User's Guide for Draft AERSURFACE Tool
(Version 19039 DRFT)
-------
ii
-------
EPA-454/B-19-001
February 2019
User's Guide for Draft AERSURFACE Tool (Version 19039 DRFT)
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Air Quality Assessment Division
Research Triangle Park, NC
111
-------
Preface
This document provides a technical description and user instructions specific to the draft
version of the AERSURFACE tool, 19039 DRFT. AERSURFACE was designed to aid in
determining surface characteristic values required by AERMET, the meteorological processor for
AERMOD. This draft version has been updated to read and process more recent land cover data
from the National Land Cover Database (NLCD) than past versions and reconfigured, replacing
the interactive interface of past versions with a path/keyword approach similar to AERMET,
AERMAP, and AERMOD.
iv
-------
V
-------
Contents
Section Page
1.0 Introduction 1-1
1.1 When to Use AERSURFACE 1-1
1.2 Changes from Version 13016 1-3
1.3 Status of AERSURFACE, Version 19039_DRFT 1-3
1.4 User Feedback Requested for Version 19039_DRFT 1-4
2.0 Technical Description of AERSURFACE 2-1
2.1 Description of USGS Land Cover Data 2-1
2.2NLCD Sources 2-5
2.3 Assignment of Surface Characteristics by Land Cover Category 2-6
2.3.1 Seasonal Values 2-6
2.3.2 Airports vs. Non-airport Locations 2-7
2.3.3 Climate 2-8
2.4 AERSURFACE Calculation Methods 2-9
2.4.1 Surface Roughness Length 2-10
2.4.1.1 ZORAD - Default Method for Determining Roughness Length 2-11
2.4.1.2 ZOEFF - Experimental Method for Determining Roughness Length 2-12
2.4.1.3 Supplemental Percent Impervious and Canopy Data 2-13
2.4.2 Daytime Bowen Ratio 2-15
2.4.3 Noontime Albedo 2-15
3.0 Detailed keyword reference 3-1
3.1 Overview 3-1
3.1.1 Pathway IDs 3-1
3.1.2 Starting and ending a Pathway Block 3-2
3.1.3 Blank Lines and Comments 3-2
3.2 Control Pathway (CO) 3-3
3.2.1 Title information (TITLEONE, TITLETWO) 3-3
3.2.2 Options (OPTIONS) 3-4
vi
-------
3.2.3 Debug Options (DEBUGOPT) 3-5
3.2.4 Location of Meteorological Tower (CENTERXY, CENTERLL) 3-6
3.2.5 NLCD Filenames (DATAFILE) 3-7
3.2.6 Fixed Radial Distance for Roughness (ZORADIUS) 3-9
3.2.7 Anemometer Height (ANEM_HGT) 3-9
3.2.8 Climate, Surface Moisture, and Continuous Snow Cover (CLIMATE) 3-10
3.2.9 Temporal Frequency (FREQ_SECT) 3-11
3.2.10 Surface Roughness Length Wind Sectors (SECTOR) 3-13
3.2.11 Assigning Months to Seasons (SEASON) 3-15
3.2.12 To Run or Not (RUNORNOT) 3-16
3.3 Output Pathway (OU) 3-17
3.3.1 Surface Characteristic Values File for AERMET (SFCCHAR) 3-17
3.3.2 Debug Output Files 3-18
3.4 Sample AERSURFACE Control File 3-20
4.0 Running AERSURFACE 4-1
4.1 Command Prompt and Command-line Arguments 4-1
4.2 Error and Warning Messages 4-2
4.3 Summary of Output Files Generated by AERSURFACE 4-2
4.3.1 Auto-generated Files 4-2
4.3.1.1 Summary File (aersurface.out) 4-3
4.3.1.2 Log File (aersurface.log) 4-3
4.3.2 Surface Characteristics 4-3
4.3.3 Debug Files 4-4
4.3.3.1 Effective Radius File (default = effective _rad.txt) 4-4
4.3.3.2 TIFF Debug Files (defaults = lc_tif_dbg.txt, imp_tif_dbg.txt, and
can tif dbg. txt) 4-5
4.3.3.3 Grid Files (defaults = landcover.txt, impervious.txt, and canopy.txt) 4-5
5.0 Appendix A: National Land Cover Database Definitions 5-1
6.0 Appendix B. Surface Characteristic Lookup Tables 6-1
7.0 Appendix C. Alphabetical keyword reference 7-1
vii
-------
8.0 Appendix D. Functional keyword/parameter reference 8-1
9.0 Appendix E: Implementation of ZOEFF Option in AERSURFACE, Version 19039 DRFT.. 9-1
9.1 Method 9-1
9.2 Scientific Basis 9-1
9.3 Implementation 9-3
10.0 Appendix F: Venkatram Model Coding Abstract - Estimating Effective Roughness 10-1
11.0 Appendix G: Inter-comparison of AERSURFACE 11-1
11.1 AERSURFACE Scenarios and Meteorological Data Processing with AERMET 11-1
11.2 Emission Sources and AERMOD Setup 11-15
11.3 Inter-comparison of AERSURFACE and AERMOD Results 11-17
12.0 References 12-1
viii
-------
Figures
Figure 2-1. Surface Roughness Value Adjustment to Post-1992 Developed Categories (21-24)
Using Percent Impervious and Canopy Data 2-14
Figure 3-1. Sample AERSURFACE Control File 3-22
Figure 3-2. 2001 NLCD for RDU International with Wind Sectors Starting at 30, 60, and 225
Degrees 3-23
Figure 10-1. Concentric Rings Defined around Meteorological Tower to Calculate IBL Growth. 9-4
Figure 12-1. ATL 10 x 10 km Area and 1 km Radius with Wind Sectors 11-4
Figure 12-2. BTR: 10 x 10 km Area and 1 km Radius with Wind Sectors 11-5
Figure 12-3. RDU: 10 x 10 km Area and 1 km Radius with Wind Sectors 11-6
Figure 12-4. 2001 NLCD Land Cover for ATL 11-8
Figure 12-5. 2001 NLCD Percent Impervious and Percent Canopy for ATL 11-9
Figure 12-6. 1992 NLCD Land Cover for BTR 11-10
Figure 12-7. 2001 NLCD Land Cover for BTR 11-11
Figure 12-8. 2001 NLCD Percent Impervious and Percent Canopy for BTR 11-12
Figure 12-9. 2001 NLCD Land Cover for RDU 11-13
Figure 12-10. 2001 NLCD Percent Impervious and Percent Canopy for RDU 11-14
Figure 12-11. ATL Surface Roughness Length by Season, Sector, and AERSURFACE Scenario 11-
20
Figure 12-12. ATL H1H Predicted Concentrations by AERSURFACE Scenario and Emission
Source 11-21
Figure 12-13. ATL H2H Predicted Concentrations by AERSURFACE Scenario and Emission
Source 11-22
Figure 12-14. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-IMP-CAN-ZOEFF 11-23
Figure 12-15. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 I.C-IY1P-ZORAD 11-24
Figure 12-16. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-IMP-ZOEFF 11-25
Figure 12-17. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
ix
-------
CAN-ZORAD Vs. 2001 LC-CAN-ZORAD
11-26
Figure 12-18. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-CAN-ZOEFF 11-27
Figure 12-19. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-ZORAD 11-28
Figure 12-20. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-ZOEFF 11-29
Figure 12-21. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 LC-IMP-ZORAD Vs.
2001 LC-IMP-ZOEFF 11-30
Figure 12-22. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 LC-CAN-ZORAD Vs.
2001 LC-CAN-ZOEFF 11-31
Figure 12-23. ATL, Scatter Plots, H1H and H2H at each Receptor, 2001 LC-ZORAD Vs. 2001
LC-ZOEFF 11-32
Figure 12-24. BTR Surface Roughness Length by Season, Sector, and AERSURFACE Scenario 11-
33
Figure 12-25. BTR H1H Predicted Concentrations by AERSURFACE Scenario and Emission
Source 11-34
Figure 12-26. BTR H2H Predicted Concentrations by AERSURFACE Scenario and Emission
Source 11-35
Figure 12-27. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
C.W-ZORAD Vs. 1992 LC-ZORAD 11-36
Figure 12-28. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 1992 LC-ZOEFF 11-37
Figure 12-29. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-IMP-CAN-ZOEFF 11-38
Figure 12-30. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-IMP-ZORAD 11-39
Figure 12-31. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-IMP-ZOEFF 11-40
Figure 12-32. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-CAN-ZORAD 11-41
Figure 12-33. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-CAN-ZOEFF 11-42
x
-------
Figure 12-34. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-ZORAD 11-43
Figure 12-35. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-ZOEFF 11-44
Figure 12-36. BTR, Scatter Plots, H1H and H2H at each Receptor, 1992 LC-ZORAD Vs. 1992
LC-ZOEFF 11-45
Figure 11-37. BTR, Q-Q Plots, H1H and H2H at each Receptor, 2001 LC-IMP-ZORAD Vs. 2001
LC-IMP-ZOEFF 11-46
Figure 12-38. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 LC-CAN-ZORAD Vs.
2001 LC-CAN-ZOEFF 11-47
Figure 12-39. BTR, Scatter Plots, H1H and H2H at each Receptor, 2001 LC-ZORAD Vs. 2001
LC-ZOEFF 11-48
Figure 12-40. RDU Surface Roughness Length by Season, Sector, and AERSURFACE Scenario
11-49
Figure 12-41. RDU H1H Predicted Concentrations by AERSURFACE Scenario and Emission
Source 11-50
Figure 12-42. RDU H2H Predicted Concentrations by AERSURFACE Scenario and Emission
Source 11-51
Figure 12-43. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-IMP-CAN-ZOEFF 11-52
Figure 12-44. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-IMP-ZORAD 11-53
Figure 12-45. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-IMP-ZOEFF 11-54
Figure 12-46. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-CAN-ZORAD 11-55
Figure 12-47. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-CAN-ZOEFF 11-56
Figure 12-48. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-ZORAD 11-57
Figure 12-49. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 Base Case, LC-IMP-
CAN-ZORAD Vs. 2001 LC-ZOEFF 11-58
Figure 12-50. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 LC-IMP-ZORAD Vs.
xi
-------
2001 LC-IMP-ZOEFF 11-59
Figure 12-51. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 LC-CAN-ZORAD Vs.
2001 LC-CAN-ZOEFF 11-60
Figure 12-52. RDU, Scatter Plots, H1H and H2H at each Receptor, 2001 LC-ZORAD Vs. 2001
LC-ZOEFF 11-61
xii
-------
Tables
Table 2-1. Inventory of National Land Cover Database 2-2
Table 2-2. NLCD 1992 Classification Categories 2-3
Table 2-3. NLCD 2001-2011 Classification Categories 2-4
Table 2-4. AERSURFACE Season Definitions 2-7
Table 3-1. Default Month/Season Assignments in AERMET 3-12
Table 3-2. Season Secondary Keywords and Definitions 3-16
Table 3-3. OU Pathway Primary Keywords and Default Filenames 3-19
Table 5-1. NLCD 1992 Class and Category Descriptions and Color Legend 5-1
Table 5-2. NLCD 2001-2011 Class and Category Descriptions and Color Legend 5-3
Table 6-1. Seasonal Values of Albedo for the NLCD 1992 6-2
Table 6-2. Seasonal Values of Bowen Ratio for the NLCD 1992 6-4
Table 6-3. Seasonal Values of Surface Roughness (m) for the NLCD 1992 6-6
Table 6-4. Seasonal Values of Albedo for the NLCD 2001-2011 6-8
Table 6-5. Seasonal Values of Bowen Ratio for the NLCD 2001-2011 6-9
Table 6-6. Seasonal Values of Surface Roughness for the NLCD 2001-2011 6-11
Table 7-1. All Primary Keywords Available in AERSURFACE 7-2
Table 8-1. Description of Control Pathway Keywords 8-2
Table 8-2. Description of Control Pathway Keywords and Parameters 8-3
Table 8-3. Description of Output Pathway Keywords 8-8
Table 8-4. Description of Output Pathway Keywords and Parameters 8-8
Table 11-1. 2001 NLCD AERSURFACE Scenarios for ATL, BTR, and RDU 11-2
Table 11-2. 1992 NLCD AERSURFACE Scenarios for BTR 11-2
Table 11-3. NWS/FAA Meteorological Tower Location and Wind Sector Definitions 11-3
Table 11-4. Surface and Upper Air Station Pairings for Meteorological Data Processing 11-15
Table 11-5. Emission Sources 11-16
xiii
-------
1.0 Introduction
When applying the AERMET meteorological processor (EPA, 2018a) to process
meteorological data for the AERMOD model (EPA, 2018b), the user must determine
appropriate values for three surface characteristics: surface roughness length, noontime
albedo, and daytime Bowen ratio. The surface roughness length is related to the height of
obstacles to the wind flow and is, in principle, the height at which the mean horizontal wind
speed is zero based on a logarithmic profile. The surface roughness length influences the
surface shear stress and is an important factor in determining the magnitude of mechanical
turbulence and the stability of the boundary layer. The albedo is the fraction of total incident
solar radiation reflected by the surface back to space without absorption. The Bowen ratio, an
indicator of surface moisture, is the ratio of sensible heat flux to latent heat flux and, together
with albedo and other meteorological observations, is used for determining planetary boundary
layer parameters for convective conditions driven by the surface sensible heat flux. Further
details regarding the AERMOD model formulations and their dependence on surface
characteristics are provided in Cimorelli, et al. (2004).
The AERSURFACE tool has been developed to aid users in obtaining realistic and
reproducible surface characteristic values for albedo, Bowen ratio, and surface roughness
length, for input to AERMET. The tool uses data from the national land cover database
(NLCD) from the United States Geological Survey (USGS) and look-up tables of surface
characteristic values that vary by land cover type and season. This user's guide provides a
technical description of the AERSURFACE tool, including information on the data used by
AERSURFACE to provide these surface characteristics for AERMET. Detailed user
instructions for application of AERSURFACE are also provided.
1.1 When to Use AERSURFACE
User-defined values for the surface characteristics referenced above must be developed
for input to AERMET when processing site-specific surface meteorology, commonly collected
1-1
-------
onsite near the emission source, and/or surface meteorology collected at National Weather
Service (NWS)ZFederal Aviation Administration (FAA) surface meteorological stations,
typically located at airports across the country. AERMET can also accept prognostic
meteorology generated by the Weather Research Forecast (WRF) model and extracted using
the Mesoscale Model Interface (MMIF) program (EPA, 2016). User-defined surface
characteristics are not needed when prognostic data are extracted using MMIF since surface
characteristics are included in the formatted MMIF output.
When processing site-specific and NWS/FAA surface data simultaneously with
AERMET and the NWS/FAA wind data are used to substitute missing site-specific wind data,
AERMET requires user-defined surface characteristic values for both meteorological station
locations. In that case, the site-specific station is considered the primary site and NWS/FAA
site is considered the secondary site. When NWS/FAA surface data are processed without site-
specific data, the NWS/FAA site is considered the primary site since it is the only source of
surface meteorology.
AERSURFACE is not a regulatory component of the AERMOD Modeling System as
listed in Appendix A to the Guideline on Air Quality Models (published as "Appendix W" to
40 CFR Part 51), which includes the AERMAP and AERMET terrain and meteorological
preprocessors, respectively, in addition to the AERMOD dispersion model. However, Section
8.4.2(b) of the Guideline recommends the use of the latest version of AERSURFACE for
determining surface characteristics when processing measured meteorological data through
AERMET (i.e., representative site-specific data or data from a nearby National Weather
Service or comparable station). Where it is not possible to run AERSURFACE, Section
8.4.2(b) recommends using the methods in AERSURFACE to determine surface characteristic
values. The methods implemented in AERSURFACE are also discussed in the AERMOD
Implementation Guide (EPA,2018c).
1-2
-------
1.2 Changes from Version 13016
AERSURFACE has been updated from version 13016 to 19039 DRFT. This version is
in draft form and represents substantial updates to the user interface over version 13016. The
major updates include:
• User interface modified to read a user-generated input control file that makes
use of a keyword/pathway approach similar to AERMOD, AERMET, and
AERMAP. The interface is no longer prompt driven and interactive.
• Updated to process most recent land cover data from the National Land Cover
Database (NLCD) including 2001, 2006, and 2011 land cover which can be
supplemented with percent impervious and percent tree canopy data, when
available.
• Addition of a research grade method for determining surface roughness length,
based on the estimated growth of the internal boundary layer due to surface
roughness approaching the meteorological tower.
• Generates formatted output with appropriate keywords for AERMET based on
whether the site location is defined as the primary or secondary meteorological
site.
1.3 Status of AERSURFACE, Version 19039 DRFT
The EPA is releasing this draft version (19039 DRFT) of the AERSURFACE tool for informal
public review, testing, and comment. Testing and evaluation of this draft revision and
subsequent feedback is critical to inform a final version which will replace 13016. Given the
issues with land cover/land use representativeness or data accessibility of the 1992 NLCD,
there may be regulatory applications of AERMOD where an applicant wishes to use this draft
version of AERSURFACE. In such cases, consultation with the appropriate reviewing
1-3
-------
authority and the EPA Regional Office is necessary with AERSURFACE results closely
inspected and a written rationale for the results provided to the reviewing authority and the
EPA Regional Office.
If this draft version of AERSURFACE is used for a regulatory application, then the EPA
recommends the following:
• The default method for determining surface roughness length (ZORAD) should
be used. As previously stated, the ZOEFF method is considered research grade
and should be used only for testing and evaluation purposes.
• For the NLCD year of the land cover being processed, if only one of
impervious or tree canopy data is available, or neither is available, then the land
cover data should be processed by itself without the use of the impervious or
canopy data. Land cover data should not be supplemented with impervious data
only or canopy data only.
1.4 User Feedback Requested for Version 19039 DRFT
The EPA is requesting feedback from the user community in general but particularly
interested in the following items:
• Reference lookup tables for the 2001 NLCD and later used to compute albedo,
Bowen ratio, and surface roughness length
Many of the land cover classes and categories in the 2001 NLCD and later map
directly to the those defined in the 1992 NLCD. However, there are some
substantial changes in the class and category definitions in the later
classification scheme that have been problematic in the assignment of
representative values. These are primarily associated with the surface
roughness length values assigned to the four categories in the "Developed"
class which include "Open Space," "Low Intensity," "Medium Intensity," and
1-4
-------
"High Intensity." Ambiguity in the definitions make it difficult to assign values
of roughness that are representative in all cases. We are requesting feedback on
value assignments for these categories specifically, though we welcome
feedback on the assignment of surface characteristic values for any of the land
cover categories.
• Implementation of the percent impervious and percent tree canopy data
To mitigate some of the ambiguity in the definitions of the "Developed"
categories, the percent impervious and canopy data, when provided, are used to
refine the definition of individual 30 x 30-meter land cover grid cell and the
assigned surface roughness. Surface roughness is then weighted based on the
fraction of the cell that is an impervious surface vs tree canopy. We are seeking
feedback on the implementation of the use of the impervious and canopy data.
• Implementation of the research grade ZOEFF methodfor computing surface
roughness length
The ZOEFF method for computing surface roughness uses the roughness
associated with the land cover across defined distance intervals to estimate the
fetch required for the internal boundary layer (IBL) to grow to a default height
as the wind flows toward the meteorological tower. An effective roughness is
then computed based on the estimated fetch. The reference height for the IBL is
defined as a multiple of the height where the wind measurements are taken.
The default reference height is currently set at 6 times the measurement height
but can be changed by the user. A separate fetch and subsequently a separate
effective roughness length is estimated for each user-defined wind sector. We
are seeking feedback on the implementation of the ZOEFF method as described
here, including the default factor of 6 for computing the IBL reference height.
Additional areas of interest for which feedback would be valuable include:
1-5
-------
Guidance needs (e.g., determining climate conditions, urban vs. rural
determination, defining wind sectors, and defining a wind sector as airport
non-airport);
Methods for evaluating AERSURFACE;
Bug reports;
Usefulness and accuracy of Draft User's Guide; and
Additional documentation needed by the user community.
1-6
-------
2,0 Technical Description of AERSURFACE
This section discusses the land cover data that are input to AERSURFACE and a
technical description of how those data are processed to determine representative values of
albedo, Bowen ratio, and surface roughness length.
2.1 Description of USGS Land Cover Data
AERSURFACE requires the input of land cover data from the U.S. Geological Survey
(USGS) National Land Cover Database (NLCD) to determine the land cover types at a user-
specified location. The NLCD identifies the predominant land cover at a resolution of 30 x
30-meter grid cells. In simple terms, AERSURFACE assigns each land cover category within
each 30 x 30-meter land cover grid cell seasonal values of albedo, Bowen ratio, and surface
roughness. Temporally representative average values (e.g., annual, seasonal, or monthly) are
calculated for the area of interest from the seasonal values. AERSURFACE results are output
in a format that is input-ready for AERMET.
The NLCD includes land cover for the conterminous U.S., representative of the
following years: 1992, 2001, 2006, and 2011. The land cover classification system changed
after the 1992 NLCD but has since remained static for the 2001, 2006, and 2011 NLCD.
Beginning with the 2001 NLCD, the datasets were expanded to include land cover for Alaska,
Hawaii, and Puerto Rico for certain years. In addition, new products were added to the NLCD
to include percent impervious and percent tree canopy data which supplement the land cover
data with the percent of the surface in a land cover grid cell that is impervious material and the
percent of the grid cell that is covered with a tree canopy. The impervious and canopy data are
not available for all areas or for all years. Table 2-1 lists the data availability by area, year, and
data type.
2-1
-------
Table 2-1. Inventory of National Land Cover Database
Year
Data
Conterminous US
Alaska
Hawaii
Puerto Rico
1992
Land Cover
2001
Land Cover
Impervious
Canopy
2006
Land Cover
Impervious
Canopy
2011
Land Cover
Impervious
Canopy
The 1992 NLCD is based on a 21-category system while the post-1992 NLCDs are
based on a 16-category system with 4 additional categories that are specific to Alaska.
Category codes and names for each of the two classification systems are shown in Table 2-2
and Table 2-3. Complete category descriptions are provided in Section 5.0. The seasonal
values assigned to albedo, Bowen ratio, and surface roughness length, by land cover category,
for each of the two classification systems (1992 NLCD and post-1992 NLCDs) are provided in
Section 6.0. Discussions of the methods implemented in AERSURFACE to calculate
representative values for the three surface characteristics are provided in Section 2.4.
2-2
-------
Table 2-2. NLCD 1992 Classification Categories
Classification
Category
Number
Category Name
Water
11
Open Water
12
Perennial Ice/Snow
Developed
21
Low Intensity Residential
22
High Intensity Residential
23
Commercial/Industrial/Transportation
Barren
31
Bare Rock/Sand/Clay
32
Quarries/Strip Mines/Gravel Pits
33
Transitional
Forested Upland
41
Deciduous Forest
42
Evergreen Forest
43
Mixed Forest
Shrubland
51
Shrubland
Non-natural Woody
61
Orchards/Vineyards/Other
Herbaceous Upland
71
Grasslands/Herbaceous
Herbaceous
Planted/Cultivated
81
Pasture/Hay
82
Row Crops
83
Small Grains
84
Fallow
85
Urban/Recreational Grasses
Wetlands
91
Woody Wetlands
92
Emergent Herbaceous Wetlands
2-3
-------
Table 2-3. NLCD 2001-2011 Classification Categories
Classification
Category
Number
Category Name
Water
11
Open Water
12
Perennial Ice/Snow
Developed
21
Developed, Open Space
22
Developed, Low Intensity
23
Developed, Medium Intensity
24
Developed, High Intensity
Barren
31
Bare Land (Rock/Sand/Clay)
Forest
41
Deciduous Forest
42
Evergreen Forest
43
Mixed Forest
Shrubland
51
Dwarf Scrub (Alaska Only)
52
Shrub/Scrub
Herbaceous
71
Grassland/Herbaceous
72
Sedge/Herbaceous (Alaska Only)
73
Lichens (Alaska Only)
74
Moss (Alaska Only)
Planted/Cultivated
81
Pasture/Hay
82
Cultivated Crops
Wetlands
90
Woody Wetlands
95
Emergent Herbaceous Wetlands
Previous versions of AERSURFACE were limited to the use of the 1992 NCLD which
subsequently limited its application to the conterminous U.S. Beginning with version
19039 DRFT, AERSURFACE can process land cover data from the 1992, 2001, 2006, and
2011 NLCDs. Where available, impervious and canopy data can be input into AERSURFACE
to supplement land cover data. This is a refinement for certain post-1992 land cover categories
that are more difficult to assign roughness values due to a broader characterization of land
cover for those categories (e.g., the "Developed" categories in the 2001-2011 NLCD
classification).
