Spatial variability and landscape controls of near‐surface permafrost within the Alaskan Yukon River Basin

Abstract The distribution of permafrost is important to understand because of permafrost's influence on high‐latitude ecosystem structure and functions. Moreover, near‐surface (defined here as within 1 m of the Earth's surface) permafrost is particularly susceptible to a warming climate and is generally poorly mapped at regional scales. Subsequently, our objectives were to (1) develop the first‐known binary and probabilistic maps of near‐surface permafrost distributions at a 30 m resolution in the Alaskan Yukon River Basin by employing decision tree models, field measurements, and remotely sensed and mapped biophysical data; (2) evaluate the relative contribution of 39 biophysical variables used in the models; and (3) assess the landscape‐scale factors controlling spatial variations in permafrost extent. Areas estimated to be present and absent of near‐surface permafrost occupy approximately 46% and 45% of the Alaskan Yukon River Basin, respectively; masked areas (e.g., water and developed) account for the remaining 9% of the landscape. Strong predictors of near‐surface permafrost include climatic indices, land cover, topography, and Landsat 7 Enhanced Thematic Mapper Plus spectral information. Our quantitative modeling approach enabled us to generate regional near‐surface permafrost maps and provide essential information for resource managers and modelers to better understand near‐surface permafrost distribution and how it relates to environmental factors and conditions.