not thaw to depths of more than 50 cm. Organic materials of variable thickness
overlie silt-loam-textured mineral soils (Everett 1980). The maximum depth of
soil thawed above the permafrost averaged 66 cm between 1996 and 1999
(Brown and Hinkel 2000).
A wetland study site (BET) (latitude 7017'N, longitude 14854'W) was
established near Betty Pingo within the Prudhoe Bay oilfield in May 1994. This
site was located on the Arctic Coastal Plain in an area of little topographic relief
at an elevation of about 12 m and about 12 km from the coast. The vegetation
consists of wet sedge tundra and forb tundra. The soils are organic overlying
layers of fine sand and silts. The 10-m tower was established in a wetland area;
however, nearby dryer areas were also equipped with soil thermistors and net
frost averaged 55 cm between 1993 and 1999 (Brown and Hinkel 2000).
In July 1994 the West Kuparuk site (WKU) (latitude 6926'N, longitude
15020'W) was established near the western margin of the Kuparuk Basin
approximately 63 km west of the Sagwon site. The site is located on a hill over-
looking the main branch of the Kuparuk River at an elevation of about 160 m.
The vegetation is characteristic of tussock tundra. The soils, which are loamy
with a peaty surface layer and are poorly drained, are very similar to the Sagwon
site. The depth of thaw above permafrost is typically about 50 cm.
Two other major meteorological sites exist in the Kuparuk River basin: West
Dock and Upper Kuparuk River. The West Dock site was established along the
Arctic coastline near the Betty Pingo site where strong horizontal gradients of
temperature and wind speed exist. The Upper Kuparuk River site is about 5 km
from the Imnavait Creek site, where meteorological variation exists over vertical
gradients of 170 m. Five micrometeorological sites exist in the headwaters where
summer precipitation and continuous air temperature, relative humidity, and
wind speed are measured.