2-4
-------
The USGS NLCD files processed by AERSURFACE provide land cover data at a
spatial resolution of 30 meters, mapped using an Albers Conic Equal Area projection. The files
input to AERSURFACE must be in the Georeferenced Tagged Image File Format (GeoTIFF)
(Aldus, 1992; Ritter and Ruth, 1995). Complete product descriptions for the 2001, 2006, and
2011 NLCD products are available on the Multi-Resolution Land Characteristics Consortium
(MRLC) website at https://www.mrlc.gov/index.php.
Note: The USGS has indicated that support for the 1992 NLCD is being
discontinued as it has been replaced by the more recent 2001, 2006, and 2011 NLCD
products. Further, the MRLC website will no longer distribute the 1992 NLCD or
provide the 2001, 2006, and 2011 NLCD products as GeoTIFF files (.tif). Alternate
sources for obtaining the 2001, 2006, and 2011 products as GeoTIFF files which are
compatible with the draft version of AERSURFACE are provided in Section 2.2. Also
note, beginning with version 19039 DRFT, the 1992 NLCD "binary" (.bin) state files,
previously available from the USGS, are no longer supported by AERSURFACE. The
EPA has provided an archive of the binary state files on the Support Center for
Atmospheric Modeling (SCRAM) website at https://www.epa.gov/scram/interim-access-
and-process-use-1992-nlcd-and-ned. These files can be processed with version 13016.
2.2 NLCD Sources
As mentioned in the previous section, the 1992 NLCD is no longer supported or
distributed by the USGS, and 2001, 2006, and 2011 products are no longer available as
GeoTIFF files, from the MRLC website.
NLCD 2001, 2006, and 2011 products in GeoTIFF format that can be input directly
into AERSURFACE are available from the USGS Science Base Catalogue at
https://www.sciencebase.gov/catalog/item/4f70a43ce4b058caae3f8db3. State-wide files as
well as 3 x 3-degree files are available for download. Similarly, state-level and 3x3 degree
data files can be downloaded as GeoTIFF files via the USGS National Map at
https://viewer.nationalmap.gov/basic/.
2-5
-------
2.3 Assignment of Surface Characteristics by Land Cover Category
Each of the land cover categories in the two classification systems is mapped within
AERSURFACE to a set of seasonal values of albedo, surface roughness length, and Bowen
ratio. However, there are categories for which one or more of these surface characteristics
cannot be adequately represented by a single seasonal value due to the climate of the area or
the physical setting and broader use of the area, such as if the location is an airport. This
section addresses the assignments of seasonal values and the special cases that are considered.
The seasonal values to the surface characteristics, by land use category, are provided in
Section 6.0.
2.3.1 Seasonal Values
The values of the surface characteristics, by land cover category, were developed for
five seasonal categories. The seasonal categories and the default months that comprise each
season are listed in Table 2-4. These seasonal categories are the same as those used by the
AERMOD model (EPA, 2018b) for the gas deposition algorithms (GDSEASON keyword).
When seasonal surface values are generated for input to AERMET, default monthly
assignments will be used. For monthly and annual values, the user is given the option of
assigning the individual months to a seasonal category that is appropriate for the climate and
conditions at the specific location. This option will allow a more locally appropriate estimate
that is more reflective of the area. Otherwise, the user can select to use the program's default
setting which assigns the months of March, April, and May to "Transitional spring with partial
green coverage or short annuals;" June, July, and August to "Midsummer with lush
vegetation;" and September, October, and November "Autumn with unharvested cropland."
The user can indicate whether the area experiences continuous snow cover in the winter. If the
area experiences periods of continuous snow cover during the winter, then the months of
December, January, and February are assigned to "Winter with continuous snow on ground."
If the area does not experience continuous snow cover, then the months of December, January,
and February will be paired with surface characteristic values listed "Late autumn after frost
and harvest, or winter with no snow." The user can opt to redefine the month-to-season
2-6
-------
assignments and separately identify which months experience continuous snow cover and
those that do not. Further details regarding these user options are provided in Section 3.0.
Table 2-4. AERSURFACE Season Definitions
Season Description
Default Month
Assignments
Midsummer with lush vegetation
Jun, Jul, Aug
Autumn with unharvested cropland
Sep, Oct, Nov
Late autumn after frost and harvest, or winter with no snow
Dec, Jan, Feb
Winter with continuous snow on the ground
Dec, Jan, Feb
Transitional spring with partial green coverage or short annuals
Mar, Apr, May
2.3.2 Airports vs. Non-airport Locations
In both the 1992 and post-1992 NLCD classification systems, there are categories that
are more broadly defined and can have a mix of land cover that make it difficult to assign
surface roughness values. More specifically, these are category 23,
Commercial/Industrial/Transportation, in the 1992 NLCD and categories 21-24 in the
Developed class of the 2001-2011 NLCD which are the Open Space, High Intensity, Medium
Intensity, and Low Intensity categories, respectively. In the case of the 1992 NLCD, the
referenced category covers both transportation (e.g. roadways and airport runways) and
commercial and industrial areas (e.g. industrial parks). If the site is at an airport,
AERSURFACE will use surface characteristics that reflect an area dominated by
transportation type land cover such as roadways, parking lots, and runways. For non-airport
sites, AERSURFACE will choose higher surface roughness values that are more
representative of an area dominated by buildings associated with commercial and industrial
sites. Surface roughness value assignments are more challenging in the 2001-2011 NLCD
since there is less specificity in the differentiation of the four Developed categories referenced
above. They are made up of a more diverse mix of land cover types than the 1992 NLCD
Commercial/Industrial/Transportation category. The Developed categories in 2001 - 2011 are
defined based on types of and amount of residences, vegetation (trees and grass), parks,
2-7
-------
roadways, runways, and industrial parks. The main distinction between these categories is the
difference in the amount of vegetation and impervious surfaces, but the category definitions do
not give much insight as to the types of impervious surfaces or the types of vegetation. Like
the 1992 NLCD, AERSURFACE assumes airports have lower roughness due to the presence
of roads and runways while non-airport sites are assumed to have higher roughness due to the
presence of more buildings (i.e., lesser coverage of hard smooth surfaces at ground-level). As
for vegetation, there is generally more grassy areas, common between the runways, than trees.
As a refinement, when available, AERSURFACE can now read and apply the percent
impervious and percent tree canopy values to these post-1992 "Developed" categories. When
the land cover is supplemented with these data, the assigned values of surface roughness are
weighted based on the amount of the grid cell that is impervious vs. covered with a tree
canopy. This method of weighting the surface roughness is discussed in more detail below in
Section 2.4.1.
Separate values of surface roughness can be calculated for user-defined wind sectors.
Previous versions of AERSURFACE treated all sectors as an airport site or all sectors as a
non-airport site. Realistically, some sectors that are predominately made up of one or more
categories that are ambiguous in their description may have a makeup that is more typical of
an airport while others may not. Beginning with version 19039 DRFT, individual sectors can
be identified as either airport or non-airport sectors to more accurately represent the makeup of
those categories (e.g., a "Developed" category that is predominately made up of airport
runways vs apartment buildings). This option will be discussed further in Section 3.0.
2.3.3 Climate
Albedo, Bowen ratio, and roughness can each be influenced differently for certain
land cover categories based on if the region typically experiences arid conditions. The land
cover categories that are differentiated based on arid vs non-arid conditions are those
associated with the Barren, Shrubland, and Planted/Cultivated classes in the 1992 NLCD and
2001-2011 NLCD classification systems. In general, the albedo and Bowen ratio will be
higher and the surface roughness lower for arid regions than for non-arid regions. Note: If the
2-8
-------
user specifies that the location experiences continuous snow cover for at least one month
during the year, AERSURFACE assumes that the area is non-arid.
In addition, different values are assigned to Bowen ratio based on surface moisture
due to precipitation and whether the site has experienced wetter than normal, dryer than
normal, or average conditions. The surface moisture condition for the site may vary depending
on the meteorological data period for which the surface characteristics will be applied.
AERSURFACE applies the surface moisture condition for the entire data period. Therefore, if
the surface moisture condition varies significantly across the data period, then AERSURFACE
may need to be applied multiple times to account for those variations. The surface moisture
condition can be determined by comparing precipitation for the period of data to be processed
to the 30-year climatological record. It is recommended the user specify "wet" conditions if
precipitation is in the upper 30th-percentile, "dry" conditions if precipitation is in the lower
30th-percentile, and "average" conditions if precipitation is in the middle 40th-percentile.
2.4 AERSURFACE Calculation Methods
Determining effective surface characteristics for processing meteorological data for use
with the AERMOD model presents challenges. AERMOD is a steady-state plume model
which assumes spatially uniform meteorological conditions across the modeling domain for
each hour of meteorology, while land cover across the domain is typically very heterogeneous.
A sound understanding of the important physical processes represented in the AERMOD
model algorithms (Cimorelli, et al., 2004) and the sensitivity of those algorithms to surface
characteristics is needed to properly interpret the available data and make an appropriate
determination.
The recommendations for determining surface characteristics are presented in Section
3.1 of the AERMOD Implementation Guide (EPA, 2018c) and have been incorporated into
AERSURFACE. These recommendations are summarized below, along with some additional
options that are included in the draft version of AERSURFACE (19039 DRFT) for evaluation
2-9
-------
and feedback, to refine the methods currently used and extend the use of AERSURFACE with
more recent land cover data (e.g., NCLD 2001, 2006, and 2011).
2.4.1 Surface Roughness Length
Based on model formulations and model sensitivities, the relationship between the
surface roughness upwind of the measurement site and the measured wind speeds is generally
the most important consideration. The surface roughness length should be based on an upwind
distance from the measurement site that captures the net influence of surface roughness
elements on the measured wind speeds needed to properly characterize the magnitude of
mechanical turbulence in the approach flow. Such changes in surface roughness result in the
development of an internal boundary layer (IBL) which grows with distance downwind of the
roughness change, and defines the layer influenced by the roughness elements.
Previous versions of AERSURFACE have calculated surface roughness length as an
inverse distance weighted geometric mean, based on the land cover within the area around the
meteorological tower out to a default fixed radial distance of a 1 kilometer (km) from the
tower. Refer to the AERMOD Implementation Guide (EPA, 2018c) for a more detailed
discussion of the selection of the default value of 1 km as it relates to growth of the IBL
relative to the location and height of the wind measurements, as well as conditions for possible
exceptions to this default distance. Beginning with version 19039 DRFT of AERSURFACE,
this method is referred to as the "ZORAD" (fixed radius) option for estimating surface
roughness length in AERSURFACE and is considered the program default. Also, beginning
with version 19039 DRFT a research grade method, "ZOEFF" (effective roughness), was
added that does not limit the upwind fetch to a fixed 1 km distance from the tower. Rather, the
distance and resulting area over which the roughness length is estimated is based on the
estimated growth of the IBL from the land cover encountered as the air flows toward the
meteorological tower. The distance over which roughness is determined is sector dependent.
Surface roughness length can be computed as a single value over the full circular area
around the tower or may be varied by multiple wind sectors based on variations in land cover
2-10
-------
around the tower. Sector widths are limited to a minimum of 30 degrees for a maximum of 12
sectors for use in AERMET. Beginning with version 19039 DRFT, the option was added to
generate roughness length values for 16 sectors, 22.5 degrees each, for comparison with a
standard wind rose plot; however, this option is for diagnostic purposes only and cannot be
input into AERMET.
The two distinct methods for estimating surface roughness length, ZORAD and
ZOEFF, and the incorporation of impervious and canopy data are discussed in the next
sections. As mentioned previously, version 19039 DRFT can incorporate percent impervious
and percent tree canopy data into the roughness calculation for several land cover categories in
the 2001-2011 NLCD that have somewhat ambiguous definitions. The method for
incorporating these data into the roughness calculations is independent of the roughness option
specified and will be discussed in a subsequent section.
2.4,1,1 ZORAD - Default Method for Determining Roughness Length
The default method for determining surface roughness length (ZORAD) in
AERSURFACE is based on an inverse distance-weighted geometric mean. The mean is
calculated from the roughness values associated with the land cover category that defines each
land cover grid cell within the area or individual sectors out to a fixed radial distance from the
meteorological tower. The recommended and default radial distance as previously stated is
1 km.
The roughness values associated with each grid cell are weighted based on the inverse
distance from the meteorological tower. This is due in part to the fact that the width of a
sector increases with distance from the measurement site, such that there are more grid cells
included as the distance from the tower increases. Without including an inverse-distance
weighting, the land cover farther from the site would receive a higher effective weight than
land cover closest to the site if a direct area-weighted averaging approach were used. In
addition, a geometric mean is recommended for calculating the surface roughness length due
to the fact that the AERMOD formulations are dependent on the natural log (In) of the
2-11
-------
roughness length. The arithmetic average of the natural log of the roughness length is
mathematically equivalent to the geometric mean of the roughness length. The inverse
distance-weighted geometric mean roughness ( Zo ) is computed as follows:
where: n is the total number of grid cells over which the geometric mean is computed, i is one
of n grid cells, d is the distance between the center of the grid cell and the meteorological
tower,/? is 1, and Zo is the surface roughness length for individual grid cell i.
Individual monthly mean roughness values are computed separately for each sector.
Annual or seasonal values are then computed from the monthly values as simple arithmetic
means for each sector based on the temporal frequency of values specified by the user in the
control file. The input requirements for the ZORAD option are provided in Section 3.2
2.4,1,2 ZOEFF - Experimental Method for Determining Roughness Length
A research grade method (ZOEFF) for determining the effective surface roughness
length for the tower location has been added to AERSURFACE. The ZOEFF option is based
on the calculated growth of the internal boundary layer (IBL) as roughness elements are
encountered approaching the meteorological tower. Rather than computing the average
roughness over a default 1 km distance, the ZOEFF method estimates the distance required for
IBL growth to a certain predefined height defined as some multiple of the wind measurement
height. The fetch is computed separately for each month and sector. Monthly values of the
effective roughness length are then computed separately for each sector based on the derived
sector-specific fetch. The input requirements for the ZOEFF option are provided in Section
3.2 and a technical description of the ZOEFF method and its implementation in AERMOD is
presented in Section 0.
1
2-12
-------
As with the ZORAD method, individual roughness values are computed separately for
each month and sector. Annual or seasonal values are then computed from the monthly values
as simple arithmetic means for each sector based on the temporal frequency of values
specified by the user in the control file.
2,4,1,3 Supplemental Percent Impervious and Canopy Data
Regardless which method is specified for determining roughness length, ZORAD or
ZOEFF, post-1992 land cover data can be supplemented with percent impervious and percent
tree canopy data, when available. These data products report the percent (0-100) of each grid
cell that is covered by an impervious surface and the percent (0-100) covered by tree canopy,
respectively. The percent impervious surface and percent tree canopy for a given cell can sum
to less than 100 percent, but the sum should not exceed 100 percent. AERSURFACE checks
the total for each grid cell. If the total should exceed 100%, AERSURFACE normalizes the
individual percentages based on the total percentage reported so that they sum to 100 percent.
When impervious and canopy data are used to supplement land cover data, the
Developed categories (21, 22, 23 and 24) of the post-1992 NLCDs are adjusted based on
values assigned to 1992 NLCD categories that better define land use. The Developed
categories are reassigned as a mix of the 1992 categories that make up High Intensity
Residential (22), Bare Rock/Sand/Clay (31), Mixed Forest (43), and Urban/Recreational
Grasses (85). Airport sectors assume a majority of the impervious area is bare rock/sand/clay
to represent the runways, while non-airport sectors assume a majority of the impervious area is
more similar to the 1992 category High Intensity Residential to account for a greater
percentage of buildings. The Mixed Forest portion is further weighted based on the percent of
the area that is tree canopy while the Bare Rock/Sand/Clay and High Intensity Residential
categories are weighted based on the percent of the grid cell that is impervious. The
Urban/Recreational Grasses portion is weighted based on the amount that is neither
impervious nor tree canopy. As mentioned previously, a substantial percent of the impervious
surfaces for some portion of an airport will be runways, which are not present at non-airport
sites. A substantial amount of the vegetation at an airport is grass between and around the
2-13
-------
runways, rather than trees. Reassigning the post-1992 Developed categories with weighted
values from the NLCD 1992 classification is an attempt to better estimate the roughness for a
given grid cell where the category description is not specific with regard to the type of
impervious surface or vegetation. NOTE: This draft version of AERSURFACE (19039)
includes the option to separately characterize individual wind sectors as airport or non-airport
based on the predominant land use within each sector (refer to 3.2.9 and 3.2.10). Users may
want to consider characterizing sectors at an airport for which the impervious surfaces are
predominantly buildings rather than paved surfaces or that are predominantly vegetation as
non-airport. Similarly, sectors at a measurement site that is not an airport but the impervious
surfaces are predominantly paved surfaces can be characterized as airport. These
considerations for characterizing a sector as an airport or non-airport are valid regardless
whether land cover data are supplemented with percent impervious and canopy data. A
decision tree for the post-1992 NLCD Developed categories, as implemented in this draft
version of AERSURFACE, is provided in Figure 2-1 that demonstrates how the surface
roughness values are reassigned for an individual grid cell using the impervious and canopy
data.
Land Cover Supplemented with
Impervious and Canopy Data?
No
Use AERSURFACE Roughness Table
Yes
Airport
Sector?
No
Yes
Recategorize as Combination of:
Mixed Forest (43) x %Canopy/100
90%: 1992 High Intensity Residential (22) x %lmpervious/100
* 10%: Bare Rock/Sand/Clay (31) x %lmpervious/100
1992 Urban Recreational Grasses (85) x (1.0-%Canopy/100-%lmpervious/10Q)
Ex. Developed-Medium Intensity (23): summer, 60% impervious, 10% canopy
z0 = exp( ln(1.3)*0.1 + 0.9*ln(1.0)*0.6 + 0,l*ln(0.05)*0.6 + ln(0,02)*0,3 ) = 0.27
Recategorize as Combination of:
• Mixed Forest (43) x %Canopy/100
10%: 1992 High Intensity Residential (22) x %lmpervious/100
90%: Bare Rock/Sand/Clay (31) x %lmpervious/100
1992 Urban Recreational Grasses (85) x (1.0-%Canopy/100- %lmpervious/100)
Ex. Developed-Medium Intensity (23): summer, 60% impervious, 10% canopy
z„ = exp( ln(1.3)*0.1 + 0.1*ln(1.0)*0.6 + 0,9*ln(0.05)*0.6 + ln(0.02)*0.3 ) = 0.06
Figure 2-1. Surface Roughness Value Adjustment to Post-1992 Developed Categories (21-24)
Using Percent Impervious and Canopy Data.
2-14
-------
Similarly, surface roughness length for the post-1992 Woody Wetlands category (91)
is redefined as a mixture of: Woody Wetlands (91), weighted by the fraction of the grid cell
that is tree canopy; Bare Rock/Sand/Clay (31), weighted by the fraction of the cell that is
impervious; and the 1992 category Urban/Recreational Grasses (85), weighted by the fraction
of the grid cell that is neither canopy nor impervious. Whether or not the sector is identified as
airport or non-airport is not considered in this case.
2.4.2 Daytime Bowen Ratio
Bowen ratio is calculated as the simple geometric mean of the Bowen ratio values of
the individual grid cells that make up the 10 km x 10 km area centered on the measurement
site. The Bowen ratio is an unweighted value in the sense that there is no distance or
directional dependency in the calculation. Each grid cell in the 10 km x 10 km area is given
equal weight in the calculation of the mean value over. The simple, unweighted geometric
mean Bowen ratio ( B ) is calculated using the following equation:
where: n is the total number of grid cells over which the geometric mean is computed, i is one
of n grid cells, Bi is the Bowen ratio for the individual grid cell /.
Individual monthly mean Bowen ratio values are computed. Annual or seasonal values
are then computed from the monthly values as simple arithmetic means based on the temporal
frequency of values specified by the user in the control file.
2.4.3 Noontime Albedo
Albedo is calculated as the simple arithmetic mean, also unweighted (i.e., no direction
or distance dependency), for the same 10 km by 10 km area defined for Bowen ratio. The
simple arithmetic mean albedo (a) is calculated using the following equation:
2
2-15
-------
_ Z?=i«i
a =
n
3
where: n is the total number of grid cells over which the geometric mean is computed, i is one
of n grid cells, m is the albedo for the individual grid cell i.
Individual monthly mean albedo values are computed. Annual or seasonal values are
then computed from the monthly values as simple arithmetic means based on the temporal
frequency of values specified by the user in the control file.
2-16
-------
3.0 Detailed keyword reference
Beginning with version 19039 DRFT, AERSURFACE was updated to read an ASCII
text input control file that makes use of the path/keyword approach, to inform AERSURFACE of
user options, like AERMOD. This section provides a detailed description of the keywords and
related parameters, their use, and the format of the control file.
3.1 Overview
The descriptive keywords and parameters that make up the control file informs
AERSURFACE of the user-defined options and parameters to apply during processing. These
include specific processing options, control values, and input/output directory paths and
filenames. Each line of the control file consists of a 2-character pathway ID, a primary keyword,
and a parameter list. The keywords specify the type of option or input data being entered on each
line of the input file, and the parameters following the keyword define the specific options or
input data that will be used during processing. Some of the parameters are also input as
descriptive secondary keywords.
3.1.1 Pathway IDs
The AERSURFACE control file is divided into two functional "pathways." The pathways
IDs and the order in which they should appear in the control is as follows:
• CO - for specifying overall job COntrol options; and
• OU - for specifying OUtput options.
The pathway ID must be present on the first and last input lines of the ID block of text
but may be omitted on the lines in between. However, the primary keyword that would follow
the pathway ID must begin in column 3 of the control file. An example control is provided in
Section 3.4.
3-1
-------
3.1.2 Starting and ending a Pathway Block
Regarding the format of a control file, a basic rule is that all inputs for a particular
pathway must be contiguous within a block of text, i.e., all inputs for the CO pathway must come
first, followed by the inputs for the OU pathway. The beginning of each pathway is identified
with a "STARTING" keyword, and the ending of the pathway with the "FINISHED" keyword.
Thus, the first functional record of each control file must be "CO STARTING," followed by the
separate lines for each primary keyword and related parameter list. The CO pathway is then
ended with "CO FINISHED" and, subsequently, the OU pathway is started with "OU
STARTING," and the last functional record of each control file must be "OU FINISHED" which
ends the OU pathway. As shown in the example control file in Section 3.4, the pathway ID (e.g.,
CO and OU) do not need to be included on every record except the first and last records of the
pathway. This is to improve the readability of the control file. The pathway ID does not have to
be omitted; however, on those records where the pathway ID is omitted, the primary keyword
must begin in column 3, and columns 1 and 2 should be filled with blank spaces.
3.1.3 Blank Lines and Comments
Two special provisions to increase flexibility in the structuring of the control file include:
allowing blank records to separate input data for readability and comment lines that enable the
user to annotate the control file. Comment lines are identified with two asterisks ("**") in the
pathway field (i.e., first two columns of a line). Any input image that has "**" for the pathway
ID will be ignored. While comment lines are useful for including descriptions in the control file,
it may also be used to "comment out" certain options for a run without deleting the options and
associated data completely from the input file.
The information in the remainder of this section is organized by pathway ID and function,
i.e., the keywords are grouped by pathway. The syntax for each keyword is provided, and the
keyword type is specified as mandatory, optional, or conditional and either repeatable or non-
repeatable. Unless noted otherwise, there are no special requirements for the order of keywords
3-2
-------
within each pathway. Any keyword which has special requirements for its order within the
pathway is so noted following the syntax and type description.
The syntax descriptions in the following sections use certain conventions. Primary
keywords are in all capital letters (may also contain numbers). Primary keywords are not
underlined. Parameters that are in all capital letters and underlined in the syntax description are
secondary keywords that are to be entered as indicated for that keyword. Other parameters are
given descriptive names to convey the meaning of the parameter and are italicized. Parentheses
around a parameter indicate that the parameter is optional for that keyword. The default that is
taken when an optional parameter is left blank is explained in the discussion for that keyword.
3.2 Control Pathway (CO)
The CO pathway contains the keywords that provide the overall control of the
preprocessor run. The CO pathway must be the first pathway in the control file.
3.2.1 Title information (TITLEONE. TITLETWO)
There are two keywords that allow the user to specify up to two lines of title information.
The title is included as comment cards in the output data file. The first keyword, TITLEONE, is
mandatory, while the second keyword, TITLETWO, is optional. The syntax and type for the
keywords are summarized below:
Syntax:
CO TITLEONE Uile 1
CO TITLEONE title2
Type:
TITLEONE - Mandatory, Non-repeatable
TITLETWO - Optional, Non-repeatable
The parameters title2 and title2 are character parameters of length 200, which are read as a
single field from columns 13 to 200 of the input record.
