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Teton
Wilderness Area |
(Also see Yellowstone National Park,
Grand Teton National Park, and
Red Rock
Lakes Wilderness Area)
Site Name
IMPROVE:
YELL2
(Yellowstone National Park)
CASTNET: YEL408 (Yellowstone National Park)
Region
Central Rockies
Terrain
Terrain is shown in the 2 km terrain map and the 20 km terrain map.
The Teton Wilderness occupies 585,468 acres straddling the Continental
Divide in western Wyoming. It borders Yellowstone National Park to the
north, Grand Teton National Park to the west, and the Washakie Wilderness to
the east. West of the Continental Divide, Wilderness terrain is typically
mountain ridges and high basins, with elevations from 2,300 to 2,950 m
(7,500 to 9,675 ft). East of the Divide terrain is high plateaus broken by
ridges, with elevations from 2,440 to 3,709 m (8,000 to 12,165 ft) at the
summit of Younts Peak.
The IMPROVE site representing the Teton Wilderness, as well as Red Rock
Lakes National Wildlife Wilderness, Yellowstone National Park, and Grand
Teton National Park, is YELL2, located in central Yellowstone National Park
near the north shore of Yellowstone Lake. YELL2 is 50 km (30 mi) north and
west of nearest Teton Wilderness boundaries. Much of the Teton Wilderness
consists of headwater drainages of the Yellowstone River that flows into
Yellowstone Lake, and the Wilderness is largely within the same watershed
and air basin as YELL2. The YELL2 site elevation is 2,425 m (7,954 ft), 67 m
(220 ft) above the nearby Yellowstone Lake elevation of 2,358 m (7,733 ft).
The Yellowstone National Park CASTNET
site YEL408 is nearby, elevation 2,400 m (7,872 ft), 42m (138 ft) above Lake
level.
Representativeness
YELL2 is near the center of Yellowstone National Park and linked to Teton
Wilderness locations west of the Continental Divide by the Yellowstone River
above Yellowstone Lake and YELL2 aerosol measurements should be quite
representative of composition and characteristics in the Teton Wilderness.
It may at times be decoupled from air at higher elevations when contained
within a surface inversion over Yellowstone Lake.
Nearby Population/Industrial Centers and Local Sources
YELL2, located in central Yellowstone National Park, is remote from
any major source regions. The nearest population centers are the Idaho
Falls/Pocatello Idaho area 200 km (120 mi) southwest of YELL2 in the eastern
Snake River Plain region of Idaho, and Helena Montana 225 km (140 mi)
north-northwest of YELL2. The Naughton and Bridger Power Plants in
southwestern Wyoming are ~ 300 km (200 mi) to the south. Nearby emission
sources may include smoke from natural and anthropogenic burning. Highest
aerosol concentrations at YELL2 resulting from local/regional sources may
occur during regional wildfire events. A wintertime study of snowmobile
emissions indicated that particulate emissions from 2-stroke snowmobile
engines have a potential for visibility impacts in the Yellowstone National
Park airshed (Sive et al, 2003). The YELL2 site is near the Lake Ranger
Station, one of the sampling sites for that study. References to this and
other related studies are available at the
Montana
DEQ Clean Snowmobile Facts web page.
Nearby Meteorological Network Monitoring Stations
Meteorological monitoring network stations close to YELL2 are shown in the
data network map and at the
US Climate Archive
and RAWS station US Climate
Archive sites. The Yellowstone
National Park CASTNET site YEL408 is in close proximity to YELL2 and
should provide the best available representation of local surface
meteorology concurrent with aerosol monitoring. Historical data for regional
first order NWS stations are available via the
EPA Technology Transfer
Network website.
The closest upper air site is at Riverton Wyoming (RIW). 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 north-central U.S. and
Canadian interior in the winter. Monthly
Pocatello Idaho wind roses
are indicative of this pattern, with southwesterly flow predominant at this
surface station and a significant northeasterly component in the winter.
Note that these surface wind patterns may differ from upper level winds
because of local terrain effects such as the eastern Snake River Plain where
Pocatello is located. Aerosol transport from distant source regions to the
vicinity the YELL2 monitoring site will most often be via the upper level
predominantly westerly winds.
Locally, YELL2 is near the northern shore of Yellowstone Lake. Local surface
wind patterns are shown in
Yellowstone National Park wind roses based on 1996-2003 data from the
Yellowstone National Park CASTNET
site YEL408. These show predominantly southwesterly flow, especially for
higher wind speeds. Light wind speeds have a significant north-northwest
component associated with drainage flow and a possible land/lake breeze from
higher terrain north of the site during nighttime. Annual daytime strong
winds are almost exclusively from the southwest in line with prevailing
upper level synoptic flow, and light winds from the south to southeast the
probable direction for upslope and possible lake breeze flow.
Inversions/Trapping
The YELL2 IMPROVE site is sufficiently close to the level of Yellowstone
Lake to be beneath frequent prolonged wintertime surface trapping inversions
during periods of cold temperatures and regional high pressure. During these
inversions episodes the site is subject to the buildup of emissions from
local and nearby sources while decoupled from upper level transport flow and
higher elevations. In the summer regional subsidence inversions during
periods of high pressure and stagnation can result in widespread aerosol
buildup over periods of days. High summertime aerosol concentrations at
YELL2 may result from more regional sources such as western wildland fires
in conjunction with such episodes.
Climatological Statistics
Climatological data derived from
Yellowstone NP CASTNET site YEL408 data should be most representative of
YELL2.
Other Wyoming
Climate Summaries
Idaho Climate
Summaries and
Montana Climate Summaries are available from the
Western Regional Climate Center.
Meteorological Indicators for Local Sources
Keywords
Reference
Sive, B., D. Shively, and B. Pape, 2003. Spatial Variation of Volatile
Organic Compounds Associated with Snowmobile Emissions in Yellowstone
National Park. University of New Hampshire Climate Change Research Center.
Submitted to the National Park Service, US DOI. October 25, 2003.
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Last updated 16 December 2004
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