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Maroon Bells-Snowmass Wilderness Area |
Site Name
Nearest IMPROVE site is the White River National Forest site, WHRI1, near
Aspen.
Nearest CASTNET site is Gothic, GTH161, located near the southern Wilderness
Area boundary
Region
Southern Rocky Mountains
Terrain
Terrain is shown in the 2 km terrain
map and the 20 km terrain
map.
Maroon Bells-Snowmass Wilderness is located in west-central Colorado, just
west of the Continental Divide. Terrain is high peaks and basins. Elevations
vary from ~2,300 m (7,500 ft) to the highest peak elevation of 4,349 m (14,265
ft).
The nearest IMPROVE site is the White River National Forest site, WHRI1,
located near Aspen at an elevation of 3,418 m (11,211 ft) and ~ 4 km outside
of the Wilderness boundary to the northeast.
Data Representativeness
The White River National Forest site, WHRI1, is at a high elevation and
should be representative of aerosol composition and concentration at similar
elevations in Maroon Bells-Snowmass Wilderness Area. At this high elevation
it may be above regional haze. It will probably not be representative of
lower elevations in the Maroon Bells-Snowmass Wilderness, which may
frequently be isolated within lower level terrain-induced radiation
inversions.
Nearby Population/Industrial Centers and Local Sources
Nearby Data Stations
For surface meteorological data, the
Gothic CASTNET site
(GTH161), at an elevation of 2,926 m (9,597 ft) on the Wilderness Area's southern
boundary should be reasonably representative of similar elevations in the
Wilderness Area. Other nearby monitoring network stations are shown
in the data network
map and at the
US Climate Archive
and RAWS station US Climate
Archive sites. Upper air structure is best represented by upper air data
from the Grand Junction NWS site, 120 km west-northwest of the Wilderness
Area.
Wind Patterns
Gothic wind roses are based on surface meteorological data collected at the
Gothic CASTNET site, GTH161, for the period 1995 – 2001 and indicate annual
and seasonal wind direction (direction from which the wind is blowing)
frequencies. Annual and seasonal wind roses may have some local terrain
effect. Prevailing wind directions are predominantly westerly, which at the
Gothic site are steered to a more northerly direction in the seasonal and
annual wind roses. Nighttime and daytime wind roses show the diurnal pattern
at GTH161. Nighttime winds are dominated by light wind speeds with
directions from the north to north-northeast. The daytime wind rose shows
higher wind speeds from a more northwesterly direction as synoptic westerly
winds are steered by local terrain
Transport pathways into the Maroon Bells - Snowmass Wilderness Area are
primarily via upper level transport from distant source regions, consistent
with regional haze. Locally, transport from local sources such as wildland
fires will be upslope/downslope within the valleys and basins.
Inversions/Trapping
The deep canyons and basins of the Wilderness Area are subject to frequent
diurnal radiation temperature inversions that could trap aerosols locally,
especially during wildland fire episodes. Regional stagnation and subsidence
inversions could occur, especially during summer months. From May to
October, long term records show an average of nearly one air stagnation
event per month during this period in western Colorado, where a stagnation
event is defined as stagnation conditions that persist for 4 days or longer
(Wang and Angell,
1999).
Higher elevations are probably above trapped local haze and may also be
above regional haze trapped below large-scale subsidence inversions.
Climatological Statistics
Regional normals means and extremes are compiled for the
Grand Junction
NWS station. Climate data representative of Maroon Bells-Snowmass
Wilderness Area is also collected at the Gothic CASTNET site, GTH161.
Meteorological Indicators for Local Sources
Keywords
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