value invalid

Total amount of sky covered by
the indicated layers.

0   ™ Clear or less than .1
1-9 • .1 to .9 covered
    = > .9 covered
A   » Unknown

0 » None
1 - Thunderstorm - lightning
    and thunder.  Kind gusts
    less than 50 knots, and hail,
    if any, less than 3/4 inch
    diameter.
2 = Heavy or severe thunderstorm -
    frequent intense lightning
    and thunder.  Wind gusts 50
    knots or greater and hail, if
    any, 3/4 inch or greater
    diameter.
3 - Report of tornado or
    waterspout.
4 - Light squall (through 5/51
    only)
5 - Moderate squall
6   Heavy squall (through 5/51
    only)

Note:  Beginning June  1951  only
       moderate  squall is recorded
       Squall is sudden increase
       of wind speed by at  least
        16 knots, reaching 22
       knots or more and lasting
        for at least  one minute.

A = Unknown
* - Original value  invalid

0 • None
1 - Light rain
2 - Moderate rain
3 " Heavy rain
4 • Light rain  showers
5 • Moderate rain  showers
6 • Heavy rain  showers
7 - Light freezing  rain
8 » Moderate  freezing  rain
9 " Heavy  freezing  rain
A = Unknown
 * - original value  invalid
                                                      41

-------
TAPE DECK
   1440
                                        AIRWAYS SURFACE OBSERVATIONS
                                                                                                    PAGE  NO.
                                                                                                       ID
    TAPE         TAPE
FIELD NUMBER   POSITIONS
    130
    131
               083
               084
   ELEMENT

OCCURRENCE OF RAIN,  RAIN
SHOWERS OR FREEZING  RAIN
OCCURRENCE OF RAIN  SQUALLS,
DRIZZLE OR FREEZING DRIZZLE
    132
               085
                               OCCURRENCE OF SNOW,
                               SNOW PELLETS OR ICE CRYSTALS
    TAPE                 CODE DEFINITIONS
CONFIGURATION              AND REMARKS

                Light - Trace (<  .OOSin.)  to
                        .10 inches per hour
                Moderate = .11 to .30 inches
                           per hour
                Heavy = > .30 inches per hour

      0-9       0 = None
      A         1 " Light rain squalls
      *         2 = Moderate rain squalls
                3 = Heavy rain squalls
                    See note under field 129.
                    Beginning Jan 1949 squalls
                    were reported separately
                    and these figures should
                    not appear thereafter.
                4 = Light drizzle
                5 " Moderate drizzle
                6 = Heavy drizzle
                7 = Light freezing drizzle
                8 » Moderate freezing drizzle
                9 = Heavy freezing drizzle
                i ~ unknown
                * « Original value invalid

                When drizzle or freezing
                drizzle occurs with  other weather
                phenomena:
                Light - Trace (< .005 in) to .01
                        inches per hour
                Moderate = > .01  to  .02 inches
                           per hour
                Heavy = > .02 inches per hour

                When drizzle or freezing drizzle
                occurs alone:
                Light • Visibility 5/8 mile
                        or greater
                Moderate - Visibility 5/16    1/2
                           mile
                Heavy - Visibility 1/4 mile or
                        less

      0-9       0 = None
      A         1   Light snow
      *         2 • Moderate snow
                3 = Heavy snow
                4 * Light snow pellets
                5 • Moderate snow pellets
                6 » Heavy snow pellets
                7 = Light ice crystals
                8 - Moderate ice  crystals
                9 ™ Heavy ice crystals
                A tt Unknown
                * ™ Original value invalid

                Beginning April 1963 any
                occurrence of ice crystals  is
                recorded as an 8.  Prior to
                this date intensities were
                reported.
   Oct 1975
                                                     42

-------
 TAPE DECK
   1440
                                         AIRWAYS SURFACE OBSERVATIONS
                                                                                                     PAGE NO.
                                                                                                        11
    TAPE         TAPE
FIELD NUMBER   POSITIONS
    133
               086
   ELEMENT

OCCURRENCE OF SNOW SHOWERS,
SNOW SQUALLS OR SNOW GRAINS
    TAPE
CONFIGURATION

    0-9
    A
    *
         CODE DEFINITIONS
           AND REMARKS

0 » None
1 » Light snow showers
2 = Moderate snow showers
3 " Heavy snow showers
4 - Light snow squall
5 » Moderate snow squall
6 - Heavy snow squall

Beginning Jan 1949 squalls were
reported separately and these
figures should not appear
thereafter.

7   Light snow grains
8   Moderate snow grains
9   Heavy snow grains
A = Unknown
* - Original value invalid
    134
               087
                                OCCURRENCE OF SLEET,
                                SLEET SHOWERS OR HAIL
                                     0-9
                                     A
    135
               088
OCCURRENCE OF FOG,
BLOWING DUST OR
BLOWING SAND
    0-5
    A
0 • None
1 - Light sleet or sleet showers
    (ice pellets)
2 - Moderate sleet or sleet
    showers (ice pellets)
3 • Heavy sleet or sleet showers
    (ice pellets)
4 - Light hail
5 - Moderate hail
6 • Heavy hail
7 • Light small hail
8 - Moderate small hail
9 • Heavy small hail
A • Unknown
* - Original value invalid

Prior to April 1970 ice pellets
were coded as sleet
Beginning April 1970 sleet and
small hail were redefined as
ice pellets and are coded as
a 1, 2 or 3 in this position.
Beginning Sep 1956 intensities
of hail were no longer reported
and all occurrences were
recorded as a 5.

0 • None
1 - Fog
2 - Ice fog
3 • Ground fog
4 - Blowing dust
5 " Blowing sand
A » Unknown
* » Original value invalid

These values recorded only when
visibility less  than 7 miles.
    Oct 1975
                                                       43

-------
 TAPE DECK
   1440
                                        AIRWAYS SURFACE OBSERVATIONS
                                                                                                     PAGE NO.
                                                                                                        12
    TAPE
FIELD NUMBER

    136
  TAPE
POSITIONS

089
   ELEMENT

OCCURRENCE OF SMOKE,  HAZE
SMOKE AND HAZE, DUST,
BLOWING SNOW, BLOWING SPRAY
    137
               090   091
                                WIND DIRECTION    36 POINTS
    TAPE                 CODE DEFINITIONS
CONFIGURATION              AND REMARKS

  0-6         0 - None
  A             1 • Smoke
  *             2 - Haze
                3 - Smoke and haze
                4 - Dust
                5 ™ Blowing snow
                6 • Blowing spray
                A " Unknown
                * » Original value invalid

                These values recorded only
                when visibility less than 7
                miles.

 00 - 36        Direction from which the wind
 AA             is blowing, in tens of degrees.
                Stations began using this system
                on 01 Jan 1964.  To achieve
                continuity with earlier records
                these values are converted to
                the 16 point scale and placed
                in field 104.
    138

    139
092   094

095
BLANK

RECORD MARK
 AM

 t. A
                                                                                 00  "  Calm
                                                                                 AA  "  Unknown

                                                                                        CONVERSION CODE

                                                                                 tens  of       16 pt.
                                                                                  35-01
                                                                                  02-03   -
                                                                                  04-05
                                                                                  06-07
                                                                                  08-10   -
                                                                                  11-12   -
                                                                                  13-14
                                                                                  15-16   -
                                                                                  17-19   -
                                                                                  20-21
                                                                                  22-23   -
                                                                                  24-25   -
                                                                                  26-28   •
                                                                                  29-30
                                                                                  31-32   -
                                                                                  33-34
                                                                                  11
                                                                                  12
                                                                                  22
                                                                                  32
                                                                                  33
                                                                                  34
                                                                                  44
                                                                                  54
                                                                                  55
                                                                                  56
                                                                                  66
                                                                                  76
                                                                                  77
                                                                                  78
                                                                                  88
                                                                                  18
                                                                                 This position may contain a
                                                                                 blank or record mark.

                                                                                 Record mark • 0,2,8, card punch
    Oct 1975
                                                      44
                                                                                          USCO1U-NOAA-ASHEVI LLE

-------
                                APPENDIX B
                    DESCRIPTION OF THE TD-3280 FORMAT

     This description is reproduced from documentation provided by the National
Climatic Data Center (NCDC).
                                      45

-------
                               SURFACE AIRWAYS
                                   HOURLY
                                   TD-3280
                                 Prepared  by
                         National Climatic  Data Center
                               Federal  Building
                           Asheville, North Carolina
                                  March 1986
     This document was prepared by the  U.S.  Department of Commerce, National
Oceanic and Atmospheric Administration, National Environmental Satellite Data
and Information Service, National Climatic Data Center, Asheville, North
Carolina.

     This document is designed to provide general information on the content,
origin, format, integrity and the availability of this data file.

     Errors found in this document should be brought to the attention of the
Data Base Administrator, NCDC.
                                       46

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                               TABLE OF CONTENTS


INTRODUCTION

     HISTORY AND DATA SOURCE                                       Pages 3-4
     PURPOSE OF THE MANUAL                                         Page 5
     SPECIAL NOTES                                                 Pages 5-7


TAPE FORMAT

     MANUAL AND TAPE NOTATIONS

          1.  FILE (NCDC Variable Length Storage Structure)
              A.  Physical Characteristics                         Page 8
              B.  COBOL or FORTRAN Data Descriptions               Pages 8-9
                  (1)  Typical ANSI COBOL
                  (2)  Typical FORTRAN 77
              C.  IBM JCL Notes                                    Page 9

          2.  RECORD
              A.  Physical Characteristics                         Pages 9-10
              B.  Format (Variable Record)                         Pages 11-12

 v-
RECORD POSITION AND CODE DEFINITIONS                               Pages 13-33


SAMPLE VARIABLE RECORD                                             Page 34


APPENDIX A

     FIXED DATA STRUCTURE                                          Pages 35-39
                                        47

-------
                                 INTRODUCTION

HISTORY AND DATA SOURCE

     Weather observations, in support of aircraft operations, have been taken
since the earliest days of aviation.  Rapid growth of the industry during the
1940's made it evident that some mechanical means of summarizing the data must
be developed.  Adequate statistical information was needed in order to select
appropriate airport sites.  Military stations provided most of the early
observations for archiving from 1941 through June 1948.  Major changes in
observing and recording practices during 1948 represent the primary basis of
digital information for all the principle reporting stations residing in this
data set.

     A major airport study was conducted by the'FAA in the early 1960's.  To
facilitate handling large masses of data necessary for this effort, the Weather
Bureau, Air Force, Navy, and the FAA devised common tape formats called Tape
Data Family-14 (TDF-14).

     These principle reporting stations are usually fully instrumented and
therefore record a complete range of meteorological parameters.  Beginning
January 1, 1965, for most National Weather Service stations and March 1, 1972,
for most Naval Weather Service stations the digitizing of the Airways
Observations was reduced from 24 obs/day to 8 obs/day.  These observations, at
3-hourly intervals, coincide with the normal GMT schedule of OOZ, 03Z, 06Z etc.
This means, of course, that the observations, keyed in Local Standard Time
(LST) differ according to time zone.  Beginning with August 1981 data, 24
obs/day were again digitized for most active stations.

     Through the years approximately 1,380 principle stations have recorded
observations in this program.  In 1984 there were just under 300 active
stations being processed for inclusion in the digital data base.

     Surface Airways Hourly data were initially transferred to punched cards
beginning in the late  1940's to facilitate summarizing climatological data.
The late 1960's saw the transfer of punched cards to magnetic tape.  These
TDF-14 formats represented the digital file through 1983.  During  1983 a new
element file structure was developed and processing of airways hourly data was
revised.  This new processing system became operational Jan 1984.  Data are
currently processed utilizing the new element file structure.  The conversion
of historical data included gross data checks on the TD-1440 data  file.  No
edited values were derived during the historical conversion but undecodable
data were flagged.

     Areal coverage includes the U.S., Caribbean Islands, Pacific  Islands, and
other overseas stations of the National Weather Service, U.S. Navy, and U.S.
Air Force.

     The digital file  contains Record Type, Station Identification, Units  of
Measurement Indicators, Source Codes, Data Quality Flags, and Element Types:
                                        48

-------
CLOUD DATA;  Amount, ceiling height, summation of cloud layer amounts, type of
cloud, and cloud height.

VISIBILITY DATA:  Horizontal.

WIND DATA:  Speed and direction.

TEMPERATURE DATA;  Dry Bulb, Wet Bulb and Dew Point.

SKY COVER DATA;  Total Sky, total opaque, and the condition of the sky.

RELATIVE HUMIDITY DATA;  Relative humidity.

PRESSURE DATA;  Station pressure, sea level pressure, and altimeter.

PRESENT WEATHER DATA;  The occurrences of thunderstorms, tornados,
precipitation  (Rain, squalls, snow, freezing rain/drizzle, etc.!), fog, blowing
dust, smoke, hail, etc.

     Air Force data are available only to the early 1970's.  Navy data are
available  through current period of record.  At the request of the Navy Office,
DATSAV (Global Data Save from U.S. Air Force) telecommunicated data have been
used as the primary source of Navy surface observations since the beginning of
the 1981 data  year.  These data include 48 Airways stations and 11 Metar
stations.  See special notes on DATSAV Source Data.

