INTERPOLATING RELATIVE HUMIDITY WEIGHTING FACTORS TO
CALCULATE VISIBILITY IMPAIRMENT
March 17, 2003
Submitted to:
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
Submitted by:
Science Applications International Corporation
615 Oberlin Road, Suite 100
Raleigh, NC 27605
EPA Contract No. 68-D-98-113, WA No. 5-78
SAIC Project No. 1-0825-08-2566-000
-------
Interpolating Relative Humidity Weighting Factors
To Calculate Visibility Impairment
Under the 1977 Amendments to the Clean Air Act, the U.S. Congress set a national goal calling
for "the prevention of any future, and the remedying of any existing, impairment of visibility in
mandatory Class I Federal areas which impairment results from manmade air pollution." The
Amendments required the Environmental Protection Agency (EPA) to issue regulations that
assure "reasonable progress" toward the national goal. In 40 CFR 51 Subpart P, the EPA issued
the regulations known as the Regional Haze Rule that are aimed at improving visibility
conditions and decreasing haze in 156 national parks and wilderness areas (the mandatory Class I
areas where visual range is considered a significant parameter).
The Regional Haze Rule sets a timeline that requires States to aim for restoring natural
conditions by 2064. For the time period from 2014 through 2018 and every ten years after that,
the States must demonstrate that they have met reasonable progress goals. To accomplish this
task, monitoring programs have been established in the Class I areas to measure visibility
impairment parameters and determine the types of particulate matter which extinguish light
transmission. The Regional Haze Rule (40CFR51.301(bb)) specifies that the deciview haze
index should be used to determine progress and that the deciviews are calculated from the
formula
deciview haze index = 10 In (bext/10 Mm"1) [1]
where bext represents the total atmospheric light extinction coefficient calculated from aerosol
measurements.
The EPA is developing guidance to help the States and regional planning organizations track
progress under the regional haze program. The guidance will be based on recommendations
from the EPA-Federal Land Manager Group on Regional Haze Guidance for Tracking Progress.
The workgroup discusses issues associated with the calculation of regional haze conditions, and
the tracking of progress, such as accounting for regional differences, choosing appropriate light
extinction coefficients, and the approaches for dealing with missing data.
Light extinction from a single species is calculated by multiplying a scattering or absorption
efficiency for that species by the concentration of that species.1 Some chemical species are
hygroscopic, so the scattering efficiency depends on the water content of the species. The light
extinction (bscattering) from a single species is then expressed as
blattering (in Mm"1) = dry specific scattering efficiency (in m2/g)
x relative humidity weighting factor (dimensionless)
x species concentration (in |ig/m3)
The formula most commonly used by visibility experts working in the national parks and
wilderness areas and the one currently being considered by the Tracking Progress Workgroup2
for calculating total atmospheric light extinction values from aerosol measurements1 is listed
below:
-------
3 m2/g x f(RH) x [Sulfate] [2]
+ 3 m2/g x f(RH) x [Nitrate]
+ 4 m2/g x [Organic Carbon]
+ 10 m2/g x [Elemental Carbon]
+ 1 m2/g x [Soil]
+ 0.6 m2/g x [Coarse Mass]
+ bRayleigh
The f(RH) multiplier represents a dimensionless weighting factor based on relative humidity
(RH) that accounts for the hygroscopicity of certain particulate species, [Sulfate] the measured
concentration of sulfate species as H2SO4, [Nitrate] the measured concentration of nitrate species
as HNO3, [Organic Carbon] the total organic carbon concentration, [Elemental Carbon] the light
absorbing carbon concentrations, [Soil] the soil concentration approximated by measured soil
constituent concentrations, [Coarse Mass] the difference between the particulate matter measured
on 10-micron filters and particulate matter concentrations reconstructed from measurements on
2.5-micron filters, and bRayieigh the light extinction from Rayleigh light scattering by gases in the
atmosphere. All concentrations are reported in micrograms per cubic meter.
Atmospheric Light Ext. (Mm" ) =
Equation 2 shows that the calculation of total atmospheric light extinction requires both
speciated particulate concentrations and a weighting factor to account for the hygroscopic nature
of sulfates and nitrates. Figure 1 shows the weighting factor curve used by the Tracking
Progress Workgroup, based on laboratory and field work.1 This non-linear curve suggests that
the light extinction and the deciview haze indices are highly dependent on the RH conditions at
any site with significant sulfate and/or nitrate concentrations.
Figure 1. Weighting Factor Curve for the Hygroscopicity of Sulfates and Nitrates
Relative Humidity (percent)
-------
The National Park Service Air Resources Division has collected RH data at approximately 50
sites during the last twelve years. However, further expansion of the instrumentation used to
collect RH measurements will be limited. Of the 156 Class I areas, only about one quarter will
have RH measurements collected directly in their Class I area. To accommodate limited
monitoring resources, the 156 Class I areas were grouped into 110 clusters. Each cluster
contains at least one IMPROVE particulate sampler, and the behavior at all of the areas within
the cluster will be characterized by the cluster monitor(s).
Recognizing that a data gap for RH measurements would persist in future years, the Tracking
Progress Workgroup concluded that f(RH) factors needed to be established to describe each
Class I area. Since RH conditions vary from season to season and even from day to day, an
acceptable compromise allows the local f(RH) values to be described on a monthly basis. To
avoid changes in the RH readings in future years (which may have been based on exceptional
weather conditions or even on new monitor information), the workgroup chose to use
climatological averages based on a ten-year block of prior meteorological data, instead of data
that continues to be collected each year. Recognizing that RH may vary considerably
geographically, the workgroup chose to find f(RH) values for each individual Class I area rather
than estimating regional averages.
The following sections describe how the data were processed to find monthly average f(RH)
factors for each individual Class I area and for the 15,000 ^-degree grid cells of
latitude/longitude across the United States. Monthly maps are presented to illustrate how f(RH)
varies across the United States and during a year.
METHODOLOGY
A similar analysis of the relative humidity data was originally published in August 2001. That
analysis relied on an extrapolation of the relationship of RH to f(RH) out to 98% relative
humidity, which led to f(RH) values as high as 26.4. The EPA received a comment that
questioned the ability to accurately measure RH in the high ranges where f(RH) is very sensitive
to a single percent change in RH, so the workgroup revised the methodology.
The revised analysis of f(RH) values assigned a value of 7.3976 to any hourly relative humidity
value greater than or equal to 95%. The revised analysis was completed in December 2002, and
a brief comparison of the two methods is included in Attachment 1. This report describes the
data from the December 2002 analysis.
The EPA Tracking Progress Workgroup established the procedures for determining monthly
average f(RH) values. The procedures aimed to develop climatological f(RH) factors for Class I
areas as well as other areas of the United States. Since the curve in Figure 1 is nonlinear, the
climatological f(RH) values will be dependent on the distribution of hourly RH measurements.
Hourly relative humidity (RH) measurements for 292 National Weather Service (NWS) stations
across the fifty States and District of Columbia were collected.3 Additional rural information
was gathered from two networks: the Interagency Monitoring of Protected Visual Environments
-------
(IMPROVE) and the Clean Air Status and Trends Network (CASTNet). At least five years of
hourly RH measurements were available from 29 IMPROVE and IMPROVE protocol monitor
sites, 4 48 CASTNet sites,5 and 13 additional sites administered by the National Park Service.6
The hourly RH data from 1988 through 1997 were converted into RH weighting factors, f(RH),
using the nonlinear curve provided in Figure 1. The curve describes RH values from 1 to 100
percent and f(RH) values from 1 to 7.3976. An hourly f(RH) value was calculated for each valid
hourly RH measurement in the meteorological site data.
Daily average f(RH) values were calculated from the valid hourly data. Only days with at least
16 valid hourly RH values were processed. The daily averages were combined for all years from
1988 through 1997 to find climatological monthly f(RH) averages. Lastly, all monthly average
f(RH) values based on fewer than 140 days of data over the 10-year period were removed. This
criterion ensured that variations caused by a single climatological condition (e.g., those caused
during El Nino years) would not dominate the data set describing a site.