3-3
-------
3.2.2 Options (OPTIONS^)
The OPTIONS keyword is not required but can be included to specify non-default
options. The options available and usage is shown below:
Syntax:
CO OPTIONS PRIMARY
ZORAD
or
or
SECONDARY
ZOEFF
Type:
Optional, Non-repeatable
The PRIMARY and SECONDARY options inform AERSURFACE whether the site processed is
the primary or secondary location. This determines which keywords to include in the output file
that contains the surface characteristic values and that are input directly into AERMET.
AERMET can require up to two sets of surface characteristic values (primary and secondary),
depending on the meteorological data that are processed. A set of surface characteristic values
for the primary meteorological site is always required. The primary site is the location of the
National Weather Service (NWS)/Federal Aviation Administration (FAA) weather station if only
NWS/FAA surface data collected at an airport are processed. When site-specific meteorological
data are processed, the primary location is the site-specific meteorological tower. AERMET can
substitute missing site-specific wind data with NWS/FAA data if NWS/FAA data are provided as
input. In that case, AERMET requires a set of secondary surface characteristic values for the
location of NWS/FAA met tower. The primary set of surface characteristics are defined for
AERMET through the three keywords FREQ SECT, SECTOR and SITE CHAR used to specify
the temporal frequency, number of sectors, and the site characteristics (albedo, Bowen ratio, and
surface roughness length), respectively. The secondary set of site characteristics are specified
using similar keywords, FREQ SECT2, SECTOR2, and SITE CHAR2. AERSURFACE can
only process a single site at a time and will need to be run twice when site-specific
meteorological data are to be processed with AERMET and NWS/FAA data will be used to
substitute missing wind data. (Refer to the AERMET User's Guide (EPA, 2018a) for more
information on processing site-specific meteorological data and data substitution using
3-4
-------
concurrent NWS/FAA surface data.) AERSURFACE will generate the required AERMET
keywords for the primary site by default if the OPTIONS keyword is not included in the CO
pathway or if PRIMARY or SECONDARY is not included with the OPTIONS keyword.
The ZORAD and ZOEFF options inform AERSURFACE of the method to use to calculate
surface roughness length. ZORAD is the default method used in previous versions and described
above. This method calculates the average roughness from the meteorological tower out to a
default radial distance of 1 km. ZOEFF is a research grade method that estimates fetch based the
growth of the IBL due to changes in roughness downwind. Average roughness is computed over
the estimated fetch, approaching the meteorological tower. Roughness length can be calculated
for individual user-defined wind sectors using either method. When ZOEFF is specified, the
fetch over which the roughness is calculated is estimated separately for each wind sector
specified.
3.2.3 Debug Options (DEBUGOPT^
AERSURFACE provides several debug options using the DEBUGOPT keyword which
will generate various output files that contain different types of diagnostic information. The
syntax for the DEBUGOPT keyword and the different options are summarized below:
Syntax: CO DEBUGOPT EFFRAD and/or GRID and/or TIFF or ALL
Type: Optional, Non-repeatable
The order of the secondary keywords is not important. A description the output file that each
option will generate follows:
EFFRAD: File containing the effective radius for surface roughness computed for each
sector/month (only applicable for ZOEFF option specified with the
OPTIONS keyword).
3-5
-------
GRID: Separate grid file of land cover data and, if applicable, impervious, and
canopy data, displaying the 10x10 km grid of values extracted from each
GeoTIFF data file.
TIFF: Separate file for each GeoTIFF data file containing a list of all TIFF tags,
GeoKeys, and associated values read from the file.
ALL: This option can be used to inform AERSURFACE to generate all debug
files listed above without having to list each debug option separately.
Each file generated from the debug options has a default filename. Default filenames can be
overridden with user-defined filenames using file-specific keywords on the OU pathway (refer to
Section 0).
NOTE: AERSURFACE automatically generates a LOG file that includes a summary of TIFF
parameters, land cover counts by category for each sector for surface roughness and land cover
counts by category for the 10km x 10km domain used for Bowen Ratio and Albedo. The LOG
file also includes tables of final calculated roughness values and estimated fetch by month and
sector.
3.2.4 Location of Meteorological Tower (CENTERXY. CENTERED
The location of the meteorological tower where representative values of the surface
characteristics will be calculated can be specified using either the Universal Transverse Mercator
(UTM) coordinate system or latitude and longitude. UTM coordinates are entered using the
CENTERXY keyword while latitude and longitude are entered using the CENTERLL keyword.
The syntax and required parameters are discussed below:
Syntax: CO CENTERXY easting northing utm zone datum
or
3-6
-------
CO CENTERLL latitude longitude datum
Type: Mandatory, Non-repeatable
where:
UTM easting coordinate in meters.
UTM northing coordinate in meters.
UTM zone entered as a positive integer.
Latitude in decimal degrees. (Northern hemisphere = positive value)
Longitude in decimal degrees. (Western hemisphere = negative value)
Geodetic datum on which coordinates are based. The datum should be
entered using one of the following secondary keywords: NAD27 or NAD83.
which refer to the North American 1927 datum and the North American
1983 datum, respectively. NAD83 should also be used for coordinates
referenced to the GRS80 and WGS84 datums since the small differences are
inconsequential for the purposes of AERSURFACE.
3.2.5 NLCD Filenames (DATAFILE^
NLCD data filenames, including the names of impervious and canopy files when used to
supplement land cover data, are specified using the DATAFILE keyword. The keyword is
repeatable so that multiple file types can be specified when more than one type of data will be
processed. At a minimum, a land cover file is required. At most, three files can be processed
including a single land cover file, a single impervious file, and a single canopy file. The syntax
and type of the keyword are summarized below:
easting:
northing:
utm zone:
latitude:
longitude:
datum:
Syntax: CO DATAFILE datajype pathJilename
3-7
-------
Type: Mandatory, Repeatable
The data type is entered using a secondary keyword to represent the type of data and year the
data represent. The following are valid secondary keywords for data type:
NLCD1992:
1992 NLCD land cover
NLCD2001:
2001 NLCD land cover
NLCD2006:
2006 NLCD land cover
NLCD2011:
2011 NLCD land cover
MPRV2001:
2001 percent impervious
MPRV2006:
2006 percent impervious
MPRV2011:
2011 percent impervious
CNPY2001:
2001 percent canopy
CNPY2011:
2011 percent canopy
Note: Canopy data are not available for the 2006 NLCD
The path Jilename can be entered using either the relative or absolute path. The relative path is
relative to the working directory. Enter the path Jilename using the syntax that is appropriate for
the operating system on which AERSURFACE is run. For example, when running under the
Microsoft Windows command prompt, the path and filename are not case-sensitive, but directory
names should be separated with a "\" rather than a "/". Conversely, the path and filename are
case-sensitive on Unix/Linux systems and directory names should be separated with a
Regardless, the operating system, a path and filename that includes spaces should be wrapped in
double quotes (""). The combined path and filename is limited to a maximum of 200 characters
in AERSURFACE.
3-8
-------
3.2.6 Fixed Radial Distance for Roughness (ZORADIUS)
When the default method (ZORAD) is used to calculate the surface roughness length, the
default radial length of 1 km, the distance over which the roughness length is averaged from the
tower, can be overridden by the user using the ZORADIUS keyword. This keyword is only
applicable when ZORAD is included with the OPTIONS keyword or both ZORAD and ZOEFF
are omitted in which case, ZORAD is the default method. The syntax for the ZORADIUS
keyword is as follows:
Syntax:
CO ZORADIUS radius
Type:
Optional, Non-repeatable
where radius is the distance from the meteorological tower in kilometers over which the effective
surface roughness will be computed. The valid range for the user-defined radius is 0.5 km to 5.0
km; however, any distance other than the 1 km default radius may require justification and
should be discussed with the reviewing agency. If the ZORADIUS keyword is omitted, the
recommended default radius of 1.0 km will be used.
3.2.7 Anemometer Height (ANEM HGT)
When the method ZOEFF is used to calculate the surface roughness length, the
ANEMHGT keyword is required to specify the height of the anemometer is required. The
syntax and parameters associated with the ANEM HGT keyword is summarized below:
Syntax: CO ANEM HGT anem ht (ibl Jactor)
Type: Mandatory, Non-repeatable
where anem ht is the height, in meters, at which the wind measurements are taken at the site that
will be processed. The accepted value for anem ht ranges from 1.0 meter to 100.0 meters.
3-9
-------
The iblJactor is an optional unitless parameter, ranging from 5.0 - 10.0, used to compute
the reference height of the IBL at the location of the meteorological tower. The IBL reference
height is the product of the anemjit and the iblJactor. The default value for ibl Jactor is 6.0
based on Wieringa's suggested 60 m "roughness blending height" (Wieringa, 1976), and given
that 10 m is a common anemometer height at NWS/FAA meteorological stations. Refer to
Section 0 for more information on the implementation of the ZOEFF method in AERSURFACE.
3.2.8 Climate. Surface Moisture, and Continuous Snow Cover (CLIMATE)
As previously discussed in Section 2.4, the surface characteristic values calculated by
AERSURFACE can vary based on local climate and surface moisture conditions, including
whether the site experienced extended periods of continuous snow cover. The CLIMATE
keyword is used to inform AERSURFACE of this information. This is an optional keyword for
which default entries will be assumed if the CLIMATE keyword is omitted. The syntax for the
CLIMATE keyword and related parameters are summarized below:
Syntax: CO CLIMATE sfcjnoisture snow cover arid condition
Type: Optional, Non-repeatable
where sfcjnoisture refers to the surface moisture based on precipitation amounts for the period
that will be modeled, relative to the previous 30-year climatological record for the region;
snow cover indicates whether the site experienced one or more extended periods of continuous
snow cover; and arid condition defines the typical climate of the region as arid such as desert-
like or non-arid.
sfcjnoisture should be entered as either WET. DRY, or AVERAGE where WET is
defined as precipitation amounts equal to or greater than the 70th percentile of the 30-year
climatological records; DRY is equal to or less than the 30th percentile; and AVERAGE is
between the 30th and 70th percentiles. If omitted, AERSURFACE assumes an AVERAGE default
surface moisture. A recommended approach is to determine moisture conditions either seasonally
3-10
-------
or monthly, then run AERSURFACE separately for each condition and use the results to compile
a single input file for AERMET that contains the appropriate seasonal or monthly surface
characteristic values.
Whether the site experienced periods of continuous snow cover during the winter should
be specified using either the SNOW or NOSNOW secondary keywords. If omitted,
AERSURFACE assumes a default of NOSNOW. meaning there were no winter months that
experienced periods of continuous snow cover. Continuous snow cover is defined as a calendar
month during which the ground was covered with snow more than 50% of the time. If the
secondary keyword SNOW, is specified, then AERSURFACE will treat all winter months
assigned to "Winter with continuous snow on the ground," as having continuous snow cover.
The user has the option to use the default month-to-season assignments or to reassign months to
each of the five seasons recognized by AERSURFACE, listed in Table 2-4, using the SEASON
keyword discussed in Section 3.2.11, below. If default assignments are used, then all winter
months will be treated as either having continuous snow or having no snow. The default winter
months, per Table 2-4, are December, January, and February.
The last parameter associated with the CLIMATE keyword, arid condition, is only
applicable if NOSNOW was entered for snow cover and should be specified using the secondary
keyword ARID or NONARID where ARID refers to a desert-like climate. The default condition
is NONARID when the CLIMATE keyword is omitted. AERSURFACE also assumes
NONARID if any month experiences continuous snow cover. Note: AERSURFACE will
report abort processing and report an error if the secondary keywords SNOW and ARID
are used in combination with each other.
To summarize, if the CLIMATE keyword is omitted from the control file,
AERSURFACE assumes the following settings by default: AVERAGE. NOSNOW. and
NONARID.
3.2.9 Temporal Frequency (FREO SECT)
3-11
-------
Surface characteristics should reflect how they change temporally for a location.
Depending on the climatology and land cover, there may be little change throughout the year, or
there may be large changes on a seasonal or even monthly basis. The FREQSECT keyword
defines time period over which the surface characteristics will be computed. This keyword is also
used to specify the number of wind sectors that will be defined for determining roughness length
and whether the whole site should be characterized as an airport or non-airport site or if sectors
will be characterized individually. The syntax and usage of the mandatory FREQ SECT
keyword is summarized below:
Syntax: CO FREQ SECT frequency number sectors airport flag
Type: Mandatory, Non-repeatable
where frequency is the period of time for which the surface characteristics are calculated which
include ANNUAL. SEASONAL, or MONTHLY. When ANNUAL or MONTHLY is entered,
the user has the option to override program defaults and reassign months to seasons based on
local climatology. The default assignments, which are always used when SEASONAL is
specified, are as follows:
Table 3-1. Default Month/Season Assignments in AI RM I T
Season #
Season
Default Months
1
Winter*
December, January, February
2
Spring
March, April, May
3
Summer
June, July, August
4
Autumn
September, October, November
* Winter will either be defined as winter with continuous snow cover or winter with
without snow based on the option specified with the CLIMATE keyword, discussed
previously.
3-12
-------
The number sectors parameter should be entered as the integer number of wind sectors
that will later be defined using the SECTOR keyword. Wind sectors are only applicable to
roughness length. The number of sectors can range from 1 to 12 or 16. AERMET allows a
maximum of 12 sectors, but AERSURFACE can calculate roughness for 16 sectors which can be
useful for comparing roughness lengths to a standard 16-direction wind rose plot. When 16
sectors are specified, AERSURFACE results cannot used as input to AERMET.
The last parameter, airport Jlag, requires a secondary keyword that determines whether
AERSURFACE will apply airport or non-airport roughness values to all wind sectors, or if the
sectors vary. The airport Jlag should be specified using one of the following secondary
keywords: AP. NONAP. or VARYAP where: AP indicates airport roughness values will be
applied to all sectors for any land cover category that has separate airport and non-airport values;
NONAP indicates that non-airport values will be applied; and VARYAP informs
AERSURFACE to treat each sector separately based on how the sector is identified using the
SECTOR keyword discussed next. NOTE: Users may want to consider characterizing sectors at
an airport for which the impervious surfaces are predominantly buildings rather than paved
surfaces or that are predominantly vegetation as non-airport. Similarly, sectors at a measurement
site that is not at an airport but the impervious surfaces are predominantly paved surfaces can be
characterized as airport. (Refer to Sections 2.3.2 and 2.4.1.3 for additional discussion on airport
vs non-airport characterization of a measurement site or individual sectors.)
3.2.10 Surface Roughness Length Wind Sectors (SECTOR)
Individual wind sectors for which roughness length is determined are defined using the
SECTOR keyword by specifying a starting and ending wind direction for each sector. As
mentioned above, the SECTOR keyword is also used to indicate whether airport or non-airport
roughness values should be applied to individual sectors. The usage and syntax of the SECTOR
keyword are summarized below:
Syntax: CO SECTOR sector index start dir end dir airport Jlag
3-13
-------
Type: Conditional, Repeatable
While there are circumstances for which the SECTOR keyword is not required, when
included, the number of occurrences of the SECTOR keyword must match the number of sectors
{number sectors) specified on the FREQSECT keyword. The sector index links a specific
sector to a set of site characteristics and should be entered as consecutive integers beginning with
the number 1. As discussed, the number of sectors can range from 1 to 12 for input to
AERMET, and sectors must be a minimum of 30°. AERSURFACE can also generate surface
characteristic values for a discrete number of 16 sectors that are each 22.5° that may be useful for
comparing roughness length by sector to a standard 16-direction wind rose plot but cannot be
used as input to AERMET.
Sectors should be defined in a clockwise manner and must cover the full 360° circle
around the meteorological tower without gaps or overlap, (i.e., They must be defined so that the
end of one sector corresponds to the beginning of another.) The starting direction (start dir) is
considered part of the sector, while the ending direction (end dir) is excluded from the sector.
The starting and ending directions reference the wind direction, the direction from which the
wind is blowing. A sector can cross through north (e.g., 345 - 15) or can start and stop at north
(e.g., 0-30 and 270 - 360). AERSURFACE will verify that the entire 360° circle is covered.
The airport Jlag on the SECTOR keyword identifies whether the individual sector should
be processed using airport or non-airport related roughness length values. This attribute is
required when the secondary keyword VARYAP is entered as the airport Jlag attribute for the
FREQ SECT keyword which means each sector will be assigned individually. When that is the
case, the airport Jlag should be specified using the secondary keyword AP to indicate it is an
airport sector or NONAP to indicate it is a non-airport sector.
When 1, 8, 12 or 16 is entered for the number of sectors on the FREQ SECT keyword,
the SECTOR keyword may be omitted, and default sectors can be used unless VARYAP is
3-14
-------
entered as the airport Jlag attribute for the FREQSECT keyword. For those cases in which 1,
8, 12, or 16 sectors are specified and the SECTOR keyword is omitted, AERSURFACE will, by
default, generate one 360-degree, eight 45-degree, twelve 30-degree, or sixteen 22.5-degree
sector(s), respectively. Eight sectors are centered on 0, 45, 90, etc. degrees. Twelve sectors are
centered on 15, 45, 75, etc. degrees. Sixteen sectors are centered on 0, 22.5, 45, etc. degrees.
When VARYAP is specified on the FREQ SECT keyword, the SECTOR keyword is required
and the airport Jlag attribute is required for each sector, though the starting and ending
directions may be omitted if default directions are intended.
3.2.11 Assigning Months to Seasons (SEASON)
AERSURFACE provides the option to override default month-to-season assignments
when the temporal resolution for the surface characteristics, or the frequency attribute on the
FREQ_SECT keyword, is ANNUAL or MONTHLY. When the frequency is SEASONAL, the
default assignments are used, listed in Table 3-1, above. This is to maintain consistency with
AERMET and its seasonal definitions. Calculating annual or monthly surface characteristic
values and reassigning months from the default season assignments provides for greater
representativeness for those areas of the country that do not experience the traditional seasons.
The SEASON keyword is used to override the default assignments. The usage and syntax of the
SEASON keyword are summarized below:
Syntax: CO SEASON season months (space delimited list)
Type: Optional, Repeatable
where season is a secondary keyword that identifies one of five seasonal definitions and months
is a space-delimited list of integer months assigned to the season. Valid secondary keywords
used to specify season, along with the season definition are listed in Table 3-2, below. Valid
entries for the attribute months are a "0" to indicate no months are being reassigned to the season
or a space-delimited list with each value ranging from 1 to 12 where 1 represents January and 12
represents December. A season may be specified only once. The months reassigned to a season
3-15
-------
should be listed on a single record separated by at least one space. A month can only be assigned
to one season. It is only necessary to specify the seasons/months that are to be reassigned. If 0 is
entered for a season, then default assignments will be used for any month that is not listed for a
different season.
Table 3-2. Season Secondary Keywords and Definitions
Secondary
Keyword
Season Description
Default Month Assignments
SUMMER
Midsummer with lush vegetation
June, July, August
AUTUMN
Autumn with unharvested cropland
September, October, November
WINTERNS
Late autumn after frost and harvest, or
winter with no snow
December, January, February
WINTERWS
Winter with continuous snow on the
ground
December, January, February
SPRING
Transitional spring with partial green
coverage or short annuals
March, April, May
3 .2.12 To Run or Not (RUNORNOT)
Before beginning to read and process the datafiles, AERSURFACE will read through all
of the inputs in the control file regardless of any errors or warnings that may be encountered. If a
fatal error is encountered, then further program calculations will be aborted. Otherwise, the
program will attempt to run. The RUNORNOT keyword has been included on the CO pathway
to allow the user to specify whether to RUN the program and perform all the calculations, or
only process the control file and check for warnings and errors and summarize the setup
information. The syntax of the RUNORNOT keyword is summarized below:
Syntax: CO RUNORNOT RUN or NOT
Type: Mandatory, Non-repeatable
3-16
-------
3.3 Output Pathway (OU)
The OUtput pathway is used to specify user-defined filenames for program generated
output files that cannot be entered as an argument at the command prompt when AERSURFACE
is executed. Those that can be entered as a command-line argument include: 1) an input
summary file that replicates the control file inputs and includes a summary of warnings and
errors encountered during processing and 2) a log file that records more detailed information
about the input data that are read during program execution (see Section 3.0). For all other
output files, there is a distinct primary keyword associated with each file that can be entered in
the OU pathway along with a path and filename. Only one of the files specified in the OU
pathway is required; that is the output file that will contain the calculated surface characteristic
values that are formatted for input to AERMET. All other file options have default filenames
and are debug files that are generated based on the debug options that are specified with the
DEBUGOPT keyword in the CO pathway (see Section 3.2.3) and the types of data that are used
to derive the surface characteristic values (i.e., land cover, percent impervious, and percent
canopy).
3.3.1 Surface Characteristic Values File for AERMET (SFCCHAR)
As referenced above, the user is required to enter the name of the file that will contain the
surface characteristic values calculated by AERSURFACE that will be input to AERMET. There
is not a default filename assigned for this file. It is entered in the OU pathway with the
SFCCHAR keyword. The usage and syntax of SFCCHAR keyword is summarized below:
Syntax:
OU SFCCHAR pathJilename
Type:
Mandatory, Non-repeatable
where pathJilename is the user-defined path and filename of the surface characteristics file. The
path can be entered as the absolute path or a relative path, relative to the working directory. If the
path is omitted, the file will be created in the working directory. The combined path and filename
3-17
-------
is limited to 200 characters and should be enclosed in quotes ("") if either the path or filename
includes spaces.
3.3.2 Debug Output Files
There are several debug files that can be generated by AERSURFACE. A file's creation
is based on the debug options that are specified with the DEBUGOPT keyword in the CO
pathway (see Section 3.2.3) and the types of data that are input to AERSURFACE (i.e., land
cover, percent impervious, and percent canopy). The user has the option to enter a user-defined
path and filename for any of these debug files by specifying the primary keyword associated with
the debug file, followed by a path and filename. For any keyword and path\filename
combination that are omitted on OU pathway, AERSURFACE will use the default filename and
create the file in the working directory. As stated, there is a distinct primary keyword associated
with each debug file. The general usage and syntax for the keywords is summarized below and a
list of the keywords as well as the associated debug option, description, and default filename is
provided in Table 3-3. Note: Though the entry of any of the debug file keywords and
associated path and filenames are optional, each keyword specified must include an
associated filename and a filename must be preceded by the associated keyword.
Syntax: OU primary keyword pathfilename
Type. Optional, Non-repeatable (each primary keyword in Table 3-3 can only be
used once)
where primary keyword is a primary keyword from Table 3-3 and pathfilename is the user-
defined path and filename of the output file. The path can be entered as the relative or absolute
path. A relative path is relative to the working directory. The combined path and filename is
limited to 200 characters and should be enclosed in quotes ("") if either the path or filename
includes spaces.
3-18
-------
Table 3-3. OU Pathway Primary Keywords and Default Filenames
Keyword
DEBUGOPT
Description
Default Filename
EFFRAD
EFFRAD
Table of effective radius values by
sector and month
effective_rad.txt
NLCDGRID
GRID
Land cover grid for import into GIS
landcover.txt
MPRVGRID
GRID
Impervious data grid for import into
GIS
impervious.txt
CNPYGRID
GRID
Canopy data grid for import into GIS
canopy.txt
NLCDTIFF
TIFF
Land cover debug file containing TIFF
tag and GeoKey values
lc_tif_dbg.txt
MPRVTIFF
TIFF
Impervious debug file containing TIFF
tag and GeoKey values
imp_tif_dbg.txt
CNPYTIFF
TIFF
Canopy debug file containing TIFF tag
and GeoKey values
can_tif_dbg.txt
In addition to the files listed in Table 3-3, AERSURFACE will also automatically
generate an input summary file that replicates the control file inputs and a summary of warnings
and errors encountered during processing and a log file that records more detailed information
about the input data that are read during program execution. These filenames can be defined by
the user at the time the program is executed at the command-line prompt. Refer to Section 1.0
details about how to run AERSURFACE from the command-line and how to specify the paths
and filenames for the input control file, log file, and summary file. Refer to Section 4.3 for
additional descriptive information about the various output files generated by AERSURFACE.
3-19
-------
3.4 Sample AERSURFACE Control File
Figure 3-1 is a sample AERSURFACE control file for the location of the meteorological tower at
the Raleigh-Durham International Airport (RDU). This example is for demonstration purposes
only, to demonstrate the usage of various keywords and is not intended to be representative of
how the site would normally be processed. A summary of the options used in the sample control
file follows.
In this example, the RDU station is processed as the PRIMARY meteorological station
which means site-specific data are not used. Otherwise, the NWS/FAA station would be
specified as the SECONDARY station. The default ZORAD option will be used to calculate the
surface roughness length. Because default options are used, the OPTIONS keyword and
parameters could be omitted in this case. For the ZORAD option, a default radius of 1 km will
be used to compute surface roughness length. Because this is the default radius value, the
ZORADIUS keyword and parameter could be omitted. Surface characteristics will be based on
2001 land cover which is supplemented with both impervious and canopy data. GRID and TIFF
debug files will be generated for each of the land cover, impervious, and canopy GeoTIFF data
files. Per the OU pathway, user-defined filenames will be used for the GRID debug files, but
default filenames will be used for the TIFF debug files.
