Modelling and mapping climate change impacts on permafrost at high spatial resolution for an Arctic region with complex terrain

摘要

Most spatial modelling of climate change impacts on permafrost has beenconducted at half-degree latitude/longitude or coarser spatial resolution. Atsuch coarse resolution, topographic effects on insolation cannot beconsidered accurately and the results are not suitable for land-use planningand ecological assessment. Here we mapped climate change impacts onpermafrost from 1968 to 2100 at 10 m resolution using a process-based modelfor Ivvavik National Park, an Arctic region with complex terrain in northernYukon, Canada. Soil and drainage conditions were defined based on ecosystemtypes, which were mapped using SPOT imagery. Leaf area indices were mappedusing Landsat imagery and the ecosystem map. Climate distribution wasestimated based on elevation and station observations, and the effects oftopography on insolation were calculated based on slope, aspect and viewshed.To reduce computation time, we clustered climate distribution and topographiceffects on insolation into discrete types. The modelled active-layerthickness and permafrost distribution were comparable with field observationsand other studies. The map portrayed large variations in active-layerthickness, with ecosystem types being the most important controllingvariable, followed by climate, including topographic effects on insolation.The results show deepening in active-layer thickness and progressivedegradation of permafrost, although permafrost will persist in most of thepark during the 21st century. This study also shows that ground conditions and climate scenarios are the major sources of uncertainty forhigh-resolution permafrost mapping.