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Wind
Cave National Park |
Site Name
IMPROVE:
WICA1 (Wind Cave)
Region
Northern Great
Plains
Terrain
Wind Cave National Park consists of
28,295 acres of mixed-grass prairie near the town of Hotsprings in
southwestern South Dakota. The Wind Cave National Park IMPROVE site, WICA1,
is located on southerly sloping flat land 14 km north of Hotsprings. The
site elevation is 1300 m (4265 ft). Surrounding terrain includes mountainous
terrain to the west and north, with elevations up to 2,050 m at Henry Peak,
34 km north of WICA1 and 750 m higher in elevation. Wind patterns at the
site may be thus be subject to orographic influence in this relatively
complex terrain, but on a synoptic scale it is still well exposed to
regional scale transport winds because the higher mountains are 15 to 40 km
distant. Surrounding land cover is predominantly evergreen forest and mixed
grass prairie. Terrain in the area is depicted in detailed
20 km terrain
map and 2
km terrain map.
Representativeness
Aerosol data collected at the WICA1 IMPROVE site should be very
representative of visibility conditions within and surrounding Area.
Nearby Data Stations
This map shows the location of the nearest air quality and meteorological
monitoring sites, with respect to WICA1 and Wind Cave National Park Area.
Meteorology is not presently monitored at the site. There are many COOP and
a few RAWS sites within the 50 km radius but most of them are recently
established. The nearest CASTNET
site, with meteorological monitoring, is the Theodore Roosevelt NP site,
THR422, located 370 km north of WICA1. Historical meteorological data from
this site should provide reasonable representation of meteorological
patterns at WICA1.
The nearest upper air site is Rapid City RAOB site 62 km northeast of WICA1,
where atmospheric soundings are conducted twice daily. Meteorological data
from Rapid City provides good representation of vertical atmospheric
structure at WICA1 and Wind Cave National Park.
Wind Patterns
Although there is mountainous terrain within 40 km of WICA1, (it is on the
southern slope of the higher mountains to the north and the eastern slope of
Elk Mountain just to the west) it is still reasonably exposed to prevailing
synoptic wind patterns because of the relatively flat to gently sloping
terrain nearby. Winter is characterized by northerly winds associated with
frequent outbreaks of cold continental air from the Canadian interior.
During the rest of the year the migration of the jet stream to more
northerly latitudes results in more frequent transport of warmer moist air
from the Gulf of Mexico and warm dry air from the southwestern U.S. Long
term (1961-2002) Rapid City wind roses illustrate regional patterns,
although this surface data may be subject to influence by local terrain.
Diurnal variations in wind directions depend on terrain and water features
that establish diurnally varying gradients of temperature and pressure.
Surrounding evergreen forest canopy and moderate grass prairie and rolling
slope in the region might affect wind on a local scale. Such local
conditions would not have great significance with respect to transport of
particulate matter from distant sources and source regions.
Inversions/Trapping
Because of the moderately complex terrain in the region surrounding WICA1,
there may be surface radiation inversion episodes, especially in the winter.
Worst and most persistent stagnation and buildup of visibility reducing
particulate matter is probably the result of elevated subsidence inversions
associated with persistent synoptic high pressure ridges. These cover a
large area and are regional in nature. They may persist for periods of days
until ventilation occurs in conjunction with frontal passages or onset of
stormy low pressure systems.
Climatological Statistics
Historical meteorological data from 1998 onward for the Theodore Roosevelt
NP CASTNET site, THR422, is available from the
CASTNET website. The two
sites, THR422 and WICA1, are located in same region and are separated by
~370 km. The
South
Dakota State University climate website is also a good source of
climate data for South Dakota.
Meteorological Indicators
Keywords
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Last updated 9 December 2004
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