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Bryce
Canyon National Park |
Site Name
IMPROVE: BRCA1
Region
Colorado Plateau
Terrain
Terrain is shown in the 20 km BRCA1 terrain map and the 20 km BRCA1 terrain
map.
Bryce Canyon National Park is located in south-central Utah and consists of
a series of horseshoe-shaped amphitheaters carved from the eastern edge of
the Paunsaugunt Plateau. Plateau elevations are near 2,450 to 2,480 m (8,040 to
8,130 ft). To the west of the Park, terrain on the Plateau is relatively flat
and forms a rim overlooking the Park. At the bottom of Bryce Canyon proper,
elevations are near 2,070 m (6,790 ft). To the east of the Park, terrain is
still highly contorted badlands and small plateaus, but elevations continue
to generally drop down to the Colorado River at Lake Powell above the Grand
Canyon, a distance of ~ 100 km (60 mi) southeast, elevation 1,130 m (3,706
ft). The Park is thus generally a north-south oriented section of the
ruggedly carved upper western reaches of the Colorado River valley. Terrain
orientation with respect to large-scale features (plateau areas, Colorado
River valley) has the same general characteristics as Capitol Reef National
Park, and the two areas should have similar meteorological factors
contributing to haze.
The BRCA1 monitoring site is at an exposed location on the Paunsagunt rim,
overlooking the Park.
Representativeness
Aerosol data collected at the BRCA1 monitoring site should be very
representative of vistas overlooking Bryce Canyon National Park.
Nearby Data Stations
Climate data (temperature, precipitation, snowfall) are available from the
Bryce Canyon NP
site, also located on the rim and thus representative of conditions at
the BRCA1 aerosol monitoring site and at higher rim locations in the Park.
Wind data are also now collected at the
Bryce Canyon
RAWS site. Other local data stations are shown in the data network
map,
and many of these can be referenced at the
US Climate Archive
and the RAWS station US Climate
Archive sites for western U.S. These sites include length of record
information and wind rose generation capability. The most representative
site for upper air data is probably the Flagstaff RAOB site.
Wind Patterns
Long-term wind roses from the
Cedar City NWS site for
January,
April,
July, and
October should be regionally representative of exposed areas and
somewhat representative of seasonal patterns at Bryce Canyon, although Cedar
City is located ~ 80 km west of Bryce Canyon. These wind roses show the
preponderance of southerly flow, especially in the summer, with significant
frequencies of northerly wind directions in other seasons. Below the rim, an
upslope/downslope diurnal pattern may exist during light wind conditions,
bringing lower Colorado River and interior Bryce Canyon air towards the
monitoring site during the daytime, and draining Paunsaugunt Plateau and
upper canyon air towards the Colorado River valley at night. Daytime
southerly and upslope flow may have implications for transport into the Park
area from sources located within the Colorado River valley in the region.
Potential transport routes into Bryce Canyon NP include low level transport
into the area via Colorado River drainage and upper air transport via upward
mixing in source regions and advection aloft.
Inversions/Trapping
Although the canyons of Bryce Canyon National Park may be narrow and
confining in places, they still have downslope portals into the Colorado
River valley. Valley inversions that affect Park areas will thus probably
have bases at River elevations, some 1,350 m (4,430 ft) below the rim, and 940
m (3,080 ft) below lower Park elevations. Park elevations may thus be above
these diurnal inversions much of the time. The BRCA1 monitoring site, at the
rim, will be well above valley-based inversions. Aerosol buildup may occur
during large-scale subsidence inversions associated with a surface high
pressure that persists over periods of a few days or longer. Such stagnation
events are most likely to occur during the extended summer (May – October),
when pressure and temperature gradients in the region are weakest, and wind
circulations therefore weaker.
Climatological Statistics
Climate data summaries representative of rim locations (temperature,
precipitation, snowfall) are shown for the
Bryce Canyon NP
site. Meteorological data including wind and humidity are accessible at
the RAWS station US Climate
Archive, with data beginning in January, 2003.
Long term climatological data summaries including relative humidity are also
available from the Cedar City municipal airport monitoring site.
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