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Black
Canyon of the Gunnison Wilderness Area |
Site Name
The nearest IMPROVE site is the Weminuche Wilderness site, WEMI1.
Region
Colorado Plateau
Terrain
Terrain is shown in the 2 km terrain
map and the 20 km terrain
map.
The Black Canyon of the Gunnison National
Park is located in west-central Colorado. The canyon, carved through the
uplifted Colorado Plateau by the Gunnison River, is deep and sheer, with a
typical rim width of ~ 335 m (1,100 ft) and depths from 555 to 830 m (1,820 to
2,722 ft). The length of the canyon within National Park boundaries is 22.5
km (14 mi). At rim level, terrain is varied, consisting of steep ridges and
valleys, rocks and pinnacles, with Park elevations from 2,200 to 2,600 m (7,200
to 8,500 ft).
The nearest IMPROVE monitoring site is at Weminuche Wilderness, site WEMI1,
about 100 km (62 mi) south and in mountainous terrain more typical of the
southern Rocky Mountains.
Data Representativeness
The Weminuche Wilderness IMPROVE site, WEMI1, may be representative of
regional haze conditions in the western Colorado-eastern Utah portions of
the Colorado Plateau, including Black Canyon of the Gunnison, but is not
likely representative of more local haze that may be present in the vicinity
of the National Park. WEMI1 is located in steep mountainous terrain, while
the terrain in the vicinity of Black Canyon is more open, typical of exposed
Colorado Plateau locations.
Nearby Population/Industrial Centers and Local Sources
Nearby Data Stations
Nearby monitoring network stations are shown in the data network
map and at
the US Climate Archive
and RAWS station US Climate
Archive sites.
The Black Canyon
RAWS site, elevation 2,610 m (8,560 ft) is located within the National
Park boundary and has meteorological data, including wind data, beginning
with June, 1997. The most representative upper air site is the
Grand Junction
NWS station located 90 – 100 km (60 mi ) to the northwest.
Wind Patterns
Grand Junction long-term wind roses show predominantly southeasterly flow,
with additional northwesterly flow during winter. These wind roses may be
influenced by terrain channeling by the Colorado River valley near Grand
Junction, but should be indicative of regional transport flow into the
National Park, as well as low level transport via Colorado River drainage
from sources at downriver locations. More detailed area-specific wind data
can be accessed at the
Black Canyon
RAWS site. Within the narrow confines of the canyon, wind directions
will be steered to up-canyon and down-canyon directions.
Transport pathways into the Black Canyon of the Gunnison National Park are
primarily via upper level transport from distant source regions, especially
source regions west of the Continental Divide, consistent with regional
haze. There may be some local low level transport into the area via the
Colorado and Gunnison River drainages.
Inversions/Trapping
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). In such cases, the entire National Park area is
likely to be within the inversion. Surrounding terrain at rim elevations is
relatively open and exposed, and may be less subject to diurnal radiation
inversions than within the narrow confines of the Canyon itself
Climatological Statistics
Regional normals means and extremes are compiled for the
Grand Junction
NWS station. These data should be representative of conditions within
the National Park.
Meteorological Indicators for Local Sources |
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