The monthly average f(RH) values at the meteorological sites were used as the basis for the data
describing the entire country. Monthly average f(RH) values were interpolated at ^-degree
increments using the inverse distance weighting technique, using 1 as the distance interpolation
exponent:
f(J?TT) -
f(RH)>- V/k,
where the monthly f(RH)g of the grid cell is calculated from f(RH)w, the monthly f(RH) at the
meteorological site, and xwg, the horizontal distance between the grid cell center and the
meteorological site, summed over all of the valid meteorological site within a 250-mile radius
(350 miles in Alaska). No f(RH) values were corrected for elevation or temperature, but the
elevation at which the data is interpolated is presented by the HazeCalc tool. ' The ^-degree grid
resolution (28-km grid cells) was chosen so that the map generation files and the associated
computer software for all States could be handled easily on a personal computer without
significant memory consumption.
RESULTS
Figures 2 through 13 show the monthly f(RH) values interpolated from the 382 sites for each
month. The maps show individual f(RH) ranges. The maps show that the calculated monthly
f(RH) values are predominantly regional in nature, and the measurements at individual sites
almost always agree well with the regional averages. Table 1 reports the monthly variations seen
in some areas of the nation.
f The HazeCalc tool is a freeware package that the EPA will provide at
http://www.epa.gov/ttn/naaqs/pm/pm25_tech.html to determine monthly f(RH) values at any U.S. location. The tool
will also download raw data from the IMPROVE monitors and convert these numbers into five-year averages
according to the USEPA Guidance for Tracking Progress under the Regional Haze Rule.
-------
Figure 2. Monthly average f(RH) values for January
4* ^
+ ++i
*r
7k
tfD x+
'+
+ll
+ /
¦4-'
Relative Humidity
Weighting Factors
¦ >6
¦ 5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
-f NWS Site
$ NPS Site
f- IMPROVE Site
4* CASTNetSite
-------
Figure 3. Monthly average f(RH) values for February
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
-f NWS Site
$ NPS Site
# IMPROVE Site
<4* CASTNetSite
-------
Figure 4. Monthly average f(RH) values for March
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
+ NWS Site
$ NPS Site
flf IMPROVE Site
4* CASTNetSite
-------
Figure 5. Monthly average f(RH) values for April
+^3
4
4
4
® \ 4
4
G .+
4^§
9
+ j
4-
o
;-ul
4
4
o
4
4 4
4
4
4
4
4
4 ,,
4 4
4
4 *1 4
4
: +
4 4
4
4
4
V
4
4
4
4
f
4
©
4
^ 4-
4 4
,4
'+
4
4
^ I
4
4
#'
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
^ NWS Site
$ NPS Site
flf IMPROVE Site
4* CASTNetSite
-------
Figure 6. Monthly average f(RH) values for May
' -4- M
jft
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
+ NWS Site
$ NPS Site
flf IMPROVE Site
CASTNetSite
-------
Figure 7. Monthly average f(RH) values for June
' -4- M
jf
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
+ NWS Site
$ NPS Site
flf IMPROVE Site
4* CASTNetSite
-------
Figure 8. Monthly average f(RH) values for July
+ 0
m
YA
4-
HK
+
H#
¦ i
%. MS
¦4
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
^ NWS Site
$ NPS Site
flf IMPROVE Site
4* CASTNetSite
-------
Figure 9. Monthly average f(RH) values for August
>K
ZMA
4-
HK
+
4-
4^-
J ¦ H
%. s
3 + V.
' ' A. ' ~
w.
+r
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
+ NWS Site
$ NPS Site
flf IMPROVE Site
^ CASTNetSite
-------
Figure 10. Monthly average f(RH) values for September
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
+ NWS Site
$ NPS Site
flf IMPROVE Site
4* CASTNetSite
-------
Figure 11. Monthly average f(RH) values for October
a
H
u ^ 5
E >
(uf,
-f
:"r +
% Wj
1 +
X rf
+r
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
+ NWS Site
$ NPS Site
flf IMPROVE Site
4* CASTNetSite
-------
Figure 12. Monthly average f(RH) values for November
HK
+o
Wmm
A
A
WA
^ I
* +
1
[j ,+
<+¦
Vir
[Ifl
4-
4
m
4
4
¦ m
- *? i
" ( + f
T rf
-w. .
+ i
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
+ NWS Site
$ NPS Site
flf IMPROVE Site
CASTNetSite
-------
Figure 13. Monthly average f(RH) values for December
%
+
'<1 f"
± rf
J
jf
Relative Humidity
Weighting Factors
¦ >6
5.5-6.0
5.0-5.5
4.5-5.0
4.0-4.5
3.5-4.0
3.0-3.5
2.5-3.0
2.0-2.5
1.5-2.0
1.0-1.5
+ NWS Site
$ NPS Site
flf IMPROVE Site
^ CASTNetSite
-------
Table 1. Regiona
Ranges Of Monthly Average Relative Humidity Weighting Factors
Area
Lowest Values
Lowest Month
Highest
Values
Highest Month
Northwest
Under 2.0
July
Over 5.0
December
Southwest
Under 1.5
June
Over 2.0
January
East of the
Mississippi
Under 2.5
April
Over 3.5
September
Western Alaska
Under 3.0
March
Over 4.5
August
Eastern Alaska
Under 2.0
May
Over 3.0
October
Southern California
and Hawaii
Few annual variations
Tables 2 and 3 present the monthly average relative humidity and f(RH) factors for the
mandatory class I areas (based on the geographic location of the class I areas' centroids). The
class I areas are listed alphabetically.
Table 2. Monthly Average Relative Humidity for Mandatory Class I Areas Listed