     Due to many special projects performed at NCDC and other Centers, 24
hourly observations may have been keyed for varying periods of time for
selected stations.  Inventories must be consulted to determine the exact period
of record  for  each station.

     Beginning with the data for January 1984 the Surface Airways Hourly
observations were processed  through a completely revised system.  Relying
heavily on new computer editing procedures, data are subjected to internal
consistency checks, compared against climatological limits, checked serially,
and evaluated  against  surrounding stations.

     Quality control  "flags" are appended  to  each element  to  show how they
fared during the edit  procedures and to indicate what,  if  any, action was
taken.  The files then, consist of observed values  and, as necessary,  an edited
value.  Flag 2 must be checked at all times to determine if an edited value is
present.

     Source codes were added to this file  indicating (1) the  primary  source of
the original record the element was taken  from, and (2)  the back-up source  of
the original record the element was taken  from.  The sources  include:
(1) Original manuscript; (2) SRRS - Service Record  Retention  System;  (3) AFOS -
Automated  Field Operations and Services; (4)  DATSAV -  Global  Data Save from
U.S. Air Force;  (5) NMC - National Meteorological Center;  (6) Foreign Keyed;
(7) MAPSO  - Microcomputer Aided Paperless  Surface Observations;  (8) SRRS
Manuscript; (9) Other/unknown.  Source  codes  for pre-1984  data were reported  as
"original  manuscript"  only for all  stations.
                                       49

-------
PURPOSE OF THE MANUAL

     This manual was designed so that reference to other reference material
should be unnecessary.  However, additional information may be obtained by
writing or calling:

                    National Climatic Data Center E/CC42
                    ATTN:  USER Services Branch
                    Federal Building
                    Asheville, North Carolina  28801-2696

                    Telephone inquiries may be directed to:

                    Commercial 704 259-0682
                    FTS 672-0682

     Read carefully "Manual and Tape Notations," and "Code Definitions and
Remarks" sections.
                                 SPECIAL NOTES

QUALITY

     Quality of the Surface Airways Hourly data is considered quite good.  All
observations have been subjected to some form of quality control.  During  the
earlier years this was almost entirely a manual effort.  As more  sophisticated
techniques of processing were introduced the quality control procedures were
also improved.  Today, the quality control effort is a blend of several
computer programs and manual review.  Observations are checked for conformance
to established observing and coding practices, for internal consistency,  for
serial, or time oriented consistency, and against defined limits  for  various
meteorological parameters.

TIME

     The time entered is that of the record observations, taken within 10
minutes prior to the hour  (e.g. 1355 keyed 1400).  Prior to Jun 57,
observations were taken within  10 minutes prior to the half hour; minutes are
disregarded in punching (e.g. 0222 punched 02; 1428, 14).  All "War Times" and
"Standard Meridian Times"  were  converted to Local Standard Time before
punching.  For Air Force stations in the United States,  the times were punched
in accordance with the established time zones.  Time entries for  Air  Force
stations outside the United States were edited prior to  punching  and  where
necessary converted to the Local Standard Time of the nearest meridian evenly
divisible by  15 degrees.
                                       50

-------
CEILING HEIGHT

     Ceiling was recorded in hundreds of feet above the ground to nearest 100
feet up to 5,000 feet, to nearest 500 feet from 5,000 to 10,000 feet, to
nearest 1,000 feet above that.  Before 1949, Air Force stations recorded
ceilings up to and including 20,000 feet, above which point the ceiling was
classified as unlimited; Weather Bureau and Navy stations recorded ceiling only
up to and including 9,500 feet, above which point the ceiling was considered
unlimited.  Beginning in 1949, ceiling was redefined to include the vertical
visibility into obscuring phenomena not classified as thin, that, in summation
with all lower layers, cover 6/10 or more of the sky.  Also at that time all
limits to height of ceiling were removed, so that unlimited ceiling became
simply less than 6/10 sky cover, not including thin obscuration.  Then,
beginning 1 Jun 51, ceiling heights were no longer established solely on the
basis of coverage.  The ascribing of ceilings to thin broken or overcast layers
was eliminated.  A layer became classified as "thin" if the ratio of
transparency to total coverage at that level is 1/2 or more.

SKY CONDITIONS AND CLOUD LAYERS

     Many different coding practices on sky conditions and cloud layers
occurred throughout the years.  The new element format conversion has taken all
the different practices into account and has converted all the procedures into
a common format.  If you are interested in all the changes in coding please
refer to WBAN Sfc. Observations Card Deck 144 documentation.
DATSAV SOURCE DATA

     Because of differences in Airways and Metar codes and the limited
information available on  the  telecommunicated source compared with manuscript
forms, DATSAV derived data contains  less  complete information than otherwise
available.  Element conversions unique to Metar stations are as follows:

     1.  Visibility - Metar codes are converted to Airways codes for the NCDC
         data base.  This conversion will cause 6 mile visibilities from Metar
         stations to be recorded as  7 mile visibilities.  METAR code permits
         the transmission of  a visibility of 9000 meters without obstruction
         while Airways requires a visibility of at least 7 miles without
         obstruction.  The 9000 meters is converted  to 6 miles in the program
         and flagged because  it is less than the 7 mile requirement.  These 6
         mile visibilities are changed to 7 miles so that these data will
         conform with the rest of the data in the data base.  When  'CAVOK' is
         found in the transmitted data 7  miles with  no obstructions is  entered
         in the data base.

     2.  Weather - Only the highest  numbered weather code is transmitted.  This
         causes all accompanying weather  to be lost  from the data base.  For
         example, the manuscript form might indicate moderate or heavy  rain and
         snow showers mixed (code 84) with fog (code 45).  Only code 84 will  be
         transmitted and  fog  will be eliminated.

                                       51

-------
     3.   Clouds - Total sky and sky condition are not reported on
         telecommunication data.  Layer amounts are reported in eights and
         converted to tenths.  This conversion results in.the loss of any
         entries of 2 or 7 tenths.

     4.   Ceiling - When 'CAVOK' is found in the transmitted data an unlimited
         ceiling is entered in the data base.

     5.   Temperature and Dew Point Temperature - These temperatures are given
         in Celsius on the forms, Kelvin on DATSAV, Celsius on intermediate
         output, and are stored in Fahrenheit in whole degrees in the data
         base.  Rounding during conversions can cause a loss of accuracy of one
         degree.

FILE STRUCTURE

     The element file structure is designed to allow maximum flexibility in
requesting data.  Only those elements or groups of elements of particular
interest need be ordered.  End user input programs can be modified easily to
operate  on different sets of elements.

     These variable length records contain data as originally reported through
DEC 1983.  After that the records contain both the original values and the
edited values.

LOGICAL  REFERENCE TO ELEMENT TYPES

            (Note:  Description of Elements begin on page 13 under
                        'Code Definition and Remarks')

     Logically grouped Element types are as follows:

1.  Clouds            - CLCx, CLIx, and CLHT.

2.  Present Weather   - PWTH.

3.  Pressure -        - PRES, SLVP, and ALTP.

4.  Relative Humidity - RHUM.

5.  Sky  Cover         - CC51, C2C3, and TSKC.

6.  Temperature       - DPTP, TMPD, and TMPW.

7.  Visibility        - HZVS.

8-  Wind              - WD16, and WIND.
                                        52

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                                  TAPE FORMAT

MANUAL AND TAPE NOTATIONS

     1.  FILE (NCDC Variable Length Storage Structure)

          A.  Physical Characteristics

              Data in this file are retained in chronological order by station.
Although library tapes are normally maintained as described below, different
characteristics including fixed length records can be furnished on request.
Additional charges may be accrued for special processing.

     B.  COBOL or FORTRAN Data Description

         (1)  Typical ANSI COBOL

               FD   INDATA
                    LABEL RECORDS ARE STANDARD
                    RECORDING MODE D
                    BLOCK CONTAINS 12000 CHARACTERS
                    DATA RECORD IS DATA-RECORD.
               01   DATA-RECORD.
                    02 RECORD-TYPE       PIC X(3).
                    02 STATION-ID        PICX(8).
                    02 ELEMENT-TYPE      PIC X(4).
                    02 ELEMENT-UNITS     PIC XX.
                    02 YEAR              PIC 9(4).
                    02 MONTH             PIC 99.
                    02 SOURCE-CODE-1     PIC X.
                    02 SOURCE-CODE-2     PIC X.
                    02 DAY               PIC 9(2).
                    02 NUM-VALUES        PIC 9(3).
                    02 DAILY-ENTRY
                         OCCURS 1 to  100 TIMES DEPENDING ON NUM-VALUES.
                       04 TIME-OF-VALUE  PIC 9(4).
                       04 DATA-VALUE     PIC S9(5) SIGN LEADING SEPARATE.
                       04 FLAG-1         PIC X.
                       04 FLAG-2         PIC X.
                                        53

-------
        (2)  Typical FORTRAN 77

              DEFINE FILE 10 (ANSI, VB, 1230, 12000)
              CHARACTER*3 RECTYP
              CHARACTER*8 STNID
              CHARACTER*4 ELMTYP
              CHARACTER*2 EUNITS
              CHARACTER*4 IYEAR
              CHARACTER*2 IMON
              CHARACTER*3 NUM
              CHARACTER*2 ID AY
              CHARACTER*! SCR1, SCR2, FLAG1, FLAG2
              DIMENSION ITIME(IOO), IVALUE(IOO), FLAGl(lOO), FLAG2(100)

              READ  (10,20,END-999) RECTYP,  STNID, ELMTYP, EUNITS, IYEAR,
             +IMON, SRC1, SRC2, IDAY, NUM,  (ITIME(J), IVALUE(J), FLAGl(J),
             +FLAG2(J), J-l, NUM)

              20 FORMAT (A3, A8, A4, A2, 14, 12, Al, Al, 12, 13, 100  (14, 16,
              2 AD)

              NOTE:  If you do not have FORTRAN 77  you  can read the character
              data  described above into integer variables.

        C.   IBM JCL  NOTES.

              1.  For  ASCII Variable specify;
                    LRECL   »  1234
                    RECFM   =•  DB
                    OPTCODE =•  Q

              2.  For  EBCDIC Variable  specify:
                    LRECL = 1234
                    RECFM » VB
     2.   RECORD

          A.  Physical Characteristics

               Each logical record contains  one  station's hourly data values
for a specific meteorological element for a  period of one day.  The record
consists of a control word, an identification portion,  and a data portion.  The
control word is used by the computer operating system for record length
determination.  The identification portion identifies the record type,
observing station,  element type,  element units,  year/month, source codes, day
and number of values.  The data portion contains the meteorological
observations for the hourly data values and  flags.  The data portion is
repeated for as many hourly values as occur  in a day.

     NOTE:  Present Weather Code (PWTH) is an exception.  See Code Definitions
            and Remarks on 'PWTH'.
                                       54

-------
NCDC Library Tapes are structured as follows:
     Record length
     Blocked
     Media
     Density
     Parity
     Label
     File
Variable with maximum of 1230 characters
12000 characters maximum
ASCII 9 Track
6250 BPI
Odd
ANSI Standard Labeled
1 File per tape
                              55

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          B.  FORMAT (VARIABLE RECORD)

          1.  The first ten tape fields,  the ID PORTION of the record, describe
the characteristics of the entire record.  The DATA PORTION of the record
contains information about each element value reported.  This portion is
repeated for as many hourly values as occur in a day.

     Each logical record is of variable length with a maximum of 1230
characters.  Each logical record contains a station's hourly data for a
specific meteorological element over a  one day interval.  The form of a record
is:

               ID PORTION (30 characters) Fixed length
REG
TYP
XXX
STATION
ID
XXXXXXXX
ELEM
TYPE
XXXX
DNT
XX
YEAR
XXXX
MO
XX
SRC
1
X
SRC
2
X
DAY
XX
NO.
VAL
XXX
TAPE
FIELD
001
  002
   003  004
          005  006   007   008   009   010
          DATA PORTION (12 Characters Number-Values Times)
TAPE
FIELD
   Oil
TIME
HOUR
XXXX
DATA
ELEM
S
X
VALUE
xxxxx
FL
1
X
FL
2
X
TIME
HOUR
XXXX
DATA
ELEM
S
X
VALUE
XXXXX
4
<
012
013
014  015
016
017
018
>
DATA
ELEM
S
X
VALUE
XXXXX
FL
1
X
FL
2
X
TAPE   198
FIELD
     199   200  201
                                       56

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TAPE FIELD

 001
 002
 003
 004
 005
 006
 007
 008
 009
 010

 Oil
 012
 013
 014
 015

(016-020)
(021-025)
(026-030)

(196-201)
     TAPE
RECORD POSITION

    001-003
    004-011
    012-015
    016-017
    018-021
    022-023
    024
    025
    026-027
    028-030

    031-034
    035
    036-040
    041
    042

  ( 043-054 )
  ( 055-066 )
  ( 067-078 )

  (1219-1230)
ELEMENT DESCRIPTION

RECORD TYPE
STATION I.D.
METEOROLOGICAL ELEMENT TYPE
MET. ELEMENT MEASUREMENT UNITS CODE
YEAR
MONTH
SOURCE CODE 1
SOURCE CODE 2
DAY OF MONTH
NUMBER OF DATA PORTION GROUPS THAT FOLLOW

TIME OF OBSERVATION (HOUR)
SIGN OF METEOROLOGICAL VALUE
VALUE OF METEOROLOGICAL ELEMENT
QUALITY CONTROL FLAG 1
QUALITY CONTROL FLAG 2

DATA GROUPS IN THE SAME FORM AS TAPE FIELDS
011-015.  REPEATED AS MANY TIMES AS NEEDED
TO CONTAIN ONE DAY OF RECORD.
                                        57

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   -NAME	CODE DEFINITIONS AND REMARKS	

'001     1-3        Record-      The type of data stored in this record.  Value is
                   Type         "ELY."  Each record contains one day of hourly
	•	values.	

