A model study of circum-Arctic soil temperatures

Abstract

A one-dimensional heat transfer model with phase change is applied to the entire Arctic terrestrial drainage area. The main forcing parameters are reanalysed surface air temperature that was topography-enhanced, and snow depth, derived from passive microwave satellite data. We present results based on daily fields of soil temperature, ranging from the soil surface down to 14 m depth. The horizontal grid cell resolution is 25 km × 25 km. Model results are compared to several long series of soil temperature measurements from Alaska and Siberia, with a relatively good match of the the annual cycle at different depths. We show time series of soil temperature at different depths for the 22-year period 1980 through 2001, and both seasonal and regional analyses are included. A trend analysis reveals positive trends for all permafrost regions in response to positive trends in air temperature, with the strongest warming trend in regions of continuous permafrost. A slight cooling trend is only found for the topmost soil layers in regions of seasonally frozen ground at the southern margins of the Arctic drainage domain. Copyright © 2004 John Wiley & Sons, Ltd.