Alphabetically
Cluster
Class I Area
State
January
February
March
April
May
June
"3
l~9
August
September
October
November
December
1
Acadia NP
ME
72
69
66
68
70
71
76
77
78
76
75
76
100
Agua Tibia Wilderness
CA
61
62
64
61
62
61
60
63
63
61
56
58
80
Alpine Lake Wilderness
WA
86
83
76
75
74
70
70
70
74
82
87
88
71
Anaconda-Pintler Wilderness
MT
77
71
66
61
60
58
51
49
54
63
73
76
50
Arches NP
UT
66
63
50
45
41
32
35
42
42
45
57
63
59
Badlands NP
SD
71
69
67
62
65
65
61
59
58
60
69
70
33
Bandelier NM
NM
61
56
48
41
40
36
47
55
51
45
54
59
Bering Sea Wilderness
AK
Five years o
meteoro
ogical data not available
31
Big Bend NP
TX
47
45
39
35
40
44
48
53
55
48
48
50
55
Black Canyon of the Gunnison
NM
CO
65
62
54
50
48
41
44
50
50
48
58
63
73
Bob Marshall Wilderness
MT
77
72
68
64
63
62
57
55
60
68
75
77
38
Bosque del Apache
NM
58
53
43
36
35
32
45
53
50
44
51
57
23
Boundary Waters Canoe Area
MN
76
70
68
62
61
68
72
74
75
70
77
77
20
Breton
LA
75
73
73
73
75
78
80
79
78
75
75
76
65
Bridger Wilderness
WY
68
65
60
56
55
48
42
42
47
53
65
67
49
Bryce Canyon NP
UT
65
62
52
43
40
31
34
41
40
43
55
62
75
Cabinet Mountains Wilderness
MT
81
75
70
65
64
63
56
55
61
70
79
81
29
Caney Creek Wilderness
AR
73
68
66
67
73
73
71
71
72
71
71
73
50
Canyonlands NP
UT
67
63
51
45
41
32
36
43
43
45
57
64
15
Cape Romain
SC
71
67
66
66
70
75
76
78
77
74
71
71
52
Capitol Reef NP
UT
67
64
53
46
43
34
37
43
43
46
58
65
90
Caribou Wilderness
CA
75
70
65
59
57
52
48
49
51
56
67
74
32
Carlsbad Caverns NP
NM
55
51
42
37
40
41
51
57
58
47
50
56
18
Chassahowitzka
FL
76
73
72
71
71
77
78
79
79
77
76
77
39
Chiricahua NM
AZ
54
51
43
32
30
25
46
56
50
41
46
54
39
Chiricahua Wilderness
AZ
53
50
42
31
30
24
46
56
49
40
45
54
-------
Table 2. Monthly Average Relative Humidity for Mandatory Class I Areas Listed
Alphabetically
Cluster
Class I Area
State
January
February
March
April
May
June
"3
l~9
August
September
October
November
December
12
Cohutta Wilderness
GA
73
68
66
65
72
76
77
78
77
74
72
74
86
Crater Lake NP
OR
84
79
77
75
72
68
64
64
66
75
84
85
69
Craters of the Moon NM
ID
75
70
62
56
55
49
41
39
44
54
69
75
93
Cucamonga Wilderness
CA
62
62
63
60
61
59
59
60
60
59
55
58
102
Denali Preserve NP
AK
74
72
65
61
59
63
70
76
76
77
77
77
95
Desolation Wilderness
CA
72
67
62
53
51
45
42
42
45
50
61
69
86
Diamond Peak Wilderness
OR
86
81
78
76
72
70
64
64
67
77
85
86
8
Dolly Sods Wilderness
WV
71
67
66
62
72
72
74
75
76
71
69
72
109
Dome Land Wilderness
CA
62
59
57
52
50
47
46
47
48
49
51
56
76
Eagle Cap Wilderness
OR
82
75
67
62
58
54
44
43
48
63
78
83
56
Eagles Nest Wilderness
CO
62
60
55
54
54
47
48
53
52
50
59
60
5
Edwin B. Forsythe (Brigantine)
NJ
69
65
65
64
68
70
73
75
75
73
69
70
96
Emigrant Wilderness
CA
69
66
63
55
52
46
43
43
45
49
59
65
19
Everglades NP
FL
73
71
71
69
69
74
73
74
75
73
73
72
65
Fitzpatrick Wilderness
WY
68
65
62
57
55
49
43
42
48
53
66
68
56
Flat Tops Wilderness
CO
64
62
55
53
52
45
45
49
50
50
59
62
39
Galiuro Wilderness
AZ
53
49
41
30
28
23
40
50
45
40
46
54
74
Gates of the Mountains
Wilderness
MT
73
68
64
60
59
58
53
51
55
62
69
71
86
Gearhart Mountain Wilderness
OR
80
74
69
66
62
58
51
51
54
64
76
80
42
Gila Wilderness
NM
56
51
42
33
31
29
47
52
49
42
49
56
72
Glacier NP
MT
83
78
74
72
70
69
63
63
70
76
81
83
72
Glacier Peak Wilderness
WA
85
81
76
75
73
70
69
70
73
81
86
87
79
Goat Rocks Wilderness
WA
86
81
76
75
72
69
67
68
72
81
86
88
48
Grand Canyon NP
AZ
61
58
49
39
36
28
33
41
40
41
51
57
66
Grand Teton NP
WY
69
66
61
56
55
49
43
42
47
54
65
69
4
Great Gulf Wilderness
NH
70
66
65
65
67
70
73
76
77
73
71
71
53
Great Sand Dunes NM
CO
63
60
53
50
50
45
49
56
54
50
60
62
10
Great Smoky Mountains NP
TN
74
68
67
64
72
77
77
78
78
74
71
74
32
Guadalupe Mountains NP
TX
56
51
42
35
38
41
52
58
59
45
50
56
108
Haleakala NP
HI
72
71
71
71
69
69
70
69
69
71
72
72
107
Hawaii Volcanoes NP
HI
75
76
77
77
77
77
78
75
75
76
78
75
77
Hells Canyon Wilderness
OR
81
75
67
62
59
56
47
47
52
64
77
82
28
Hercules-Glades Wilderness
MO
73
69
65
65
71
72
72
72
73
69
71
73
97
Hoover Wilderness
CA
69
65
61
54
51
45
42
42
44
48
58
65
25
Isle Royale NP
Ml
77
71
68
63
60
68
74
74
76
71
78
78
7
James River Face Wilderness
VA
68
64
63
60
68
72
73
75
75
70
66
69
68
Jarbidge Wilderness
NV
73
68
57
59
58
53
44
39
37
46
64
71
110
John Muir Wilderness
CA
66
64
62
56
54
48
46
47
49
51
57
62
101
Joshua Tree NM
CA
59
59
58
54
55
52
50
56
55
54
51
55
10
Joyce-Kilmer-Slickrock
Wilderness
TN
74
68
66
64
72
77
77
79
78
74
71
74
110
Kaiser Wilderness
CA
68
65
62
55
52
46
45
45
47
50
57
63
89
Kalmiopsis Wilderness
OR
83
78
77
76
73
70
67
67
68
74
82
83
98
Kings Canyon NP
CA
66
63
62
56
53
48
46
47
48
51
56
61
55
La Garita Wilderness
CO
63
60
52
48
46
41
46
54
52
48
58
62
-------
Table 2. Monthly Average Relative Humidity for Mandatory Class I Areas Listed
Alphabetically
Cluster
Class I Area
State
January
February
March
April
May
June
"3
l~9
August
September
October
November
December
90
Lassen Volcanic NP
CA
76
70
66
60
58
52
49
49
52
57
68
74
87
Lava Beds NM
CA
80
74
70
66
63
58
53
54
56
64
75
79
13
Linville Gorge Wilderness
NC
71
67
66
63
72