002     4-11       Station-     Contains the WBAN Station Number.  (Assigned by
                   ID           NCDC.)  Range of values - 00000000-00099999.  Five
                                digit station numbers are always right justified
	zero filled.	

003     12-15      Element-     The type of data element stored in this record.
                   Type         Range of values is listed below.	

                                ALT?   Altimeter setting.  Range of values - 02700
                                       to 03200.  (Navy stations only beginning
                                       SEP 1984.)	

                                CC51   The sky condition as recorded prior to June
                                       1951.  DATA-VALUE will appear as OXTYZ
                                       where:

                                         X  =• Amount of higher layer
                                         YY =• Height of lowest scattered
                                              layer in lOOrds of feet
                                         Z  ™ Amount of lowest layer

                                Note:  This element is only recorded for data
                                prior to June 1, 1951.  Check Flags 1 and 2 for
                                further definition of CC51.  C-A-U-T-I-O-N must be
                                taken when using this element.

                                Sky condition is a descriptive symbolic coding of
                                the state of the sky, referring in general to the
                                amount of the celestial dome covered by clouds or
                                obscuring phenomena.

                                              X and Z Code Amounts

                                          0 - clear or less than .1 coverage
                                          1 - thin scattered
                                          2 =» scattered
                                          3 » dark scattered
                                          4 - thin broken
                                          5 = broken
                                          6 - dark broken
                                          7 = thin overcast
                                          8 » overcast
                                          9 - dark overcast
                                          - - obscuration 10/10ths obscured
                                          X - (blank) partial obscuration

                                         58

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                                        YY Code

                                       00  to 95 - Height  in hundreds  of  feet,
                                             96 • Value unknown.
                                                  Manuscript  entry was  'Jitf'.
                                             97 » No low  scattered clouds.
                                                  Manuscript  entry was  '	'.
                                             98 = Invalid original value.
                                                  Manuscript  entry was  '**'.
                                             99 = 10,000  feet or  higher.
                                 CLC"x"    The  sky condition and cloud coverage  by
                                          layer where:   The "x" in  CLCx.

                                          CLC1 »  lowest cloud layer
                                          CLC2 -  2nd  cloud layer
                                          CLC3 -  3rd  cloud layer
                                          CLC4 =  4th  cloud layer
                                          CLCN =  N'th cloud layer if necessary
                                     s

                                 Cloud  information pertaining to sky condition  and
                                 cloud  coverage  are contained within one  element
                                 per level.  Check data Flags 1 and 2 for further
                                 definition.

                                 The DATA-VALUE  portion of the record will appear
                                 as: Example  OXXYY constitutes the five  character
                                 field  where

                                            XX = code for sky condition
                                            YY = cloud coverage (tenths)

                                                 XX Code - Sky Condition

                                            00 =• clear or less than .1 coverage
                                            01 = thin scattered .1 to .5  coverage
                                            02 = scattered .1 to .5 coverage
                                            03 = thin broken  .6 to .9 coverage
                                            04 * broken .6 to  .9 coverage
                                            05 » thin overcast 1.0 coverage
                                            06 • overcast 1.0 coverage
                                            07 » obscuration  1.0 coverage
                                            08 - partial obscuration <1.0 coverage
                                            09 • unknown

                                                 YY Code - Cloud Coverage

                                          Cloud coverage is expressed in tenth's.
                                          Value of 9's indicate unknown values.
                                          59

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                             CLHT   Ceiling height is-defined as the height of
                                       the lowest sky cover layer that is more
                                       than 1/2 opaque.  Heights are defined in
                                       hundreds of feet.  The DATA-VALUE will
                                       appear as OOXXX.  Range of value - 00000 to
                                       00999.  Unknown or missing value is 00999.
                                CLT"x" The cloud type and height by layer where:
                                       The "x" in CLTx.

                                       CLT1 » lowest cloud layer or obscuring
                                              phenomena
                                       CLT2 - 2nd cloud layer
                                       CLT3 - 3rd cloud layer
                                          •
                                       CLTN = N'th cloud layer if necessary

                                       Cloud information pertaining to cloud type
                                       and cloud height are contained within one
                                       element per level.  The DATA-VALUE portion
                                       of the record will appear as:  example
                                       XXYYY constitutes the five character field
                                       where

                                         XX  = Code for cloud type (or obstruction
                                               to vision code at lowest cloud
                                               layer)  Code listed on following
                                               page.
                                         YYY = cloud height (hundreds of feet)

                                         9's for any value = unknown

                                       Note:  Cloud type/obscuring phenomena code
                                              on following page.  Also check Flags
                                              1 and 2 for further definition.
                                          60

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS 	

003                             CLT"x" Generic cloud type or obscuring phenomena
                                       codes are:

                                                  CLOUD TYPE

                                         00 » None
                                         11 » Cumulus
                                         12 - Towering Cumulus
                                         13 - Stratus Fractus
                                         14 = Stratus Cumulus Lenticular
                                         15 - Stratus Cumulus
                                         16 » Stratus
                                         17 =• Cumulus Fractus
                                         18 = Cumulonimbus
                                         19 = Cumulonimbus Mammatus
                                         21 - Altostratus
                                         22 = Nimbostratus
                                         23 » Altocumulus
                                         24 = Altocumulus Lenticular
                                         28 « Altocumulus Castellanus
                                         29 = Altocumulus Mammatus
                                         32 = Cirrus
                                         35 = Cirrocumulus Lenticular
                                         37 = Cirrostratus
                                         39 = Cirrocumulus

                                            OBSCURING PHENOMENA
                                             (Began  Jan.  1984)

                                         01 = Blowing spray
                                         03 = Smoke and  haze
                                         04 = Smoke
                                         05 = Haze
                                         06 = Dust
                                         07 = Blowing dust
                                         30 = Blowing sand
                                         36 = Blowing snow
                                         44 = Ground fog
                                         45 = Fog
                                         48 = Ice fog
                                         50  = Drizzle
                                         60 = Rain
                                         70  = Snow
                                         76 = Ice crystals
                                         98  = Obscuring phenomena other than fog
                                               (prior to 1984)


                                         61

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                             C2C3   The total amount of sky covered by the
                                       first two cloud layers and the first three
                                       cloud layers.  DATA-VALUE will appear as
                                       OXXYY. where:

                                         XX - Summation of 1st two cloud layers
                                              (lOths)
                                         YY » Svmmation of 1st three cloud layers
                                              (lOths)

                                       Range - 00 to 99.

                                         00 - Clear or < .1
                                         01 - 0.1
                                         02 - 0.2
                                         03 - 0.3
                                         04 - 0.4
                                         05 - 0.5
                                         06 = 0.6
                                         07 - 0.7
                                         08-0.8
                                         09 - 0.9
                                         10 - 1.0
                                         99 » Unknown or missing

                                       NOTE:  Check Flags 1 and 2 for further
                                              definition.
                                DPTP   Dew Point Temperature.  The DATA-VALUE will
                                       appear as OOXXX.  Range of value = 00000 to
                                       00140.  00999 = unknown or missing.  (Whole
                                       degrees F.)
                                           62

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TAPE
FIELD
TAPE
RECORD
POSITION
ELEMENT
.NAME
CODE DEFINITIONS AND REMARKS
003
                        HZVS   The prevailing "Horizontal Visibility"
                               (usually at an elevation of 6 feet above
                               the ground).  The DATA-VALUE will appear as
                               XXXXX.  Range of value = 00000 to 99999.
                               9's indicate unknown or missing values.
                               (100th's of miles.)  Code follows on next
                               page.

                                     HZVS CODE
00000 => Zero vsby
00006 =1/16 mile
00012 = 1/8
00019 - 3/16
00025 - 1/4
00031 =• 5/16
00038 = 3/8
00050 = 1/2
00062 = 5/8
00075 - 3/4
*00081 = 3/4 or 7/8
00087 - 7/8
00100 = 1 mile
00112 - 1 1/8
00125 = 1 1/4


00138
00150
00162
00175
00200
00225
00250
00275
00300
00400
etc!
01000
10000
99999



- 1 3/8
= 1 1/2
- 1 5/8
= 1 3/4
= 2 miles
= 2 1/4
- 2 1/2
- 2 3/4
= 3
= 4

= 10
= 100
= Missing
Unknown or
Unlimited
(See Flag 1)
                                       Note:  Historical archived data prior to
                                       Jan.  1984 did not differentiate between 3/4
                                       and 7/8 visibilities.  This ambiguous
                                       TD-1440 Historic Data was converted to
                                       TD-3280 as  '00081' .
                                PRES   The station pressure at  station  level in
                                       inches  and thousandths of mercury
                                       generally.  The DATA-VALUE will  appear  as
                                       XXXXX.  Range  of  value = 19000  to  39990.
                                       99999 = unknown or missing.
                                           63

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                             PWTH   The present (or prevailing) weather
                                       occurring at the time of the observation.
                                       DATA-VALUE will appear as follows:

                                                 PRESENT WEATHER CODES

                                       Present weather codes are two characters in
                                       length.  The leftmost character indicates
                                       the general class of present weather while
                                       the rightmost character is a qualifier.

                                       The two digit codes are stored into the
                                       five digits of the DATA-VALUE portion.
                                       ***If there is no occurrence of present
                                       weather the valid DATA-VALUE will always be
                                       00000.  Within the five digits used, the
                                       leftmost digit is always set to zero.  The
                                       two-digit weather codes are entered left
                                       justified for the remaining four digits.
                                       Thus, if one type of weather occurs during
                                       an hour the code would appear as OXXOO,
                                       where XX is the appropriate code.  If two
                                       types of weather occur for the same hour,
                                       the value field would appear as OXXYY.

                                       If more than two types occur for the same
                                       hour they will be stored into additional
                                       PWTH records as necessary.

                                       Consider the following examples:

                                       On day 11 Feb 1981 at 12 noon and 1300
                                       hours no present weather occurred.

                                       0054HLY00005264PWTHNA1981021111002120Qif
                                       OOOOQi511300bOOOOO#l
                                          64

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                                    On day 11 Feb 1981 at 12 noon light snow,
                                       light freezing rain, ice fog, and blowing
                                       snow all occur.  The records will appear
                                       as:

                                       0042HLY000005264PWTHNA19810211110011200
                                       0402631
                                       0042HLY000052664PWTHNA19810211110011200
                                       07184,151

                                       Note:  PWTH DATA-VALUE  codes are described
                                       on pages 20 thru 25.
                                        CODE FOR PWTH RANGE  00.

                                        00  ********** No Occurrence
                                        where:

                                        00  «• No present weather  occurred
                                        CODE  FOR PWTH RANGE  10  TO 19.

