Time Series of Active Layer Thickness in the Russian Arctic, 1930-1990

The active layer is the top layer of ground that freezes in the winter and thaws in the summer over permafrost. Changes in ALT over northern high-latitude permafrost regions have important impacts on the surface energy balance, hydrologic cycle, carbon exchange between the atmosphere and the land surface, plant growth, and ecosystem as a whole.

Warming may thicken the active layer and induce permafrost thaw. Investigators collected data from 31 ground-based stations. Derived from monthly averages, the record includes annual maximum active layer depths from 1930 to 1990.