76
77
79
79
73
70
72
62
Lostwood
ND
78
75
73
60
59
63
63
59
60
63
77
78
3
Lye Brook Wilderness
VT
69
66
65
64
66
69
72
74
75
72
70
70
9
Mammoth Cave NP
KY
75
70
68
66
77
83
83
76
76
72
72
75
104
Marble Mountain Wilderness
CA
82
77
76
73
71
67
65
65
66
71
79
81
56
Maroon Bells-Snowmass
Wilderness
CO
63
61
55
54
52
45
49
55
54
50
59
61
46
Mazatzal Wilderness
AZ
56
52
45
34
31
25
38
47
43
40
48
55
63
Medicine Lake
MT
78
75
72
60
59
61
61
57
59
62
76
78
54
Mesa Verde NP
CO
66
63
54
44
42
34
45
53
49
45
56
63
110
Minarets (in Ansel Adams
Wilderness)
CA
68
64
61
54
51
45
43
43
45
49
57
63
26
Mingo
MO
75
70
67
65
69
71
73
73
73
69
71
74
73
Mission Mountains Wilderness
MT
79
74
68
64
63
62
56
55
61
69
77
80
95
Mokelumne Wilderness
CA
72
67
62
54
51
45
42
42
45
50
60
68
2
Moosehorn
ME
72
68
65
67
67
70
74
76
78
74
74
74
79
Mount Adams Wilderness
WA
85
81
76
74
72
69
66
67
71
80
86
87
43
Mount Baldy Wilderness
AZ
58
54
45
35
32
27
42
51
46
42
50
58
85
Mount Hood Wilderness
OR
85
81
77
76
72
70
66
66
70
80
86
87
84
Mount Jefferson Wilderness
OR
86
82
79
77
73
71
65
65
68
79
86
87
78
Mount Rainier NP
WA
87
82
78
77
74
72
69
70
74
83
88
88
84
Mount Washington Wilderness
OR
88
83
80
79
75
72
65
65
67
80
87
88
58
Mount Zirkel Wilderness
CO
62
61
57
56
55
49
47
50
51
51
60
61
86
Mountain Lakes Wilderness
OR
82
76
73
70
66
62
57
57
60
68
80
82
67
North Absaroka Wilderness
WY
68
64
61
57
56
52
46
44
48
55
64
67
81
North Cascades NP
WA
84
80
76
75
73
71
69
70
74
81
86
86
16
Okefenokee
GA
73
70
70
69
71
77
76
79
78
76
74
75
83
Olympic NP
WA
85
81
79
78
74
75
72
75
78
84
87
87
8
Otter Creek Wilderness
WV
71
67
66
62
70
72
74
76
76
71
69
72
82
Pasayten Wilderness
WA
85
80
76
74
72
69
67
68
72
80
86
86
35
Pecos Wilderness
NM
61
57
49
43
42
39
47
56
52
47
55
60
41
Petrified Forest NP
AZ
61
57
46
37
33
26
39
50
46
43
53
60
46
Pine Mountain Wilderness
AZ
57
54
46
36
33
26
38
47
44
41
49
56
92
Pinnacles NM
CA
72
72
72
62
59
55
53
54
55
57
60
64
91
Point Reyes NS
CA
77
73
72
66
64
61
61
61
62
63
68
73
4
Presidential Range-Dry River
Wilderness
NH
70
66
65
65
67
70
74
76
77
73
72
71
58
Rawah Wilderness
CO
60
60
56
56
56
51
49
52
52
51
58
59
66
Red Rock Lakes
MT
72
67
62
58
57
53
47
45
49
57
68
71
88
Redwood NP
CA
81
78
80
79
79
78
79
80
76
75
79
79
57
Rocky Mountain NP
CO
55
57
55
56
56
51
49
52
51
49
55
55
2
Roosevelt Campobello
International Park
ME
72
68
65
67
67
70
74
76
78
74
74
74
40
Saguaro NM
AZ
51
46
39
26
25
21
39
49
44
38
44
52
-------
Table 2. Monthly Average Relative Humidity for Mandatory Class I Areas Listed
Alphabetically
Cluster
Class I Area
State
January
February
March
April
May
June
"3
l~9
August
September
October
November
December
36
Salt Creek
NM
56
52
42
38
41
41
49
55
56
47
50
55
93
San Gabriel Wilderness
CA
63
63
63
59
60
58
58
59
59
58
55
58
99
San Gorgonio Wilderness
CA
58
61
60
55
56
51
48
52
51
49
48
53
99
San Jacinto Wilderness
CA
60
61
61
57
58
56
51
57
57
55
52
55
34
San Pedro Parks Wilderness
NM
63
58
49
42
41
36
45
53
50
46
56
61
94
San Rafael Wilderness
CA
68
67
67
62
62
61
61
62
63
61
59
63
70
Sawtooth Wilderness
ID
78
71
62
56
54
49
39
38
41
53
70
77
73
Scapegoat Wilderness
MT
75
70
66
62
61
60
55
53
58
65
72
74
71
Selway-Bitterroot Wilderness
ID
79
73
67
62
60
58
50
49
54
65
76
79
22
Seney
Ml
79
74
71
66
64
69
74
77
77
75
79
80
98
Sequoia NP
CA
64
62
63
59
56
50
47
48
49
51
56
59
6
Shenandoah NP
VA
68
64
64
60
68
72
74
75
75
70
66
70
11
Shining Rock Wilderness
NC
72
68
66
64
72
77
77
79
79
74
71
73
45
Sierra Ancha Wilderness
AZ
56
53
45
34
31
25
39
48
44
41
49
56
105
Simeonof
AK
85
86
83
84
84
87
89
90
87
83
84
85
21
Sipsey Wilderness
AL
73
69
66
65
71
75
76
76
76
73
72
74
87
South Warner Wilderness
CA
77
71
65
59
56
51
44
44
48
56
69
76
17
St. Marks
FL
75
71
71
70
72
77
79
79
78
75
75
76
76
Strawberry Mountain
Wilderness
OR
83
77
70
67
63
59
49
49
54
68
80
84
44
Superstition Wilderness
AZ
54
50
43
32
29
23
37
46
42
39
46
54
14
Swanquarter
NC
69
66
65
64
69
73
75
76
74
72
69
69
47
Sycamore Canyon Wilderness
AZ
59
57
49
38
35
28
38
48
45
43
51
57
66
Teton Wilderness
WY
69
65
61
56
56
51
45
43
48
55
65
68
61
Theodore Roosevelt NP
ND
75
73
70
61
62
63
61
58
58
62
74
76
90
Thousand Lakes Wilderness
CA
76
70
66
61
58
53
49
50
52
57
68
74
84
Three Sisters Wilderness
OR
87
82
80
79
75
72
66
65
68
80
87
87
103
Tuxedni
AK
80
77
70
70
69
72
78
81
80
77
78
80
64
UL Bend
MT
72
68
65
59
58
58
53
49
52
59
69
71
27
Upper Buffalo Wilderness
AR
73
69
65
65
71
72
72
72
73
70
71
73
92
Ventana Wilderness
CA
72
71
70
63
60
57
57
57
58
59
62
67
106
Virgin Islands NP
VI
Five years o
meteoro
ogical data not available
24
Voyageurs NP
MN
74
68
66
62
61
68
68
71
73
69
76
73
67
Washakie Wilderness
WY
68
64
61
57
56
51
45
43
48
55
65
67
55
Weminuche Wilderness
CO
64
60
52
46
45
38
45
53
51
47
57
62
56
West Elk Wilderness
CO
63
61
56
55
52
45
49
56
55
51
59
61
35
Wheeler Peak Wilderness
NM
63
59
50
46
45
42
48
56
53
48
57
62
37
White Mountain Wilderness
NM
57
52
42
36
37
37
48
55
54
46
50
56
30
Wichita Mountains
OK
66
63
60
61
68
66
61
63
67
63
65
67
60
Wind Cave NP
SD
68
67
64
61
64
63
58
57
56
58
67
68
