Site Name
IMPROVE:
DOME1
Region
Sierra Nevada Range
Terrain
Terrain is shown in the 2 km terrain
map and the 20 km terrain
map.
Dome Land is the southernmost wilderness in the Sierra Nevada range. It
consists of about 131,000 acres of the southern end of the Kern plateau, 110
km (70 mi) northeast of Bakersfield. Wilderness elevations range from 900 to
2,966 m (3000 to 9,730 ft). The Wilderness is bisected by the South Fork of
the Kern River that flows southwest towards Bakersfield and the southern end
of the San Joaquin Valley, where the elevation is near 150 m (500 ft) and
which is the nearest source region for anthropogenic emissions that may
affect visibility in the Dome Land Wilderness Area.
The IMPROVE site representing Dome Land Wilderness Area is DOME1, located in
the valley of the South Fork of the Kern River a few km downstream from its
exit from the Wilderness. DOME1 site elevation is 925 m (3,034 ft), the
lowest end of the range of Wilderness elevations.
Representativeness
Aerosol data from DOME1 should be representative of locations in Dome Land
Wilderness Area.
Nearby Population/Industrial Centers and Local Sources
The nearest population center is Bakersfield and the southern San Joaquin
Valley, 110 km (70 mi) southwest. This source region is the nearest source
for emissions that could contribute to haze in Dome Land Wilderness, via
low-level transport up the South Fork of the Kern River, via upward mixing
and upper level transport by prevailing westerly winds, or trapped beneath a
regional subsidence inversion.
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. The
Kernville
California RAWS site is located about 20 km (12 mi) west of the
Wilderness near the main Kern River, elevation 829 m (2,720 ft). Data from
this site may indicate upvalley/downvalley flow near the Kern River that
could be correlated with aerosol concentration trends at DOME1 to indicate
low-level transport from Bakersfield and southern San Joaquin Valley. Data
from the Bear
Peak California RAWS site located just east of the Wilderness, elevation
2,506 m (8,228 ft) should represent higher level flow patterns capable of
transport to Wilderness locations.
Regionally representative and routine upper air data is collected at the
Mercury/Desert Rock RAOB site in southern Nevada.
Wind and Transport Patterns
Bakersfield California Wind Roses show prevailing wind directions in southern San Joaquin Valley. The
predominant wind direction is northwest, with a significant southeast
component in the summer. There is probably a significant upvalley/downvalley
flow pattern along the Kern River Valley that could transport southern San
Joaquin Valley emissions upriver into the Dome Land Wilderness. This pattern
would be seen as upvalley southerly flow and downvalley northerly flow at
the Kernville
California RAWS site.
Potential local transport routes into the Dome Land Wilderness Area include
southern San Joaquin Valley emissions transported directly via diurnal
upslope/downslope flow or upvalley /downvalley flow along the Kern River,
mixed upwards with afternoon mixing, or trapped regionally under a
persistent subsidence inversion. The most likely season for valley flow
transport of San Joaquin Valley emissions into the Dome Land Wilderness Area
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
Inversions/Trapping
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 which are generally greater than 750 m
(2,500 ft) higher than San Joaquin Valley elevations. Consequently, fall and
winter are less likely to see trapped Valley emissions at Dome Land
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, within range of Dome Land Wilderness
elevations, including the DOME1 IMPROVE site. 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), above and near the
range of Wilderness elevations that are between 900 and 2,966 m (3,000 and
9,730 ft). During extended subsidence inversion stagnation conditions over
the southern San Joaquin Valley, haze measured at the DOME1 IMPROVE site is
likely associated with Valley emissions.
Climatological Statistics
Bakersfield
California Normals Means and Extremes are representative of climate
characteristics in the southern San Joaquin Valley.
Keywords