The CLIMATE keyword indicates that moisture conditions are AVERAGE, but there is
at least on month with continuous snow cover (SNOW) and the regional climate conditions are
non-arid (NONARID). Months are reassigned from the default season assignments with March
reassigned from Spring to winter without continuous snow cover, and January is defined as
having continuous snow cover meaning more than 50% of the month experienced continuous
snow cover. Note, because SNOW was specified on the CLIMATE keyword, AERSURFACE
will assume all winter months experience continuous snow cover if winter months are explicitly
assigned to either winter with continuous snow (WINTERWS) or winter without continuous
snow (WINTERNS).
3-20
-------
Based on the FREQSECT and SECTOR keywords, monthly values of surface
characteristics will be computed. Surface roughness length will be computed for three wind
sectors and only sector 2 which is largely comprised of runways will be processed using airport
surface characteristic values. Figure 3-2 Shows the three sectors defined in the sample control
file in Figure 3-1, overlaid with land cover from the 2001 NLCD for RDU.
The RUNORNOT keyword indicates that AERSURFACE will attempt to run after
checking the control file.
3-21
-------
"A" "A"
Sample control file
- for demonstration purposes only
CO
STARTING
TITLEONE
Sample AERSURFACE Control File
TITLETWO
RDU - Met
Tower, 2001 NLCD
¦A" "A*
Using default options so OPTIONS keyword and parameters
OPTIONS
PRIMARY ZORAD
DEBUGOPT
GRID TIFF
CENTERLL
35.892300
-78.781900 NAD83
DATAFILE
NLCD2 0 01
"RDU 2001 NLCD LC.tif"
DATAFILE
CNPY2 0 01
"RDU 2001 NLCD Can.tif"
DATAFILE
MPRV2 0 01
"RDU 2001 NLCD Imp.tif"
¦A* "A*
Use default 1 km radius
ZORADIUS
1.0
CLIMATE
AVERAGE SNOW NONARID
¦A* "Jr
Get monthly values for three sectors
Treat all
sectors as
airport
FREQ SECT
MONTHLY
3 VARYAP
¦A*
index start
end
SECTOR
1 30.00
60.00 NONAP
SECTOR
2 60.00
225.00 AP
SECTOR
3 225.00
3 0.00 NONAP
¦A* "A*
Reassign
months with
continuous snow cover in January
SEASON
WINTERNS
12 2 3
SEASON
WINTERWS
1
SEASON
SPRING
4 5
SEASON
SUMMER
6 7 8
SEASON
AUTUMN
9 10 11
RUNORNOT
RUN
CO
FINISHED
ou
STARTING
SFCCHAR
"rdu 2001
lc can imp zorad sfc.txt"
NLCDGRID
"rdu 2001
lc can imp zorad lc grid.txt"
CNPYGRID
"rdu 2001
lc can imp zorad can grid.txt"
MPRVGRID
"rdu 2001
lc can imp zorad imp grid.txt"
ou
FINISHED
Figure 3-1. Sample AERSURFACE Control File
3-22
-------
NLCD Land Cover Classification Legend
111 Open Water
112 Perennial Ice/ Snow
[ ! 21 Developed, Open Space
22 Developed, Low Intensity
123 Developed, Medium Intensity
¦ 24 Developed, High Intensity
_ 31 Barren Land (Rock/Sand/Clay)
_ 41 Deciduous Forest
¦ 42 Evergreen Forest
| 43 Mixed Forest
| 151 Dwarf Scrub*
I 152 Shrub/Scrub
[ j 71 Grassland/Herbaceous
172 Sedge/Herbaceous*
H] 73 Lichens*
| | 74 Moss*
I 181 Pasture/Hay
f :l 82 Cultivated Crops
I 190 Woody Wetlands
i 95 Emergent Herbaceous Wetlands
* Alaska only
\WfT
*r?.
is
Figure 3-2. 2001 NLCD for RDU International with Wind Sectors
Starting at 30, 60, and 225 Degrees
3-23
-------
4.0 Running AERSURFACE
4.1 Command Prompt and Command-line Arguments
The AERSURFACE executable file available on EPA's SCRAM website has been
compiled for the Microsoft Windows operating system and runs at a command prompt.
AERSURFACE, can be run from the command prompt by entering the path and filename of the
AERSURFACE executable file (e.g., aersurface.exe) with up to three command-line arguments
which can be included to specify the path and filename of the input control file, the output
summary file, and the output log file, in that order. This is demonstrated as follows:
Path-to-aersurface.exe\aersurface
Path-to-aersurface.exe\aersurface path\controlJile
Path-to-aersurface.exe\aersurface path\controlJile path\summaryJile
Path-to-aersurface.exe\aersurface path\controlJile path\summaryJile path\logJile
The first example assumes that the control file is located in the working directory and is named
aer surf ace.inp. When executed in this way, the default names aersurf ace. out and aersurface.log
will be used for the names of the summary and log files, respectively. In the remaining examples,
the path and filename of the control file is specified. If the path and filename of the summary
file or subsequently the log file is not included, AERSURFACE will get the base path and
filename of the control file (without the extension) and set the path and filename of the summary
and log files equal to the base path and filename and add the extension .out and .log,
respectively. The path to each of the files entered in the command prompt can be entered as an
absolute or relative path (i.e., relative to the working directory).
4-1
-------
4.2 Error and Warning Messages
While processing the control file and input data files, AERSURFACE writes messages to
the summary file, log file, and to the screen. These could be in the form of errors and warnings
that were encountered when initially checking the format of the control file as well as
dependencies in the options selected or issues encountered while reading the data input files
during processing. Informational messages may also be recorded to document specific
information about the data that were processed. Errors, such as a malformed control file, invalid
options, or missing or incorrectly formatted data files will cause AERSURFACE to abort
processing prematurely. These errors will need to be corrected before AERSURFACE can
complete successfully. Warnings, however, do not halt processing, but should be evaluated by
the user after AERSURFACE has completed to ensure results were not affected. Some examples
of warnings include data values that are out-of-bounds or a default value is assumed. The user
should inspect both the summary and log output files and review all messages that were recorded
during processing and determine if the control file or data need to be evaluated to ensure the
results were not impacted in an adverse or unexpected manner.
4.3 Summary of Output Files Generated by AERSURFACE
This section provides a summary of the different files that can be generated by
AERSURFACE and their contents. The files that are described include the summary and log files
that are generated automatically during each AERSURFACE run, the required surface
characteristics file that contains the calculated values and is formatted for input to AERMET, and
the various optional debug files. For additional information on the output options used to
generate specific files, refer to Section 3.2.
4.3.1 Auto-generated Files
Each time an AERSURFACE run is performed, a summary file and a log file are
automatically generated. The default filenames for these two files if not provided by the user are
4-2
-------
aer surf ace.out and aersurface.log, respectively. These default filenames can be overridden with
user-defined names when AERSURFACE is executed from the command-prompt (see Section
4.1). Additional descriptions of these two files and their contents are provided in the next two
sections.
4.3.1.1 Summary File (aer surf ace, out)
The first part of the summary file replicates the AERSURFACE control file verbatim as a
record of the control file structure and exact options and inputs. The summary file also indicates
if the setup completed successfully, meaning there were no formatting issues or conflicts with the
options specified in the control file when it was checked before processing. If the setup
completes without error, then the summary file will subsequently indicate if processing the data
files completed successfully. All error, warning, and informational messages encountered are
listed at the bottom of the summary file.
4.3.1.2 Log File (aersurface.los)
The log file records detailed information about the datafiles as they are read such as the
filename and if the file was opened successfully, the spatial resolution of the file, the number of
rows and columns of data, and the organization of the data in the file. The log file also provides
the counts of each land category by sector within the area used to calculate the surface
characteristics values. Detailed warning and error messages are also recorded in the log file as
processing continues.
4.3.2 Surface Characteristics
As stated in Section 3.3.1, the keyword SFCCHAR and the user-defined path and
filename of the surface characteristics file that contains calculated surface characteristic values
formatted for input to AERMET are the only required entries in the OU pathway. This file
includes a compact summary, in list format, of the processing options specified in the control
file. The lines that make up the summary of options contain the double asterisks (**) in the first
4-3
-------
two columns of each line so that AERMET will ignore them. Following the options summary are
the frequency, number of sectors, and airport flag, along with the sector definitions and surface
characteristic values formatted with the appropriate keywords as required by AERMET.
4.3.3 Debug Files
Whether or not debug files are created by AERSURFACE and which files are created is
controlled with the DEBUGOPT keyword on the CO pathway (see Section 3.2.3) in conjunction
with the type of datafiles processed in addition to land cover (i.e., impervious and canopy), and
the method used to calculate surface roughness length (i.e., ZORAD or ZOEFF, see Sections
2.4.1 and 3.2.2). Regardless which method is chosen or which debug options are selected,
AERSURFACE will only create those debug files that are consistent with the method specified
and the data that are input. AERSURFACE will not generate an error or abort processing if
debug options on the CO pathway or file types specified on the OU pathway are inconsistent
with the surface method specified or data that are input. For debug files created that are not
specified on the OU pathway, AERSURFACE will use the default filenames.
There are three categories of debug files: effective radius, TIFF debug, and grid files.
Each of these are ASCII text files that can be opened with a standard text editor. A summary of
the contents of each these are discussed in the sections that follow.
4,3,3.1 Effective Radius File (default = effective radtxf)
The effective radius file is only applicable with the ZOEFF option for calculating
effective surface roughness. AERSURFACE generates this file when the ZOEFF secondary
keyword is specified with the OPTIONS keyword on the CO pathway and the EFFRAD
secondary keyword is specified with the DEBUGOPT keyword, also on the CO pathway. This
file provides a summary, by sector and month, of the calculated fetch, the effective roughness
computed traversing from the tower location, the effective roughness computed traversing
toward the tower, the final effective roughness value, and the mean roughness computed for each
4-4
-------
concentric ring from the tower to just beyond 5 km. The default path and filename of this file
can be overridden using the EFFRAD primary keyword on the OU pathway. If omitted from the
OU pathway, the default filename, effective rad. txt, will be used, the file will be created in the
working directory.
4.3.3.2 TIFF Debug Files (defaults = Ic tif dbg.txt, imy tif dbg.txt, andean tif dbg.txf)
AERSURFACE will create a separate TIFF debug file for each TIFF datafile processed
(i.e., land cover, impervious, and canopy) when the TIFF option is specified with the
DEBUGOPT keyword on the CO pathway (see Section 3.3.2). These debug files contain a
record of each of the TIFF tags and GeoKeys read during processing. The TIFF tags and
GeoKeys store information about the organization of the data within the file and how the data are
georeferenced for extraction and interpretation. This information can be used to troubleshoot the
data files if warnings are issued during processing or results are questionable. The default paths
and filenames of these files can be overridden using the primary keywords NLCDTIFF,
MPRVTIFF, and/or CNPYTIFF on the OU pathway. If omitted from the OU pathway, the
default filenames, Ic tif dbg.txt, imp tif dbg.txt, and can tif dbg.txt, will be used, and the files
will be created in the working directory.
4.3.3.3 Grid Files (defaults = landcover.txt. impervious.txt. and canopy.txt)
Similar to the TIFF debug files, AERSURFACE will create separate grid debug files for
each TIFF datafile processed (e.g., land cover, impervious, and canopy) when the GRID option is
specified with the DEBUGOPT keyword on the CO pathway (see Section 3.3.2). Each of these
debug files contain a grid of the values extracted from the corresponding datafile with reference
information about the number of rows, columns, and the horizontal resolution of the data. The
default paths and filenames of these files can be overridden using the primary keywords
NLCDGRID, MPRVGRID, and/or CNPYGRID on the OU pathway. If omitted from the OU
pathway, the default filenames, landcover.txt, impervious.txt, and canopy.txt, will be used, and
the files will be created in the working directory.
4-5
-------
5.0 Appendix A: National Land Cover Database Definitions
Table 5-1. NLCD 1992 Class and Category Descriptions and Color Legend
Class\ Value
Classification Description
Water
areas of open water or permanent ice/snow cover.
11
Open Water - areas of open water, generally with less than 25% cover of vegetation/land cover.
12
Perennial Ice/Snow - areas characterized by year-long surface cover of ice and/or snow.
Developed
areas characterized by a high percentage (30 % or greater) of constructed materials (e.g. asphalt, concrete,
buildings, etc.).
21
Low Intensity Residential - areas with a mixture of constructed materials and vegetation. Constructed
materials account for 30% to 80% of the cover. Vegetation may account for 20% to 70 % of the cover. These
areas most commonly include single-family housing units. Population densities will be lower than in high
intensity residential areas.
22
High Intensity Residential - areas highly developed where people reside in high numbers. Examples include
apartment complexes and row houses. Vegetation accounts for less than 20% of the cover. Constructed
materials account for 80% tol00% of the cover.
23
Commercial/lndustrial/Transportation - areas of infrastructure (e.g. roads, railroads, etc.) and all highly
developed areas not classified as High Intensity Residential
Barren
areas characterized by bare rock, gravel, sand, silt, clay, or other earthen material, with little or no "green"
vegetation present regardless of its inherent ability to support life. Vegetation, if present, is more widely
spaced and scrubby than that in the green vegetated categories; lichen cover may be extensive.
31
Bare Rock/Sand/Clay - perennially barren areas of bedrock, desert pavement, scarps, talus, slides, volcanic
material, glacial debris, beaches, and other accumulations of earthen material.
32
Quarries/Strip Mines/Gravel Pits - areas of extractive mining activities with significant surface expression.
33
Transitional - areas of sparse vegetative cover (less than 25% of cover) that are dynamically changing from
one land cover to another, often because of land use activities. Examples include forest clear cuts, a
transition phase between forest and agricultural land, the temporary clearing of vegetation, and changes
due to natural causes (e.g. fire, flood, etc.).
Forest
areas characterized by tree cover (natural or semi-natural woody vegetation, generally greater than 6
meters tall); tree canopy accounts for 25% to 100% of the cover.
41
Deciduous Forest - areas dominated by trees where 75% or more of the tree species shed foliage
simultaneously in response to seasonal change.
42
Evergreen Forest - areas dominated by trees where 75% or more of the tree species maintain their leaves all
year. Canopy is never without green foliage.
43
Mixed Forest - areas dominated by trees where neither deciduous nor evergreen species represent more
than 75% of the cover present.
Shrubland
areas characterized by natural or semi-natural woody vegetation with aerial stems, generally less than 6
meters tall, with individuals or clumps not touching to interlocking. Both evergreen and deciduous species of
true shrubs, young trees, and trees or shrubs that are small or stunted because of environmental conditions
are included.
51
Shrubland - areas dominated by shrubs; shrub canopy accounts for 25 to 100% of the cover. Shrub cover is
generally greater than 25% when tree cover is less than 25%. Shrub cover may be less than 25% in cases
when the cover of other life forms (e.g. herbaceous or tree) is less than 25% and shrubs cover exceeds the
cover of the other life forms.
Non-natural
woody
areas dominated by non-natural woody vegetation; non-natural woody vegetative canopy accounts for 25%
to 100% of the cover. The non-natural woody classification is subject to the availability of sufficient ancillary
data to differentiate non-natural woody vegetation from natural woody vegetation.
5-1
-------
61
Orchards/Vineyards/Other - orchards, vineyards, and other areas planted or maintained for the production
of fruits, nuts, berries, or ornamentals.
Herbaceous
Upland
upland areas characterized by natural or semi-natural herbaceous vegetation; herbaceous vegetation
accounts for 75% to 100% of the cover.
71
Grasslands/Herbaceous - areas dominated by upland grasses and forbs. In rare cases, herbaceous cover is
less than 25%, but exceeds the combined cover of the woody species present. These areas are not subject to
intensive management, but they are often utilized for grazing.
Planted/Cultivated
areas characterized by herbaceous vegetation that has been planted or is intensively managed for the
production of food, feed, or fiber; or is maintained in developed settings for specific purposes. Herbaceous
vegetation accounts for 75% to 100% of the cover.
81
Pasture/Hay - areas of grasses, legumes, or grass-legume mixtures planted for livestock grazing or the
production of seed or hay crops.
82
Row Crops - areas used for the production of crops, such as corn, soybeans, vegetables, tobacco, and
cotton.
83
Small Grains - areas used for the production of graminoid crops such as wheat, barley, oats, and rice.
84
Fallow - areas used for the production of crops that do not exhibit visible vegetation as a result of being
tilled in a management practice that incorporates prescribed alternation between cropping and tillage.
85
Urban/Recreational Grasses - vegetation (primarily grasses) planted in developed settings for recreation,
erosion control, or aesthetic purposes. Examples include parks, lawns, golf courses, airport grasses, and
industrial site grasses.
Wetlands
areas where the soil or substrate is periodically saturated with or covered with water as defined by Cowardin
et a!., (1979).
91
Woody Wetlands - areas where forest or shrubland vegetation accounts for 25% to 100 % of the cover and
the soil or substrate is periodically saturated with or covered with water.
92
Emergent Herbaceous Wetlands - areas where perennial herbaceous vegetation accounts for 75% to 100%
of the cover and the soil or substrate is periodically saturated with or covered with water.
Reproduced from the Multi-Resolution Land Characteristics Consortium Website at http://www.mrlc.gov
5-2
-------
Table 5-2. NLCD 2001-2011 Class and Category Descriptions and Color Legend
Class\ Value
Classification Description
Water
11
Open Water - areas of open water, generally with less than 25% cover of vegetation or soil.
12
Perennial Ice/Snow - areas characterized by a perennial cover of ice and/or snow, generally greater than
25% of total cover.
Developed
21
Developed, Open Space - areas with a mixture of some constructed materials, but mostly vegetation in the
form of lawn grasses. Impervious surfaces account for less than 20% of total cover. These areas most
commonly include large-lot single-family housing units, parks, golf courses, and vegetation planted in
developed settings for recreation, erosion control, or aesthetic purposes.
22
Developed, Low Intensity - areas with a mixture of constructed materials and vegetation. Impervious
surfaces account for 20% to 49% percent of total cover. These areas most commonly include single-family
housing units.
23
Developed, Medium Intensity - areas with a mixture of constructed materials and vegetation. Impervious
surfaces account for 50% to 79% of the total cover. These areas most commonly include single-family
housing units.
24
Developed High Intensity -highly developed areas where people reside or work in high numbers. Examples
include apartment complexes, row houses and commercial/industrial. Impervious surfaces account for 80%
to 100% of the total cover.
Barren
31
Barren Land (Rock/Sand/Clay) - areas of bedrock, desert pavement, scarps, talus, slides, volcanic material,
glacial debris, sand dunes, strip mines, gravel pits and other accumulations of earthen material. Generally,
vegetation accounts for less than 15% of total cover.
Forest
41
Deciduous Forest - areas dominated by trees generally greater than 5 meters tall, and greater than 20% of
total vegetation cover. More than 75% of the tree species shed foliage simultaneously in response to
seasonal change.
42
Evergreen Forest - areas dominated by trees generally greater than 5 meters tall, and greater than 20% of
total vegetation cover. More than 75% of the tree species maintain their leaves all year. Canopy is never
without green foliage.
43
Mixed Forest - areas dominated by trees generally greater than 5 meters tall, and greater than 20% of total
vegetation cover. Neither deciduous nor evergreen species are greater than 75% of total tree cover.
Shrubland
51
Dwarf Scrub - Alaska only areas dominated by shrubs less than 20 centimeters tall with shrub canopy
typically greater than 20% of total vegetation. This type is often co-associated with grasses, sedges, herbs,
and non-vascular vegetation.
52
Shrub/Scrub - areas dominated by shrubs; less than 5 meters tall with shrub canopy typically greater than
20% of total vegetation. This class includes true shrubs, young trees in an early successional stage or trees
stunted from environmental conditions.
Herbaceous
71
Grassland/Herbaceous - areas dominated by gramanoid or herbaceous vegetation, generally greater than
80% of total vegetation. These areas are not subject to intensive management such as tilling, but can be
utilized for grazing.
72
Sedge/Herbaceous - Alaska only areas dominated by sedges and forbs, generally greater than 80% of total
vegetation. This type can occur with significant other grasses or other grass like plants, and includes sedge
tundra, and sedge tussock tundra.
73
Lichens - Alaska only areas dominated by fruticose or foliose lichens generally greater than 80% of total
vegetation.
5-3
-------
74
Moss - Alaska only areas dominated by mosses, generally greater than 80% of total vegetation.
Planted/Cultivated
81
Pasture/Hay - areas of grasses, legumes, or grass-legume mixtures planted for livestock grazing or the
production of seed or hay crops, typically on a perennial cycle. Pasture/hay vegetation accounts for greater
than 20% of total vegetation.
82
Cultivated Crops - areas used for the production of annual crops, such as corn, soybeans, vegetables,
tobacco, and cotton, and also perennial woody crops such as orchards and vineyards. Crop vegetation
accounts for greater than 20% of total vegetation. This class also includes all land being actively tilled.
Wetlands
90
Woody Wetlands - areas where forest or shrubland vegetation accounts for greater than 20% of vegetative
cover and the soil or substrate is periodically saturated with or covered with water.
95
Emergent Herbaceous Wetlands - Areas where perennial herbaceous vegetation accounts for greater than
80% of vegetative cover and the soil or substrate is periodically saturated with or covered with water.
Reproduced from the Multi-Resolution Land Characteristics Consortium Website at http://www.mrlc.gov
5-4
-------
6,0 Appendix B. Surface Characteristic Lookup Tables
Table 6-1 through Table 6-6 provide the values of albedo, Bowen ratio, and surface roughness,
respectively, based on the NLCD92 land cover categories. Each table includes a column containing
references used in estimating the values for each surface characteristic parameter and each land cover
category. As explained in Section 2.0, more than one value of surface characteristics may be listed for
certain land cover categories depending on user responses to specific prompts regarding the site location.
6-1
-------
Table 6-1. Seasonal Values of Albedo for the NLCD 1992
Class
Number
Class Name
Seasonal Albedo Values1
Reference
1
2
3
4
5
11
Open Water
0.1
0.1
0.1
0.1
0.1
AERMET2'3
12
Perennial Ice/Snow
0.7
0.7
0.6
0.6
0.6
Stull & Garratt4
21
Low Intensity Residential
0.18
0.45
0.16
0.16
0.16
Estimate5
22
High Intensity Residential
0.18
0.35
0.18
0.18
0.18
Stull6 & AERMET7
23
Commercial/lndustrial/Transp
0.18
0.35
0.18
0.18
0.18
Stull6 & AERMET7
31
Bare Rock/Sand/Clay (Arid Region)
0.2
NA
0.2
0.2
0.2
Garratt8
Bare Rock/Sand/Clay (Non-arid Region)
0.2
0.6
0.2
0.2
0.2
Garratt8 & AERMET7
32
Quarries/Strip Mines/Gravel
0.2
0.6
0.2
0.2
0.2
Garratt8 & AERMET7
33
Transitional
0.18
0.45
0.18
0.18
0.18
Estimate9
41
Deciduous Forest
0.17
0.5
0.16
0.16
0.16
Stull6 & AERMET7
42
Evergreen Forest
0.12
0.35
0.12
0.12
0.12
Stull6 & AERMET7
43
Mixed Forest
0.14
0.42
0.14
0.14
0.14
Estimate10
51
Shrubland (Arid Region)
0.25
NA
0.25
0.25
0.25
Stull6
Shrubland (Non-arid Region)
0.18
0.5
0.18
0.18
0.18
Estimaten&AERMET7
61
Orchards/Vineyards/Other
0.18
0.5
0.14
0.18
0.18
Estimate12
71
Grasslands/Herbaceous
0.2
0.6
0.18
0.18
0.18
AERMET2
81
Pasture/Hay
0.18
0.6
0.14
0.2
0.2
AERMET2,13
82
Row Crops
0.18
0.6
0.14
0.2
0.2
AERMET2,13
83
Small Grains
0.18
0.6
0.14
0.2
0.2
AERMET2,13
84
Fallow
0.18
0.6
0.18
0.18
0.18
Garratt8
85
Urban/Recreational Grasses
0.18
0.6
0.15
0.15
0.15
Estimate14
91
Woody Wetlands
0.14
0.3
0.14
0.14
0.14
Stull6 & AERMET7
92
Emergent Herbaceous Wetlands
0.14
0.3
0.14
0.14
0.14
Stull6 & AERMET7
6-2
-------
1 Values are listed for the following seasonal categories: 1 - Late autumn after frost and harvest; or winter with
no snow; 2 - Winter with continuous snow on ground; 3 - Transitional spring with partial green coverage or
short annuals; 4 - Midsummer with lush vegetation; 5 - Autumn with unharvested cropland
2 Estimate based on AERMET User's Guide, Table 4-1.
3 We assume no freeze of the water and no seasonal changes in albedo.
4 Estimate based on Stull, Table C-7 and Garratt, Table A8. Assume fresher snow and more ice in seasonal categories 3 & 4
and older snow in seasonal categories 1, 2, & 5.