16
Wolf Island
GA
73
69
69
68
70
76
76
78
77
75
73
74
66
Yellowstone NP
WY
69
65
61
57
57
53
47
44
49
56
66
68
104
Yolla Bo My Middle Eel
Wilderness
CA
77
72
69
64
62
57
55
55
57
61
70
75
96
Yosemite NP
CA
67
65
64
57
54
47
43
42
44
48
57
63
51
Zion NP
UT
65
62
52
43
39
31
31
38
38
42
54
62
-------
Table 3. Monthly Average Relative Humidity Weighting Factors, f(RH), for Mandatory
Cluster
Class I Area
State
January
February
March
April
May
June
"3
l~9
August
September
October
November
December
1
Acadia NP
ME
3.21
2.80
2.81
3.13
3.17
3.25
3.64
3.70
3.87
3.47
3.42
3.51
100
Agua Tibia Wilderness
CA
2.39
2.34
2.36
2.19
2.20
2.16
2.16
2.25
2.29
2.24
2.09
2.18
80
Alpine Lake Wilderness
WA
4.84
4.44
3.67
3.50
3.60
3.01
3.07
3.15
3.58
4.48
5.05
5.01
71
Anaconda-Pintler Wilderness
MT
3.25
2.84
2.52
2.31
2.28
2.21
1.89
1.83
2.05
2.50
3.11
3.23
50
Arches NP
UT
2.59
2.36
1.84
1.64
1.57
1.29
1.36
1.52
1.58
1.63
2.05
2.36
59
Badlands NP
SD
2.68
2.68
2.71
2.54
2.72
2.60
2.36
2.30
2.25
2.29
2.79
2.71
33
Bandelier NM
NM
2.33
2.07
1.84
1.59
1.62
1.42
1.73
2.03
1.94
1.66
2.02
2.26
Bering Sea Wilderness
AK
Five years o
meteorological data not availab
e
31
Big Bend NP
TX
1.85
1.70
1.49
1.43
1.52
1.49
1.62
1.83
1.95
1.70
1.70
1.80
55
Black Canyon of the Gunnison
NM
CO
2.47
2.31
1.96
1.86
1.86
1.55
1.63
1.85
1.91
1.76
2.13
2.33
73
Bob Marshall Wilderness
MT
3.35
2.94
2.68
2.50
2.49
2.47
2.17
2.10
2.41
2.79
3.29
3.33
38
Bosque del Apache
NM
2.24
1.96
1.63
1.40
1.40
1.29
1.69
1.91
1.85
1.60
1.84
2.21
23
Boundary Waters Canoe Area
MN
2.90
2.53
2.56
2.30
2.47
2.78
2.95
3.16
3.27
2.69
3.09
3.08
20
Breton
LA
3.53
3.33
3.32
3.28
3.41
3.59
3.83
3.79
3.65
3.41
3.42
3.54
65
Bridger Wilderness
WY
2.46
2.30
2.17
2.08
2.09
1.73
1.47
1.44
1.74
1.95
2.38
2.40
49
Bryce Canyon NP
UT
2.63
2.42
1.96
1.64
1.53
1.28
1.31
1.50
1.51
1.62
2.03
2.41
75
Cabinet Mountains Wilderness
MT
3.71
3.21
2.82
2.55
2.53
2.49
2.18
2.11
2.47
2.93
3.64
3.76
29
Caney Creek Wilderness
AR
3.28
2.95
2.71
2.79
3.15
3.18
3.00
3.01
3.18
3.16
3.14
3.31
50
Canyonlands NP
UT
2.64
2.41
1.90
1.65
1.58
1.29
1.39
1.58
1.62
1.66
2.09
2.42
15
Cape Romain
SC
3.15
2.90
2.79
2.70
2.89
3.31
3.30
3.59
3.56
3.35
3.12
3.13
52
Capitol Reef NP
UT
2.70
2.49
1.99
1.72
1.62
1.33
1.38
1.58
1.62
1.70
2.13
2.50
90
Caribou Wilderness
CA
3.54
3.02
2.70
2.35
2.24
2.03
1.96
1.99
2.07
2.27
2.90
3.35
32
Carlsbad Caverns NP
NM
2.32
1.96
1.57
1.48
1.60
1.54
1.82
2.05
2.25
1.73
1.89
2.22
18
Chassahowitzka
FL
3.51
3.22
3.13
2.99
2.98
3.49
3.54
3.71
3.65
3.47
3.37
3.59
39
Chiricahua NM
AZ
2.03
1.94
1.58
1.24
1.22
1.13
1.73
2.01
1.74
1.47
1.60
2.07
39
Chiricahua Wilderness
AZ
1.99
1.89
1.54
1.21
1.20
1.12
1.74
2.01
1.72
1.45
1.56
2.04
12
Cohutta Wilderness
GA
3.38
3.06
2.88
2.71
3.20
3.55
3.59
3.70
3.72
3.47
3.22
3.40
86
Crater Lake NP
OR
4.62
3.97
3.70
3.49
3.18
2.91
2.64
2.67
2.90
3.60
4.57
4.67
69
Craters of the Moon NM
ID
3.07
2.70
2.25
2.00
2.00
1.76
1.42
1.40
1.57
1.95
2.73
3.00
93
Cucamonga Wilderness
CA
2.53
2.42
2.39
2.16
2.15
2.10
2.12
2.17
2.20
2.19
2.10
2.26
102
Denali Preserve NP
AK
2.88
2.81
2.39
2.11
2.16
2.36
2.84
3.46
3.54
3.38
3.17
3.17
95
Desolation Wilderness
CA
3.23
2.79
2.46
2.00
1.86
1.63
1.51
1.54
1.65
1.84
2.37
2.97
86
Diamond Peak Wilderness
OR
4.78
4.15
3.87
3.67
3.32
3.05
2.66
2.69
3.03
3.88
4.75
4.84
8
Dolly Sods Wilderness
WV
2.95
2.74
2.74
2.49
3.45
3.09
3.24
3.45
3.52
3.12
2.84
3.06
109
Dome Land Wilderness
CA
2.59
2.33
2.22
1.94
1.87
1.74
1.72
1.75
1.82
1.85
1.98
2.25
76
Eagle Cap Wilderness
OR
3.97
3.33
2.72
2.36
2.21
2.00
1.57
1.53
1.73
2.49
3.69
4.10
56
Eagles Nest Wilderness
CO
2.22
2.20
2.02
2.04
2.12
1.80
1.79
1.97
2.03
1.85
2.14
2.16
5
Edwin B. Forsythe (Brigantine)
NJ
2.89
2.64
2.73
2.59
2.92
2.99
3.19
3.37
3.37
3.24
2.84
2.91
96
Emigrant Wilderness
CA
3.15
2.80
2.58
2.10
1.96
1.66
1.53
1.55
1.65
1.83
2.33
2.85
19
Everglades NP
FL
2.80
2.64
2.57
2.43
2.41
2.76
2.67
2.89
2.96
2.81
2.69
2.77
65
Fitzpatrick Wilderness
WY
2.49
2.32
2.24
2.12
2.13
1.76
1.49
1.46
1.78
1.97
2.45
2.42
56
Flat Tops Wilderness
CO
2.33
2.25
2.02
2.00
2.03
1.71
1.66
1.81
1.93
1.83
2.15
2.23
39
Galiuro Wilderness
AZ
1.93
1.77
1.52
1.21
1.18
1.09
1.46
1.75
1.57
1.45
1.62
2.04
74
Gates of the Mountains
MT
2.84
2.54
2.40
2.27
2.23
2.19
1.95
1.90
2.08
2.40
2.70
2.77
-------
Table 3. Monthly Average Relative Humidity Weighting Factors, f(RH), for Mandatory
Cluster
Class I Area
State
January
February
March
April
May
June
"3
l~9
August
September
October
November
December
Wilderness
86
Gearhart Mountain Wilderness
OR
4.03
3.44
3.08
2.84
2.63
2.41
2.08
2.10
2.27
2.87
3.74
4.00
42
Gila Wilderness
NM
2.12
1.91
1.59
1.33
1.30
1.23
1.86
1.88
1.78
1.55
1.76
2.15
72
Glacier NP
MT
3.89
3.37
3.16
2.95
3.01
2.98
2.53
2.52
2.99
3.33
3.70
3.79
72
Glacier Peak Wilderness
WA
4.59
4.17
3.59
3.43
3.32
2.99
2.91
3.07
3.53
4.29
4.80
4.79
79
Goat Rocks Wilderness
WA
4.80
4.23
3.75
3.57
3.35
3.05
2.87
2.98
3.45
4.32
4.92
5.01
48
Grand Canyon NP
AZ
2.38
2.21
1.87
1.52
1.39
1.20
1.30
1.55
1.52
1.56
1.86
2.18
66
Grand Teton NP
WY
2.58
2.38
2.20
2.07
2.06
1.78
1.51
1.46
1.72
1.99
2.41
2.52
4
Great Gulf Wilderness
