The N-factor of nonsorted circles along a climate gradient in Arctic Alaska

Three study sites were selected on zonal sites from north to south along a climate gradient in Arctic Alaska. Air and mineral soil surface temperatures of nonsorted circles and adjacent well-vegetated tundra plots were monitored from September 2003 through September 2004, and the depths of vegetation, soil organic horizons and snow were measured. N-factors, the ratio of ground-surface temperature to air temperature, were determined for the summer and winter seasons. N-factors and thaw depths were greater for relatively barren nonsorted circles than for adjacent well-vegetated tundra. Along the climate gradient, the thickness of vegetation, soil organic layer and snow increased from north to south, while n-factors and thaw depths decreased at bare circles from 1.43 +/- 0.02 to 0.74 +/- 0.01 and from 81.2 +/- 1.4 cm to 59.5 +/- 2.4 cm, respectively, and at the tundra from 0.99 +/- 10.02 to 0.17 +/- 0.01 and from 62.6 +/- 1.4 cm to 21.0 +/- 2.8 cm, respectively. Copyright (C) 2006 John Wiley & Sons, Ltd.