                                        IX  **********   Thunderstorm,  Tornado,
                                                        Squall
                                        where:

                                        X « 0 thunderstorm - lightning and  thunder.
                                              Wind gust  < 50 knots - hail < .75  in.
                                         = 1 heavy or severe thunderstorm  -
                                              frequent intense  lightning and
                                              thunder.  Wind gust > 50 knots - hail
                                              > .75 in.
                                         = 2 report of tornado or water spout
                                         - 3 light squall (through May 1951 only)
                                         = 4 moderate squall
                                              Moderate squall is recorded.   Squall
                                              is sudden increase of wind speed by
                                              at least 16 knots, reaching  22 knots
                                              or more and lasting for at least one
                                              minute.
                                         = 5 heavy  squall (through May 1951 only)
                                         =• 6 water spout (began Jan  1984)
                                         - 7 funnel cloud (began Jan 1984)
                                         = 8 tornado (began Jan  1984)
                                         » 9 unknown

                                           65	

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION-	NAME	CODE DEFINITIONS AND REMARKS	

                                       CODE FOR PWTH RANGE 20 TO 29

                                       2x *********   Rain, Rain Showers, Freezing
                                                      Rain

                                       where:

                                       X - 0 light Rain
                                         » 1 moderate Rain
                                         • 2 heavy Rain
                                         - 3 light Rain showers
                                         " 4 moderate Rain showers
                                         =• 5 heavy Rain showers
                                         = 6 light freezing Rain
                                         * 7 moderate freezing Rain
                                         » 8 heavy freezing Rain
                                         = 9 Unknown

                                       Light =•    Trace « .005 in.) to  .10 inches
                                                  per hour
                                       Moderate =» .11 to .30 inches per  hour
                                       Heavy =•    >  .30 inches per hour
                                           66

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                                    CODE FOR PWTH RANGE 30 TO 39

                                       3X *********   Rain Squalls, Drizzle,
                                                      Freezing Drizzle

                                       where:

                                       X = 0 light rain squalls
                                         = 1 moderate rain squalls
                                         = 2 heavy rain squalls (through 1948
                                             only)
                                         = 3 light drizzle
                                         = 4 moderate drizzle
                                         = 5 heavy drizzle
                                         = 6 light freezing drizzle
                                         = 7 moderate freezing drizzle
                                         = 8 heavy freezing drizzle
                                         = 9 unknown

                                       When drizzle or freezing drizzle occurs
                                       with other weather phenomena:

                                       Light =    Trace « .005 in.) to .01 inches
                                                  per hour
                                       Moderate = > .01 to .02 inches per hour
                                       Heavy =    > .02 inches per hour

                                       When drizzle or freezing drizzle occurs
                                       alone:

                                       Light =    Visibility 5/8 mile or greater
                                       Moderate = Visibility 5/16 - 1/2 mile
                                       Heavy    = Visibility 1/4 mile or less
                                         67

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                                    CODE. FOR PWTH RANGE 40 TO 49

                                       4X *********   Snow, Snow Pellets, Ice
                                                      Crystals

                                       where:

                                       X - 0 light snow
                                         » 1 moderate snow
                                         » 2 heavy snow
                                         » 3 light snow pellets
                                         ™ 4 moderate snow pellets
                                         » 5 heavy snow pellets
                                         • 6 light ice crystals
                                         » 7 moderate ice crystals
                                         » 8 heavy ice crystals
                                         = 9 unknown

                                       Beginning April 1963 any occurrence of ice
                                       crystals is recorded as a 47.  Prior to
                                       this date intensities were reported.
                                       CODE FOR PWTH RANGE 50 TO 59

                                       5X *********   Snow Showers, Snow Squalls,
                                                      Snow Grains

                                       where:

                                       X = 0 light snow showers
                                         = 1 moderate snow showers
                                         =* 2 heavy snow showers
                                         = 3 light snow squall
                                         = 4 moderate snow squall
                                         = 5 heavy snow squall

                                       Beginning Jan 1949 squalls were reported
                                       separately and these figures below should
                                       not appear thereafter.

                                         ** 6 light snow grains
                                         = 7 moderate snow grains
                                         = 8 heavy snow grains
                                         = 9 unknown
                                           68

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                                    CODE FOR PWTH RANGE 60 TO 69

                                       6x *********   Sleet, Sleet Showers, Hail

                                       where:

                                       X ** 0 light ice pellet showers
                                         » 1 moderate ice pellet showers
                                         = 2 heavy ice pellet showers
                                         - 3 light hail
                                         = 4 moderate hail
                                         = 5 heavy hail
                                         = 6 light small hail
                                         = 7 moderate small hail
                                         = 8 heavy small hail
                                         = 9 unknown

                                       Prior to April 1970 ice pellets were coded
                                       as sleet.  Beginning April 1970 sleet and
                                       small hail were redefined as ice pellets
                                       and are coded as 60, 61, or 62.  Beginning
                                       Sep 1956 intensities of hail were no longer
                                       reported and all occurrences were recorded
                                       as a 64.
                                       CODE FOR PWTH RANGE 70 to 79

                                       7X *********   Fog, Blowing Dust, Blowing
                                                      Sand

                                       where:

                                       X = 0 fog
                                         = 1 ice fog
                                         = 2 ground fog
                                         = 3 blowing dust
                                         = 4 blowing sand
                                         = 5 heavy fog
                                         = 6 glaze (begin 1984)
                                         = 7 heavy ice fog (begin  1984)
                                         = 8 heavy ground fog (begin 1984)
                                         = 9 unknown

                                       These values recorded only when visibility
                                       less than 7 miles.

                                           69

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                                    CODE FOR PWTH RANGE 80 TO 89

                                       gx *********   Smoke, Haze, Smoke and Haze,
                                                      Blowing Snow, Blowing Spray,
                                                      Dust

                                       where:

                                       X - 0 smoke
                                         » 1 haze
                                         - 2 smoke and haze
                                         - 3 dust
                                         = 4 blowing snow
                                         - 5 blowing spray
                                         - 6 dust storm (begin 1984)
                                         = 9 unknown

                                       These values recorded only when visibility
                                       less than 7 miles.
                                       CODE FOR PWTH RANGE 90 TO 92 AND 99

                                       9X *********   ice Pellets

                                       where:

                                       X =• 0 light ice pellets
                                         =• 1 moderate ice pellets
                                         = 2 heavy ice pellets
                                         = 9 Unknown
                                RHUM   Relative Humidity expressed in whole
                                       percent.  The DATA-VALUE will appear as
                                       OOXXX.  Range of value - 00000 to 00100.
                                       00999 indicates unknown or missing values.
                                 SLVP   Pressure, reduced to sea level, expressed
                                       in millibars and tenths.  The DATA-VALUE
                                       will appear as XXXXX.  Range of value  »
                                       09000 to  10999.  99999 indicates  unknown or
                                       missing values.
                                           70

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TAPE
FIELD
TAPE
RECORD
POSITION
ELEMENT
NAME
CODE DEFINITIONS AND REMARKS
003
                        TMPD   Dry Bulb  (Air)  Temperature.   The  specified
                               temperature  in  whole  degrees  Fahrenheit.
                               The DATA-VALUE  will appear as OOXXX.   Range
                               of value  = 00000-00140.   00999 =  unknown  or
                               missing.
                                TMPW   Wet Bulb Temperature  expressed in degrees
                                       Fahrenheit to tenths.  The DATA-VALUE will
                                       appear as OXXXX.  Range  of value 00000  to
                                       01400.  00999 = unknown  or missing.
                                TSKC   Total sky cover and  total opaque sky cover.
                                       Range of value 00  to 10  (tenths) and 99.

                                       The amount of the  celestial dome covered by
                                       clouds  or obscuring  phenomena.  Opaque
                                       means clouds or obscuration through which
                                       the sky or higher  cloud  layers  cannot be
                                       seen.

                                       The DATA-VALUE will  appear as OXXYY where
                                       XX is the total sky  cover and Tf is the
                                       total opaque sky cover.

                                       00 = clear or less than  .1 coverage
                                       01 = scattered clouds .1 coverage
                                       02 = scattered clouds .2 coverage
                                       03 « scattered clouds .3 coverage
                                       04 = scattered clouds .4 coverage
                                       05 = scattered clouds .5 coverage
                                       06 = broken clouds .6 coverage
                                       07 = broken clouds .7 coverage
                                       08 = broken clouds .8 coverage
                                       09 = broken clouds .9 coverage
                                       10 = overcast 1.0  coverage
                                       99 = unknown
                                           71

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME 	CODE DEFINITIONS AND REMARKS	

003                             WD16   Wind direction and speed to 16 point WBAN
                                       code.  Direction is the direction from
                                       which the wind is blowing.  Speed in knots.

                                               WIND DIRECTION CODES
                                                 (through Dec. 1963 only)

                                                16 Pt
                                              WBAN Code      Degrees

                                              00 » Calm      Calm
                                              11 - N         349-011
                                              12 = NNE       012-033
                                              22 = NE        034-056
                                              32 - ENE       057-078
                                              33 - E         079-101
                                              34 » ESE       102-123
                                              44 - SE        124-146
                                              54 - SSE       147-168
                                              55 =» S         169-191
                                              56 =• SSW       192-213
                                              66 - SW        214-236
                                              76 - WSW       237-258
                                              77 = W         259-281
                                              78 = WNW       282-303
                                              88 - NW        304-326
                                              18 - NNW       327-348

                                       Example of DATA-VALUE XXYYY for wind
                                       direction and speeds:  12037 Wind is from
                                       the NNE at 37 knots.  12 » Wind from NNE.
                                       037 = Wind speed is 37 knots.

                                       NOTE:  Beginning 1 Jan 1964 wind directions
                                              were observed and coded to tens of
                                              degrees.  WD16 code no longer
                                              reported.
                                         72

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

003                             WIND   Wind Direction and Speed.  Direction is the
                                       direction from which the wind is blowing.
                                       Speed in knots.  Range of value (direction)
                                       = 00 to 36 and 99.  Range of value (speed)
                                       = 000 to 250.

                                       Example of DATA-VALUE XXYYY for wind
                                       direction and speeds:  02037 Wind is from
                                       020 degrees at 37 knots.  02 = Wind 020
                                       degrees.  037 = Wind speed is 37 knots.


                                       NOTE:  WIND (10's of Degrees Code) element
                                              begins January 1964.  Prior to 1964
                                              winds observed in the WD16 (16 point
                                              code).

                                                 WIND DIRECTION CODES
                                                     (begin 1964)

                                                10s of
                                              Degrees Code         Degrees

                                                   00      =       Calm
                                                   01      =       010
                                                   02      =       020

                                                        through
                                                   36      =       360
                                                   99      =       Unknown
                                         73

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TAPE
FIELD
TAPE
RECORD
POSITION.
ELEMENT
NAME
CODE DEFINITIONS AND REMARKS
004     16-17      ELEMENT-     The units and decimal position of the DATA-VALUE
                   UNITS        for this record.

                                          ELEMENT-UNITS TABLE

                                DT  Wind direction in tens of degrees
                                F   Whole degrees Fahrenheit
                                HF  Hundreds of feet
                                HM  Miles and hundredths
                                IH  Inches and hundredths of mercury
                                IT  Inches and thousandths of mercury
                                KD  Knots and direction in tens of degrees
                                KS  Knots and direction in 16 point WBAN Code
                                MT  Millibars and tenths
                                NA  No units applicable (non-dimensional)
                                Nl  No units applicable - element to tenths
                                N2  No units applicable - element to hundredths
                                P   Whole percent
                                TF  Degrees Fahrenheit in tenths

                                NOTE:  Single digits are left justified blank
                                       filled.
005
 18-21
YEAR
This is the year of the record.
1900-current year processed.
Range of value is
006
22-23
MONTH
This is the month of the record.
is 01-12.
 Range of value
                                          74

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        TAPE
TAPE    RECORD     ELEMENT
FIELD   POSITION   NAME	CODE DEFINITIONS AND REMARKS	

007     24         SOURCE       Contains a code indicating the primary
                   CODE-1       source of the original record this element was
                                taken from.  Range is 1-9.

                                         SOURCE CODE TABLE

                                       1 Original manuscript
                                       2 SRRS
                                       3 AFOS
                                       4 DATSAV
                                       5 NMC
                                       6 Foreign keyed
                                       7 MAPSO-
                                       8 SRRS plus
                                       9 Other/unknown

                                Source codes reflect normally expected data
                                sources and do not necessarily indicate the actual
                                source of a specific item.  Pre-1984 data will
                                only contain a 1.


008     25         SOURCE       Contains a code indicating the back-up
                   CODE-2       source of the original record this element was
                                taken from.  Range is 1-9.

                                         SOURCE CODE TABLE

                                       1 Original manuscript
                                       2 SRRS
                                       3 AFOS
                                       4 DATSAV
                                       5 NMC
                                       6 Foreign keyed
                                       7 MAPSO
                                       8 SRRS plus
                                       9 Other/unknown

                                Pre-1984 data will only contain a 1.


009     26-27      DAY          Contains the day of the record.  Range is 01-31.
                                          75

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TAPE
FIELD
TAPE
RECORD
POSITION
ELEMENT
NAME
CODE DEFINITIONS AND REMARKS
010
28-30
NUM-
VALUES
This notates the actual number of values reported.
Range of values is 001-048.

NOTE:  A record may contain fewer or more data
values than you might expect.  A daily record of
hourly values may contain as few as 1 data value
or as many as 48.  This is primarily due to
missing or edited data.  If a particular data
value was not taken or is unavailable there is no
entry for it.  Also, when erroneous data are
encountered during quality control the original
values are flagged and are followed by replacement
values (see FLAG-2 TABLE for details).
Oil     31-34      TIME-OF-     Contains the hour and minute of the
                   .VALUE        hourly element value.  Range is 0000-2300.  The
                                hour is.in the leftmost two digits and the minute
                                is in the rightmost two digits.  Hour is reported
                                using the 24 hour clock.  (Minutes are always 00.)
                                See 'Special Notes' on time of record
                                observations.
012
35
SIGN OF
METEOR-
OLOGICAL
VALUE
This is the 'SIGN' of the meteorological data
value (Tape Field 013).  This field contains
either a blank or a minus sign (never a plus
sign).
013
36-40
DATA-
VALUE
Actual data value.  This field is a five digit
integer.  Units and decimal position are indicated
in the ELEMENT-UNITS field described in Tape Field
004.
                                          76

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TAPE
FIELD
TAPE
RECORD
POSITION
ELEMENT
NAME
CODE DEFINITIONS AND REMARKS
014
41
FLAG-1
The data measurement FLAG.