NH
2.82
2.56
2.65
2.76
2.88
3.02
3.30
3.51
3.64
3.28
3.03
2.93
53
Great Sand Dunes NM
CO
2.36
2.26
2.01
1.92
1.96
1.72
1.82
2.16
2.11
1.84
2.26
2.33
10
Great Smoky Mountains NP
TN
3.40
3.00
2.92
2.69
3.20
3.57
3.58
3.72
3.75
3.44
3.21
3.40
32
Guadalupe Mountains NP
TX
2.43
1.98
1.55
1.44
1.57
1.53
1.90
2.16
2.36
1.68
1.91
2.33
108
Haleakala NP
HI
2.67
2.57
2.54
2.47
2.37
2.31
2.42
2.40
2.34
2.46
2.66
2.61
107
Hawaii Volcanoes NP
HI
2.97
2.85
2.88
2.87
2.88
2.85
2.96
3.02
2.97
3.01
3.29
2.97
77
Hells Canyon Wilderness
OR
3.73
3.15
2.59
2.26
2.19
2.07
1.71
1.68
1.92
2.53
3.51
3.83
28
Hercules-Glades Wilderness
MO
3.19
2.88
2.61
2.61
2.99
3.01
2.96
3.03
3.15
2.91
2.98
3.21
97
Hoover Wilderness
CA
3.10
2.75
2.51
2.05
1.91
1.63
1.50
1.51
1.62
1.79
2.28
2.80
25
Isle Royale NP
Ml
2.96
2.51
2.56
2.29
2.21
2.67
3.13
3.21
3.39
2.64
3.28
3.23
7
James River Face Wilderness
VA
2.80
2.62
2.60
2.36
2.85
3.01
3.11
3.29
3.35
2.99
2.70
2.92
68
Jarbidge Wilderness
NV
2.91
2.59
2.06
2.10
2.16
1.98
1.57
1.38
1.35
1.62
2.39
2.78
110
John Muir Wilderness
CA
2.93
2.62
2.50
2.16
2.02
1.73
1.66
1.68
1.79
1.91
2.27
2.62
101
Joshua Tree NM
CA
2.32
2.22
2.18
1.98
1.98
1.90
1.83
2.00
2.02
2.00
1.91
2.07
10
Joyce-Kilmer-Slickrock
Wilderness
TN
3.42
3.01
2.92
2.70
3.20
3.57
3.59
3.72
3.75
3.45
3.22
3.40
110
Kaiser Wilderness
CA
3.03
2.71
2.52
2.09
1.95
1.70
1.62
1.64
1.74
1.87
2.26
2.72
89
Kalmiopsis Wilderness
OR
4.42
3.84
3.65
3.44
3.26
3.05
2.94
2.95
3.05
3.50
4.34
4.39
98
Kings Canyon NP
CA
2.88
2.58
2.47
2.14
2.01
1.73
1.66
1.67
1.79
1.90
2.23
2.55
55
La Garita Wilderness
CO
2.40
2.25
1.95
1.81
1.82
1.56
1.72
2.03
1.99
1.77
2.17
2.31
90
Lassen Volcanic NP
CA
3.60
3.05
2.74
2.39
2.27
2.05
1.98
2.02
2.10
2.30
2.96
3.41
87
Lava Beds NM
CA
4.09
3.46
3.14
2.86
2.66
2.44
2.24
2.26
2.41
2.85
3.71
4.02
13
Linville Gorge Wilderness
NC
3.20
2.96
2.88
2.65
3.17
3.55
3.59
3.88
3.87
3.40
3.08
3.24
62
Lostwood
ND
2.95
2.86
2.96
2.29
2.23
2.49
2.51
2.27
2.23
2.38
3.17
3.16
3
Lye Brook Wilderness
VT
2.78
2.57
2.65
2.63
2.80
2.86
3.06
3.27
3.40
3.18
2.90
2.87
9
Mammoth Cave NP
KY
3.32
2.99
2.85
3.00
4.05
4.74
4.60
3.48
3.52
3.18
3.06
3.36
104
Marble Mountain Wilderness
CA
4.29
3.71
3.53
3.29
3.15
2.96
2.92
2.94
2.99
3.30
4.07
4.20
56
Maroon Bells-Snowmass
Wilderness
CO
2.22
2.18
1.97
1.99
1.99
1.67
1.80
2.07
2.07
1.81
2.10
2.13
46
Mazatzal Wilderness
AZ
2.09
1.94
1.68
1.34
1.26
1.12
1.40
1.68
1.57
1.49
1.70
2.06
63
Medicine Lake
MT
2.97
2.86
2.85
2.23
2.19
2.37
2.36
2.13
2.17
2.33
3.09
3.12
54
Mesa Verde NP
CO
2.83
2.55
2.20
1.66
1.74
1.34
1.72
2.04
1.88
1.78
2.22
2.63
110
Minarets (in Ansel Adams
Wilderness)
CA
3.01
2.69
2.50
2.06
1.93
1.67
1.57
1.58
1.68
1.82
2.22
2.69
26
Mingo
MO
3.23
2.92
2.66
2.55
2.86
2.94
3.04
3.12
3.13
2.86
2.96
3.21
73
Mission Mountains Wilderness
MT
3.51
3.06
2.70
2.47
2.48
2.46
2.17
2.11
2.42
2.84
3.47
3.54
95
Mokelumne Wilderness
CA
3.21
2.79
2.49
2.03
1.88
1.63
1.52
1.55
1.65
1.84
2.36
2.94
2
Moosehorn
ME
3.01
2.66
2.68
2.93
2.94
3.05
3.45
3.61
3.77
3.33
3.18
3.19
-------
Table 3. Monthly Average Relative Humidity Weighting Factors, f(RH), for Mandatory
Cluster
Class I Area
State
January
February
March
April
May
June
"3
l~9
August
September
October
November
December
79
Mount Adams Wilderness
WA
4.69
4.14
3.69
3.50
3.25
2.97
2.75
2.86
3.32
4.18
4.81
4.90
43
Mount Baldy Wilderness
AZ
2.21
2.02
1.71
1.38
1.32
1.18
1.56
1.84
1.68
1.57
1.83
2.22
85
Mount Hood Wilderness
OR
4.64
4.10
3.72
3.56
3.24
2.96
2.67
2.78
3.22
4.11
4.77
4.83
84
Mount Jefferson Wilderness
OR
4.89
4.29
4.00
3.84
3.42
3.12
2.67
2.69
3.09
4.09
4.92
4.97
78
Mount Rainier NP
WA
4.94
4.39
3.94
3.79
3.55
3.25
3.06
3.17
3.68
4.57
5.10
5.14
84
Mount Washington Wilderness
OR
5.19
4.52
4.32
4.21
3.70
3.33
2.72
2.67
3.08
4.21
5.16
5.19
58
Mount Zirkel Wilderness
CO
2.19
2.19
2.05
2.10
2.20
1.83
1.71
1.80
1.96
1.87
2.15
2.13
86
Mountain Lakes Wilderness
OR
4.33
3.65
3.33
3.08
2.82
2.57
2.34
2.35
2.55
3.13
4.14
4.36
67
North Absaroka Wilderness
WY
2.41
2.25
2.21
2.13
2.11
1.89
1.64
1.54
1.76
2.03
2.35
2.38
81
North Cascades NP
WA
4.47
4.07
3.60
3.45
3.23
3.03
2.88
3.10
3.57
4.23
4.71
4.69
16
Okefenokee
GA
3.32
3.06
3.10
2.98
3.11
3.63
3.45
3.66
3.59
3.43
3.29
3.43
83
Olympic NP
WA
4.66
4.25
3.95
3.82
3.27
3.37
3.03
3.44
3.89
4.58
4.94
4.87
8
Otter Creek Wilderness
WV
2.96
2.77
2.75
2.51
3.10
3.16
3.32
3.54
3.60
3.17
2.87
3.08
82
Pasayten Wilderness
WA
4.54
4.09
3.57
3.38
3.21
2.95
2.83
3.00
3.44
4.17
4.73
4.76
35
Pecos Wilderness
NM
2.33
2.11
1.86
1.66
1.68
1.50
1.75
2.06
1.99
1.72
2.07
2.28
41
Petrified Forest NP
AZ
2.35
2.14
1.75
1.44
1.34
1.19
1.51
1.83
1.66
1.60
1.94
2.32
46
Pine Mountain Wilderness
AZ
2.16
2.02
1.74
1.38
1.30
1.14
1.40
1.70
1.59
1.52
1.74
2.11
92
Pinnacles NM
CA
3.40
3.43
3.46
2.60
2.43
2.21
2.11
2.20
2.21
2.37
2.44
2.86
91
Point Reyes NS
CA
3.56
3.23
3.06
2.60
2.49
2.27
2.38
2.44
2.47
2.54
2.86
3.26
4
Presidential Range-Dry River
Wilderness
NH
2.83
2.56
2.68
2.79
2.93
3.10
3.38
3.59
3.72
3.33
3.05
2.93
58
Rawah Wilderness
CO
2.07
2.14
2.05
2.15
2.27
1.93
1.82
1.91
2.02
1.88
2.10
2.05
66
Red Rock Lakes
MT
2.75
2.46
2.28
