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Galiuro Wilderness Area |
Site Name
IMPROVE:
CHIR1
Region
Mexican Highlands
Terrain
Terrain is shown in the
2 km terrain map and the
20 km terrain map.
The Galiuro Wilderness occupies 52,717 acres of the Galiuro Mountains of
southwestern Arizona. The Galiuro Mountains drain through two major canyons,
Rattlesnake Creek and Canyon flowing to the north from the center of the
Wilderness, and Redfield Canyon exiting to the south. Elevations range from
near 1,200 m (4,000 ft) at points along the western boundary to several
peaks with elevations above 2,100 m (7,000 ft). The highest elevation is
Basset Peak, elevation 2,339 m (7,671 ft).
The IMPROVE monitoring site representing the Galiuro Wilderness is
CHIR1 (Chiricahua
National Monument and Wilderness), located just west of the Chiricahua
National Monument, located about 100 km (60 mi) southeast of the Galiuro
Wilderness.
Also, see Chiricahua National Monument and Wilderness Assessment.
Representativeness
The IMPROVE monitoring site CHIR1 is at a relatively low elevation near the
mouth of one of the canyons that exit the Chiricahua National Monument. It is about
100 km east across the Sulphur Springs Valley that separates the Galiuro and
Chiricahua Mountains. It should be generally representative of aerosol
concentration and composition within the Galiuro Wilderness except if
inversion conditions at its lower elevation isolate it from air at higher
Wilderness elevations, when it may also be influenced by local air flowing
from the Chiricahua Mountains.
Nearby Population/Industrial Centers and Local Sources
Nearby Meteorological Data Stations
Nearby meteorological monitoring network stations are shown in the data
network map and at the RAWS
station US Climate Archive sites. There are no network monitoring sites
within the Wilderness boundaries. The nearest RAWS station is the
Muleshoe Ranch
Arizona RAWS site located just south of the Wilderness at a lower
elevation of 1,273 m (4,175 ft). Long term regionally representative climate
data has also been collected at the Tucson Airport and Davis-Monthan AFB
Surface Airways Observations (SAO) sites.
The nearest routinely operated upper air site is the Tucson RAOB site, about
75 km (50 mi) southwest, which conducts atmospheric soundings twice daily.
Sounding data from Tucson should be representative of regional upper air
structure including the Galiuro Wilderness Area.
Also, see Chiricahua National Monument and Wilderness Assessment.
Wind Patterns
Wind patterns of the region are characterized by
Tucson wind roses that show
prevailing east to southeasterly wind directions, with some strong westerly
winds during the spring. The Chiricahuas are well within the influence of
the North American
Monsoon. that typically establishes itself in early July and persists
through mid- September. During this period moisture bearing winds move into
the region from the southwest at the surface, from the Gulf of California,
and aloft from the southeast, from the Gulf of Mexico.
Locally, in the absence of strong regional pressure gradients, flows will be
dominated by the upslope/downslope winds typical of mountainous areas.
Nighttime drainage flow will be towards lower terrain to the north and south
via Rattlesnake and Redfield canyons, respectively.
Potential transport routes into the Galiuro Wilderness Area include long
distance transport via upward mixing from more distant source regions and
transport into the region via upper level flow. Possible source regions
include areas to the south and east, including the Gulf Coast region and
northern Mexico. Nearby urban areas include Tucson 75 km (50 mi) to the
southwest and Phoenix some 200 km (120 mi) northwest.
Also, see Chiricahua National Monument and Wilderness Assessment.
Inversions/Trapping
Wang and Angell,
1999 describe two regions of the U.S. with high frequencies of regional
stagnation events, in the southwest and south-central U.S. The southeastern
Arizona area that includes the Galiuro and Chiricahua Mountains is between
these two regions. According to long term data the region typically has one
to two stagnation episodes per month from May to October, where an air
stagnation episode is defined as stagnation conditions that persist for 4
days or longer. During this period, pressure and temperature gradients in
the region are weakest, and wind circulations weakest. Subsidence inversions
during these conditions may trap regional haze with buildup over periods of
several days.
The area may experience low-level surface-based radiation inversions. When
the Sulphur Springs Valley is within a low surface inversion, data from the
CHIR1 IMPROVE site may not be representative of aerosol characteristics at
higher Wilderness elevations.
Also, see Chiricahua National Monument and Wilderness
Assessment.
Climatological Statistics
Tucson Normals Means
and Extremes are representative of regional climatology at lower
elevations. Tucson is located about 75 km (50 mi) to the southwest.
Meteorological Indicators for Local Sources
Keywords
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Last updated 17 December 2004
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