Active‐layer mapping at regional scales: a 13‐year spatial time series for the Kuparuk region, north‐central Alaska

Results from extensive, spatially‐oriented field investigations conducted in the Kuparuk River region of north‐central Alaska were used in conjunction with a simple analytical procedure to provide a comprehensive analysis of active‐layer variability under contemporary climate. This approach, based on Stefan's solution to the heat‐conduction problem with phase change, uses air temperature as the forcing function. An edaphic parameter represents the landcover‐specific response of the ground thermal regime to such local factors as lateral variations in soil, vegetation and moisture conditions. Regional estimates of climatic conditions were used within the framework of the spatial active‐layer model to map active‐layer thickness over the Kuparuk region on an annual basis, yielding a 13‐year spatial time series of regional thaw‐depth estimates. Results indicate that high‐resolution active‐layer mapping at regional scales is feasible given moderate amounts of climatic and edaphic information, obtained through extensive active‐layer sampling at locations representative of a number of environmental conditions. The analysis of annual thaw‐depth fields indicates that interannual climatic variability causes significant changes in active‐layer thickness.