5 Assume an equal mix of three classes: "High Intensity Residential", "Mixed Forest", and "Urban/Recreational Grasses."
6 Estimate based on Stull, Table C-7.
7 Estimate based on AERMET User's Guide, Table 4-1 albedo value for winter with continuous snow cover.
8 Estimate based on Garratt, Table A8.
9 Assume "Transitional" is similar to Class 84: "Fallow". A warning will be issues to the user if this category appears in more
than 10% of the land cover data.
10 Estimate based on the average of Classes 41 and 42.
11 Estimate based on the non-arid shrubland having more vegetation that the arid-region shrubland.
12 Estimate based Class 51: "Shrubland (non-arid region)" for seasonal categories 1, 2 & 4 and AERMET User's Guide
("Cultivated Land") for seasonal categories 3 & 5.
13 Estimate based on AERMET User's Guide; assume more vegetation in summer and soil being wetter in spring than in fall.
14 Estimate based on AERMET User's Guide ("Cultivated Land") for seasonal category 3 & 4, and Garratt, Table A8 for
seasonal categories 1, 2 & 5.
6-3
-------
Table 6-2. Seasonal Values of Bowen Ratio for the NLCD 1992
Class
Number
Class Name
Seasonal Bowen Ratio1
Average
Seasonal Bowen Ratio1
Wet
Seasonal Bowen Ratio1
Dry
Reference
1
22
3
4
5
1
22
3
4
5
1
22
3
4
5
11
Open Water
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
AERMET&Oke3
12
Perennial Ice/Snow
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
AERMET&Oke3
21
Low Intensity Residential
1.0
0.5
0.8
0.8
1.0
0.6
0.5
0.6
0.6
0.6
2.5
0.5
2.0
2.0
2.5
Estimate4
22
High Intensity Residential
1.5
0.5
1.5
1.5
1.5
1.0
0.5
1.0
1.0
1.0
3.0
0.5
3.0
3.0
3.0
AERMET&Oke3
23
Commercial/lndustrial/Transp
1.5
0.5
1.5
1.5
1.5
1.0
0.5
1.0
1.0
1.0
3.0
0.5
3.0
3.0
3.0
AERMET&Oke3
31
Bare Rock/Sand/Clay
(Arid Region)
6.0
NA
3.0
4.0
6.0
2.0
NA
1.0
1.5
2
10.0
NA
5.0
6.0
10
AERMET&Oke3
Bare Rock/Sand/Clay
(Non-arid Region)
1.5
0.5
1.5
1.5
1.5
1.0
0.5
1.0
1.0
1.0
3.0
0.5
3.0
3.0
3.0
AERMET&Oke3
32
Quarries/Strip Mines/Gravel
1.5
0.5
1.5
1.5
1.5
1.0
0.5
1.0
1.0
1.0
3.0
0.5
3.0
3.0
3.0
AERMET&Oke3
33
Transitional
1.0
0.5
1.0
1.0
1.0
0.7
0.5
0.7
0.7
0.7
2.0
0.5
2.0
2.0
2.0
Estimate5
41
Deciduous Forest
1.0
0.5
0.7
0.3
1.0
0.4
0.5
0.3
0.2
0.4
2.0
0.5
1.5
0.6
2.0
AERMET&Oke3
42
Evergreen Forest
0.8
0.5
0.7
0.3
0.8
0.3
0.5
0.3
0.2
0.3
1.5
0.5
1.5
0.6
1.5
AERMET&Oke3
43
Mixed Forest
0.9
0.5
0.7
0.3
0.9
0.35
0.5
0.3
0.2
0.35
1.75
0.5
1.5
0.6
1.75
Estimate6
51
Shrubland (Arid Region)
6.0
NA
3.0
4.0
6.0
2.0
NA
1.0
1.5
2.0
10.0
NA
5.0
6.0
10.0
AERMET&Oke3
Shrubland (Non-arid Region)
1.5
0.5
1.0
1.0
1.5
1.0
0.5
0.8
0.8
1.0
3.0
0.5
2.5
2.5
3.0
Estimate7
61
Orchards/Vineyards/Other
0.7
0.5
0.3
0.5
0.7
0.4
0.5
0.2
0.3
0.4
2.0
0.5
1.0
1.5
2.0
AERMET&Oke3
6-4
-------
71
Grasslands/Herbaceous
1.0
0.5
0.4
0.8
1.0
0.5
0.5
0.3
0.4
0.5
2.0
0.5
1.0
2.0
2.0
AERMET&Oke3
81
Pasture/Hay
0.7
0.5
0.3
0.5
0.7
0.4
0.5
0.2
0.3
0.4
2.0
0.5
1.0
1.5
2.0
AERMET&Oke3
82
Row Crops
0.7
0.5
0.3
0.5
0.7
0.4
0.5
0.2
0.3
0.4
2.0
0.5
1.0
1.5
2.0
AERMET&Oke3
83
Small Grains
0.7
0.5
0.3
0.5
0.7
0.4
0.5
0.2
0.3
0.4
2.0
0.5
1.0
1.5
2.0
AERMET&Oke3
84
Fallow
0.7
0.5
0.3
0.5
0.7
0.4
0.5
0.2
0.3
0.4
2.0
0.5
1.0
1.5
2.0
AERMET&Oke3
85
Urban/Recreational Grasses
0.7
0.5
0.3
0.5
0.7
0.4
0.5
0.2
0.3
0.4
2.0
0.5
1.0
1.5
2.0
AERMET&Oke3
91
Woody Wetlands
0.3
0.5
0.2
0.2
0.2
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
Estimate7
92
Emergent Herbaceous
Wetlands
0.1
0.5
0.1
0.1
0.1
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
AERMET&Oke3
1 Values are listed for the following seasonal categories: 1 - Late autumn after frost and harvest; or winter with no snow; 2 - Winter with
continuous snow on ground; 3 - Transitional spring with partial green coverage or short annuals; 4 - Midsummer with lush vegetation; 5 -
Autumn with unharvested cropland
2 Values for seasonal category 2 are based on the AERMET User's Guide (EPA, 2018a) and Oke (1978), Tables 4-2a-c, Bowen ratio values for winter with
continuous snow cover, except for class 11 with the assumption the water does not freeze.
3 Values for seasonal categories 1, 2, 3 & 5 are based on AERMET User's Guide (EPA, 2018a), Tables 4-2a-c and Oke (1978).
4 Estimate based on composition being an equal mix of three classes: "High Intensity Residential", "Mixed Forest", and "Urban/Recreational Grasses.
5 Estimate based on the Bowen ratio of "Transitional" being between the Bowen ratio of Classes 31 and 71.
6 Assume "Mixed Forest" is composed of equal parts of "Deciduous Forest" and "Evergreen Forest."
7 Estimate based on comparison to Bowen ratio for other classes.
6-5
-------
Table 6-3. Seasonal Values of Surface Roughness (m) for the NLCD 1992
Class
Number
Class Name
Seasonal Surface Roughness1 (m)
Reference
1
2
3
4
5
11
Open Water
0.001
0.001
0.001
0.001
0.001
Stull2
12
Perennial Ice/Snow
0.002
0.002
0.002
0.002
0.002
Stull2
21
Low Intensity Residential
0.30
0.30
0.40
0.40
0.40
Estimate3
22
High Intensity Residential
1.0
1.0
1.0
1.0
1.0
AERMET4
23
Commercial/lndust/Transp
(Airport)
0.07
0.07
0.07
0.07
0.07
Estimate5
Commercial/lndustrial/Transp
(Non-airport)
0.7
0.7
0.7
0.7
0.7
Estimate5
31
Bare Rock/Sand/Clay
(Arid Region)
0.05
NA
0.05
0.05
0.05
Slade6
Bare Rock/Sand/Clay
(Non-arid Region)
0.05
0.05
0.05
0.05
0.05
Slade6
32
Quarries/Strip Mines/Gravel
0.3
0.3
0.3
0.3
0.3
Estimate7
33
Transitional
0.2
0.2
0.2
0.2
0.2
Estimate8
41
Deciduous Forest
0.6
0.5
1.0
1.3
1.3
AERMET4
42
Evergreen Forest
1.3
1.3
1.3
1.3
1.3
AERMET4
43
Mixed Forest
0.9
0.8
1.1
1.3
1.3
Estimate9
51
Shrubland
(Arid Region)
0.15
NA
0.15
0.15
0.15
50% Cat. 51 (Non-Arid)10
Shrubland
(Non-arid Region)
0.3
0.15
0.3
0.3
0.3
AERMET4
61
Orchards/Vineyards/Other
0.1
0.05
0.2
0.3
0.3
Garratt11
71
Grasslands/Herbaceous
0.01
0.005
0.05
0.1
0.1
AERMET4
81
Pasture/Hay
0.02
0.01
0.03
0.15
0.15
Garratt11 & Slade12
82
Row Crops
0.02
0.01
0.03
0.2
0.2
Garratt11 & Slade12
83
Small Grains
0.02
0.01
0.03
0.15
0.15
Garratt11 & Slade12
84
Fallow
0.02
0.01
0.02
0.05
0.05
Estimate13
85
Urban/Recreational Grasses
0.01
0.005
0.015
0.02
0.015
Randerson14
91
Woody Wetlands
0.4
0.3
0.5
0.5
0.5
Estimate15
92
Emergent Herbaceous
Wetlands
0.2
0.1
0.2
0.2
0.2
AERMET4
6-6
-------
1 Values are listed for the following seasonal categories: 1 - Late autumn after frost and harvest; or winter with
no snow; 2 - Winter with continuous snow on ground; 3 - Transitional spring with partial green coverage or short
annuals; 4 - Midsummer with lush vegetation; 5 - Autumn with unharvested cropland
2 Estimate based on Stull, Fig 9.6. We have specified a larger roughness than the AERMET "calm open sea"
roughness value because we have assumed that most of the water is closer to land and will experience waves
and be closer to the shoreline, increasing roughness.
3 Assume 50% "High Intensity Residential" (22), 25% "Mixed Forest" (43), and 25% "Urban/Recreational Grasses"
(85), using a weighted geometric mean value.
4 Based on the AERMET User's Guide (EPA, 2018a).
5 For airport sites, assume 90% of land cover is "Transportation" with roughness similar to Class 31 (Bare Rock/
Sand/ Clay) and 10% is "Commercial/Industrial" with roughness similar to Class 22 (High Intensity Residential).
For non-airport, assume 10% of land cover is "Transportation" and 90% is "Commercial/Industrial". Weighted
geometric mean values are used.
6 Estimate based on Slade, Table 3-1, assuming the surface is not completely level due to inclusion of some
larger rocks.
7 Estimate reflecting "significant surface expression"
8 Estimate reflecting significant mix of different land cover classes. A warning will be issued to the user if this
category appears in more than 10% of the land cover data.
9 Assume "Mixed Forest" is 50% "Deciduous Forest" and 50% "Evergreen Forest", using a weighted geometric
mean value.
10 Assume arid region would have approximately 50% less vegetation than a non-arid region.
11 Estimate based on Garratt, Table A6.
12 Estimate based on Slade, Table 3-1
13 Based on class 31 ("Bare Rock/Sand/Clay") for seasonal categories 1 &2 and 81, 82, 83 ("Pasture/Hay", "Row
Crops" & "Small Grains") for seasonal categories 3, 4, & 5, with seasonal category 5 having a more similar
amount of vegetation to seasonal category 3 and, therefore, the same roughness.
14 Estimate based on Randerson, Table 5.4
15 Assume 50% Mixed Forest (43) and 50% Emergent Herb Wetlands (92), using a weighted geometric mean
value.
6-7
-------
Table 6-4. Seasonal Values of Albedo for the NLCD 2001-2011
Class
Number
Class Name
Seasonal Albedo Values1
Reference
1
2
3
4
5
11
Open Water
0.1
0.1
0.1
0.1
0.1
NLCD 1992 Cat. 11
12
Perennial Ice/Snow
0.7
0.7
0.6
0.6
0.6
NLCD 1992 Cat. 12
21
Developed, Open Space
0.18
0.6
0.15
0.15
0.15
NLCD 1992 Cat. 85
22
Developed, Low Intensity
0.18
0.45
0.16
0.16
0.16
NLCD 1992 Cat. 21
23
Developed, Medium Intensity
0.18
0.18
0.18
0.18
0.18
NLCD 1992 Cat. 23
24
Developed, High Intensity
0.18
0.25
0.18
0.18
0.18
NLCD 1992 Cat. 23
31
Barren Land (Rock/Sand/Clay) (Arid Region)
0.2
NA
0.2
0.2
0.2
NLCD 1992 Cat. 31
Barren Land (Rock/Sand/Clay) (Non-arid Region)
0.2
0.6
0.2
0.2
0.2
NLCD 1992 Cat. 31
32
Unconsolidated Shore
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 91
41
Deciduous Forest
0.17
0.5
0.16
0.16
0.16
NLCD 1992 Cat. 41
42
Evergreen Forest
0.12
0.35
0.12
0.12
0.12
NLCD 1992 Cat. 42
43
Mixed Forest
0.14
0.42
0.14
0.14
0.14
NLCD 1992 Cat. 43
51
Dwarf Scrub (Arid Region)
0.25
NA
0.25
0.25
0.25
NLCD 1992 Cat. 51
Dwarf Scrub (Non-arid Region)
0.18
0.5
0.18
0.18
0.18
NLCD 1992 Cat. 51
52
Shrub/Scrub (Arid Region)
0.25
NA
0.25
0.25
0.25
NLCD 1992 Cat. 51
Shrub/Scrub (Non-arid Region)
0.18
0.5
0.18
0.18
0.18
NLCD 1992 Cat. 51
71
Grasslands/Herbaceous
0.2
0.6
0.18
0.18
0.18
NLCD 1992 Cat. 71
72
Sedge/Herbaceous
0.2
0.6
0.18
0.18
0.18
NLCD 1992 Cat. 71
73
Lichens
0.2
0.6
0.18
0.18
0.18
NLCD 1992 Cat. 71
74
Moss
0.2
0.6
0.18
0.18
0.18
NLCD 1992 Cat. 71
81
Pasture/Hay
0.18
0.6
0.14
0.2
0.2
NLCD 1992 Cat. 81
82
Cultivated Crops
0.18
0.6
0.14
0.2
0.2
NLCD 1992 Cat. 82
90
Woody Wetlands
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 91
91
Palustrine Forested Wetland
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 91
92
Palustrine Scrub/Shrub Wetland
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 91
93
Estuarine Forested Wetland
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 91
94
Estuarine Scrub/Shrub Wetland
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 91
95
Emergent Herbaceous Wetland
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 92
96
Palustrine Emergent Wetland (Persistent)
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 92
97
Estuarine Emergent Wetland
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 92
98
Palustrine Aquatic Bed
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 92
99
Estuarine Aquatic Bed
0.14
0.3
0.14
0.14
0.14
NLCD 1992 Cat. 92
1 Values are listed for the following seasonal categories: 1 - Late autumn after frost and harvest; or winter with
no snow; 2 - Winter with continuous snow on ground; 3 - Transitional spring with partial green coverage or
short annuals; 4 - Midsummer with lush vegetation; 5 - Autumn with unharvested cropland
6-8
-------
Table 6-5. Seasonal Values of Bowen Ratio for the NLCD 2001-2011
Class
Number
Class Name
Seasonal Bowen Ratio1
Average
Seasonal Bowen Ratio1
Wet
Seasonal Bowen Ratio1
Dry
Reference
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
11
Open Water
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
NLCD 1992 Cat. 11
12
Perennial Ice/Snow
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
NLCD 1992 Cat. 12
21
Developed, Open Space
0.7
0.5
0.3
0.5
0.7
0.4
0.5
0.2
0.3
0.4
2.0
0.5
1.0
1.5
2.0
NLCD 1992 Cat. 85
22
Developed, Low Intensity
1.0
0.5
0.8
0.8
1.0
0.6
0.5
0.6
0.6
0.6
2.5
0.5
2.0
2.0
2.5
NLCD 1992 Cat. 21
23
Developed, Medium Intensity
1.2
0.5
1.1
1.1
1.2
0.8
0.5
0.8
0.8
0.8
3.0
0.5
3.0
3.0
3.0
Estimated2
24
Developed, High Intensity
1.5
0.5
1.5
1.5
1.5
1.0
0.5
1.0
1.0
1.0
3.0
0.5
3.0
3.0
3.0
NLCD 1992 Cat. 23
31
Barren Land (Rock/Sand/Clay)
(Arid Region)
6.0
NA
3.0
4.0
6.0
2.0
NA
1.0
1.5
2.0
10.0
NA
5.0
6.0
10.0
NLCD 1992 Cat. 31
Barren Land (Rock/Sand/Clay)
(Non-arid Region)
1.5
0.5
1.5
1.5
1.5
1.0
0.5
1.0
1.0
1.0
3.0
0.5
3.0
3.0
3.0
NLCD 1992 Cat. 31
32
Unconsolidated Shore
0.2
0.5
0.2
0.2
0.2
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
NLCD 1992 Cat. 91
41
Deciduous Forest
1.0
0.5
0.7
0.3
1.0
0.4
0.5
0.3
0.2
0.4
2.0
0.5
1.5
0.6
2.0
NLCD 1992 Cat. 41
42
Evergreen Forest
0.8
0.7
0.3
0.3
0.8
0.3
0.5
0.3
0.2
0.3
1.5
0.5
1.5
0.6
1.5
NLCD 1992 Cat. 42
43
Mixed Forest
0.9
0.5
0.7
0.3
0.9
0.35
0.5
0.3
0.2
0.35
1.75
0.5
1.5
0.6
1.75
NLCD 1992 Cat. 43
51
Dwarf Scrub
(Arid Region)
4.0
NA
2.0
3.0
4.0
1.5
NA
0.8
0.9
1.5
7.0
NA
4.0
6.0
7.0
Estimated from Cat 52
Dwarf Scrub
(Non-arid Region)
1.5
0.5
1.0
1.0
1.5
1.0
0.5
0.8
0.8
1.0
3.0
0.5
2.5
2.5
3.0
NLCD 1992 Cat. 51
52
Shrub/Scrub
(Arid Region)
6.0
NA
3.0
4.0
6.0
2.0
NA
1.0
1.5
2.0
10.0
NA
5.0
6.0
10.0
NLCD 1992 Cat. 51
Shrub/Scrub
(Non-arid Region)
1.5
0.5
1.0
1.0
1.5
1.0
0.5
0.8
0.8
1.0
3.0
0.5
2.5
2.5
3.0
NLCD 1992 Cat. 51
71
Grasslands/Herbaceous
1.0
0.5
0.4
0.8
1.0
0.5
0.5
0.3
0.4
0.5
2.0
0.5
1.0
2.0
2.0
NLCD 1992 Cat. 71
6-9
-------
72
73
74
81
82
90
91
92
93
94
95
96
97
98
99
1
2
Sedge/Herbaceous
1.0
0.5
0.4
0.8
1.0
0.5
0.5
0.3
0.4
0.5
2.0
0.5
1.0
2.0
2.0
NLCD 1992 Cat. 71
Lichens
1.0
0.5
0.4
0.8
1.0
0.5
0.5
0.3
0.4
0.5
2.0
0.5
1.0
2.0
2.0
NLCD 1992 Cat. 71
Moss
1.0
0.5
0.4
0.8
1.0
0.5
0.5
0.3
0.4
0.5
2.0
0.5
1.0
2.0
2.0
NLCD 1992 Cat. 71
Pasture/Hay
0.7
0.5
0.3
0.5
0.7
0.4
0.5
0.2
0.3
0.4
2.0
0.5
1.0
1.5
2.0
NLCD 1992 Cat. 81
Cultivated Crops
0.7
0.5
0.3
0.5
0.7
0.4
0.5
0.2
0.3
0.4
2.0
0.5
1.0
1.5
2.0
NLCD 1992 Cat. 82
Woody Wetlands
0.2
0.5
0.2
0.2
0.2
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
NLCD 1992 Cat. 91
Palustrine Forested Wetland
0.2
0.5
0.2
0.2
0.2
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
NLCD 1992 Cat. 91
Palustrine Scrub/Shrub
0.2
0.5
0.2
0.2
0.2
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
NLCD 1992 Cat. 91
Estuarine Forested Wetland
0.2
0.5
0.2
0.2
0.2
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
NLCD 1992 Cat. 91
Estuarine Scrub/Shrub
0.2
0.5
0.2
0.2
0.2
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
NLCD 1992 Cat. 91
Emergent Herbaceous
0.1
0.5
0.1
0.1
0.1
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
NLCD 1992 Cat. 92
Palustrine Emergent Wetland
0.1
0.5
0.1
0.1
0.1
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
NLCD 1992 Cat. 92
Estuarine Emergent Wetland
0.1
0.5
0.1
0.1
0.1
0.1
0.5
0.1
0.1
0.1
0.2
0.5
0.2
0.2
0.2
NLCD 1992 Cat. 92
Palustrine Aquatic Bed
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
NLCD 1992 Cat. 11
Estuarine Aquatic Bed
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
NLCD 1992 Cat. 11
Values are listed for the following seasonal categories: 1 - Late autumn after frost and harvest; or winter with no snow; 2 - Winter with continuous
snow on ground; 3 - Transitional spring with partial green coverage or short annuals; 4 - Midsummer with lush vegetation; 5 - Autumn with
unharvested cropland
Estimated from categories 22 (Developed - Low Intensity) and 24 (Developed - High Intensity).
