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 andmineral 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 andwinter seasons. N-factors and thaw depthswere 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 0.02 to 0.17 0.01 and from 62.6 1.4 cm to 21.0 2.8 cm, respectively. Copyright # 2006 John Wiley & Sons, Ltd.