   FLAG-1 TABLE (Measurement Value)

C  Ceiling of cirroform clouds at unknown height
   (Sept 56 - Mar 70)
D  Derived value
R  Dew Point and/or Relative Humidity, originally
   calculated with respect to ice have been
   recomputed with respect to water. (DPTP,RHUM)
U  Unlimited ceiling height (DATA-VALUE = 99999).
   (CLHT)
)S  (blank) Flag not needed.  (All elements except
   CC51)

The following 4 flags apply only to the 'CC511
element type produced for cloud coverage prior to
July 1951. .

B  The 0 found in byte 2 should be a '#' = Thin
   obscuration
*  The 0 found in byte 2 should be a '*' =
   Original value invalid
-  The 0 found in byte 2 should be a '-' = Total
   obscuration.
9  The digit found in byte 2 (high cloud amount)
   is a valid code.  See Pre-6/51 Cloud Cover
   Table.
                                          77

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TAPE
FIELD
TAPE
RECORD
POSITION.
'ELEMENT
 NAME
CODE DEFINITIONS AND REMARKS
015
42
 FLAG-2
The data.quality FLAG.

         FLAG-2 (Quality Flag)
         (Valid for all elements except CC51)

0  Observed data has passed all internal
   consistency checks
1  Validity indeterminable (primarily for pre-1984
   data)
2  Observed data has failed an internal
   consistency check - subsequent edited value
   follows observed value
3  Data beginning 1 JAN 84 - Observed data has
   failed a consistency check - No edited value
   follows.

   Data prior to 1 JAN 84 - Observed data exceeded
   preselected climatological limits during
   conversion from historic TD-1440 files.  No
   edited value follows.

4  Observed data value invalid - no edited value
   follows
5  Data converted from historic TD-1440 exceeded
   known climatological extremes - no edited value
   follows
E  Edited data value passes all system checks - no
   observed value present
M  Manually edited data value added to data set
   after original archival.  Automated edit not
   performed on this item.
S  Manually edited data passes all systems checks

The following 4 flags apply only to the  'CC51'
element type produced for cloud coverage prior to
June 1951.

B  The 0 found in byte 5 should be a  'b' - Thin
   obscuration
-  The 0 found in byte 5 should be a  '-' - Total
   obscuration
*  The 0 found in byte 5 should be a  '*' -
   Original value invalid
9  The digit found in byte 5  (low cloud  amount) is
   a valid code.  See Pre-6/51 Cloud  Cover Table
   for Element  'CC51'.
                                          78

-------
                              SAMPLE VARIABLE RECORD
                             (As seen from tape dump)
NOTE:  ]6

(column
scale)
          Blank Space
                   123456
          123456789012345678901234567890123456789012345678901234567890
(data)     0058HLY00034564TMPDF^19840241100021200J50001ZK11800-00005^1

DUMP      RECORD
POSITION  POSITION  CONTENTS  MEANING
1-4
5-7
8-15
16-19
20-21
22-25
26-27.
28
29
30-31
32-34
35-38
39
40-44
45
46
47-50
51
52-56
57
58
In this
1-3
4-11
12-15
16-17
18-21
22-23
24
25
26-27
28-30
31-34
35
36-40
41
42
43-46
47
48-52
53
54
HLY
00034
TMPD
F#
1984
02
4
1
10
002
1200
»
00012
*
1
1800
-
00005
X
1
case, values for
                    0058      Record control word used by the operating system.
                              (Contains the total number of characters in the
                              record - not available to user programs)

                              RECORD-TYPE

                    00034564  STATION-ID (WBAN station number)

                              ELEMENT-TYPE

                              ELEMENT-UNITS  (Left justified blank filled)

                              YEAR

                              MONTH

                              SOURCE-CODE-1 (Primary source = DATSAV)

                              SOURCE-CODE-2 (Back-up source = Manuscript)

                              DAY OF THE MONTH

                              NUM-VALUES; Two data entries follow
                              TIME-OF-VALUE (HOUR 12, MINUTE 00)

                              SIGN OF METEOROLOGICAL VALUE

                              DATA-VALUE

                              FLAG-1

                              FLAG-2
                                                                          FIRST
                                                                       1— DATA
                                                                          ENTRY
                              TIME-OF-VALUE (HOUR 18, MINUTE 00)

                              SIGN OF METEOROLOGICAL VALUE

                              DATA-VALUE

                              FLAG-1

                              FLAG-2
                                                                          SECOND
                                                                        — DATA
                                                                          ENTRY
        case,  values for hours 00-11, 13-17, and l°-23 are missing.

-------
                                    APPENDIX A
                          FIXED DATA STRUCTURE (TD-3280)  .


     Definitions and general information about the Surface  Airways Hourly
observations are-contained in the basic documentation used  to describe the format
of variable length records.


MANUAL AND TAPE NOTATIONS

     1.  FILE (NCDC Fixed Length (User Services))

          A.  Physical Characteristics

              Data in this file are retained in chronological order by station.
The fixed length records described below can be furnished upon request.
Additional charges may be accrued for this special processing.

          B.  COBOL or FORTRAN Data Description

              (1) Typical ANSI COBOL

                    FD  INDATA
                        LABEL RECORDS ARE STANDARD (FOR STD LABEL TAPES)
                        RECORDING MODE F
                        BLOCK CONTAINS 12000 CHARACTERS
                        DATA RECORD IS DATA-RECORD.
                    01  DATA-RECORD.
                        02 RECORD-TYPE           PIC X(3).
                        02 STATION-ID            PIC X(8).
                        02 ELEMENT-TYPE          PIC X(4).
                        02 ELEMENT-UNITS         PIC XX.
                        02 YEAR                  PIC 9(4).
                        02 MONTH                 PIC 99.
                        02 SOURCE-CODE-1         PIC X.
                        02 SOURCE-CODE-2         PIC X.
                        02 DAY                   PIC 9(2).
                        02 NUM-VALUES            PIC 9(3).
                        02 DAILY-ENTRY
                             OCCURS 24 TIMES.
                           04 TIME-OF-VALUE      PIC 9(4).
                           04 DATA-VALUE         PIC S9(5)  SIGN LEADING SEPARATE.

                           04 FLAG-1             PIC X.
                           04 FLAG-2             PIC X.
                                          80

-------
            (2)  Typical  FORTRAN 77

                   DEFINE  FILE  10 (ANSI, VB, 318, 6360)
                   CHARACTER*3  RECTYP
                   CHARACTER*8  STNID
                   CHARACTER*4  ELMTYP
                   CHARACTER*2  EUNITS
                   CHARACTER*!  SCR1, SCR2,  FLAG1, FLAG2
                   DIMENSION ITIMEC24), IVALUE(24),  FLAG1(24), FLAG2(24)

                   READ  (10,20,END=999) RECTYP,  STNID, ELMTYP, EUNITS,  IYEAR,
                   +IMON,  SRC1, SCR2,  IDAY, NUM,  (ITIME(J),  IVALUE(J),  FLAGl(J),
                   +FLAG2(J), J-l,  24)

                   20  FORMAT (A3, A8,  A4, A2,  14, 12, Al, Al, 12,.13, 100  (14,
                   16, 2A1))

                   NOTE:   If you do not have FORTRAN 77  you  can "read the
                           character data  described  above  into integer
                           variables.

     1.   RECORD

          A.  Physical  Characteristics

              Each logical  record contains one  station's  hourly data values for a
specific  meteorological element  for  a period of one  day.   The record consists of
an identification  portion,  and  a data portion.   The  identification portion
identifies the record type, observing station,  element type,  element units,
year/month,  source codes, day,  and number  of values.  The  data portion contains
the meteorological observations  for  the hourly  data  values and quality flags.  The
data portion is  repeated  24 times.

NOTE:  Present Weather  Code (PWTH) is an exception.   See  Code Definitions and
      Remarks on  'PWTH'  in documentation  on variable format.

           NCDC  Library Tapes are structured as follows:
              Record length
              Blocked
              Media
              Density
              Parity
              Label
              File
FIXED 318 characters
6360 characters
ASCII or EBCDIC Modes - 9 Track
800, 1600, or 6250 BPI
Odd
ANSI standard labeled (ASCII only) or unlabeled
1 File per tape
     These  fixed length records may be selected in either of the following two
forms:

     1.   The  data values as originally reported.
              2.  The data values as originally reported with edited replacement
                  values substituted for the values which did not pass the quality
                  checks.

     If  no  choice is made by the User, NCDC will supply form //2.
                                         81

-------
          B.   FORMAT (FIXED RECORD)

              1.  The first ten tape fields, the ID PORTION of the record,
describe the  characteristics of the entire record.  The DATA PORTION of the record
contains information about each element value reported.  This portion is repeated
for 24 hourly values representing 1 full day of observations.

     Each logical record is of fixed length with 318 characters.  Each logical
record contains a station's data for a specific meteorological element over a one
day interval.  The form of a record is:

                        ID PORTION (30 characters) Fixed length
TAPE
FIELD
REG
TYP
XXX
STATION
ID

JUUULXXXX
ELEM
TYPE
xxxx
UNT
XX
YEAR
XXXX
MO
XX
SRC
1
X
SRC
2
X
DAY
XX
NO.
VAL
XXX
 001
002
003   004
005   006
007   008
009   010
             DATA PORTION (12 Character Data Portion repeats the number of times
                          indicated by the data value stored in Tape Field 010,
                          Fixed are 12 characters repeated 24 times.)
TAPE
FIELD
TIME
HOUR
XXXX
DATA
ELEM
S
X
VALUE
xxxxx
FL
1
X
FL
2
X
TIME
HOUR
XXXX
DATA
. ELEM
S
X
VALUE
XXXXX
<
    Oil   012   013   014  015
                      016
                      017   018
TAPE
FIELD
>
>
DATA
ELEM
S
X
VALUE
XXXXX
FL
1
X
FL
2
X
127    128   129  130
                                           82

-------
                               SAMPLE FIXED RECORD
                             (As seen from tape dump)
NOTE:  X> - Blank Space
(column 123456
scale) 123456789012345678901234567890123456789012345678901234567890
(data) HLY00001102TMPDE81981011101024010CW500012KX0200-99999M)J
RECORD
POSITION CONTENTS MEANING
1-3
4-11
12-15
16-17
18-21
22-23
24
25
26-27
28-30
31-34
35
36-40
41
42
43-46
47
48-52
53
54
ELY
00001102
TMPD
F#
1981
01
1
1
01
024
0100
(BLANK)
00012
(BLANK)
(BLANK)
0200
-
99999
M
(BLANK)
RECORD-TYPE.
STATION-ID 01102 (WBAN Station Number).
ELEMENT-TYPE.
ELEMENT-UNITS. (Left justified blank filled)
YEAR.
MONTH.
SOURCE CODE 1. (Manuscript)
SOURCE CODE 2. (Manuscript)
DAY OF MONTH.
NUM-VALUES: 24 data entries follow.
TIME-OF-VALUE (0100 Hour)
SIGN OF METEOROLOGICAL VALUE
DATA-VALUE
FLAG-1
FLAG- 2

TIME-OF-VALUE (0200 Hour)
SIGN OF METEOROLOGICAL VALUE
DATA-VALUE
FLAG-1
FLAG- 2


FIRST
— DATA
ENTRY


SECOND
-DATA
ENTRY

   (55-318  contains  repeats  for hourly values 3 thru 24.)
                                          83

-------
                     TAPE
TAPE FIELD      RECORD POSITION     ELEMENT DESCRIPTION

 001                001-003         RECORD TYPE
 002                004-011         STATION I.D.
 003                012-015         METEOROLOGICAL ELEMENT TYPE
 004                016-017         MET.  ELEMENT  MEASUREMENT UNITS
 005                018-021         YEAR
 006                022-023         MONTH
 007                024             SOURCE CODE 1
 008                025             SOURCE CODE 2
 009                026-027         DAY OF MONTH                        ;
 010                028-030         NUMBER OF DATA PORTION GROUPS THAT FOLLOW (24)

 Oil                031-034         TIME OF OBSERVATION (HOUR - LEFT JUSTIFIED)
 012                035             SIGN OF METEOROLOGICAL VALUE
 013                036-040         VALUE OF METEOROLOGICAL ELEMENT
 014                041             QUALITY CONTROL FLAG 1
 015                042             QUALITY CONTROL FLAG 2

(016-020)         (  043-054 )        DATA GROUPS IN THE SAME FORM AS TAPE FIELDS
(021-025)         (  055-066 )        011-015.
(026-030)         (  067-078 )        REPEATED 24 TIMES.

(126-130)         (  307-318)
                                          84

-------
                                APPENDIX C
                    DESCRIPTION OF THE TD-5600 FORMAT

     This description is reproduced from documentation provided by the National
Climatic Data Center (NCDC).
                                      85

-------
NAME:

TIME PERIOD:


GEOGRAPHIC COVERAGE:


FORMAT:
FILE SIZE:
FILE STRUCTURE:
CONTENTS:
UPPER AIR (RAWINSONDE) OBSERVATIONS (TD-5600).

1952 (some as early as November 1945)  through  present
(updated monthly).

United States stations and U.S.  controlled  stations,
Global.