6-10
-------
Table 6-6. Seasonal Values of Surface Roughness for the NLCD 2001-2011
Class
Number
Class Name
Seasonal Surface Roughness1 (m)
Reference
1
2
3
4
5
11
Open Water
0.001
0.001
0.001
0.001
0.001
NLCD 1992 Cat. 11
12
Perennial Ice/Snow
0.002
0.002
0.002
0.002
0.002
NLCD 1992 Cat. 12
21
Developed, Open Space (Airport)
0.02
0.01
0.02
0.03
0.03
Estimated2
Developed, Open Space (Non-airport)
0.02
0.01
0.03
0.04
0.03
Estimated2
22
Developed, Low Intensity (Airport)
0.03
0.02
0.03
0.04
0.03
Estimated2
Developed, Low Intensity (Non-airport)
0.07
0.05
0.09
0.1
0.09
Estimated2
23
Developed, Medium Intensity (Airport)
0.05
0.04
0.06
0.06
0.06
Estimated2
Developed, Medium Intensity (Non-airport)
0.3
0.2
0.3
0.3
0.3
Estimated2
24
Developed, High Intensity (Airport)
0.07
0.07
0.07
0.08
0.08
Estimated2
Developed, High Intensity (Non-airport)
0.7
0.7
0.7
0.7
0.7
Estimated2
31
Barren Land (Rock/Sand/Clay) (Arid Region)
0.05
NA
0.05
0.05
0.05
NLCD 1992 Cat. 31
Barren Land (Rock/Sand/Clay) (Non-arid
Region)
0.05
0.01
0.05
0.05
0.05
NLCD 1992 Cat. 31
32
Unconsolidated Shore
0.05
0.01
0.05
0.05
0.05
NLCD 1992 Cat. 31
41
Deciduous Forest
0.6
0.5
1.0
1.3
1.3
NLCD 1992 Cat. 41
42
Evergreen Forest
1.3
1.3
1.3
1.3
1.3
NLCD 1992 Cat. 42
43
Mixed Forest
0.9
0.8
1.1
1.3
1.3
NLCD 1992 Cat. 43
51
Dwarf Scrub (Arid Region)
0.05
NA
0.05
0.05
0.05
NLCD 1992 Cat. 51
Dwarf Scrub (Non-arid Region)
0.1
0.05
0.1
0.1
0.1
NLCD 1992 Cat. 51
52
Shrub/Scrub (Arid Region)
0.15
NA
0.15
0.15
0.15
NLCD 1992 Cat. 51
Shrub/Scrub (Non-arid Region)
0.3
0.15
0.3
0.3
0.3
NLCD 1992 Cat. 51
71
Grasslands/Herbaceous
0.01
0.005
0.05
0.1
0.1
NLCD 1992 Cat. 71
72
Sedge/Herbaceous
0.01
0.005
0.05
0.1
0.1
NLCD 1992 Cat. 71
73
Lichens
0.01
0.005
0.05
0.05
0.05
Estimated
6-11
-------
74
Moss
0.01
0.005
0.05
0.05
0.05
Estimated
81
Pasture/Hay (Airport)
0.02
0.01
0.02
0.03
0.03
NLCD 1992 Cat. 21
Pasture/Hay (Non-airport)
0.02
0.01
0.03
0.15
0.15
NLCD 1992 Cat. 81
82
Cultivated Crops (Airport)
0.02
0.01
0.02
0.03
0.03
NLCD 1992 Cat. 21
Cultivated Crops (Non-airport)
0.03
0.014
0.04
0.2
0.2
Estimated
90
Woody Wetlands
0.4
0.3
0.5
0.5
0.5
NLCD 1992 Cat. 91
91
Palustrine Forested Wetland
0.4
0.3
0.5
0.5
0.5
NLCD 1992 Cat. 91
92
Palustrine Scrub/Shrub Wetland
0.2
0.1
0.2
0.2
0.2
NLCD 1992 Cat. 92
93
Estuarine Forested Wetland
0.4
0.3
0.5
0.5
0.5
NLCD 1992 Cat. 91
94
Estuarine Scrub/Shrub Wetland
0.2
0.1
0.2
0.2
0.2
NLCD 1992 Cat. 92
95
Emergent Herbaceous Wetland
0.2
0.1
0.2
0.2
0.2
NLCD 1992 Cat. 92
96
Palustrine Emergent Wetland (Persistent)
0.2
0.1
0.2
0.2
0.2
NLCD 1992 Cat. 92
97
Estuarine Emergent Wetland
0.2
0.1
0.2
0.2
0.2
NLCD 1992 Cat. 92
98
Palustrine Aquatic Bed
0.05
0.05
0.05
0.05
0.05
Estimated
99
Estuarine Aquatic Bed
0.05
0.05
0.05
0.05
0.05
Estimated
1 Values are listed for the following seasonal categories: 1 - Late autumn after frost and harvest; or winter with
no snow; 2 - Winter with continuous snow on ground; 3 - Transitional spring with partial green coverage or
short annuals; 4 - Midsummer with lush vegetation; 5 - Autumn with unharvested cropland
2 Surface roughness lengths for categories 21-24 that make up the Developed class of categories in the 2001,
2006, and 2011 NLCD are calculated as a weighted geometric mean of a combination of the following 1992
NLC-D categories (see applied weights in tables below):
® High Intensity Residential (22)
® Bare Rock/Sand/Clay (31)
• Mixed Forest (43)
• Urban/Recreational Grasses (85)
1992 NLCD Values are italicized on gray background
Roughness length assigned to 2001, 2006, 2011 categories on orange background
Applied weights are on yellow background
AP = Airport, NonAP
= Non-airport, GM = Geometric Mean
Season 1 -
Late autumn or Winter without snow:
Season 2-
Winter with sr
1992 Cat:
22
H
43
85
1992 Cat:
22
31
43
85
2001 Cat
1
0.05
0.9
0.01
GM
2001 Cat
1
0.05
0.8
0.005
GM
21 AP"
0.05
0.05
0.05
0.85
0.017
21 AP
0.05
0.05
0.05
0.85
0.009
21 NonAP"
0.05
0.05
0.1
0.8
0.021
21 NonAP
0.05
0.05
0.1
0.8
0.012
22 AP
0.05
0.3
0.05
0.6
0.026
22 AP
0.05
0.3
0.05
0.6
0.017
22 NonAP
0.3
0.05
0.1
0.55
0 068
22 NonAP
0.3
0.05
0.1
0.55
0.046
23 AP
0.1
0.55
0.05
0.3
0.048
23 AP
0.1
0.55
0.05
0.3
0.039
23 NonAP
0.6
0.05
0.1
0.25
0.269
23 NonAP
0.6
0.05
0.1
0.25
0.224
24 AP
0.1
0.8
0.05
0.05
0.072
24 AP
0.1
0.8
0.05
0.05
0.069
24 NonAP
0.85
0.05
0.05
0.05
0.680
24 NonAP
0.85
0.05
0.05
0.05
0.653
Season 3 -
Transitional SDrina
Season 4 -
Midsummer with lush veaetation:
1992 Cat:
22
31
43
85
1992 Cat:
22
31
43
85
2001 Cat
1
0.05
1.1
0.015
GM
2001 Cat
1
0.05
1.3
0.02
GM
21 AP
0.05
0.05
0.05
0.85
0.024
21 AP
0.05
0.05
0.05
0.85
0.031
21 NonAP
0.05
0.05
0.1
0.8
0.030
21 NonAP
0.05
0.05
0.1
0.8
0.039
22 AP
0.05
0.3
0.05
0.6
0.033
22 AP
0.05
0.3
0.05
0.6
0.039
22 NonAP
0.3
0.05
0.1
0.55
0.086
22 NonAP
0.3
0.05
0.1
0.55
0.103
23 AP
0.1
0.55
0.05
0.3
0.055
23 AP
0.1
0.55
0.05
0.3
0.060
23 NonAP
0.6
0.05
0.1
0.25
0.304
23 NonAP
0.6
0.05
0.1
0.25
0.332
24 AP
0.1
0.8
0.05
0.05
0.074
24 AP
0.1
0.8
0.05
0.05
0.076
24 NonAP
0.85
0.05
0.05
0.05
0.701
24 NonAP
0.85
0.05
0.05
0.05
0.717
Season 5 -
Autumn with unhaivested cropland
1992 Cat:
21
43
85
2001 Cat
1
0.05
1.3
0.015
GM
* GM =EXP(LN($B$3)
*B4+LN($C$3)*C4+LN($D$3)*D4+LN($ES3)*E4)
21 AP
0.05
0.05
0 05
0.85
0.025
21 NonAP
0.05
0.05
0.1
0.8
0.031
22 AP
0.05
0.3
0.05
0.6
0.033
22 NonAP
0.3
0.05
0.1
0.55
0.088
23 AP
0.1
0.55
0.05
0.3
0.055
23 NonAP
0.6
0.05
0.1
0.25
0.309
24 AP
0.1
0.8
0.05
0.05
0.075
24 NonAP
0.85
0.05
0.05
0.05
0.707
6-12
-------
7.0 Appendix C. Alphabetical keyword reference
This appendix provides an alphabetical listing of all of the keywords used by the
AERSURFACE program. Each keyword is identified as to the pathway for which it applies, the
keyword type: mandatory (M), optional (O) or conditional (C), and either repeatable (R) or non-
repeatable (N), and with a brief description of the function of the keyword. For a more
complete description of the keywords, including a list of associated parameters, refer to the
Detailed Keyword Reference in Section 3.0 or the Functional Keyword/Parameter Reference in
Section 8.0.
7-1
-------
Table 7-1. All Primary Keywords Available in AERSURFACE
Keyword
Path
Type
Keyword Description
ANEM HGT
CO
O-N
Anemometer height (for ZOEFF roughness option)
CNPYGRID
OU
O-N
Debug file - Canopy data grid
CNPYTIFF
OU
O-N
Debug file - Canopy debug file containing TIFF tag and GeoKey
values
CENTERLL*
CO
M-N
Met tower coordinates in latitude and longitude
CENTERXY*
CO
M-N
Met tower location in UTM coordinates
CLIMATE
CO
O-N
Climate and moisture parameters of study area
DATAFILE
CO
M-R
Land cover input datafiles (including impervious and canopy data)
DEBUGOPT
CO
O-N
Debug options for debug files
EFFRAD
OU
O-N
Table of effective radius values by sector and month
FREQ SECT
CO
O-N
Indicates temporal frequency of surface values, number of roughness
sectors and if site is an airport or if airport flag is sector dependent
FINISHED
ALL
M-N
Identifies the end of pathway inputs
MPRVGRID
OU
O-N
Debug file - Impervious data grid
MPRVTIFF
OU
O-N
Debug file - Impervious debug file containing TIFF tag and GeoKey
values
NLCDGRID
OU
O-N
Debug file - Land cover data grid
NLCDTIFF
OU
O-N
Debug file - Land cover debug file containing TIFF tag and GeoKey
values
OPTIONS
CO
O-N
Processing options
RUNORNOT
CO
M-N
Indicates to stop execution after checking control file setup or continue
processing if not errors found
SFCCHAR
OU
M-N
Averaged surface characteristic values formatted for input to AERMET
SEASON
CO
0 - R
Used to reassign months to seasons to override default
assignments
SECTOR
CO
C-R
Define roughness sectors and indicate if airport values should be used.
STARTING
ALL
M-N
Identifies the end of pathway inputs
TITLEONE
CO
M-N
First line of title for output
TITLETWO
CO
O-N
Optional second line of output title
ZORADIUS
CO
O-N
Fixed radius for averaging roughness (for ZORAD roughness option)
* User must specify either CENTERXY or CENTERLL.
Type: M - Mandatory N - Non-Repeatable
O - Optional R - Repeatable
C - Conditional
7-2
-------
8,0 Appendix D. Functional keyword/parameter reference
This appendix provides a functional reference for the keywords and parameters used by the
control for the AERSURFACE program. The keywords are organized by functional pathway, and
within each pathway the order of the keywords is based on the function of the keyword within the
preprocessor. The pathways used by the preprocessor are as follows, in the order in which they appear
in the control file and in the tables that follow:
CO - for specifying overall job COntrol options; and
OU - for specifying OUtput file information.
The pathways and keywords are presented in the same order as in the Detailed Keyword Reference in
Section 3.0.
Two types of tables are provided for each pathway. The first table lists all of the keywords for
that pathway, identifies each keyword as to its type (either mandatory or optional and either repeatable
or non-repeatable), and provides a brief description of the function of the keyword. The second type of
table presents the parameters for each keyword in the order in which they should appear in the control
file where order is important and describes each parameter in detail.
The following convention is used for identifying the different types of input parameters.
Parameters corresponding to secondary keywords which should be input "as is" are listed on the tables
with all capital letters (they are underlined in the table). Other parameter names are given with an initial
capital letter and are not input "as is." In all cases, the parameter names are intended to be descriptive
of the input variable being represented, and they often correspond to the Fortran variable names used in
the preprocessor code. Parentheses around a parameter indicate that the parameter is optional for that
keyword. The default that is taken when an optional parameter is left blank is explained in the
discussion for that parameter.
8-1
-------
Table 8-1. Description of Control Pathway Keywords
CO Keywords
Type
Keyword Description
STARTING
M-N
Identifies the start of pathway inputs
TITLEONE
M-N
First line of title for output
TITLETWO
O-N
Optional second line of title for output
OPTIONS
O-N
Processing options
DEBUGOPT
O-N
Debug options for debug files
CENTERXY*
M-N
Met tower location in UTM coordinates
CENTERLL*
M-N
Met tower coordinates in latitude and longitude
DATAFILE
M-R
Land cover input datafiles (including impervious and canopy data)
ZORADIUS
O-N
Fixed radius for averaging roughness (for ZORAD roughness option)
ANEM HGT
O-N
Anemometer height (for ZOEFF roughness option)
CLIMATE
O-N
Climate and moisture parameters of study area
FREQ SECT
M-N
Indicates temporal frequency of surface values, number of roughness
sectors and if site is an airport or if airport flag is sector dependent
SECTOR
C-R
Define roughness sectors and indicate if airport values should be used.
SEASON
0 - R
Used to reassign months to seasons to override default assignments
RUNORNOT
M-N
Identifies whether to run program or process setup information
onlv
FINISHED
M-N
Identifies the end of pathway inputs
* User must specify either CENTERXY or CENTERLL.
Type: M - Mandatory N - Non-Repeatable
O - Optional R - Repeatable
C - Conditional
8-2
-------
Table 8-2. Description of Control Pathway Keywords and Parameters
Keyword
Parameters
TITLEONE
titlel
where:
titlel
First line of title for output, character string of up to 200
characters
TITLETWO
titlel
where:
titlel
Second line of title for output, character string of up to 200
characters
OPTIONS
PRIMARY ZORAD
or or
SECONDARY ZOEFF
where:
PRIMARY
SECONDARY
ZORAD
ZOEFF
Site processed for primary surface characteristics and will generate
keywords for primary values for AERMET (default)
Site processed for secondary surface characteristics and will
generate keywords for secondary values for AERMET.
Calculates the average roughness from the meteorological tower
out to a default radial distance of 1 km. (default)
Research grade method for calculating roughness that estimates
fetch based the growth of the IBL due to changes in roughness
downwind. Average roughness is computed over the estimated
fetch, approaching the meteorological tower.
DEBUGOPT
EFFRAD and/or GRID and/or TIFF or ALL
where:
EFFRAD
GRID
TIFF
ALL
Generates file containing the effective radius for surface roughness
computed for each sector/month (only applicable for ZOEFF option
specified with the OPTIONS keyword)
Generates grid file of land cover data and, if applicable, separate
files for impervious, and canopy data, displaying the 10x10 km grid
of values extracted from each GeoTIFF data file
Generates debug file containing a list of all TIFF tags, GeoKeys,
and associated values read from the land cover file and, if
applicable, separate files for impervious and canopy data files
Generates all debug files listed above without having to list each
debug option separately
8-3
-------
CENTERXX
easting northing utm zone datum
where:
easting
northing
utm zone
datum
UTM easting coordinate in meters
UTM northing coordinate in meters
UTM zone entered as a positive integer
Geodetic datum on which coordinates are based. The datum should
be entered using one of the following secondary keywords: NAD27
or NAD83. which refer to the North American 1927 datum and the
North American 1983 datum, respectively. NAD83 should also be
used for coordinates referenced to the GRS80 and WGS84 datums
since the small differences are inconsequential for the purposes of
AERSURFACE.
User must specify either CENTERXY or CENTERLL.
CENTERLL
latitude longitude datum
where:
latitude
longitude
datum
Latitude in decimal degrees (Northern hemisphere = positive value)
Longitude in decimal degrees (Western hemisphere = negative value)
Geodetic datum on which coordinates are based. The datum should be
entered using one of the following secondary keywords: NAD27 or
NAD83. which refer to the North American 1927 datum and the
North American 1983 datum, respectively. NAD83 should also be
used for coordinates referenced to the GRS80 and WGS84 datums
since the small differences are inconsequential for the purposes of
AERSURFACE.
User must specify either CENTERXY or CENTERLL.
DATAFILE
data type pathJilename
8-4
-------
where:
data type
Type of data and year the data represent. The following are
valid secondary keywords for data type:
path Jilename
NLCD1992: 1992 NLCD land cover
NLCD2001: 2001 NLCD land cover
NLCD2006: 2006 NLCD land cover
NLCD2011: 2011 NLCD land cover
MPRV2001: 2001 percent impervious
MPRV2006: 2006 percent impervious
MPRV2011: 2011 percent impervious
CNPY2001: 2001 percent canopv
CNPY2011: 2011 percent canopv
User-defined path and filename. The combined path and filename is
limited to 200 characters and should be enclosed in quotes ("") if
either the path or filename includes spaces.
ZORADIUS
radius
where:
radius
Distance from the meteorological tower in kilometers over which the
surface roughness length will be averaged
ANEM HGT
anem ht (iblJactor)
where:
anem ht
Height, in meters, at which the wind measurements are taken at the
site that will be processed. The accepted value for anem ht ranges
from 1.0 meter to 100.0 meters. Only applicable for the ZOEFF
option for calculating roughness.
(iblJactor)
Optional unitless parameter, ranging from 5.0 - 10.0, used to compute
the reference height of the IBL. The IBL reference height is the
product of the anem ht and the iblfactor. The default IBL factor is
6.0. The IBL factor is an experimental value for which a
recommended value has not yet been established.
8-5
-------
CLIMATE
sfc moisture snow cover arid condition
where:
sfc moisture
Surface moisture based on precipitation amounts for the period
that will be modeled, relative to the previous 30-year
climatoloaical record for the reaion. Valid entries: WET. DRY. or
AVERAGE (default = AVERAGE)
snow cover
Site experienced continuous snow cover within at least on month
during the winter. Valid entries: SNOW or NOSNOW (default =
NOSNOW)
arid condition
Enter ARID (desert-like) or NONARID (default = NONARID).
NONARID is an invalid entrv in combination with continuous
snow cover (SNOW)
FREQ SECT
frequency number sectors airportJlag
where:
frequency
Period of time for which the surface characteristics are calculated,
valid entries: ANNUAL. SEASONAL, or MONTHLY.
number sectors
Integer number of roughness sectors that will be defined using the
SECTOR keyword. Sectors are only applicable to roughness
length. The number of sectors can range from 1 to 12 or 16.
AERMET allows a maximum of 12 sectors, but AERSURFACE
can calculate roughness for 16 sectors which can be useful for
comparing roughness lengths to a standard 16-direction wind rose
plot. When 16 sectors are specified, AERSURFACE results
cannot used as input to AERMET.
airportJlag
Indicates whether AERSURFACE will apply airport or non-
airport roughness values to all wind sectors, or if the sectors vary.
Valid entries: AP. NONAP. or VARYAP where: AP indicates
airport roughness values will be applied to all sectors for any land
cover category that has separate airport and non-airport values;
NONAP indicates that non-airport values will be applied; and
VARYAP informs AERSURFACE to treat each sector separatelv
based on how the sector is identified based on SECTOR keyword.
8-6
-------
SECTOR
sector index start dir end dir airport flag
where:
sector index
start dir
end dir
airportJlag
Links a specific sector to a set of site characteristics and should be
entered as consecutive integers beginning with the number 1.
Starting direction of the sector in whole degrees. Considered part of
the sector.
Ending direction of the sector in whole degrees, but excluded from
sector.
Sectors should be defined in a clockwise manner, and must cover the
full 360° circle around the meteorological tower without gaps or
overlap, (i.e., They must be defined so that the end of one sector
corresponds to the beginning of another. When 2-12 sectors are
defined, each sector must be a minimum of 30°. 16 sectors must each
be 22.5°. When 1,8, 12 or 16 is entered for the number of sectors on
the FREQ SECT keyword, the SECTOR keyword may be omitted
and default sectors used unless VARYAP is entered as the
airport Jlag attribute for the FREQ SECT keyword
Identifies whether the individual sector should be processed using
airport or non-airport related roughness length values. This attribute
is required when the secondary kevword VARYAP is entered as the
airport Jlag attribute for the FREQ SECT keyword which means
each sector will be assigned individually. When that is the case, the
airport Jag should be specified using the secondary keyword AP to
indicate it is an airport sector or NONAP to indicate it is a non-airport
sector.
SEASON
season months
where:
season
months
Secondary keyword that identifies one of five seasonal definitions:
SUMMER. AUTUMN. WINTERNS. WINTERWS. SPRING.
Space-delimited list of integer months assigned to the season. Valid
entries are 0 - 12, where 1 = Jan, 2 = Feb ... 12 = Dec. Zero (0)
indicates no months are being reassigned to the season. A season may
be specified only once. The months reassigned to a season should be
listed on a single record separated by at least one space. A month can
only be assigned to one season. It is only necessary to specify the
seasons/months that are to be reassigned. If 0 is entered for a season,
then default assignments will be used for any month that is not listed
for a different season.
RUNORNOT
RUN or NOT
where:
RUN
NOT
Indicates to run full preprocessor calculations
Indicates to process setup data and report errors, but to not run full
preprocessor calculations
8-7
-------
Table 8-3. Description of Output Pathway Keywords
OU Keywords
Type
Keyword Description
STARTING
M-N
Identifies the start of output pathway inputs
SFCCHAR
M-N
Averaged surface characteristic values formatted for input to AERMET
EFFRAD
O-N
Table of effective radius values by sector and month
NLCDGRID
O-N
Land cover data grid
MPRVGRID
O-N
Impervious data grid
CNPYGRID
O-N
Canopy data grid
NLCDTIFF
O-N
Land cover debug file containing TIFF tag and GeoKey values
MPRVTIFF
O-N
Impervious debug file containing TIFF tag and GeoKey values
CNPYTIFF
O-N
Canopy debug file containing TIFF tag and GeoKey values
FINISHED
M-N
Identifies the end of output pathway inputs
Table 8-4. Description of Output Pathway Keywords and Parameters
Keyword
Parameters
SFCCHAR
path Jilename
EFFRAD
NLCDGRID
MPRVGRID
CNPYGRID
NLCDTIFF
MPRVTIFF
CNPYTIFF
where:
path Jilename
User-defined path and filename. The combined path and filename is limited to
200 characters and should be enclosed in quotes ("") if either the path or
filename includes spaces.
8-8
-------
9.0 Appendix E: Implementation of ZOEFF Option in AERSURFACE, Version 19039 DRFT
9.1 Method
A research grade method (ZOEFF) for computing an effective surface roughness length, Zo,
using land cover data from the National Landcover Database (NLCD) has been implemented in the
draft version of AERSURFACE (19039 DRFT). In prior versions of AERSURFACE, Zo was
computed as an inverse distance weighted geometric mean of the representative roughness values
extracted from the NLCD for a default fixed upwind radial distance of 1 kilometer, relative to the
location of the meteorological measurement site. Zo, can be calculated for multiple wind sectors to
account for substantial directional differences in land cover type.
While the original method (hereon referred to as ZORAD) is currently retained in this draft
version of AERSURFACE, the ZOEFF method also included in this version determines the upwind
distance from the meteorological tower, or fetch, over which to compute an effective roughness value,
rather than using a fixed radial distance. The method is based on the distance required to grow the
internal boundary layer (IBL) to some defined height at the measurement tower due as changes in
surface roughness are encountered as the air flows toward the tower. A final effective roughness length
is then calculated over the derived fetch. As with the original method, Zo can be computed for multiple
wind sectors. The estimated fetch for which the effective roughness is computed will vary by sector.
9.2 Scientific Basis
The growth of the IBL is influenced, in part, by the mechanical forcing due to friction caused
by the roughness of the earth's surface. This method (ZOEFF) for calculating effective roughness is
based on the cumulative growth of the IBL as air flow encounters surface roughness elements as it
approaches the tower.
9-1
-------
This method was adapted from a model coding abstract (MCA) and MATLAB code developed
by Dr. Akula Venkatram1, based on methods proposed by Miyake (1965) and Wiering (1993), to
estimate surface roughness as a function of the growth of the internal boundary layer (IBL). A review
of methods for estimating the height of the IBL, which discusses Miyake's related work, was
performed by Garratt (1990). Venkatram's original MCA (edited) is included as Section 10.0 of this
User's Guide.
As described by Wieringa (1993) and stated in Venkatram's MCA and Garratt (1990), the
growth of the IBL (h), with distance (x) over a constant roughness, can be described by the following
equation:
dh u* k 4
where, Zo is the surface roughness, k\s 0.4 (von Karman constant), w* is the surface friction velocity,
and U(h) is the mean wind speed at the height of the IBL.
As described in Venkatram's MCA, integrating Equation 4 between two points, x* and x, /,
produces the following equation for the growth of the IBL and can be used to calculate the growth of
the IBL between two points based on the average roughness and distance between them:
hi+1 (ln (P^-) ~1)= hi(ln (v~L~) - A + k(Xi+1 ~ 5
\ \z0 avgj J \ \z0 avgj J
where Zoavg is the average roughness between the two points x, and x, /. (Whereas Venkatram used a
simple arithmetic mean of the two roughness values at x* and x, /, the implementation of this method
(ZOEFF) in AERSURFACE uses a geometric mean of the two roughness values for consistency with
1 Dr. Akula Venkatram is a professor at the University of California, Riverside in the Department of Mechanical
Engineering. Venkatram was an original member of the American Meteorological Society/Environmental Protection Agency
Regulatory Model Improvement Committee (AERMIC) during the development and promulgation of AERMOD.
9-2
-------
the default method in AERSURFACE version 13016, retained in this draft version as the ZORAD
method).
By setting a target IBL height, href, at the measurement site based on some multiple of the measurement
height and setting a fixed distance to represent delta x over which each Zoavg is computed, the change in
the IBL height can be calculated for each delta x to determine the distance, xrad, required for the
cumulative growth for each delta x from an initial h = Zo at xrad. The current implementation uses a
default value for /zre/that is equal to 6 times the anemometer height. This factor can be changed through
user input.
Once xrad has been determined, per Venkatram, the effective roughness {Zoefj) for the sector is
computed over the distance xrad as the solution to the following equation:
9.3 Implementation
The horizontal grid resolution of the land cover data processed by AERSURFACE is 30 meters.
To implement the ZOEFF method for determining Zoeff.; AERSURFACE first divides the land cover
into concentric rings out to an initial radial distance of 5 km from the meteorological tower, with each
ring having a depth equal to the horizontal grid resolution of the data (30 meters). The rings are then
subdivided by sector as shown in Figure 9-1.
k(.xract)
6
9-3
-------
Wind Sector
Concentric Rings
(depth = 1 grid cell, 30 m)
Met Tower
Figure 9-1. Concentric Rings Defined around Meteorological Tower to
Calculate IBL Growth
As with previous versions of AERSURFACE, seasonal roughness values have been assigned to
each land cover category and are stored in a data table in the AERSURFACE source code. Monthly
values of Zo are computed for each ring segment within each sector using the seasonal lookup tables
and the values associated with the season to which each month is assigned. The monthly Zo value for a
ring segment is computed as an inverse distance weighted geometric mean of the roughness values
associated with each of the grid cells that make up the ring segment based on the distance of each grid
cell from the meteorological tower. The inverse distance weighted geometric mean is computed using
equation 1 in Section 2.4.1.1 for the default ZORAD option but limited to the grid cells that comprise
the ring segment. Like the ZORAD option, an inverse distance weighted approach is used because the
width of a sector increases with distance from the measurement site. Thus, ring segments farther from
the met tower are comprised of more grid cells than ring segments closer to the tower. If a direct area
weighted approach were used, the land cover farther from the site would receive a higher effective
weight than land cover closest to the site when the fetch is derived as described next.
