Site Name

IMPROVE: nearest is IKBA (see Mazatzal Wilderness Meteorological Description).
Tribal Area

Region

Mexican Highlands (Verde Valley)

Terrain

Terrain is shown in the 2 km terrain map and the 20 km terrain map.

The Yavapai-Apache Nation (also known as Camp Verde Indian Reservation) is a Native American tribe from the Verde Valley in central Arizona, about 130 km north of the Phoenix/Mesa metropolitan area. The reservation today spans 665 acres in and around the four communities of Camp Verde, Middle Verde, Clarkdale, and Rimrock. It lies in the northwest-southeast oriented Verde Valley, some 40 km upvalley (north) of the Mazatzal Wilderness Area (see Mazatzal Wilderness Meteorological Description Page). The valley of the Verde River is in the area of transition between the uplifted Mogollon Rim and Colorado Plateau to the northeast and the lowlands around Phoenix and Mesa. Elevation of the Verde valley floor in the Yavapai-Apache Nation is ~ 950-1,100m (3,100 – 3,600 ft).

If a monitoring site is established in this area it should be representative of aerosol concentration and composition across the valley. Presently reservation visibility is best represented by the Ike’s Backbone (IKBA) IMPROVE site, located in the northern Mazatzal Wilderness.

Representativeness

IKBA is located in the Mazatzal Wilderness some 30 km southeast of Yavapai-Apache Nation. The monitoring site elevation is 1,303 m (4,274 ft), 600 to 1,000 ft higher than valley floor elevations in Yavapai-Apache Nation land. It should thus be representative of reservation visibility except during persistent valley inversion episodes.

Nearby Meteorological Data Stations

Nearby meteorological monitoring network stations, with respect to IKBA, are shown in the data network map and at the US Climate Archive and RAWS station US Climate Archive sites. The nearest RAWS site is Verde Arizona which is also the nearest site that includes wind data.

The nearest upper air site is the Flagstaff RAOB site, which conducts atmospheric soundings twice daily. Sounding data from Flagstaff should be representative of regional upper air structure.

Wind Patterns

See the Mazatzal Wilderness Area Meteorological Description Page for discussion of wind pattern characteristics relevant to visibility measurements at IKBA.

The wind roses from Verde RAWS site should be representative of the Verde valley in the vicinity of Yavapai-Apache Nation. The wind roses for winter, spring, summer and fall show a dominant southeasterly and northwesterly pattern year-round with strong southerly wind in the spring and summer time. Summertime southerly flow may in part result from the North American Monsoon, bringing with it frequent precipitation events. .

Inversions/Trapping

The southwestern U.S. region that includes the Yavapai-apache Region is subject to frequent stagnation events. In central Arizona long-term data indicate an average of at least one stagnation episode per month from May to October, where an air stagnation episode is defined as stagnation conditions that persist for 4 days or longer (Wang and Angell, 1999).  During this period, pressure and temperature gradients in the region are weakest, and wind circulations weakest. Subsidence inversions during these conditions may trap regional haze with buildup over periods of several days.

Climatological Statistics

Phoenix Normals, Means and Extremes are representative of regional climatology at lower elevations. The Verde RAWS Site provide long-term data that should be more representative of localities within the Yavapai-Apache Nation proper.

Meteorological Indicators for Local Sources

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