Site Name
IMPROVE:
PINN1 (Pinnacles Wilderness Area)
Region
California Coast Ranges
Terrain
Terrain is shown in the 2 km terrain
map and the 20 km terrain
map.
The Ventana Wilderness Area consists of 95,152 acres straddling the Santa
Lucia Mountains, ~ 25 km (15 mi) south of Monterey Bay overlooking the
California coast. Terrain is steep ridges and peaks. The Wilderness is in
two sections, a large sections consisting of most of the northwest Santa
Lucias, and a smaller section to the southeast that includes Juniper Serra
Peak. Elevations range from 182 m (600 ft) where the Big Sur River exits the
Wilderness on the west side, to 1,787 m (5,862 ft) at the crest of Junipero
Serra Peak, the highest point in the Santa Lucia range. The Santa Lucia
range is the first barrier to westerly winds and presents a rain shadow over
inland areas. Annual precipitation on the coast side totals up to 75 inches,
mostly in the winter, with as little as 25 inches a few miles inland.
Summertime fog can cover lower elevations on the west side that reach within
0.5 km (0.25 mi) of the coast, but seldom reaches more than a few miles
inland. Ventana Wilderness and the Santa Lucia range are bordered on the
west side by the Pacific Ocean and on the east side by Carmel Valley, Sierra
de Salinas, and the Salinas Valley. Carmel Valley and Salinas Valley both
exit into the Monterey Bay area to their northwest. The Santa Lucia range is
thus within the maritime influence of the Pacific Ocean on the west and east
side.
The IMPROVE site presently representing the Ventana Wilderness is PINN1, the
Pinnacles site located on the eastern side of the Pinnacles Wilderness Area,
about 50 km (30 mi) to the east across the Salinas Valley, further inland
and more removed from the Ocean influence. Its elevation is 317 m (1,038
ft). The Pinnacles CASTNET
site PINN414 is also located here.
Also, see Pinnacles Wilderness Area.
Representativeness
The PINN1 IMPROVE site is some 50 km (30 mi) inland from the Ventana
Wilderness, separated from it by the Salinas Valley, and is on the inland
side of the Galiban range. It is likely much more influenced by the San
Francisco Bay and San Joaquin Valley source regions, and less influenced by
the Pacific Ocean, than the Ventana Wilderness locations. Its representation
of the Ventana Wilderness may thus be marginal, and aerosol concentrations
in the Ventana Wilderness are probably much less than indicated by
measurements at PINN1.
Also, see Pinnacles Wilderness Area.
Nearby Population/Industrial Centers and Local Sources
The nearest population center is the Monterey Bay area. There may also be
some impact from the Bay Area with transport southward via interior Santa
Clara and Santa Bonita valleys, although emissions from those areas are
likely pushed further east towards the Galiban Range and Pinnacles
Wilderness area.
Also, see Pinnacles Wilderness Area.
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 is one site, the
Arroyo Seco (Mt.
Diablo) California RAWS site, located within Wilderness boundary on the
east side in the Arroyo Seco between the two Wilderness sections at an
elevation of 299 m (980 ft) that should be representative of similar
elevations on the east side of the Santa Lucia range.
The Big Sur
California RAWS site is on the coast just west of the Wilderness and is
representative of lower elevations on the upwind coast side. The best site
for relating aerosol data from the PINN1 IMPROVE site to local meteorology
is the CASTNET site
PIN414, at the same location as PINN1. However, see discussion of monitoring
site representativeness. Also, wind directions at PIN414 may not be
regionally representative of transport flow since there is evidence of local
terrain effects in Pinnacles wind roses. (wind roses provided as gif files
with prefix PIN)
Twice daily upper air data is collected at the Vandenburg AFB RAOB site on
the coast ~ 160 km (100 mi) south of Ventana WA.
Wind Patterns
Regional winds are generally from the north or northwest throughout the
year, a consequence of the semi-permanent high pressure that lies off the
Pacific Coast. Southerly and easterly winds occur during the winter,
especially in the morning. Upper-level winds from the south and east are
infrequent during the summer. This pattern is indicated in monthly
Santa Maria Wind Roses, from Santa Maria
located on the coast ~ 160 km (100 mi) to the south. The Wilderness is
subject to summertime sea breezes that impinge upon lower elevations on the
coast facing west side, and that may penetrate to the east side via Carmel
valley that extends inland from the Monterey Bay area.
Potential local transport routes into the Ventana Wilderness include
Monterey Bay area emissions transported directly during northwesterly wind
conditions or carried with summertime sea breeze to lower Wilderness
elevations on the east and west sides. Interior emissions from the San
Joaquin valley could impact Ventana Wilderness during infrequent easterly
flow conditions when an east to west pressure gradient is present, as can
occur with low pressure aloft off the coast and/or interior high pressure
over the Great Basin. There may also be impacts in the Ventana Wilderness
resulting from prescribed fires locally.
Also, see Pinnacles Wilderness Area.
Inversions/Trapping
The west side of the Ventana Wilderness is well exposed to westerly winds
and not subject to trapping surface-based radiation inversions, although
these may occur in the winter on the more sheltered eastern Carmel valley
side. In the extended summer months, May to October, the more common
inversion is a subsidence inversion over the eastern Pacific caused by the
persistent sub-tropical high pressure system. This inversion can extend
inland to distances of Ventana Wilderness locations. Its base is typically
marked by a stratus cloud layer and is the height to which the atmosphere
pollutants can be mixed, the mixing height. High relative humidity below
drops drastically above. This situation is typical of California coastal
areas during the summer, and its inland extent can vary diurnally. Vertical
mixing is commonly restricted to 600 m (2,000 ft) or less.
Also, see Pinnacles Wilderness Area.
Climatological Statistics
Carmel
Valley Climate data and
Monterey
Climate data should be representative of coastal and near-coastal areas
of the Ventana Wilderness Area at similar low elevations. More detailed data
including humidity and wind data can be accessed at the
Arroyo Seco (Mt.
Diablo) California RAWS site, and
Big Sur
California RAWS site.
Keywords