IBM EBCDIC variable length records with  no  more  than
6000 characters per block are on NCDC's  library  reels
of magnetic tape which can be copied.  NCDC cannot copy
variable length to  ASCII  mode.    A  standard  record
length format is available, however, in either ASCII or
EBCDIC modes.  In the fixed format, blanks  are  filled
in following  the  last  reporting  level  making  each
observation (record) 2000 characters in length.
232 magnetic tapes;
EBCDIC mode.
9-track,  odd  parity,  1600  bpi,
This file was  produced  from  rawinsonde  observations
recorded on WBAN 31's and digital computer  output  for
Automatic Raob stations.  The file record allows for up
to 89 levels, including the surface level.  The surface
level is always  first  and  follows  25  positions  of
identification.  Standard and significant levels follow
the surface level  in  descending  pressure  (ascending
height) order.  The data are sorted on tape by  station
(WBAN number) in sets; beginning of  record-June  1970,
July 1970-December 1976,  January  1977-December  1980,
1981, and 1982, and monthly thereafter.  The  data  are
also sorted by time for the beginning of record through
June 1970 and 1977, 1978, and  1979.    These  magnetic
tapes are available for purchase from the NCDC.

The  major  parameters  that  make  up  this  file  are
observation time (year, month, day,  hour),  number  of
levels, pressure of level  (MB  to  lOths),  height  of
level (geopotential meters), temperature of level  (Deg
C to lOths), relative humidity of level (%),  and  wind
direction (whole degrees) and wind  speed   (meters  per
second) of level.
                                     86

-------
      S  DECS
TDF-56 VAR AND STN
                                    TAPE FORMAT  DOCUMENTATION
                       RAWTNSONDE OBSERVATIONS
                                                                                                    PAGS NO,
VARIABLE1

  TAPE
POSITIONS

  39-43
  44-46




  47-49




  50-52

  53-55

  56

  57

  53
STANDARD




31-33





36-38




39-41




42-44

45-47

48

49

50
                   Heighc of the level,  above sea level,  in geopoeenci.il
                   meters.
                         Signed plus  » HGT above sea level
                        •Signed minus » HCT below sea level
                   In laeer years Che positive HGT may or may noe  be  signed.

TEMPERATURE        Temperature of the level in degrees celsiu* and tenths.
                         Signed plus  • Positive temp
                        *Signed minus " Negative tamp
                   la Later years the positive Temp may or may not be signed.

RELATIVE HUMIDITY  Relative humidity of the level in whole percent.
                         Signed plus  - Actual SH
                        •Signed minus » Estimated RH
                   In lacer years the actual RH nay or nay not be  signed.
WIND DIRECTION

WIND SPEED

BLANK

BLANK

LEVEL TYPE
  INDICATOR
Hind direction of the leveL in whole degrees.

Wind speed of the level in meters  per second.
                                                       BLANK • Blank
                                                   1 - S?C Level
                                                   2 • First Tropopauae Level
                                                   4 • Mandatory or S{g. Level
                                                   3 " Generated Level
                                                   0 - All Others

 Each data  level  is 25 bytes.  Hissing data fields are coded as all 9's (with signed fields  being  signed minus in
 recent years).   The  firsc  level is always the surface level.  All other levels then follow  in decreasing
 pressure or ascending heighc order.

 Variable - Observations are packed as many as possible into variable length blocks that do  not exceed  6000
          bytes.

 Standard - Format allows for up to 79 levels, including the surface level of 25 positions each.  Blanks are
          filled in following the last reported  level making each observations 2000 character positions  in
          length.

          If observations contain more than 79  levels, the observations would continue in  the next record and
          th*  number of levels (tape position 13-19) would b« coded 90-99, i.e., 90 and 91 " level 30 and 31,
          etc.

 *Kight most position of these fields may contain  the characters A-I •• Positive 1 through 9  and J-R • Negative
  I  through 9.  A positive  or negative 0 in this  position may appear as a special character  or a non-printable
  character.
                                                             87

-------
                                    TAPE FORMAT DOCUMENTATION
   TAP?
TDF-56 VAR AND STN
                                            SATOJSONDE OBSERVATIONS
                                                                                                      E SO.
     BLC
     LGTH
OBS
LCTH

xxxx
DECK
 HO.

56XX
STK
NO.

XXXXX
                           oas. TIME
                          YR  MO DT HE

                          XX  XX XX XX
NO.
LVL

XX
BLANK
 OR
SHIP
POS.
XXXXXX
                                                PRESS
                                                         SURFACE  (l3t  LIVED
 HOT

xxxxx
IMP

XXX
RH

XXX
              WND
              DIR
                                                                   XXX
           UND
           SPD
                                                                       XXX
HIGHEST (LAST LEVEL)
PRESS
XHJLJ
HGT
XXXXX
TUP
XXX
33.
XXX
WND
DIR
XXX
WHO
SPD
XXX
a
T
I
X
T
I
X
B
L
K
X

OBS
LCTH
AJwU.
DECK
NO.
56XX
STN
NO.
OR
LAT.
xxxxx
OBS. TIME
YS
XX
MO
XX
DY
XX
£&
XX
VARIABLE

  TAPE
POSITIONS
  05-08


  09-12

  13-17

  18-19

  20-21

  22-23

  2'+-2 5

  26-27

  28-33
                  STANDARD
          01-04

          05-09

          10-11

          12-13

          14-15

          16-17

          13-19

          20-25
                                ELEMENT

                                BLOCK. LENGTH
                                        Number of bytes in this  physical record - in binary.  This
                                        occurs once each block..
            OBSERVATION LENGTH Number of bytes in this logical record  - in binary.  This
                               field occurs at the beginning of each observation.

                               Unique for each type or source of data.

                               VBAN number or ihip number

                               78  " 1978 etc.

                               01  - 12  • Jan.-Dec.

                               01-31  " Day of month

                               00  - 23  • GMT

                               Number of 25 character levels contained in this observation.

                               Blank  for land stations
                 DEO:

                 STATION NUMBER

                 YEAR

                 MONTH

                 DAY

                 HOUR

                 MEMBER Or LEVELS

                 BLANK OR
                 SHIP POSITION
   34-38
                    26-30
                                PRESSURE
                                              9    » Indicator
                                              o    » Octane of the globe
                                              LjLa » Hhola degrees of Utitutde
                                              LgLg • Units and tens digits  of  longitude
                                         If octane  » 1, 2, (t or 7, add one  hundred  Co 1^

                                         Pressure of the level in millibars  and tenths.

-------
                                APPENDIX D
                    DESCRIPTION OF THE TD-6200 FORMAT

     This description is reproduced from documentation provided by the National
Climatic Data Center (NCDC).
                                      89

-------
                                NCDC  UPPER AIR
                                 DIGITAL FILES
                                TD-6200  SERIES
                                  Prepared by
                         National  Climatic Data  Center
                               Federal Building
                           Asheville,  North Carolina
                                   May 1986
     This document was prepared by the U.S.  Department of Commerce,  National
Oceanic and Atmospheric Administration, National Environmental Satellite Data
and Information Service, National Climatic Data Center, Asheville, North
Carolina.

     This document is designed to provide general information on the content,
origin, format, integrity and the availability of this data file.

     Errors found in this document should be brought to the attention of the
Data Base Administrator, NCDC.
                                       90

-------
                                 INTRODUCTION

SOURCE
     The Upper Air Observations in this digital data file include stations
operated by the National Weather Service, U.S. Navy, and certain South American
stations whose data receive quality control at the National Climatic Data
Center (NCDC).  Additional Upper Air Observations from the Global
Tele-Communications System (GTS), and the U»S. Air F.orce are also included in
this digital file but are not quality controlled by NCDC.

     A list of these files are:

          TD-6201   U.S. Rawinsortde observations 1946-Present.
                         (Includes U.S. Navy observations, U.S. Air Force,
                         National Meteorological Center (NMC), and South
                         American cooperative observations.  Derived from
                         TD-5600.)

          TD-6202   Northern Hemisphere GTS observations 1963-1970, and
                         Southern Hemisphere 1966-1970.  (These data were
                         extracted from NMC Operations Archive and processed
                         into TD-5683.)'

          TD-6203   Global GTS observations 1971-1979.
                         (These data are a composite of NOAA's National
                         Meteorological Center (NMC) and U.S. Air Force Global
                         Weather Center (GWC).  Derived from TD-5681.
                                       91

-------
Background Information TD-6201

               TD-6201:                      PERIOD:
          National Weather Service       Jan. 1946 - Current
          U.S. Air Force                 Jan. 1946 - Dec. 1970
          U.S. Navy                      July 1949 - Current

     The information contained in TD-6201 includes pressure surface, height of
the pressure surface, temperature, relative humidity, wind direction and speed.
Beginning with Jan 1981, the elapsed time since release of the sonde is
included.  The pressure levels included fall into three categories:

     1.  Mandatory levels — Levels required by the WHO for transmission in
parts A and C of a coded RAW1ND report.

     2.  Standard levels — Levels used for internal processing by the NCDC,
but not generally reported in a coded message.

     3.  Significant levels — Levels required to adequately describe a
sounding, as transmitted in parts B and D of a coded message.

     The number of mandatory and standard levels has increased over time.
Table 1 lists the levels that are expected for a given period of record.
Significant levels were not generally included in the earlier periods.
Significant levels are included for most stations only after Jul-y 1952.

     Levels below the surface were generated for the period January 1, 1981
through February 28, 1986.  However, these levels only contain unknown values
('9999') for all data elements.  Beginning March 1, 1986 this practice was
stopped.

     The actual time of releases from Jan. 1946 through May 1957 were usually
03, 09, 15, 21 GMT,  16, 17 = 15Z and 20, 21, 22, 23 = 21Z.  Beginning June 1957
the scheduled time of release is used instead of the actual hour.  The time of
observations were changed from 03, 09, 15, 21 GMT to 00, 06, 12, and 18 GMT.
Observations outside the plus or minus one-hour tolerance were reported as
actual time, GMT.  Stations scheduled to record only one observation daily are
allowed a six-hour tolerance.

     Relative humidities were computed with respect to ice from Jan. 1946
through Sept. 1948 and to water after that.  Beginning Oct. 1948 relative
humidity was computed over a water surface whenever the dry bulb was below
freezing.

     Observing practice for wind measurements varied from current practice.
from Jan. 1946 to June 1949, wind directions were observed on a  16-point
compass.  These directions were converted to degrees before inclusion in
TD-6201.
                                       92

-------
                                    TABLE 1




                     Mandatory and Standard Levels TD-6201




Surface    1/46-6/49    7/49-12/55    1/56-6/57    7/57-12/60    1/61-Present
1000
950
900
850
800
750
700
650
600
550
500
450
400
350
300
250
200
175
150
125
100
80
70
60
50
40
30
25
20
15
10
7
5
4
3
2
1.5
1
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*

*
*
*
*

*

*







*
*
*
*
*
*
*
it
it
*
*
*
*
*
*
*
*
*
*
*
*
*

*
*
*
*

*
*
*
*
*
*
*
*


*
*
*
*
*
*
*
*
*
*
*
*
it
*
*
*
*
*
*
*
*
*

*
it
*
*

*
*
*
*
*
*
*
*


*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*

*
*
*
*
*
*
*
*
*
*
*
*
*


*
*
it
it
it
it
it
*
*
it
it
it
it
it
it
it
*
*
*
it
it
it
it
it
*
*
*
*
*
*
*
*
*
*
*
*
*
*
                                       93

-------
Background Information TD-6202

               TD-6202:                      PERIOD:
          National Meteorological Center (NMC)
          Northern Hemisphere            Sept. 1963 - Dec. 1970
          Southern Hemisphere            June 1966  - Dec. 1970.

     These data were assimilated from normal International communication
channels and no detailed quality control measures were employed when converting
to TD-5683.  The observations, therefore, were subject to the usual errors
inherent in such a collection.

     The U/A observations contain all available mandatory and significant
levels transmitted under International agreement.  The period of record may
vary from station to station, the general collection began Sept. 1963 and
continued through Dec. 1970 (Northern Hemisphere).  Stations in the Southern
Hemisphere are usually not available until mid 1966 or later through Dec. 1970.

     Relative humidities are derived statistically for RH's not reported
originally.
Background Information TD-6203

               TD-6203:                                          PERIOD:
          National Meteorological Center (NMC)            July 1971 - Dec. 1978
          Air Force Global Weather Center (AFGWC)         July 1971 - Dec. 1978

     These U/A observations are a collection of data built by the National
Climatic Data Center (NCDC).  These data were received from NMC and AFGWC.
NCDC converted these two data sources separately into TD-5681.  Then these data
sources were combined giving priority to the NMC source.
                                       94

-------
Areal coverage is worldwide.

     The digital file contains:  Station Identification  (land and ships),
Latitude and Longitude of location, date/time, and elements:
LEVEL QUALITY INDICATOR - results by level.

TIME - elapsed time since release4

PRESSURE - by level in kilopascals.

HEIGHT - by level in geopotential meters.

TEMPERATURE - by level in degrees Celsius.

RELATIVE HUMIDITY - by level  in degrees Celsius.

WIND - Direction and speed by level.