Using Equation 5 above, the amount fetch required for the cumulative growth of the IBL to a
default height of six (6) times the height of the anemometer at the tower location is determined. The
value, six (6), is referred to as the IBL factor and can be set by the user in the draft version of
AERSURFACE. The default value for the IBL factor is based on Wieringa's "roughness blending
height" of 60 m (Wieringa, 1976) given that 10 m is a common anemometer height at NWS/FAA
weather stations. As Venkatram points out in his MCA and is discussed by Wierenga (1993), Miyake's
9-4
-------
research was based on surface releases when the vertical plume spread is of the order of href The IBL
factor may need to be varied based on the release height or anemometer height.
The fetch (;xrad) required to grow the IBL to a target height {href) is determined by summing
smaller changes in the height of the IBL that are associated with fixed, shorter lengths of assumed
homogeneous roughness based on the previously computed Zo values for the individual ring segments
within a sector. Within a user-defined sector, the fetch is first estimated by starting at the tower location
and summing incremental IBL heights across the concentric ring segments out from the tower. The
geometric mean of the roughness (Zoavg) of two adjacent rings is computed and treated as the
homogenous surface and distance over which to compute an incremental change in the height of the
IBL. The distance is taken to be from the center of one ring segment to the center of the adjacent ring,
30 meters. This occurs outward across the concentric rings until the sum of the individual heights
equals or exceeds href. If hrc/ \s not reached within a 5 km radial distance from the tower (which can
occur for very long fetches over a very smooth surface), the estimated fetch is limited to 5 km. The
effective roughness is then computed for the sector from the tower out to the distance for this estimated
fetch using the equation 6, above.
The fetch (;xrad) is recomputed iterating across the concentric rings going toward the tower,
starting at the distance determined from the first set of iterations and stopping at the location of the
meteorological tower. If the height of the IBL at the tower is computed to be higher than the href, then
the fetch is recomputed starting one ring closer to the tower than the original estimated fetch. If the
computed height of the IBL at the tower is lower than the target IBL, the fetch is recomputed starting
one ring width farther than the original estimated fetch. An interpolated distance based on the target
IBL height at the tower is taken as xrad iterating across the rings toward the tower. The average
effective roughness is then computed for the sector for this new value of xrad using the equation 6,
above. The final value for Zoeff is computed as the simple arithmetic mean of the two calculated
effective roughness values based on the calculated for the distance xraditerating outward from the tower
and the calculated distance xrad iterating over the rings toward the tower.
9-5
-------
These steps are repeated to compute monthly values of Zoefffor each user-defined sector. Annual
and seasonal values are then computed from the monthly values based on the temporal frequency
specified by the user in the control file.
9-6
-------
10.0 Appendix F: Venkatram Model Coding Abstract - Estimating Effective Roughness
If wind speed is measured on a tower located in a spatially inhomogeneous area, we need an
effective roughness height to estimate the surface friction velocity and other micrometeorological
variables. This effective roughness should represent the combined effect of the roughness elements
that the boundary layer encounters on its way to the measurement location. A heuristic approach to
this calculation is based on estimating the combined effect of the internal boundary layers associated
with the changes in the roughness as the air travels over a spatially inhomogeneous path. If we assume
that the roughness is constant between two points along this path, the change in the internal boundary
layer height, h, between these two points is given by (Miyake, 1965 quoted in Wieranga, BLM, 63,
323-363, 1993):
On estimating effective roughness
Akula Venkatram
December 24, 2009
7
dx U(h) ln fh_\
dx U (/i)
Integrating this equation between points, Xi and Xi+i, gives
8
where
Z0avg= (zo (0+ z0 (i +1))/ 2.
9
10-1
-------
This implicit equation can be used compute the height of the internal boundary layer as a function of
distance from the measurement location.
At the measurement location, the combined internal boundary height has a vertical structure
that reflects the roughness elements contributing to its growth. The lowest part of the boundary layer is
representative of the roughness elements closest to the measurement location, and the upper part of the
boundary layer reflects the roughness elements furthest from the location. This suggests calculating h
with the initial hi = zoi and then stopping the integration when the internal boundary height reaches a
multiple, p, of Zmeas given by href= fizmeas. The radius of influence, xrad, is the distance at which this
boundary layer height reaches href.
Then, the effective roughness is the solution of the integral of Equation 7, assuming that an
effective constant roughness, zoeff, applies to the region 0 to xrad.
This equation can be solved numerically to yield zoeff.
It is clear that p is a critical parameter that needs to be determined by comparing the computed
effective zo with a value inferred from simultaneous measurements of surface friction velocity and
wind speed using sonic anemometers. Then,
The computed zoeff is likely to apply only to surface releases, and only when the vertical plume
spread is of the order of href If we want to estimate dispersion from an elevated source, we might have
to calculate a zoefffor a href corresponding to a multiple of the release height. This means that zoeff w\\
vary with source height.
10
(measured) = zmeas exp
•*
11
10-2
-------
11.0 Appendix G: Inter-comparison of AERSURFACE
An inter-comparison of values of surface roughness length, estimated using AERSURFACE
version 19039 DRFT, is presented, as well as a comparison of corresponding AERMOD results for
several different source types and configurations. Surface characteristics were estimated using the two
AERSURFACE options for estimating surface roughness length (ZORAD and ZOEFF) and by varying
combinations of input data (i.e., land cover, percent impervious, and percent canopy). The
comparisons that are presented below are not an evaluation of the updated AERSURFACE tool.
Rather, because version 19039 DRFT introduces a research grade method (ZOEFF) for estimating
surface roughness length and the use of supplemental percent impervious and percent canopy data
beginning with the 2001 NLCD, this comparison is a limited demonstration of differences in results
using the different roughness options and varying the NLCD input data. Estimated values of albedo
and Bowen ratio are unaffected by the choice of option for estimating surface roughness length or the
use of the impervious and canopy data; therefore, albedo and Bowen ratio are not presented as part of
this comparison.
11.1 AERSURFACE Scenarios and Meteorological Data Processing with AERMET
Three NWS/FAA meteorological sites were selected for this comparison, including: Hartsfield-
Jackson Atlanta International Airport (ATL), Baton Rouge Metropolitan Airport (BTR), and Raleigh-
Durham International Airport (RDU). Because the 2001 NLCD includes land cover, impervious, and
canopy data, this comparison primarily uses 2001 NLCD. Based on historical satellite imagery, BTR
appears to have experienced only a small amount of change in land use from 1992 to 2001 in the near
proximity to the tower. Thus, additional comparisons of surface roughness values estimated using the
ZORAD and ZOEFF options with the 1992 NLCD land cover data were performed to show differences
in results between the two NLCD datasets (1992 and 2001). The 1992 NLCD land cover data
combined with the default ZORAD is equivalent to running AERSURFACE version 13016 with land
cover data only from the 1992 NLCD.
As discussed in Section 2.1, the land cover classification scheme changed from the 1992 to the
2001 NLCD for certain land cover categories. These changes prompted adding the capability to
11-1
-------
AERSURFACE to supplement land cover with impervious and canopy data beginning with the 2001
NLCD. However, as presented in Table 2-1 previously, canopy and impervious data are not available
for all years after 2001 for which there is representative land cover data.
For each station location, surface characteristic values were estimated for the AERSURFACE
scenarios listed in Table 11-1. Table 11-2 lists the additional AERSURFACE scenarios for which
surface characteristic values were estimated for BTR using the 1992 NLCD.
Table 11-1. 2001 NLCD AERSURFACE Scenarios for ATL, BTR, and RDU
Roughness Option
2001 NLCD Data Inputs
Scenario Name
ZORAD
Land Cover
Percent Impervious
Percent Canopy
2001 -LC-IMP-CAN-ZORAD
Land Cover
Percent Impervious
2001 -LC-IMP-ZORAD
Land Cover
Percent Canopy
2001-LC-CAN-ZORAD
Land Cover
2001-LC -ZORAD
ZOEFF
Land Cover
Percent Impervious
Percent Canopy
2001 -LC-IMP-CAN-ZOEFF
Land Cover
Percent Impervious
2001 -LC-IMP-ZOEFF
Land Cover
Percent Canopy
2001 -LC-CAN -ZOEFF
Land Cover
2001 -LC-ZOEFF
Table 11-2. 1992 NLCD AERSURFACE Scenarios for BTR
Roughness Option
1992 NLCD Data Inputs
Scenario Name
ZORAD
Land Cover
1992-LC-ZORAD
ZOEFF
Land Cover
1992-LC-ZOEFF
11-2
-------
Seasonal surface characteristic values were estimated using AERSURFACE for each scenario
in Table 11-1 and Table 11-2, assuming average surface moisture, a non-arid climate, and without
continuous snow during the winter. The center of the study area was defined as the location of the
meteorological tower associated with the ASOS station at each airport. Wind sectors were defined for
each site to estimate surface roughness length, based on changes in roughness within a radial distance
out to 1 km from the meteorological tower. Sectors were individually identified as either airport or non-
airport based on visual inspection of satellite imagery. Sectors that consisted primarily of runways or
open parking lots were treated as an airport. Sectors that consisted primarily of buildings or vegetation
were treated as non-airport sectors. (Refer to Sections 2.3.2, 2.4.1.3 and 3.2.9 for more discussion on
the characterization of sectors as airport or non-airport.) The coordinates of the meteorological tower
for each station, sector definitions, and whether airport or non-airport reference values were used to
compute surface roughness length, by sector, are listed in Table 11-3. Figure 11-1 through Figure 11-3
show 2001 satellite imagery from Google Earth for each of the airport sites and identifies the
10x10 km area for which albedo and Bowen ratio are estimated and the circular area around the
tower, out to 1 km, including the individual wind sectors for which roughness length is estimated.
Table 11-3. NWS/FAA Meteorological Tower Location and Wind Sector Definitions
NWS/FAA
Station
Latitude
Longitude
Sector
Reference Surface
Values
ATL
33.629691
84.442249
o
0
1
Lh
o
Non-airport
145°-270°
Non-airport
270° - 90°
Airport
BTR
30.537804
-91.146804
50°-210°
Airport
210°-280°
Airport
280°-50°
Non-Airport
RDU
35.892300
-78.781900
30° - 60°
Non-airport
60° - 225°
Airport
225°-30
Non-airport
11-3
-------
ATL Meteorological Tower I I 10 x 10 km Area O lkm Radius with Sectors
Figure 11-1. ATL 10 x 10 km Area and 1 km Radius with Wind Sectors
11-4
-------
~ BTR Meteorological Tower ~ 10 x 10 km Area
O 1km Radius with Sectors
Figure 11-2. BTR: 10 x 10 km Area and 1 km Radius with Wind Sectors
11-5
-------
~ RDU Meteorological Tower ~ 10 x 10 km Area o lkm Radius with Sectors
|C;
JcS
i ••
?¦_
-
• rt*< kin I **PtFm* *
4 t3 v
Jt j
'j>: , •r
*. a . •22%
dr.
m
4r
m
&$
, • •*•
X B
^JsP. •'
If »f
I. ~ v'
* ji 'f"
:£«£
age Latfdsat / CSpermcus
I . '¦ ' v f • "» WW«IV'1_UI yr"
V » a - p- j ¦ -• •**» »
-------
Figure 11-4 through Figure 11-10 show the land cover, percent impervious, and percent canopy
data from the 2001 NLCD for each of the three sites and the 1992 NLCD land cover for BTR.
11-7
-------
ATL 2001NLCD Land Cover
¦fr ATLMeteorologicalTower
~ 10 x 10 km Area
0 1 km Radius with Sectors
2001, 2006, 2011 NLCD Land Cover Classification
1 111 Open Water
I 12 Perennial Ice/ Snow
121 Developed. Open Space
I 22 Developed. Low Intensity
123 Developed. Medium Intensity
^¦24 Developed, High Intensity
[ ] 31 Barren Land (Rock/Sand/Clay)
L J 41 Deciduous Forest
42 Evergreen Forest
] 43 Mixed Forest
l" 151 Dwarf Scrub"
52 Shrub/Scrub
J 71 Grassland/Herbaceous
172 Sedge/Herbaceous*
[ 73 Lichens*
| j 74 Moss"
I 181 Pasture/Hay
IB 82 Cultivated Crops
90 Woody Wetlands
95 Emergent Herbaceous Wetlands
* Alaska only
1
%
I
m
J&i
Figure 11-4. 2001 NLCD Land Cover for ATL
11-8
-------
ATL 2001NLCD Percent Impervious ATL 2001NLCD Percent Canopy
0% 50% 100% 0% 50% 100%
Figure 11-5. 2001 NLCD Percent Impervious and Percent Canopy for ATL
11-9
-------
BTR 1992 NLCD Land Cover
¦jir BTR Meteorological Tower
~ 10 x 10 km Area
o 1 km Radius with Sectors
NLCD 1992 Land Cover Classification Legend
| 11 Open Water
12 Perennial Ice/Srvow
] 21 Low Intensity Residential
| 22 High Intensity Residential
| 23 Commercial/lndustriaNTransportation
31 Bare Rock/Sand/Clay
| 32 Quames/Stnp Mines/Gravel Pits
| 33 Transitional Barren
| 41 Deciduous Forest
| 42 Evergreen Forest
43 Mixed Forest
] 51 Shrubland
| 61 Orchards/Vineyards/Olher
71 Grassland/Herbaceous
~~] 81 Pastur&fHay
| 82 Row Crops
j 83 Small Grains
84 Fallow
] 85 Urban/Recreational Grasses
91 Woody Wetlands
~j 92 Emergent Herbaceous Wetlands
Figure 11-6. 1992 NLCD Land Cover for BTR
11-10
-------
~ BTR Meteorological Tower
~ 10 x 10 km Area
0 1 km Radius with Sectors
2001, 2006, 2011 NLCD Land Cover Classification
H111 Open Water
1 j 12 Perennial Ice/ Snow
! 21 Developed. Open Space
122 Developed. Low Intensity
123 Developed. Medium Intensity
^H^4 Developed. High Intensity
[ J 31 Barren Land (Rock/Sand/Clay)
141 Deciduous Forest
¦¦ 42 Evergreen Forest
| 43 Mixed Forest
j 51 Dwarf Scrub"
52 Shrub/Scrub
71 Grassland/Herbaceous
72 Sedge/Herbaceous'
73 Lichens'
74 Moss"
81 Pasture/Hay
82 Cultivated Crops
90 Woody Wetlands
195 Emergent Herbaceous Wetlands
* Alaska only
BTR 2001 NLCD Land Cover
-
-------
BTR 2001NLCD Percent Impervious
J
sfvfcja.
ffll&lrSk fe* l\i
H
BTR 2001 NLCD Percent Canopy
"ajt> aom-?*fir;
|k W'" jl- i -
¦si/ fc
r*pS£
fesw
* -1
50%
100% 0%
50%
100%
Figure 11-8. 2001 NLCD Percent Impervious and Percent Canopy for BTR
11-12
-------
RDU 2001 NLCD Land Cover
¦fa RDU Meteorological Tower
~ 10 x 10 km Area
0 1 km Radius with Sectors
2001, 2006, 2011 NLCD Land Cover Classification
11 Open Water
1 112 Perennial Ice/ Snow
~ 21 Developed. Open Space
Z] 22 Developed, Low Intensity
23 Developed. Medium Intensity
124 Developed. High Intensity
[ ] 31 Barren Land (Rock/Sand/Clay)
141 Deciduous Forest
H 42 Evergreen Forest
43 Mixed Forest
51 Dwarf Scrub"
52 Shrub/Scrub
71 Grassland/Herbaceous
72 Sedge/Herbaceous*
[ ] 73 Lichens'
74 Moss"
I 181 Pasture/Hay
(¦I 82 Cultivated Crops
90 Woody Wetlands
95 Emergent Herbaceous Wetlands
* Alaska only
3
Figure 11-9. 2001 NLCD Land Cover for RDU
11-13
-------
RDU 2001 NLCD Percent Impervious
RDU 2001 NLCD Percent Canopy
t. »> «
50%
100% 0%
50%
100%
Figure 11-10. 2001 NLCD Percent Impervious and Percent Canopy for RDU
11-14
-------
AERMET version 18081 was used to process meteorological data for input to AERMOD for
each of three NWS/FAA station locations (ATL, BTR, and RDU). 2001 surface meteorological
observations for each station were retrieved from the National Centers for Environmental Information
(NCEI), archived in the Integrated Surface Hourly (ISH) format, and paired with concurrent upper air
data from a nearby upper air station. Table 11-4 lists the upper air station that was paired with each
surface station. Concurrent 1-minute ASOS wind data was also retrieved from the NCEI for each
station and processed with AERMINUTE version 15272 to generate hourly wind data for input to
AERMET as a replacement for the hourly wind data extracted from the ISH format. For each surface
station, a separate set of AERMOD-ready 2001 meteorological data files was generated for each of the
AERSURFACE scenarios listed in Table 11-1. An additional set of 2001 meteorological files were
generated using surface characteristic values based on the 1992 NLCD land cover for BTR for the
AERSURFACE scenarios listed in Table 11-2. AERMET was run identically for all scenarios using
only regulatory default options without the adjusted u-star (ADJ U*) option. A minimum wind speed
of 0.5 m/s was used as the minimum threshold applied to the 1-minute ASOS wind data.
Table 11-4. Surface and Upper Air Station Pairings for Meteorological Data Processing
Surface
Station
Upper Air
Station
Upper Air
Station Name
Upper Air
Station City
ATL
FFC
Atlanta Regional
Airport
Atlanta, GA
BTR
SIL
Slidell Airport
Slidell, LA
RDU
GSO
Piedmont Triad
International
Airport
Greensboro, NC
11.2 Emission Sources and AERMOD Setup
One-hour ground-level concentrations of a generic inert pollutant were predicted using
AERMOD version 18081. A separate model run was performed using each of the meteorological
datasets generated for the different AERSURFACE scenarios (Table 11-1 and Table 11-2) for each of
three meteorological surface stations. Emission sources were collocated at the meteorological tower
11-15
-------
and included in each AERMOD simulation. The emission sources and configurations modeled are
listed in Table 11-5. AERMOD was run using the regulatory default (DFAULT) option.
Table 11-5. Emission Sources
Point Sources
Emission
Release
Exit
Exit
Stack
Source ID
Rate (g/s)
Height (m)
Temperature (K)
Velocity (m/s)
Diameter (m)
PI
100.0
10.0
432.0
11.7
2.4
P2
100.0
35.0
432.0
11.7
2.4
P3
100.0
55.0
432.0
11.7
2.4
P4
100.0
100.0
432.0
18.8
4.6
P5
100.0
200.0
432.0
26.5
5.6
Area Source
Emission
Release
Initial X
Initial Y
Source ID
Rate (g/s-m2)
Height (m)
Dimension (m)
Dimension (m)
A1
0.00001
0.01
100.0
100.0
Volume Source
Emission
Release
Initial
Initial
Source ID
Rate (g/s)
Height (m)
Sigma Y (m)
Sigma
Z (m)
VI
100.0
100.0
14.0
16.0
Concentrations were estimated using a polar receptor grid, centered on the meteorological tower
and extending out to 10 km from the tower. Receptors were defined every 10 degrees around the tower
at the following distances from the tower: 100-meter intervals out to 500 meters; 250-meter intervals
out to 1 km; 500-meter intervals out to 5 km; 1000-meter intervals out to 10 km. The receptor grid for
each station was comprised of 720 receptors. Receptors were processed for each station using
AERMAP version 18081 with 1-arcsecond terrain data from the National Elevation Dataset (NED) to
determine receptor elevations and hill heights.
11-16
-------
11.3 Inter-comparison of AERSURFACE and AERMOD Results
Figure 11-11, Figure 11-24, and Figure 11-40, at the end of this section, compare estimated
surface roughness lengths across the different AERSURFACE scenarios, seasons, and sectors for ATL,
BTR, and RDU, respectively. Refer to Table 11-1 and Table 11-2 for descriptions of the different
AERSURFACE scenarios for which surface values were generated. Figure 11-12, Figure 11-25, and
Figure 11-41 plot the AERMOD estimated highest 1-hour (H1H) concentrations for each scenario by
source type for each of the three sites, while Figure 11-13, Figure 11-26, and Figure 11-42 plot the
second highest (H2H) estimated 1-hour concentrations.
The remaining figures at the end of this section are collections of scatter plots for each of the
sites that compare AERMOD results by source type for the different scenarios, paired in space.
Specifically, each of the scatter plots compares either the H1H or H2H predicted concentrations at each
receptor, for two of the scenarios. The data points on the scatter plots are colorized based on the
distance from the emission source. For each site, a default "base" scenario is defined. The base
scenario is that scenario that incorporates all three 2001 NLCD data products including land cover,
impervious and canopy data and utilizes the ZORAD roughness option (i.e., LC-IMP-CAN-ZORAD).
The base scenario is compared to each of the other scenarios at the respective site. Similarly, there are
scatter plots that compare each scenario that utilized the ZORAD roughness option to the analogous
scenario that utilized the ZOEFF roughness option (e.g., LC-IMP-CAN-ZORAD vs. LC-IMP-CAN-
ZOEFF)
For each of the three sites, there are generally only small differences (0.01-0.02 meters) in the
roughness length estimated using the research grade ZOEFF option for estimating surface roughness
compared to the default ZORAD option, when comparing scenarios that used the same combination of
NLCD data files (see Figure 11-11, Figure 11-24, and Figure 11-40). This suggests the two methods
for estimating roughness length are comparable to each other. There are, however, greater differences
in the estimated roughness lengths when comparing scenarios that used the same roughness option and
different combinations of NLCD products. The largest differences for the three sites are shown in
Figure 11-11, at ATL, where there is a difference of about 0.2 meters in the roughness values estimated
for Sector 2 during the summer when land cover data are supplemented with both impervious and
11-17
-------
canopy data (2001-LC-IMP-CAN-ZORAD) versus when land cover data are supplemented with
canopy data only (2001-LC-CAN-ZORAD) and similarly, between 2001-LC-CAN-ZORAD and 2001-
LC-ZORAD in which land cover data is not supplemented with either impervious or canopy data.
However, these are the largest differences between estimated values for any sector and season across
the different scenarios for any of the three locations. There is a much smaller difference between 2001-
LC-IMP-CAN-ZORAD which includes impervious and canopy data and 2001-LC-ZORAD which is
based solely on land cover data. For each of the sites, when comparing the scenario that includes both
impervious and canopy data to the scenario that uses only land cover data, the difference in the derived
roughness is generally much less than 0.1 meter.
In general, H1H and H2H concentrations for all scenarios are comparable to the base case (ratio
close to 1.0). ATL resulted in the largest differences in modeled concentrations when comparing
scenarios that used different combinations of NLCD products. In Figure 1 l-12Error! Reference
source not found., a comparison of the difference in the H1H modeled concentrations (not paired in
space or time) for source PI represents a 20% decrease in the scenarios using the ZORAD roughness
option for which land cover was supplemented with both impervious and canopy data (2001-LC-IMP-
CAN-ZORAD) compared with supplementing land cover with canopy data only (2001-LC-CAN-
ZORAD). For the same two scenarios, there is 44% increase in the concentration for the P3 source. PI
is the lowest level point source which has a 10-meter release height. P3 is also a point source with a
release height of 55 meters. For each of the sites, the greatest differences estimated concentrations
occur for the low-level point source, PI. (Refer to Table 11-5 for the source characteristics of each of
the modeled emission sources.) In keeping with the comparison of roughness values, there are
generally smaller differences in H1H and H2H estimated concentrations, not paired in time or space)
when comparing the scenario that includes both impervious and canopy data to the scenario that uses
only land cover data. The scatter plots, however, do illustrate greater differences in the estimated
concentrations across the different scenarios when paired in space which highlights the sensitivity of
AERMOD to roughness.
A comparison of the base case, which uses the 2001 NLCD, to the scenarios that use the 1992
NLCD at BTR (Figure 11-27 and Figure 11-28), where there has been little change over the years in
11-18
-------
the vicinity of the met tower, shows very little difference in the derived roughness lengths (< 0.04
meters) for all seasons and sectors, suggesting that the default base scenario which incorporates 2001
land cover, impervious, and canopy data is comparable to using the 1992 NLCD land cover data only.
To summarize:
• Supplementing the 2001 land cover data with impervious and canopy data appears to
yield comparable results to the 1992 land cover when there has been little change in land
use over.
