Created: 2014-01-02 11:14:40
Modified: 2014-02-03 11:37:58
DESCRIPTION OF AREA CONTAINING SITE:
Flat hill crest, featureless, moist acidic tundra.
Vegetation communities: Moist Eriophorum vaginatum, Betula nana, Salix pulchra, Hylocomium splendens tussock-graminoid, dwarf- shrub tundra. Cover of top 5 species: Eriophorum vaginatum (24%), Ledum decumbens (9%),Betula nana (9%), ylocomium splendens (8%), Salix pulchra (6%)
Mean vegetation height: 5.9 +/- 6.4 cm.
Mean live moss layer thickness: 2.2 +/- 1.4 cm.
Organic layer thickness: 15 + 0.9 cm.
(Walker and Bockheim, 1995)
SAMPLING DESIGN AND METHOD:
Beginning in 1995, the active layer has been probed at least annually at the site. The procedure involves pushing a metal rod, calibrated in cm, to the point of refusal, interpreted in most cases to be the frost table. Thaw depth measurements at each site were obtained by probing at 5 m intervals along the plot’s two perpendicular and one diagonal transect, resulting in 71 points per plot per probing date.
In 1995 the site was instrumented with several OnsetTM portable data loggers connected to probe-type thermistors. Each logger/thermistor system has an effective temperature range of -50oC to +33oC and resolution of approximately 0.32oC. At the site, one thermistor was placed in a radiation shield approximately 2 m above the ground surface, and nine loggers were placed at the interface between mineral soil and organic material in various microtopographic positions within the site. Temperature measurements were collected at, 1 hr, and 2 hr intervals depending on season, and year. Details on methodology are provided in Klene et. al 2001.
The soil climate station (Sagwon2) was established in June of 1996 and is located 1.5 miles west of the Haul road (Dalton Hwy.) in the Sagwon hills within CALM U32B site. The elevation is about 329 m (1080 ft). This station monitors air temperature, soil temperature at various depths to a maximum of 120 cm, and soil water contents at 10, 25, and 40 cm depths. Measurements are made at 20-minute intervals and averaged and recorded every hour.
Soil temperature and soil moisture metadata and data are also available at http://soils.usda.gov/survey/scan/alaska/Sagwon2/
CALM USA George Washington University
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