2.13
2.10
1.92
1.66
1.59
1.78
2.10
2.60
2.71
88
Redwood NP
CA
4.03
3.73
3.83
3.66
3.76
3.73
3.99
4.01
3.76
3.59
3.88
3.77
57
Rocky Mountain NP
CO
1.86
1.99
1.97
2.14
2.28
1.95
1.85
1.89
2.00
1.81
1.96
1.85
2
Roosevelt Campobello
International Park
ME
3.01
2.65
2.68
2.94
2.94
3.06
3.45
3.61
3.75
3.32
3.18
3.19
40
Saguaro NM
AZ
1.78
1.61
1.42
1.12
1.10
1.04
1.37
1.69
1.50
1.39
1.54
1.99
36
Salt Creek
NM
2.24
1.93
1.57
1.51
1.64
1.53
1.72
1.92
2.09
1.72
1.83
2.08
93
San Gabriel Wilderness
CA
2.58
2.45
2.42
2.17
2.15
2.09
2.12
2.17
2.21
2.20
2.12
2.29
99
San Gorgonio Wilderness
CA
2.54
2.55
2.40
2.09
2.09
1.81
1.71
1.83
1.85
1.83
1.88
2.14
99
San Jacinto Wilderness
CA
2.41
2.35
2.31
2.09
2.09
1.99
1.86
2.07
2.10
2.07
1.97
2.13
34
San Pedro Parks Wilderness
NM
2.40
2.16
1.85
1.63
1.62
1.41
1.68
1.98
1.91
1.70
2.08
2.32
94
San Rafael Wilderness
CA
2.92
2.73
2.69
2.38
2.35
2.30
2.37
2.43
2.50
2.44
2.32
2.57
70
Sawtooth Wilderness
ID
3.30
2.81
2.27
1.97
1.93
1.75
1.38
1.36
1.45
1.88
2.86
3.24
73
Scapegoat Wilderness
MT
3.12
2.76
2.55
2.38
2.36
2.32
2.05
1.98
2.22
2.59
3.04
3.09
71
Selway-Bitterroot Wilderness
ID
3.49
3.02
2.59
2.32
2.29
2.22
1.87
1.82
2.05
2.56
3.34
3.52
22
Seney
Ml
3.28
2.80
2.89
2.68
2.62
2.96
3.25
3.62
3.65
3.29
3.45
3.41
98
Sequoia NP
CA
2.78
2.53
2.52
2.28
2.14
1.75
1.65
1.63
1.79
1.91
2.29
2.46
6
Shenandoah NP
VA
2.86
2.61
2.63
2.38
2.86
3.03
3.16
3.37
3.39
2.97
2.70
2.95
11
Shining Rock Wilderness
NC
3.31
3.00
2.88
2.68
3.20
3.57
3.63
3.85
3.86
3.49
3.17
3.31
45
Sierra Ancha Wilderness
AZ
2.11
1.96
1.68
1.34
1.26
1.13
1.45
1.73
1.60
1.52
1.74
2.12
105
Simeonof
AK
4.16
4.18
3.84
3.99
4.16
4.58
5.03
5.22
4.47
3.74
3.91
4.24
21
Sipsey Wilderness
AL
3.32
3.02
2.78
2.70
3.08
3.40
3.51
3.48
3.49
3.31
3.12
3.34
87
South Warner Wilderness
CA
3.69
3.14
2.76
2.44
2.31
2.10
1.81
1.83
1.96
2.39
3.15
3.57
17
St. Marks
FL
3.52
3.25
3.18
3.12
3.18
3.60
3.79
3.83
3.65
3.45
3.43
3.64
-------
Table 3. Monthly Average Relative Humidity Weighting Factors, f(RH), for Mandatory
Cluster
Class I Area
State
January
February
March
April
May
June
"3
l~9
August
September
October
November
December
76
Strawberry Mountain
Wilderness
OR
4.25
3.62
3.13
2.83
2.59
2.35
1.86
1.86
2.17
3.09
4.07
4.37
44
Superstition Wilderness
AZ
2.00
1.83
1.59
1.28
1.20
1.10
1.38
1.62
1.50
1.43
1.63
2.01
14
Swanquarter
NC
2.83
2.64
2.59
2.41
2.70
2.96
3.11
3.20
3.11
2.96
2.73
2.85
47
Sycamore Canyon Wilderness
AZ
2.29
2.20
1.88
1.49
1.38
1.17
1.40
1.79
1.70
1.62
1.85
2.20
66
Teton Wilderness
WY
2.50
2.32
2.20
2.09
2.08
1.82
1.56
1.50
1.74
2.01
2.39
2.45
61
Theodore Roosevelt NP
ND
2.88
2.80
2.83
2.37
2.39
2.49
2.38
2.18
2.18
2.34
3.01
3.01
90
Thousand Lakes Wilderness
CA
3.67
3.09
2.79
2.44
2.30
2.07
1.99
2.03
2.11
2.34
3.05
3.48
84
Three Sisters Wilderness
OR
5.09
4.45
4.23
4.10
3.65
3.30
2.77
2.73
3.12
4.18
5.08
5.11
103
Tuxedni
AK
3.56
3.37
2.85
2.75
2.73
2.90
3.55
3.88
3.87
3.47
3.48
3.66
64
UL Bend
MT
2.66
2.48
2.47
2.25
2.15
2.12
1.93
1.75
1.88
2.19
2.62
2.65
27
Upper Buffalo Wilderness
AR
3.21
2.88
2.62
2.61
2.97
3.01
2.98
3.04
3.16
2.97
2.98
3.20
92
Ventana Wilderness
CA
3.34
3.16
3.10
2.50
2.36
2.17
2.17
2.24
2.29
2.37
2.51
2.94
106
Virgin Islands NP
VI
Five years o
meteorological data not availab
e
24
Voyageurs NP
MN
2.74
2.37
2.32
2.22
2.21
2.82
2.48
2.71
2.88
2.49
2.84
2.70
67
Washakie Wilderness
WY
2.42
2.26
2.21
2.12
2.11
1.85
1.59
1.51
1.75
2.02
2.35
2.38
55
Weminuche Wilderness
CO
2.46
2.27
1.95
1.75
1.75
1.49
1.69
2.01
1.94
1.75
2.15
2.36
56
West Elk Wilderness
CO
2.21
2.17
1.98
1.99
1.99
1.67
1.83
2.13
2.11
1.82
2.10
2.12
35
Wheeler Peak Wilderness
NM
2.40
2.21
1.92
1.76
1.80
1.59
1.76
2.12
2.07
1.79
2.19
2.35
37
White Mountain Wilderness
NM
2.22
1.93
1.58
1.44
1.50
1.40
1.73
1.95
2.01
1.66
1.83
2.14
30
Wichita Mountains
OK
2.75
2.55
2.35
2.35
2.74
2.51
2.20
2.37
2.67
2.50
2.59
2.78
60
Wind Cave NP
SD
2.52
2.51
2.52
2.46
2.64
2.45
2.19
2.16
2.13
2.21
2.62
2.53
16
Wolf Island
GA
3.27
3.02
2.95
2.86
2.96
3.43
3.40
3.65
3.58
3.41
3.27
3.37
66
Yellowstone NP
WY
2.53
2.33
2.24
2.13
2.12
1.91
1.66
1.58
1.79
2.08
2.45
2.50
104
Yolla Bo My Middle Eel
Wilderness
CA
3.78
3.23
2.99
2.65
2.53
2.31
2.30
2.35
2.41
2.59
3.22
3.58
96
Yosemite NP
CA
3.08
2.84
2.69
2.20
2.05
1.68
1.50
1.49
1.59
1.80
2.29
2.75
51
Zion NP
UT
2.65
2.45
1.99
1.64
1.51
1.27
1.24
1.40
1.43
1.58
1.99
2.39
REFERENCES
1. Malm, W.C. Spatial and Seasonal Patterns and Temporal Variability of Haze and Its
Constituents in the United States: Report III.
http://vista.cira.colostate.edu/improve/Publications/improve reports.htm (accessed January
2001).
2. EPA memorandum, dated August 27, 1999, Summary of July 28-29 Meeting of EPA -
Federal Land Manager Group on Regional Haze Guidance for Tracking Progress, by Rich
Damberg, EPA, Office of Air Quality Planning and Standards.
3. NCDC Surface Airways disks produced by Earthlnfo, Incorporated, 5541 Central Avenue,
Boulder, Colorado, 80301.
4. Data provided by Jim Sisler of Colorado State University.
5. CASTNet Meteorological Data page, http://www.epa.gov/acidrain/castnet/metdata.html
(accessed October 2000).