QUALITY CONTROL FLAGS - by level  for time, pressure, height, temperature,
                        relative  humidity, wind, and type of level.
                                        95

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                                 SPECIAL NOTES

QUALITY

     U.S. data processed by the NCDC are subjected to extensive quality control
procedures.  Suspect data are returned to a verifier for manual correction.
GTS data are subjected to various degrees of automated quality control by the
receiving agency.  NCDC accepts the data as correct during the reformatting
procedure.  Therefore, -the user must be prepared to perform his own quality
checks on GTS data.  (The primary function of NMC and AFGWC is to produce
forecasts, not to provide an archive data base.)

     When corrections are made to a level, that level will appear in the record
twice.  The first occurrence of the level will be the original observed values,
with a level quality indicator of "2" or "4".  The corrected data will appear
in the second occurrence of the level, with quality indicator of "6".


USE OF THE MANUAL

     This manual was designed so that reference to other reference material
should be unnecessary.  However, additional information may be obtained by
writing or calling:

                    National Climatic Data Center E/CC42
                    ATTN:  USER Services Branch
                    Federal Building
                    Asheville, North Carolina  28801-2696

                    Telephone inquiries may be directed to:

                    Commercial 704 259-0682
                    FTS 672-0682

     Read carefully, the general tape notations, and coding practices.
                                       96

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                                  TAPE FORMAT

MANUAL AND TAPE NOTATIONS

     1.  FILE (NCDC Variable Length Storage Structure)

          A.  Physical Characteristics

              Data in this file are retained in chronological order by station.
Although library tapes are normally maintained as described below, different
characteristics including fixed length records can be furnished on request.
Additional charges may be accrued for special processing.

     2.  RECORD

          A.  Physical Characteristics

              Each logical record contains one station's Upper Air (U/A)
Observation (Rawinsonde, Radiosonde, or Pibal) for each specific Upper Air
Sounding (normally 2 each day).  The record consists of a control word, an
identification portion, and a data portion.  The control word is used by the
computer operating system for record length determination.  For many systems
this control word is transparent to the "users" program.  The identification
portion identifies the observing station, latitude, longitude, day and time (of
release), and the number of repeating groups to follow.  The data portion
contains the U/A meteorological values and the quality control flag fields for
each level.  The data portion repeats for each level in the observation.  The
maximum number of levels is 200.  This number was chosen so that observations
containing one-minute wind data may be recorded in this format.
              Record  length
              Blocked
              Media
              Density
              Parity
              Label
              File
Variable with maximum of 7232 characters
12000 characters maximum
ASCII 9 Track
6250 BPI
Odd
ANSI Standard Labeled
1 File per tape
                                       97

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          B.  FORMAT (VARIABLE RECORD)
              1.  The first five fields constitute the ID PORTION, and occur at
the beginning of each record.  The next ten fields of the record contain the
DATA PORTION.  The DATA PORTION is repeated for each level in the observation.
The maximum number of levels is 200.
710'
/ ^._n
     Each logical record  is  of  variable  length with a maximum of
     Each logical record  contains a station's complete Upper Air
                             The  form of a record is:
Observation for a specific release time

              ID PORTION (32 characters) Fixed length
TAPE
FIELE
STATION
ID
XXXXXXXX
LAT
XXXX
LAT
CODE
X
LONG
XXXXX
LONG
CODE
X
DATE /TIME
XXXXXXXXXX
NUMBER
VALUES
XXX
001 002 003 004 005 006 007
)
              DATA PORTION (36 Characters) repeated Number-Values Times
TAPE
FIELD
LVL-QLTY
INDCTR
X
TIME
XXXX
PRESSURE
XXXXX
HEIGHT
XXXXXX
TEMP
XXXX
RH
XXX
WIND
DIR
XXX
WIND
SPD
XXX
QUALITY
FLAGS
XXXXXX
TYPE OF
LEVEL
X
008 009 010 Oil 012 013 014 015 016 017
RH
XXX
WIND
DIR
XXX
WIND
SPD
XXX
QUALITY
FLAGS
XXXXXX
TYPE OF
LEVEL
X
TAPE  1998
FIELD
1999
2000
2001
2002
                                       98

-------
TAPE FIELD
     TAPE
RECORD POSITION
ELEMENT DESCRIPTION
 001
 002
 003
 004
 005
 006
 007

 008
 009
 010
 Oil
 012
 013
 014
 015
 016
 017

(1958-1972)
(1973-1987)
(1988-2002)
   001-008
   009-012
     013
   014-018
     019
   020-029
   030-032

     033
   034-037
   038-042
   043-048
   049-052
   053-055
   056-058
   059-061
   062-067
     068

 (7125-7160)
 (7161-7196)
 (7197-7232)
STATION IDENTIFICATION
LATITUDE
LATITUDE CODE N/S
LONGITUDE
LONGITUDE CODE E/W
DATE AND TIME (YR/MO/DY/HR)
NUMBER OF DATA PORTION GROUPS THAT FOLLOW

LEVEL QUALITY INDICATOR
TIME (ELAPSED TIME SINCE RELEASE)
PRESSURE
HEIGHT
TEMPERATURE
RELATIVE HUMIDITY
WIND DIRECTION
WIND SPEED
FLAG FIELD (QUALITY FLAGS)
TYPE OF LEVEL

DATA GROUPS IN THE SAME FORM AS TAPE FIELDS
008-017.  REPEATED AS MANY TIMES AS NEEDED
TO COMPLETE ONE UPPER AIR OBSERVATION.  A
MAXIMUM OF 200 LEVELS ARE POSSIBLE.
                                        99

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The following COBOL and FORTRAN statements are to be used as guidelines only.
NCDC recognizes the fact that many different types of equipment are used in
processing these data.  It is impossible to cover all the idiosyncrasies of
every system.

     Typical ANSI COBOL Data Description.

          This ANSI Standard COBOL Data Description is expected to work on most
     systems.
          FD   UA-DATA
               LABEL RECORDS ARE STANDARD
               RECORDING MODE D
               BLOCK CONTAINS 12000 CHARACTERS,
          01   UA-RECORD.
               02   STATION-NUMBER
               02   LATITUDE.
                    03   LATITUDE-NUM
                    03   LATITUDE-ALPH
               02   LONGITUDE.
                    03   LONGITUDE-NUM
                    03   LONGITUDE-ALPH
               02   DATE-TIME.
                    03   YEAR
                    03   MONTH
                    03   DAYS
                    03   HOUR
               02   NUMBER-OF-LEVELS
               02   LEVEL-RECORD
                         OCCURS 1 to 200 TIMES
                    03   QUALITY-INDICATOR
                    03   ELAPSED-TIME
                    03   PRESSURE
                    03   HEIGHT

                    03   TEMPERATURE

                    03   RELATIVE-HUMIDITY
                    03   WIND-DIRECTION
                    03   WIND-SPEED
                    03   FLAGS.
                         04   TIME-FLAG
                         04   PRESSURE-FLAG
                         04   HEIGHT-FLAG
                         04   TEMPERATURE-FLAG
                         04   R-H-FLAG
                         04   WIND-FLAG
                         04   TYPE-OF-LEVEL
 PICTURE X(8).

 PICTURE 9999.
 PICTURE X.

 PICTURE 99999.
 PICTURE X.

 PICTURE 9(4).
 PICTURE 99.
 PICTURE 99.
 PICTURE 99.
 PICTURE 999.

DEPENDING ON NUMBER-OF-LEVELS,
 PICTURE X.
 PICTURE 999V9.
 PICTURE 999V99.
 PICTURE S99999
 SIGN LEADING SEPARATE.
 PICTURE S99V9
 SIGN LEADING SEPARATE.
 PICTURE 999.
 PICTURE 999.
 PICTURE 999.

 PICTURE X.
 PICTURE X.
 PICTURE X.
 PICTURE X.
 PICTURE X.
 PICTURE X.
 PICTURE X.
                                      100

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FORTRAN 77 Example 1.

     This description is for those systems that can handle variable blocked
records normally.

           IMPLICIT INTEGER (A-Z)

           OPEN (10,FILE = 'FILENAME'.ACCESS = 'SEQUENTIAL1, STATUS =» 'OLD',
          +   RFORM = 'VB'.MREL =* '1230',TYPE = 'ANSI',BLOCK = '12000')
     C        LAST line of OPEN statement is SPERRY UNIQUE

           CHARACTER*8 STNID
           CHARACTER*! LATA,LONA,QIND(200),TIMEF(200),PRESSF(200) ,
          +            HGTF(200),TEMPF(200),RHF.(200),WINDF(200),TYPLEV(200)

           REAL*4 LAT,LON,ETIME(200),PRESS(200),HGT(200),TEMP(200)

           DIMENSION ETIME(200),PRESS(200),HGT(200),
          +          TEMP(200),RH(200),WD(200),WS(200)

           READ (10,20,END=999) STNID,LAT,LATA,LON,LONA,YEAR,
          +           MONTH,DAY,HOUR,NUMLEV,(QIND(J),ETIME(J),
          +           PRESS(J),HGT(J),TEMP(J),RH(J),WD(J),WS(J),
          +           TIMEF(J),PRESSF(J),HGTF(J),TEMPF(J),RHF(J),
          +           WINDF(J),TYPLEV(J),J=1,NUMLEV)

     20    FORMAT (A8,F4.0,A1,F5.0,A1,14,3(12),13,200(A1,F4.1,F5.2,
          +        F6.0,F4.1,3(I3),7A1))

IBM JCL NOTES.

        (1)  For ASCII Variable specify:
             LREC    = 7236
             RECFM   = DB
             OPTCODE - Q

        (2)  For EBCDIC Variable specify:
             LRECL   = 7236
             RECFM   = VB
                                          101

-------
FORTRAN 77 Example 2.

     This description is for those systems that can't handle variable blocked
records normally.

     $ MOUNT/FOREIGN/BLOCKSIZE=12000 MT:  tapename TAPE:   ! THIS IS VAX
     	                                                 ! UNIQUE

          PROGRAM TAPEREAD
          IMPLICIT INTEGER (A-Z)
          • • • • •
          OPEN(1,FILE=TAPE:',ACCESS='SEQUENTIAL',FORM=FORMATTED',
         +       STATU S='OLD',READONLY)

          CHARACTER BUFFER*12000             !  YOUR MACHINE MUST SUPPORT
          CHARACTER *8 STNID                 !  CHARACTER VARIABLES THIS LARGE
          CHARACTER*! LATA,LONA,QIND(200),TIMEF(200),PRESSF(200),
         +            HGTF(200),TEMPF(200),RHF(200),WINDF(200),TYPLEV(200)

          REAL*4 LAT,LON,ETIME(200),PRESS(200),HGT(200),TEMP(200)

          DIMENSION ETIME(200),PRESS(200),HGT(200),TEMP(200),RH(200),
         +          WD(200),WS(200)
          • • • • •
          NBYTES=0
    5     NBEG=1
          READ( 1,101 ,END=99)BUFFER             IREAD IN PHYSICAL RECORD (BLOCK)
   10     NBEG=NBEG+NBYTES
          READ(BUFFER(NBEG:NBEG+3,102)NBYTES   IREAD THE CONTROL WORD
          IF( NBYTES.EQ.O )GO TO 5
          READ(BUFFER(NBEG+4:NBEG+NBYTES-1),103)STNID,LAT,LATA,LON,LONA,YEAR,
         +     MONTH,DAY,HOUR,NUMLEV,(QIND(J),ETIME(J),PRESS(J),HGT(J),TEMP(J),
         +     RH(J),WD(J),WS(J),TIMEF(J),PRESSF(J),HGTF(J),TEMPF(J),RHF(J),
         +     WINDF(J),TYPLEV(J),J=1,NUMLEV)
          GO TO 10
   99     CONTINUE
          STOP 'FINISHED'
  101     FORMAT(A)
  102     FORMATCI4)
  103     FORMATC A8 ,F4 .0 ,A1 ,F5 .0 ,A1 ,14 ,3( 12) , 13 ,200(A1 ,F4 .1 ,F5.2 ,
         4-F6.0,F4.1,3(I3),7Al))
          END
                                         102

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TAPE
FIELD
 TAPE
 RECORD
^POSITION
ELEMENT
NAME
                                CODE DEFINITIONS AND REMARKS
001
   1-8       STATION-     STATION IDENTIFICATION—For U.S. controlled and
            ID           cooperative stations, the WBAN number (TD-6201).
                         For stations received through GTS, the WHO number
                         (TD-6202).  TD-6203 has general WMO numbers but
                         some are WBAN numbers.  This field may contain
                         alphabetic characters for ships and remote sensed
                         observations.  Numeric station numbers are right
                         justified and zero filled, while alphanumeric
                         station indentifiers are left justified and blank
                         filled.  If unknown, this field contains
                         "99999999".  If the station identification is
                         unknown, both latitude and longitude must be
                         present.
002      9-12      LATITUDE     LATITUDE—The station latitude in degrees and
                                minutes.  When unknown, this field contains
                                "9999".  Latitude will not normally appear for.
                                land  stations.
003
    13       LATITUDE
            CODE
             LATITUDE CODE— CODE used to indicate the
             Northern (N) or Southern (S) latitudes.
004
  14-18      LONGITUDE
             LONGITUDE—The station longitude in degrees and
             minutes.  When unknown, this field contains
             "99999".  Longitude will not normally appear for
             land stations.
005
    19       LONGITUDE    LONGITUDE CODE—CODE used to indicate Longitudes
            CODE         East (E) or West (W).
006
  20-29      DATE-TIME
             DATE/TIME—The scheduled time of the observation,
             as defined by WMO.  The format of date/time is
             YYYYMMDDHH, i.e., year, month, day, hour.  This
             field may never be unknown.
         20-23     YEAR
                         YEAR-This is the Year of record.  Range of values
                         are 1946-current year processed.
         24-25     MONTH
                         MONTH-This is the Month of record.  Range of value
                         are 01 to 12.
                                         103

