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Anaconda Pintler Wilderness Area |
(Also see Selway Bitterroot Wilderness
Area) Site Name
IMPROVE: SULA1 (Selway Bitterroot Wilderness, Sula Montana)
Region
Central Rockies
Terrain
Terrain is shown in the 2 km terrain
map
and the 20 km terrain map.
The 158,516-acre Anaconda-Pintler Wilderness Area spans 40 miles of the
Continental Divide in southwestern Montana, 35 km (22 mi) west of Anaconda.
Terrain is steep mountains and canyons leading down from the Anaconda Range
that comprises this section of the Continental Divide. Elevations range from
1,550 m (~ 5,100 ft) at the East Fork of the Bitterroot River on the west
side to 3,291 m (10,793 ft) at the summit of West Goat Peak.
The IMPROVE site representing the Selway Bitterroot and Anaconda-Pintler
Wilderness Areas is SULA1 located near the town of Sula Montana in the
valley of the East Fork of the Bitterroot River. The site is 20 km east of
the eastern Selway Bitterroot Wilderness boundary and 17 km west of the
western Anaconda-Pintler Wilderness boundary. The East Fork of the
Bitterroot River has it headwaters in the west portion of the Anaconda-Pintler
Wilderness Area. The SULA1 IMPROVE site is near the top of Sula Peak at an
elevation of 1,903 m (6,242 ft).
Representativeness
SULA1 is at a well-exposed hilltop location above the Bitterroot River East
Fork valley that extends down from the western reaches of the Anaconda-Pintler
Wilderness and is midway between Anaconda-Pintler and Selway Bitterroot
Wilderness Areas. With respect to the Anaconda-Pintler Wilderness, it is
west of the Wilderness boundary with no intervening terrain. It should be
representative of aerosol concentration and composition at similar
elevations in the region generally. Since it is separated from eastern
Wilderness locations by the Continental Divide, it may at times be less
representative of lower elevations on the east side of the Wilderness that
are impacted by local sources.
Nearby Population/Industrial Centers and Local Sources
This southwestern Montana Wilderness area is remote from any major source
regions. The nearest large population center is Missoula Montana ~ 100 km
north of SULA1 via the Bitterroot River valley. The major industry is
timber.
Nearby Meteorological Network Monitoring Stations
Nearby meteorological monitoring network stations are shown in the data
network map and at the
US Climate Archive
and RAWS station US Climate
Archive sites. Long-term meteorological data from Missoula may be
representative of concurrent meteorological conditions at SULA1. Historical
data for Missoula and other first order NWS stations are available via the
EPA Technology Transfer
Network website.
The closest and most representative upper air site is at Great Falls Montana
(TFX). This and other upper air sites are accessible via the
University of Wyoming Dept
of Atmospheric Science web page.
Wind and Transport Patterns
Regionally, wind patterns and transport flows are dominated by westerly
synoptic flows, with frequent easterly flows from the Canadian interior in
the winter. Monthly
Missoula Montana wind roses indicate this pattern, with northwesterly
flow predominant at this surface station and a significant
east-southeasterly component in the winter. Note that these surface wind
patterns may differ somewhat from upper level winds because of terrain
effects. Locally near the SULA1 monitoring site, mountain valley circulation
will prevail in the absence of strong synoptic forcing. Nighttime drainage
along the East Fork of the Bitterroot, near SULA1, will be from the
Anaconda-Pintler Wilderness to the east, thence north towards Missoula.
Afternoon upvalley flow will be southward from Missoula.
Inversions/Trapping
The upper Bitterroot East Fork valley where SULA1 is located may be subject
to wintertime nocturnal surface based inversions, although the SULA1
elevation near the top of Sula Peak may keep it above such inversions much
of the time. In the summer regional subsidence inversions during periods of
high pressure and stagnation can result in regional aerosol buildup over
periods of days. High regional aerosol concentrations may occur during
summertime stagnation and subsidence inversion periods in conjunction with
western wildland fires.
Climatological Statistics
Missoula Montana
Normals Means and Extremes are representative of similar elevation
locations in western Montana. Other
Idaho Climate
Summaries and
Montana Climate Summaries are available from the
Western Regional Climate Center.
Meteorological Indicators for Local Sources
Keywords
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