• Supplementing the 2001 land cover data with impervious and canopy data appears to be
more comparable to using land cover data only than supplementing with only
impervious or canopy data.
• A comparison of estimated AERMOD concentrations paired in space highlights the
sensitivity of low-level sources to even small changes roughness length.
11-19
-------
ATL - Surface Roughness Length - Winter
E,
t>0A0
Sector 1(90-145)*
Sector 2 (145 - 270)'
Sector 3 (270 - 90)
® 0,10
ATL - Surface Roughness Length - Spring
E,
t040
Sector 1(90-145)*
Sector 2 (145 - 270)*
Sector 3 (270 - 90)
8 0.30
» 0.10
0.00
AERSURFACE Scenario
AERSURFACE Scenario
„ °-5°
£_
1,0-40
c
ai
8 0.30
M
I, 0.20
t
w 0.00
if
ATL - Surface Roughness Length - Summer
J3
-Sector 1(90-145)*
-Sector 2 (145 - 270)*
-Sector 3 (270 - 90)
AERSURFACE Scenario
*Processed as Non-airport Sector
£0.40
c
a
$ 0.30
a>
ao
C
¦& 0.20
3
O
a
g 0.10
ro
•t
^ 0.00
jjS'
s?
ATL - Surface Roughness Length - Autumn
-Sector 1 (90 -145)*
-Sector 2 (145 • 270)*
-Sector 3 (270 - 90)
AERSURFACE Scenario
Figure 11-11. ATL Surface Roughness Length by Season, Sector, and AERSURFACE Scenario
11-20
-------
ATL 1-Hour H1H Predicted Concentrations
Source
2000
AERSURFACE Scenario
Figure 11-12. ATL H1H Predicted Concentrations by AERSURFACE Scenario and
Emission Source
11-21
-------
ATL 1-Hour H2H Predicted Concentrations
Source
AERSURFACE Scenario
Figure 11-13. ATL H2H Predicted Concentrations by AERSURFACE Scenario and
Emission Source
11-22
-------
ATL
ZORAD Case: LC-IMP-CAN.ZORAD
ZOEFF Case: LC-IMP-CAN-ZOEFF
Point 2
Volume
LC-IMP-CAN_ZORAD (ug.'m3)
LC-IMP-CAN_ZORAD (ug.'m3)
LC-IMP-CAN_ZORAD
-------
ATL
Base: LC-IMP-CAN ZORAD
Case: LC-IMP_ZORAD
Point 2
Point 4
Volume
LC-IMP-CAN_ZORAD
-------
ATL
Base: LC-IMP-CAN ZORAD
Case: LC-IMP-ZOEFF
Figure 11-16. ATL, Scatter Plots, H1H and H2H at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-IMP-ZOEFF
LC-IMP-CAM_ZORAD
-------
ATL
Base: LC-IMP-CAN ZORAD
Case: LC-CAN-ZORAD
1-Hr H1H Scatter Plot
Area
LC-IMP-CAN_ZORAD
-------
ATL
Base: LC-IMP-CAN ZORAD
Ca&e: LC-CAN-ZOEFF
1-Hr H1H Scatter Plot
Area
LC-IMP-CAN_ZORAD
-------
ATL
Base: LC-IMP-CAN ZORAD
Case: LC-ZORAD
Figure 11-19. ATL, Scatter Plots, IIIII and II2II at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-ZORAD
11-28
-------
ATL
Base: LC-IMP-CAN ZORAD
Case: LC-ZOEFF
Point 2
Point 4
Volume
LC-IMP-CAN_ZORAD
-------
Figure 11-21. ATL, Scatter Plots, IIIII and II2II at each Receptor,
2001 LC-IMP-ZORAD Vs. 2001 LC-IMP-ZOEFF
LC-IMP-ZORAD (ug.'m3)
LC-IMP-ZORAD (ug,'m3)
-C-IMP-ZORAD (ug/m3)
LC-IMP-ZORAD (ug.'m3)
11-30
-------
Figure 11-22. ATL, Scatter Plots, Hill and H2H at each
Receptor, 2001 LC-CAN-ZORAD Vs. 2001 LC-CAN-ZOEFF
LC-CAN-ZORAD (ugi'm3)
11-31
-------
ATL
ZORAD Case: LC-ZORAD
ZOEFF Case: LC-ZOEFF
Point 4
Volume
LC-ZORAD (ug.'m3)
LC-ZORAD (ug.'m3!
i (ug.'rn3)
-C-ZORAD (ug/m3'|
Figure 11-23. ATL, Scatter Plots, H1H and 1I21I at each Receptor,
2001 LC-ZORAD Vs. 2001 LC-ZOEFF
LC-ZORAD (ug/m3)
LC-ZORAD (ug'm3)
11-32
-------
BTR - Surface Roughness Length - Winter
£
JZ
w i
-Sector 1 (50- 210)
-Sector 2 (210 - 280)
-Sector 3 (280 - 50)*
£
j
' y /
*CT <$> ,
r /
J? Sf
& -c*N'
4?
_ 0.20
.c
§ 0.15
-J
Of
M 0.10
*e
4/1 0.00
AERSURFACE Scenario
BTR - Surface Roughness Length - Summer
Sector 1(50 -210)
Sector 2 (210 - 280)
Sector 3 (280 - 50)*
J?
AERSURFACE Scenario
/ ^ J" j
> > _#N
A?
BTR - Surface Roughness Length - Autumn
of
*'V
.r/
-Sector 1(50-210)
-Sector 2 (210 - 280)
-Sector 3 (280 - 50)*
c/ esf
AERSURFACE Scenario
-------
BTR 1-Hour H1H Predicted Concentrations
3000
Source
AERSURFACE Scenario
Figure 11-25. BTR H1H Predicted Concentrations by AERSURFACE Scenario and
Emission Source
11-34
-------
BTR 1-Hour H2H Predicted Concentrations
2400
Source
AERSURFACE Scenario
Figure 11-26. BTR H2H Predicted Concentrations by AERSURFACE Scenario and
Emission Source
11-35
-------
BTR
Base: LC-IMP-CAN-ZORAD
Case: LC-ZORAD_1992
1-Hr H2H Scatter Plot
/
/
LC-IMP'CAN-ZORAD (ug.'m3)
Distance (km) H
LC-IMP-CAN-ZORAD (ug'm3)
Distance (Km)
LC-IMP-CAN-ZORAD (ug,''m3l
Distance (km)
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD (ug.'m3)
Figure 11-27. BTR, Scatter Plots, H1H and H2H at each
Receptor, 2001 Base Case, LC-IMP-CAN-ZORAD Vs. 1992 LC-
ZORAD
11-36
-------
BTR
Base: LC-IMP-CAN-ZORAD
Case: LC-20EFF_1992
1-Hr H1H Scatter Plot
Area
LC-IMP-CAN-ZORAD (ug;m3)
LC-IMP-CAN-ZORAD (ug.'m3)
f
LC-IMP-CAN-ZORAD (ug:m3)
LC-IMP-CAN-ZORAD (ug.'m3>
LC-IMP-CAN-ZORAD
-------
BTR
ZORAD Case: LC-IMP-CAN-ZORAD
ZOEFF Case: LC-IMP-CAN-ZOEFF
Figure 11-29. BTR, Scatter Plots, H1H and H2H at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-IMP-CAN-ZOEFF
LC-IMP-CAN-ZORAD (ug:m3)
LC-IMP-CAN-ZORAD <
11-38
-------
BTR
Base: LC-IMP-CAN-ZORAD
Case: LC-IMP-ZORAD
1-Hr H1H Scatter Plot
Area
>/
/
/
/•
LC-IMP-CAN-ZORAD (ugfm3)
1-Hr H2H Scatter Plot
LC-IMP-CAN-ZORAD {ugfm3>
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD {ug.'m3>
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD (ug/m3)
A7
/
LC-IMP-CAN-ZORAD (ug'm3)
Distance (Km)
J
¦ZORAD (ug,'m3)
.N-ZORAD iug/mJI
LC-IMP-CAN-ZORAD (ug.'m3)
Distance (km)
LC-IMP-CAN-ZORAD (ug;m3)
Distance (km)
Figure 11-30. BTR, Scatter Plots, HIH and H2H at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-IMP-ZORAD
11-39
-------
BTR
Base: LC-IMP-CAN-ZORAD
Case: LC-IMP-ZOEFF
Figure 11-31. BTR, Scatter Plots, H1H and H2H at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-IMP-ZOEFF
LC-IMP-CAKi-ZORAD (ug/m3)
11-40
-------
BTR
Base: LC-IMP-CAN-ZORAD
Case: LC-CAN-ZORAD
1-Hr H1H Scatter Plot
Area
/
LC-IMP-CAN-ZORAD (ugfm3)
1-Hr H2H Scatter Plot
/
LC-IMP-CAN-ZORAD {ugfm3>
/
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD {ug.'m3>
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD (ug.'m3)
¦ */*
//
/
LC-IMP-CAN-ZORAD (ug/m3)
LC-IMP-CAN-ZORAD (ug'm3)
/
i' '
/
LC-IMP-CAN-ZORAD (ug'm3)
Distance (km)
/
¦ZORAD (ug,'m3)
/
LC-IMP-CAN-ZORAD (ug.'m3)
Distance (km)
LC-IMP-CAN-ZORAD (ug;m3)
Distance (km)
Figure 11-32. BTR, Scatter Plots, H1H and H2H at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-CAN-ZORAD
11-41
-------
BTR
Base: LC-IMP-CAN-ZORAD
Case: LC-CAN-ZOEFF
1-Hr H1H Scatter Plot
Area
/
LC-IMP-CAN-ZORAD (ugfm3)
1-Hr H2H Scatter Plot
LC-IMP-CAN-ZORAD (ug.'m3)
/
LC-IMP-CAN-ZORAD {ugfm3>
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD {ug.'m3>
LC-IMP-CAN-ZORAD (ug.'m3)
/
/
/
/
LC-IMP-CAN-ZORAD (ug'm3)
Distance (km)
¦ZORAD (ug,'m3)
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD (ug/m3)
&
/
/
y
UL
/
»¦ *« .
.J/'l 1
o
o
i -c'
J
/
2
.0=0-
/
LC-IMP-CAJ
Distance (km
¦l-ZORAD (ug.'m3j
LC-IMP-CAN-ZORAD (ug;m3)
Distance (km)
Figure 11-33. BTR, Scatter Plots, H1H and H2H at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-CAN-ZOEFF
11-42
-------
BTR
Base: LC-IMP-CAN-ZORAD
Case: LC-ZORAD
1-Hr H1H Scatter Plot
Area
&
/
LC-IMP-CAN-ZORAD (ugfm3)
1-Hr H2H Scatter Plot
LC-IMP-CAN-ZORAD {ugfm3>
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD {ug.'m3>
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD (ug/m3)
LC-IMP-CAN-ZORAD (ug'm3)
Distance (Km)
LC-IMP-CAN-ZORAD (ug:'m3)
LC-IMP-CAN-ZORAD (ug.'m3)
Distance (km)
LC-IMP-CAN-ZORAD (ug;m3)
Distance (km)
Figure 11-34. BTR, Scatter Plots, H1H and H2H at each
Receptor, 2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001
LC-ZORAD
11-43
-------
BTR
Base: LC-IMP-CAN-ZORAD
Case: LC-ZOEFF
1-Hr H1H Scatter Plot
Area
/
LC-IMP-CAN-ZORAD (ugfm3)
1-Hr H2H Scatter Plot
/
/
LC-IMP-CAN-ZORAD {ugfm3>
Point 2
Point 3
Point 4
/
ar* e
i'M> "=
/
1
/
/'
/
$
/
«¦
r
/
f
it
/
/
" /
is 200 3M i 50 103 150 2C0
SO il
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD {ug.'m3>
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD (ug.'m3)
LC-IMP-CAN-ZORAD (ug/m3)
/
LC-IMP-CAN-ZORAD (ug.'m3)
Distance (Km)
/
¦ZORAD (ug,'m3)
/
LC-IMP-CAN-ZORAD
-------
BTR
20RAD Case: LC-ZORAD
ZOEFF Case: LC-ZOEFF
1 (ug.'m3)
i iugj'm3(
i (ug,'m3)
i (ug.'m3j
Figure 11-36. BTR, Scatter Plots, H1H and H2H at each
Receptor, 1992 LC-ZORAD Vs. 1992 LC-ZOEFF
LC-ZORAD (ug,'m3)
11-45
-------
ZORAD Case: LC-IMP-ZORAD
ZOEFF Case: LC-IMP-ZOEFF
Figure 11-37. BTR, Q-Q Plots, HI H and H2H at each Receptor,
2001 LC-IMP-ZORAD Vs. 2001 LC-IMP-ZOEFF
LC-IMP-ZORAD (ugi'm3)
11-46
-------
Figure 11-38. BTR, Scatter Plots, H1H and H2H at each
Receptor, 2001 LC-CAN-ZORAD Vs. 2001 LC-CAN-ZOEFF
LC-CAN-ZORAO (ug'm3)
LC-CAN-ZORAD (ug'in3)
LC-CAN-ZORAD (ug,'m3)
11-47
-------
Figure 11-39. BTR, Scatter Plots, H1H and H2H at each
Receptor, 2001 LC-ZORAD Vs. 2001 LC-ZOEFF
LC-ZORAD (ug,'m3)
11-48
-------
RDU - Surface Roughness Length - Winter
RDU - Surface Roughness Length - Spring
E
— 0.25
*
» 0.20
-Sector 1(30-60)*
-Sector 2 (60 -225)
-Sector 3 (225 - 30)*
~ 0.25
jj 0.20
a;
0.15
sz
ap
1 010
a)
•e 0.05
3
0.00
rs?
n>
at
¦T
-&¦
AERSURFACEScenario
RDU - Surface Roughness Length - Autumn
}o,s
|
3 0.20
a»
g 0.15
JZ
op
I 010
©
£ 0.05
3
0.00
Sector 1(30-60)*
Sector 2 (60 -225)
Sector 3 (225 - 30)*
J
.J
J?
&
¦f
AERSURFACEScenario
lo.2S
f
® 0.20
o 0.10
•t 0.05
sf
-------
RDU 1-Hour H1H Predicted Concentrations
Source
AERSURFACE Scenario
Figure 11-41. RDU H1H Predicted Concentrations by AERSURFACE Scenario and
Emission Source
11-50
-------
RDU 1-Hour H2H Predicted Concentrations
Source
AERSURFACE Scenario
Figure 11-42. RDU H2H Predicted Concentrations by AERSURFACE Scenario and
Emission Source
11-51
-------
RDU
ZORAD Case: LC-IMP-CAN-ZORAD
ZOEFF Case: LC-IMP-CAN-ZOEFF
Figure 11-43. RDU, Scatter Plots, H1H and H2H at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-IMP-CAN-ZOEFF
LC-IMP-CAN-ZORAD (ug.'m3)
11-52
-------
RDU
Base: LC-IMP-CAN_ZORAD
Case: LCHMP-ZORAD
Figure 11-44. RDU, Scatter Plots, H1H and II2II at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-IMP-ZORAD
LC-IMP-CAN_ZORAD (ug,'m3)
LC-IMP-CANJZORAO (ug.'m3)
LC-IMP-CAN_ZORAD (ug/m3)
11-53
-------
RDU
Base: LC-IMP-CAN_ZORAD
Case: LC-IMP-20EFF
1-Hr H1H Scatter Plot
Area
/
/
LC-IMP-CAN_ZORAD (ug.'m3)
1-Hr H2H Scatter Plot
LC-IMP-CAN_ZORAD (ug;m3)
/
LC-IMP-CAN_ZORAO (ug.'m3)
LC-IMP-CAN_ZORAD (ug.'m3)
LC-IMP-CAN_ZORAD jug.'mS)
LC-IMP-CAN_ZORAD (ug.''m3)
LC-IMP-CAN_ZORAD (ug.'m3)
P-CAN_ZORAD (ug;m3)
MZORAD (ug'm3)
/
LC-IMP-CAN_ZORAD (ug'roS)
LC-IMP-CAN_ZORAD (ug,'m3)
Distance (km)
Figure 11-45. RDU, Scatter Plots, H1H and II21I at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-IMP-ZOEFF
11-54
-------
RDU
Base: LC-IMP-CAN_ZORAD
Case: LC-CAN-ZORAD
1-Hr H1H Scatter Plot
Area
if
/
LC-IMP-CAN_ZORAD (ug.'m3)
1-Hr H2H Scatter Plot
LC-IMP-CAN_ZORAD (ug;m3)
LC-IMP-CAN_ZORAO (ug.'m3)
LC-IMP-CAN_ZORAD (ug.'m3)
LC-IMP-CAN_ZORAD jug.'mS)
LC-IMP-CAN_ZORAD (ug.''m3)
LC-IMP-CAN_ZORAD (ug.'m3)
/
P-CAN_ZORAD (ug;m3)
"¦/
,/•» .
a:**..
M ZORAD (ugOTi3)
C-IMP-CAN_ZORAD (ug-'m3)
LC-IMP-CAN_ZORAD (ug,'m3)
Distance (km)
Figure 11-46. RDU, Scatter Plots, H1H and H2H at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-CAN-ZORAD
3 „
11-55
-------
RDU
Base: LC-IMP-CAN_ZORAD
Case: LC-CAN-ZOEFF
1-Hr H1H Scatter Plot
Area
/ «-or.-
/
/
/
16M-
/
J:
/ . «*
203-
/
'Ml '
I
./ . f
E
I
/. • s
J#."*
§
Be *
iz
1
r¦¦ •
1
.• /
§
1 *»-
§'
t
/
/ •
LC-IMP-CAN_ZORAD (ug.'m3)
1-Hr H2H Scatter Plot
LC-IMP-CAN_ZORAD (ug;m3)
LC-IMP-CAN_ZORAO (ug.'m3)
./
LC-IMP-CAN_ZORAD (ug.'m3)
LC-IMP-CAN_ZORAD jug.'mS)
LC-IMP-CAN_ZORAD (ug.''m3)
LC-IMP-CAN_ZORAD (ug.'m3)
P-CAN_ZORAD (ug;m3)
'¦/
AC.-
MZORAD (ug'm3)
LC-IMP-CAN_ZORAD (ug'roS)
LC-IMP-CAN_ZORAD (ug,'m3)
Distance (km)
Figure 11-47. RDU, Scatter Plots, H1H and H2H at each Receptor,
2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-CAN-ZOEFF
11-56
-------
RDU
Base: LC-IMP-CAN_ZORAD
Case: LC-ZORAD
Figure 11-48. RDU, Scatter Plots, H1H and H2H at each
Receptor, 2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-
ZORAD
LC-IMF-CAN_ZORAD (ugtoi3)
LC-IMP-CAN_ZORAD (ug;m3)
11-57
-------
RDU
Base: LC-IMP-CAN_ZORAD
Case: LC-20EFF
1-Hr H1H Scatter Plot
Area
/
/
LC-IMP-CAN_ZORAD (ug.'m3)
1-Hr H2H Scatter Plot
LC-IMP-CAN_ZORAD (ug;m3)
LC-IMP-CAN_ZORAD (ug.'m3)
LC-IMP-CAN_ZORAD (ugfm3)
LC-IMP-CAN_ZORAD jug.'mS)
P-CAM_ZORAD (ug.''m3)
LC-IMP-CAN_ZORAD (ug.'m3)
/
LC-IMP-CAN_ZORAD (ug.'m3)
Distance (Km)
M ZORAD (ugOTi3)
LC-IMP-CAN_ZORAD (ug'roS)
,C-IMP-CAN_ZORAD (ug.'m3)
Figure 11-49. RDU, Scatter Plots, H1H and H2H at each
Receptor, 2001 Base Case, LC-IMP-CAN-ZORAD Vs. 2001 LC-
ZOEFF
11-58
-------
RDU
20RAD Case: LC-IMP-ZORAD
ZOEFF Case: LC-IMP-ZOEFF
1-Hr H1H Scatter Plot
Area
LC-IMP-ZORAD (ugrtn3)
LC-IMP-ZORAO (ug'm3)
LC-IMP-ZORAD (ug;m3>
LC-IMP-ZORAO (ugfmS)
LC-IMP-ZORAD (ug.'m3)
LC-IMP-ZORAD (ug;m3)
LC-IMP-ZORAD (ugfm3)
1-Hr H2H Scatter Plot
LC-IMP-ZORAD (ug'm3)
/
LC-IMP-ZORAO jug'm3)
Distance (km)
LC-IMP-ZORAD (ugrtn3)
LC-IMP-ZORAO {U0i'm3>
Distance (km) H
Figure 11-50. RDU, Scatter Plots, H1H and H2H at each
Receptor, 2001 LC-IMP-ZORAD Vs. 2001 LC-IMP-ZOEFF
LC-IMP-ZORAD (ug'm3)
Distance (km)
11-59
-------
RDU
20RAD Case: LC-CAN-ZORAD
ZOEFF Case: LC-CAN-ZOEFF
1-Hr H1H Scatter Plot
Area
LC-CAN-ZORAO fU9>'m3)
LC-CAN-ZORAD (ug/m3)
LC-CAN-ZORAO (ug/m3)
LC-CAN-ZORAD Iug.'m3)
LC-CAN-ZORAD (ug'm3)
LC-CAN-ZORAD (ug'in3)
Volume
LC-CAN-ZORAD (ug,'m3)
LC-CAN-ZORAO (U9''m3J
Figure 11-51. RDU, Scatter Plots, H1H and H2H at each
Receptor, 2001 LC-CAN-ZORAD Vs. 2001 LC-CAN-ZOEFF
11-60
-------
RDU
ZORAD Case: LC-ZORAD
ZOEFF Case: LC-ZOEFF
Figure 11-52. RDU, Scatter Plots, H1H and H2H at each
Receptor, 2001 LC-ZORAD Vs. 2001 LC-ZOEFF
LC-ZORAD (ug'm3)
LC-ZORAD (ug/m3)
11-61
-------
12,0 References
Aldus, 1992: TIFF, Revision 6.0. Aldus Corporation, Seattle, WA.
www, alternatiff. com/resources/TIFF 6 .pdf
Cimorelli, A. J., S. G. Perry, A. Venkatram, J. C. Weil, R. J. Paine, R. B. Wilson, R. F. Lee, W. D.
Peters, R. W. Brode, and J. O. Paumier, 2004. AERMOD: Description of Model Formulation,
EPA-454/R-03-004. U.S. Environmental Protection Agency, Research Triangle Park, NC.
EPA, 2018a: User's Guide for the AERMOD Meteorological Preprocessor (AERMET). EPA-454/B-18-
002. U.S. Environmental Protection Agency, Research Triangle Park, NC
EPA, 2018b: User's Guide for the AMS/EPA Regulatory Model - AERMOD. EPA-454/B-18- 001. U.S.
Environmental Protection Agency, Research Triangle Park, NC.
EPA, 2018c: AERMOD Implementation Guide (Revised March 2018). EPA-454/B-18-003. U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina 27711.
Garratt, J. R., 1990: The Internal Boundary Layer - A Review. Boundary-Layer Meteorology. 50: 171-
203.
Garratt, J. R., 1992: The Atmospheric Boundary Layer. Cambridge University Press, New York, New
York, 334pp.
Miyake, M., 1965: Transformation of the Atmospheric Boundary Layer over Inhomogeneous Surfaces,
Department of Atmospheric Sciences, Univ. of Washington, Scientific Report. Office of Naval
Research, Contract 477 (24) (NR 307-252). October, 1965.
Oke, T. R., 1978: Boundary Layer Climates. John Wiley and Sons, New York, New York, 372pp.
Randerson, D., 1984, "Atmospheric Boundary Layer," in Atmospheric Science and Power Production,
ed., D. Randerson. Technical Information Center, Office of Science and Technical Information,
U.S. Department of Energy, Springfield, VA, 850pp.
Slade, D.H. (ed.), 1968. Meteorology and Atomic Energy. Division of Technical Information, U.S.
Atomic Energy Commission. Oak Ridge, TN, 445pp.
Stull, R. B., 1988. An Introduction to Boundary Layer Meteorology. Kluwer Academic Publishers, The
Netherlands, 666pp.
12-1
-------
Ritter, N. and M. Ruth, 1995: GeoTIFF Format Specification.
www.remotesensing.org/geotiff/spec/geotiffhome.html.
Wieringa, J., 1976: An objective exposure correction method for average wind speeds measured at a
sheltered location. Quarterly Journal of the Royal Meteorological Society. 102 (431): 241-253,
doi:10.1002/qj.49710243119.
Wieringa, J., 1993: Representative roughness parameters for homogeneous terrain. Boundary Layer
Meteorology. 63: 323-363.
12-2
-------
United States Office of Air Quality Planning and Standards Publication No. EPA-454/B-19-001
Environmental Protection Air Quality Assessment Division February 2019
Agency Research Triangle Park, NC
------- |