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        TAPE
TAPE    RECORD
FIELD  POSITION
ELEMENT
NAME
CODE DEFINITIONS AND REMARKS
         26-27
DAY
DAY-This is the Day of record.  Range of values
are 01 to 31.
         28-29
HOUR
HOUR-This is the Hour of record.  Range of value
are 00 to 23.  Hour is GMT.  Normal scheduled
observation times are 00 and 12 GMT.  For selected
periods and areas observations may have been taken
at other times, especially 06 and 18 GMT.
007      30-32     NUMBER-      NUMBER-OF-REPEATING-GROUPS—This number represents
                   REPEAT-      the number of data levels found in the current
                   GROUPS       observation, including edited levels.  Range of
                                values are 001-200.  Two hundred is the maximum
                                number of levels.
008       33       LEVEL-       LEVEL-QUALITY-INDICATOR—Denotes the results of
                   QUALITY-     any quality controls applied to this level.
                   INDCTR       Range is as follows:
                                0    Original values are correct.
                                1    Original values missing.
                                2    Original values doubtful, a corrected level
                                     follows.
                                3    Original values doubtful, uncorrected.
                                4    Original values in error, a corrected level
                                     follows.
                                5    Original values in error, uncorrected.
                                6    Corrected level.
                                9    Level not checked.
                                A-Z  Indicators supplied by NMC.  NMC Indicators
                                     have changed many times over the years.  If
                                     you wish to use their indicators you will
                                     have to contact NMC.
009      34-37     TIME-        TIME—The elapsed time since the release of the
                   SINCE-       sounding in minutes and tenths.  If the elapsed
                   RELEASE      time is not known, this field contains "9999".
                                Range is 0001 through 9999.  Available only for
                                U.S. quality controlled stations beginning Jan
                                1981.
                                         104

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        TAPE
TAPE    RECORD
FIELD  POSITION
ELEMENT
NAME
CODE DEFINITIONS AND REMARKS
010      38-42     PRESSURE-    PRESSURE—Atmospheric pressure at the current
                   AT-LEVEL     level  in kilopascals and  hundredths.  If unknown,
                                this field contains "99999".  (TD6201 only -
                                Subsurface levels were generated from Jan. 1,  1981
                                through Feb. 28, 1986.  The values were always
                                unknown.  This practice was stopped Mar. 1, 1986.
Oil      43-48     HEIGHT-      HEIGHT—Geopotential  height  of  the  current level
                   AT-LEVEL     in whole meters.  If  unknown, this  field contains
                                "-99999".   Range  of values are  -99999  through
                                99999.
012      49-52     TEMPERATURE  TEMPERATURE—The  free air  temperature at  the
                   AT-LEVEL     current  level  in  degrees and  tenths Celsius.   If
                                unknown,  this  field  contains  "-999".  Range of
                                values -999  through #999.


013      53-55     RELATIVE-    RELATIVE-HUMIDITY—The  relative  humidity  at the
                   HUMIDITY     current  level  in  whole  percent.  If unknown,  this
                   AT LEVEL     field contains "999".   In  TD-6202, relative'
                                humidities are derived  statistically for  RH's  not
                                reported originally.


014      56-58     WIND-        WIND-DIRECTION—Direction  of  the wind at  the
                   DIRECTION    current  level  in  whole  degrees (nearest five
                   AT-LEVEL     degrees  for  observations received  through GTS). If
                                unknown,  this  field  contains  "999".


015      59-61     WIND-SPEED   WIND-SPEED—Speed of the wind in whole meters  per
                   AT-LEVEL     second.   If  unknown,  this  field  contains  "999".
                                          105

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        TAPE
TAPE    RECORD
FIELD  POSITION
        ELEMENT
        NAME
             CODE  DEFINITIONS  AND  REMARKS
016      62-67     QUALITY-     QUALITY-FLAG-FIELD—This field contains the
                   FLAGS        results of any quality control procedures,
                                identifying each individual element found in error
                                (see table below).

                                QUALITY CONTROL FLAG
                                0    Element is correct
                                1    Element is doubtful
                                2    Element is in error
                                3    Replacement value
                                4    Assumed or estimated value
                                9    Element not checked
                                A-Z  Indicators supplied by NMC.  NMC flag
                                     indicators have changed many times over the
                                     years.  If you wish to use their indicators
                                     you will have to contact NMC.
          62
         TIME-QF
             Time Quality Flag
          63
         PRESSURE-QF  Pressure  Quality Flag
          64
         HEIGHT-QF    Height  Quality  Flag
          65
         TEMPERATURE-  Temperature  Quality  Flag
         QF
          66
         RELATIVE-    Relative Humidity Quality Flag
         HUMIDITY-QF
          67
         WIND-QF
             Wind Quality Flag
017
68
TYPE-OF
LEVEL
TYPE OF LEVEL FLAG—See Table below.

0    Surface
1    Mandatory
2    Significant
3    Generated
4    Tropopause
5    Maximum wind
9    Other/unspecified

NOTE:  TD-6201 through December 1975 will contain
       Type of Level Flags 0,1, and 9 only.  The
       significant flag is not present.

         106

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                                APPENDIX E
                    DESCRIPTION OF THE TD-9689 FORMAT

     This description is reproduced from documentation provided by  the National
Climatic Data Center (NCDC).
                                      107

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FILE NAME:

TIME PERIOD:


GEOGRAPHIC COVERAGE:

FILE SIZE:
FORMAT:

FILE STRUCTURE:
CONTENTS:
ABSTRACT:
MIXING HEIGHT STUDIES (TD-9689).

January 1, 1960 through December 31,  1964  and  various
later years.

Selected upper air stations in the United States.

One magnetic tape; 9-track, odd parity,  1600bpi,  ASCII
mode, labeled  and  two  magnetic  tapes;  9-track,  odd
parity, 6250bpi, ASCII mode labeled.   Copies  of  these
data are available on magnetic  tape  (EBCDIC  or  ASCII
mode) and other computer media.

34 characters per record, 10 records per block.

Morning and  afternoon  mixing  heights  for  the  years
1960-1964 were calculated for 62 stations  by  NCDC  for
the Environmental Protection Agency.  These data are  on
one reel of 1600bpi magnetic tape.  Mixing  heights  for
later years can be computed on demand.  A great many  of
these studies for later years have  been  generated  and
are stored on two reels of 6250bpi magnetic tape.

The major parameters that make up this  file  are  date,
morning type indicator, morning  (near  minimum)  mixing
depth (meters), morning average wind speed  (meters  per
second to  lOths)  through  the  mixing  depth,  morning
average surface wind speed,  afternoon  type  indicator,
afternoon (near maximum) mixing depth, afternoon average
wind speed  through  the  mixing  depth,  and  afternoon
average surface wind speed.

The data utilized in generating  this  file  are  hourly
surface weather observations (TD-3280),  and  upper  air
observations (TD-6201) taken at 0000 GMT and  1200  GMT.
Since it takes two  data  files  to  generate  a  mixing
height , two different stations  (upper air  and  surface)
may be used.  Usually this involves  a  surface  station
close to the user's area of interest and an  appropriate
nearby upper air  station.

For a mixing height study, it is  assumed  that  a  well
mixed unsaturated atmosphere will have a lapse rate that
is dry adiabatic  (9.8 degrees C  per  kilometer).    The
morning mixing height is  then  defined  as  the  height
above ground level where the dry adiabatic extension  of
the morning minimum surface temperature plus 5 degrees  C
intersects  the   vertical  temperature  profile   (RAOB)
observed for the  1200Z sounding.  The plus 5  degrees   C
is an overstatement of average  effects of the urban heat
island  and  therefore   includes  some   surface   solar
heating.  The estimated mixing  height  applies  at  the
time  and  place  where  the  surface  temperature   has
                                      108

-------
increased 5 degrees C above the minimum.  The  afternoon
mixing height is calculated in the  same  manner,  using
the 1200Z RAOB, but this time only the  maximum  surface
temperature is used.   In  addition,  the  average  wind
speed through the mixing depth is calculated.  Thus, for
each day , a morning and afternoon (maximum) mixing depth
is given along with the average wind speed  through  the
mixing  depth   and   precipitation   if   it   occurred
(considered to be a cleaning agent of  the  atmosphere).
An inventory of this file is available to users from the
NCDC.  There are no known related files.

This file is also available for purchase from the NCDC.
                109

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TAPE POSITION
     MIXING HEIGHT STUDY

 (34 Characters, Blocked 10)

       ITEM
   1-5
   6 9
   10
  11-12
  13-23
  *13
  14-17
  18-20
  21-23
  24-34
  25-28
  29-31
  32-34
Station number
Year, month
Season
1 = Dec, Jan, Feb
2 = Mar, Apr, May
3 = Jun, Jul, Aug
4 = Sep, Oct, Nov
Bay
Morning
Type
1 = No Precip
2 = Precip
3 = Cold Advection
4 = Missing
Mixing depth (Meters)
Average wind speed thru mixing depth
Average surface wind speed
Afternoon
Type - 1, 2, 3,  or 4

Mixing Depth
Average wind speed thru mixing depth
Average surface wind speed
   Period 1960 - 1964
   Type  CBlank,C or P)
   Blank • -Missing or -no Precipitation
   C » Cold Advection
   "P * Precipitatitjn
                                 110

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                                APPENDIX F
                    DESCRIPTION OF THE TD-9773 FORMAT

     This description is reproduced from documentation provided  by  the National
Climatic Data Center (NCDC).
                                      Ill

-------
FILE NAME:

TIME PERIOD:

GEOGRAPHIC COVERAGE:

FILE SIZE:
FORMAT:

FILE STRUCTURE:


CONTENTS:
ABSTRACT:
STABILITY ARRAY-STAR (TD-9773).

Not time dependent.

300 United States and Select World-Wide Stations.

8 magnetic tapes; 9-track, odd  parity,  1600bpi,   ASCII
mode, labeled.  Copies of these  data  are  available  on
magnetic tape (EBCDIC or ASCII mode) and other  computer
media.

84 characters per record, 10 records per block.

Data are sorted on each magnetic tape by  header  number
or station number (WBAN or WHO).

The major parameters that make up  this  file  are  wind
direction (16 points and calm),  stability  class  (A-G),
wind speed (kts) frequencies, station ID, and  beginning
and ending year.  The STAR output consists  of  monthly,
seasonal, or  annual  frequency   and  percent  frequency
tables of wind direction versus  wind  speed  groups  for
each stability category.

STAR was born from the work of Pasquill  (1951),  Turner
(1964), and Martin and Tidvart (1968).  It provides,  at
least roughly, the  diffusion  characteristics  for  the
lowest part of the atmosphere and biosphere.  It  is  an
objective method of determining stability  from  readily
available surface meteorological observations  utilizing
only the variables of ceiling height, total  sky  cover,
and wind direction and speed as  input.  The  methodology
employed recognizes that stability near  the  ground  is
dependent primarily upon net radiation and  wind  speed.
Wind  direction   is   not   a   factor   in   objective
determination of  stability  categories.    Without  the
influence of  clouds,  insolation  (incoming  radiation)
during the  day  is  dependent  mainly  upon  the  solar
elevation, which is a function of time of year, time  of
day, and station location.   When  clouds
cover  and  thickness  decrease  incoming
radiation.  In this system, insolation is
solar elevation and modified for existing conditions  of
total sky cover and ceiling height.  At night, estimates
of outgoing radiation are again based on total sky cover
and  ceiling  height.    The  STAR  output  consists  of
frequency and percent frequency tables of wind direction
versus wind speed groups for  each  stability  category-
This  system  produces   seven  categories  ranging  from
extremely unstable  (A)  to  neutral  (D)  to  extremely
stable  (G) and can  be summarized on a monthly, seasonal,
or annual basis.
                                                                  exist,   their
                                                                  and  outgoing
                                                                  estimated  by
                                       112

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NCDC can produce a STAR for any year or number of years
for any station (world-wide) whose hourly or 3-hourly
surface meteorological observations are stored in
TD-3280 or TD-9999 AFDATSAV files.  An optional output
of the STAR that NCDC can generate is formatted, 100
characters per record/10 records per block, individual
surface meteorological observations and associated
stability categories on magnetic tape or other computer
media.

A STAR TABULATIONS MASTER LIST (Index) is available to
users from the NCDC.  There are no known related files.

This file is available for purchase from the NCDC.
                 113

-------