Estimating Permafrost Active Layer Thickness (ALT) Biogeography over the Arctic Tundra †.

The geospatial model here presented estimates the permafrost active layer thickness (ALT) over the entire Arctic in the last 20 years, and it is based on the spatial and temporal oscillations measured by satellite-based essential variables associated with the thermal state of permafrost. The model integrates the climate and soil components, such as the land surface temperature, the snow depth water equivalent, and the mid-summer albedo, with the structural and functional descriptors of Arctic tundra biome such as the fraction of absorbed photosynthetically active radiation. The distribution of estimated ALT varies according to the vegetation classes (mosses and lichens or grasses and shrubs), but a general increase has been estimated across the whole Arctic tundra region, with rates of up to 2 cm/year. [ABSTRACT FROM AUTHOR]