-------
6. Data provided by David Joseph of National Park Service Air Resources Division (November
2000).
-------
ATTACHMENT 1. COMPARISON OF F(RH) CALCULATION METHODS
December 20, 2002
Mr. Thomas E. Rosendahl
Integrated Policy & Strategies Group
OAQPS, AQSSD (MD-15)
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Reference: EPA Contract No. 68-D-98-113
Work Assignment No. 5-78
SAIC Project No. 1-0825-08-2566-000
Application/Utilization of GVS Techniques in Analyzing Particulate Matter (PM)
and Regional Haze (RH) Policy and Control Issues
Dear Mr. Rosendahl:
In accordance with Science Applications International Corporation's (SAIC) Work Plan for the
above referenced Work Assignment, this memorandum and the associated computer files
constitute the first deliverable for Task 4: Letter report on new weighting factor results. The
attached table shows the monthly average weighting factors for 154 of the mandatory Federal
Class I areas, but a lack of sufficient monitor data prevented the calculation of monthly values
for the Bering Sea Wilderness and the Virgin Islands.
Also attached find twelve maps showing the monthly weighting factors across the United States.
These maps have been constructed from the quarter-degree grid, but the data has been smoothed
to display more continuous gradients. The table and the maps are also available in electronic
form at the site ftp://ftp.saic.com/raleigh/RegionalHaze 2002FRHcurve/fRH analysis/.
The remaining two pages provide some comparisons of the new relative humidity weighting
factors with those used in previous exercises. This report was prepared by Dr. Ken Walsh
(919/836-7579) and myself (919/836-7576). If you have any comments, questions, or
suggestions, please contact one of us.
Sincerely,
SCIENCE APPLICATIONS INTERNATIONAL CORPORATION
Richard Gardner
Work Assignment Manager
Enc: Table of monthly relative humidity weighting factors for Class I areas
Twelve U.S. maps showing the monthly relative humidity weighting factors
Comparison of old and new monthly relative humidity weighting factors
-------
(/)
s-
o
•*-
0
at
U,
ot
a
vc
-S3
01
*S
£
>¦
3
ffi
-Q
s
ffi
-J—»
-5
<
si
_>
\—»
cd
13
•—
o
-J—»
c/T
•—
o
-J—»
o
,cd
.s
\—»
4=
£?
*53
£
s
-J—»
g
o
T? o
G On
O On
4= 'w
>> &Q
.5
-5
. &
^ o
VO >>
^3
% I
O
-J—» ^
gj.g
T3
r-| &Q
.5? 2
ffi
g
cd
T3
Q
G
.£?
c«
c«
cd
c«
cd
T3
G
O
o
o
c«
o
43
H
o
o
c«
cd
-j—»
cd
T3
3
"3
>
Q
4=
S|
13 ^
> o
O •
^ 43
0 ti
7J G
1 I
° o
a) cs
x> aj
o rf<
+_> O
'c? 3
c5 g
-o 3
cd
13
c«
G
Q
cd
O
I ^
aj -S 45
-r; vo
co c*
5 B
^ Oh
>> l^
i-H ON
£ ^
O O
¦73 >>
a)
"3 %
O cd
O 73
Oh C
oo 5
On S
tD
t>0
_c
"-4-J
cd
3
O
13
o
Oh
-J—»
c
Q
O
•—
o
Oh
O
On
•—
O
>
o
VI
O
O
I
13
S c3
¦s 2
"O
s-h -a
aj ^
e5 03
H >
T3
O
si
-J—»
o
o
o
(N
-j—»
c«
<
O
43
43
T3
O
•—
o
c
.£?
o
a3
c
aj
CJ
i-H
> c3
i5 aj
•73 !-h
•73 >~>
r-H Th
c3 3
> O
i Si
O >,
c
c3
T3 •
aj
c«
On
On
T3 S
aj «
•^ S
-J—» ^
c ^
.3 o
73 O
o
> ^
IS 2
- §
aj c
C
aj
Oh
o
o
X)
e
c
3->
^ si
•73 ^
C T3
cd
0\ a3
On O
O g
c«
BP «
•S .2
"O 'co
c3 3
2 O
c
I!
a3 «->
Oh TJ
o S
O ^
^ 43
a S
5 ^
C3
On O
On ^
' n ^
c« .2
O "c«
^ aj
^ B
i-n a>
3 Cu
&£
O
43
-j—»
^ C
43 ^
#v
Ch rJ~J
o «
6 c
^
O C
HH O
hin
. 2
9s &
X a->
o
i-H ^
Oh M
Oh p
c3 5^
w O
si m
c 03
O GO
s ^
J3 "O
% 3
o >
% ?-h
cd O
-o
H c/5
g 2
aj aj
•tl
a ^
w e
0) s
•^ 3
-t-" -C
¦£ >
cd
cd
T3
Q
cd
c«
3 s
II
«3 ^
a-g
^ 13
si ^
^ i-H
> «
> bt)
2 c
si o
CO r—H
05 &fl
•B °
c .2
O
B «
|eS
13
> o
g §,
^3 c3
cd ^3
O
o
G
T3
o
43
H
irj
C^;
Oh
<
.s
•—
.2h
[S
s
-j—»
c
o
Q
toJ)
C
cd
43
O
o
43
-j—»
•2 o
S °
5 ^
i-H vo
t>o _;
o
-J—»
C«
o ,§
^ 73
C aj
' C
C
c3
Oh
Vj
I
o3 gj
° 2
O 43
G
o
¦S ^
o
2;
o
o
.s
$
c«
c
o
G
2
o
>%
2 c
o «
» o
O 5-1
,=5 s
^ Oh
t*0 t-H
• S -73
£ c
"Si ^
aj aj
3 b
^ .s
S CO
P i-H
o
o
<>! -Sr
CJ
.cs
I
t>0
c
o
I
SP
'S
0
Ǥ 3
-J—»
« S
t»o 2
c S
2 o
« -S
-C
G G
Q O
c« O
O '
cd
G
O
43
H
P C ^
T3
G
c3
G
O
73 S
c 5
cd 43
O
.s
"-4-J
43
£P
*53
^ o
Qh Qh
o ^
s-H O
UH oo
O <-H
^ .s
^ o
to
o S
1—I cz
cd ^
» o
Change in
Weighting
Factor
-0.01
eoo-
-0.04
zoo-
600-
-0.16
-0.19
-0.25
-0.21
-0.10
zoo-
-0.04
-0.10
Weighting
Factor-
Dec 2002
3.09
2.85
2.71
2.54
00
CD
c\i
2.73
2.80
2.97
3.01
00
00
CM
2.96
3.11
CD
00
CM
Weighting
Factor-
Aug 2001
3.10
00
00
c\i
2.75
2.61
LLZ
2.89
2.99
3.22
3.22
2.98
3.03
3.15
2.96
Change
in RH
LO
CM
CO
CO
CM
o
CO
CO
CM
CO
+
+
+
+
+
+
+
+
+
+
+
+
+
Relative
Humidity-
Dec 2002
72.3
069
CM
CD
CD
63.1
64.9
65.7
00
CD
CD
68.7
69.1
67.7
70.1
72.4
o
00
CD
Relative
Humid ity-
Aug 2001
00
o
00
l<
CD
64.9
62.0
63.6
64.5
65.8
9Z9
00
l<
CD
ti-
CD
CD
689
71.0
66.7
Valid
Monitors-
Dec 2002
366
364
368
367
372
367
376
370
366
365
362
363
382
Valid
onitors-
ig 2001
361
356
361
362
365
362
369
365
354
358
355
357
375
2<
Valid
Days-
Dec 2002
104,611
95,476
105,368
102,162
106,046
101,813
106,735
105,893
101,729
CM
CM
O
100,189
103,829
1,238,063
Valid
Days-
Aug 2001
99,102
91,130
101,352
99,310
102,601
98,863
103,163
101,736
96,258
99,530
95,632
98,105
1,186,782
Month
January
February
March
April
May
June
July
August
September
October
November
December
Annual
-------
2400
(/>
¦55 2000
CL
o 1600
------- |