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Pecos Wilderness Area
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Visibility Monitoring Site Name
IMPROVE:
WHPE1 (Wheeler Peak WA)
Region
Southern Rocky Mountains
Terrain
Terrain is shown in the
2 km terrain map and the
20 km terrain map.
The Pecos Wilderness Area is located in north-central New Mexico occupying
223,667 acres near the crest of the Sangre de Cristo Mountains. Terrain is
rugged and mountainous, with elevations ranging from 2,560 m (8,400 ft) to
3,994 m (13,100 ft) at the crest of South Truchas Peak, the second highest
point in New Mexico. It contains the headwaters of the Wild and Scenic Pecos
River that flows south from the Wilderness.
The IMPROVE monitoring site representing the Pecos Wilderness is WHPE1
(Wheeler Peak), located about 60 km (~ 40 mi) to the north near the Wheeler
Peak Wilderness at an elevation of 3,372 m (11,060 ft).
Also, see Wheeler Peak Wilderness.
Representativeness
The WHPE1 IMPROVE site is at a high elevation and should be very
representative of Wilderness vistas at high elevations of the Sangre de
Cristos, including the Pecos Wilderness. At this high elevation it may
occasionally be above regional haze, and may also at times be isolated from
lower valley bottom Wilderness locations contained within valley inversions.
Nearby Population/Industrial Centers and Local Sources
Nearby Meteorological Data Stations
Nearby meteorological monitoring network stations are shown in the data
network map. Locations and data from
nearby RAWS monitoring sites can also be accessed at the
RAWS station US Climate Archive
website. There are no network stations within Wilderness boundaries. The
nearest RAWS station, with wind data, is the
Truchas New
Mexico RAWS site, a few km to the northwest of the Wilderness on the
western slope of the Sangre de Cristo, elevation 2,5433 m (8,340 ft).
Although slightly below Wilderness elevations it should be reasonably
representative of lower Wilderness elevations. Data collection began in
October, 2001. Meteorological data from various New Mexico sites, including
Santa Fe just outside and below the southern Wilderness boundary, is also
available from the
New Mexico Air Quality Bureau Meteorological Data site.
The Pecos Wilderness is about 100 miles northeast of the Albuquerque RAOB
site. Twice daily soundings from Albuquerque should be representative of
upper air structure regionally and within the Pecos Wilderness.
Wind Patterns
Albuquerque wind roses
show regional wind patterns. Most of the year but especially in winter there
is a strong northerly component that varies according to the position of the
jet stream. During summer the jet stream migrates further north than usual,
so that synoptic westerly winds aloft are weaker and more southerly winds
dominate, coinciding with the
North American Monsoon.
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. Convective instability associated with
surface heating of the moist air, combined with orographic uplift as air is
transported towards higher terrain to the north, produces frequent
convective precipitation events often associated with intense rainfall,
lightning, hail, and damaging winds. Southerly winds may also transport
airborne particulate material into the Wilderness from sources and source
regions to the south and southeast, including Mexican sources
Locally, in the absence of strong regional pressure gradients, flows will be
dominated by upslope/downslope winds typical of mountainous areas. Within
the Pecos Wilderness this will be primarily within the Pecos River
headwaters. The Wilderness may also be influenced by upslope and return flow
along the Rio Grande drainage, upslope flow being from the south, the
direction of Albuquerque, with a potential for local transport from that
area into the Wilderness via Wilderness canyons and upward mixing.
Potential local transport routes into the Wilderness include southerly and
upslope flow via the Rio Grande valley and Pecos River headwaters from
nearby source regions to the south, including the Albuquerque urban area ~
100 mi away. Possible more distant source regions include Mexico and Gulf
Coast areas also to the south with transport into the Wilderness via upward
mixing in source regions and upper level transport to contribute to larger
scale regional haze.
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 north central
New Mexico region that includes the Pecos Wilderness is midway between these
two regions and according to long term data should typically have one
stagnation episode 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 Pecos River headwaters valley may be subject to diurnal radiation
temperature inversions that could trap aerosols locally, especially during
wildland fire episodes.
Climatological Statistics
Albuquerque
Normals Means and Extremes are representative of regional climatology at
lower elevations. Climate data nearer to the Wilderness can be accessed at
the Truchas New
Mexico RAWS site.
Meteorological Indicators for Local Sources
Keywords
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Last updated 15 November 2004
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