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Kaiser Wilderness Area |
(Also see Ansel Adams Wilderness Area)
Site Name
IMPROVE:
KAIS1
Region
Sierra Nevada Range
Terrain
Terrain is shown in the 2 km terrain
map and the 20 km terrain
map.
The Kaiser Wilderness Area occupies 22,700 acres within the western slopes
of the Sierra Nevada’s Pacific Crest. It includes Kaiser Ridge, with
elevations ranging from about 2,200 m (7,200 ft) to 3,146 m (10,320 ft) on
Kaiser Peak in the center of the Wilderness. On the north side streams flow
north into the San Joaquin River, and on the south side into Big Creek which
merges with the San Joaquin River west of the Wilderness. The San Joaquin
River flows westward and eventually opens up into the San Joaquin Valley 30
to 40 km (20 mi) west of the Wilderness and just north of Fresno. The
central San Joaquin Valley is the nearest major source region for emissions
that could affect visibility within the Wilderness.
The IMPROVE site representing Kaiser Wilderness Area is KAIS1, located 80 m
(260 ft) below the crest of Chinese Peak across Huntington Lake and the Big
Creek drainage to the south. KAIS1 is well exposed, with an unobstructed
vista into Kaiser Wilderness from a distance of 5 to 10 km. The elevation at
KAIS1 is 2,573 m (8,439 ft).
Representativeness
Data from KAIS1 should be very representative of aerosol concentration and
composition in the Kaiser Wilderness Area.
Nearby Population/Industrial Centers and Local Sources
The Kaiser Wilderness Area and vicinity are drained by the San Joaquin
River, which flows into the San Joaquin Valley, the nearest source region.
The San Joaquin River channel opens up into the San Joaquin Valley 25 to 30
km (15 to 20 mi) to the southwest, where the primary population center is
Fresno.
Nearby Meteorological Data Stations
Nearby meteorological monitoring network stations are shown in the data
network map and at the RAWS
station US Climate Archive site. There are no meteorological network
sites within Kaiser Wilderness Area boundaries. The
Mount Tom
California RAWS site is a mountain site, elevation 2,749 m (9,018 ft)
located 5 km north. Hourly data from that site includes wind data that
should be regionally representative. Lower elevation data, excluding wind
data, is collected at the
Huntington Lake
California COOP site. Data sites described for Sequoia and Kings Canyon
National Parks to the south, and Yosemite National Park to the north, may be
similarly representative of Kaiser Wilderness Area.
Upper air data is collected twice daily at the Oakland RAOB site.
Wind and Transport Patterns
Synoptic winds in the region are generally northwesterly (from the
northwest), with an additional component of more southerly winds in the
winter with the weakening of the Pacific High Pressure System. This pattern
is evident in monthly Fresno California Wind Roses. KAIS1 is well exposed to regional winds and this pattern
should be generally consistent there as well. In the absence of synoptic
forcing, a diurnal mountain/valley flow pattern may be evident at KAIS1,
with easterly (from the east) drainage flows from higher slopes of the
Sierra Nevadas at night and westerly daytime upslope flow from the direction
of the San Joaquin Valley via the San Joaquin River. Although the site is
well above San Joaquin Valley elevations, transport and return of San
Joaquin Valley air at the KAIS1 IMPROVE site would be indicated by a diurnal
pattern of aerosol concentration during periods of stagnation over central
California.
Potential local transport routes into the Kaiser and Ansel Adams Wilderness
Areas include San Joaquin Valley emissions transported directly via diurnal
upslope/downslope flow, mixed upwards with afternoon mixing, or trapped
regionally under a persistent subsidence inversion. The most likely season
for incursion of San Joaquin emissions into the Kaiser and Ansel Adams
Wilderness Areas is summer, when afternoon upslope winds combined with
highest mixing heights in San Joaquin Valley provide optimal transport
conditions. Springtime incursions may be associated with agricultural and
forest prescribed burning in San Joaquin Valley and National Forest lands.
Autumn incursions are probably less frequent because of persistent San
Joaquin Valley inversion that confines emissions to lower elevations
Inversions/Trapping
Most of the Kaiser Wilderness Area is above valley bottoms and local
trapping inversions are unlikely. Wintertime surface based inversions are
common in the San Joaquin Valley, the principal source region for local
emissions, although at heights typically below Wilderness elevations.
In the summer, the relatively shallow nighttime San Joaquin Valley boundary
layer is generally mixed to heights of at least 1,000 m (> 3,000 ft) above
the ground on a typical summer day, still well below Kaiser Wilderness
elevations. Summer inversions are usually larger scale subsidence inversions
associated with the establishment of the semi-permanent Pacific
high-pressure system and can result in aerosol buildup over periods of days.
Subsidence inversion heights are typically at elevations of 2,000 to 3,000 m
(6,000 to 10,000 ft), in the range of Wilderness elevations that are between
2,200 m (7,200 ft) and 3,146 m (10,320 ft).
Climatological Statistics
Huntington
Lake Climate Data represent lower Wilderness elevations.
Fresno
California Normals Means and Extremes are representative of climate
characteristics in San Joaquin Valley. Other
Northern California
Climate Summaries are available from the
Western Regional Climate Center.
Keywords
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Last updated 13 November 2004
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