INFLUENCES OF TERRAIN AND VEGETATION ON PERMAFROST DISTRIBUTION: CASE STUDIES FROM TANANA FLATS AND 12-MILE LAKE, ALASKA

Links exist between permafrost distribution and latitude, climate warming, vegetation succession, surface slope, aspect, hydrology, geology, winter snow cover, and forest fire activity. However, these relationships are difficult to quantify which results in only a coarsely mapped distribution (depth and extent) of permafrost in Alaska. Alaskan permafrost and ground ice act as a significant greenhouse gas sink and have tremendous impacts on local geotechnical engineering (e.g. roads, oil pipelines, polar structures). Therefore, an ultimate goal in Alaskan permafrost research is to develop accurate predictive estimates of permafrost distribution relative to climate change scenarios. Herein, I compare available digital terrain data and satellite imagery to ground-penetrating radar and galvanic resistivity surveys used to map permafrost distribution in Tanana Flats near Fairbanks and surrounding 12-Mile Lake within the drainage corridor of the Yukon River, Alaska. Results show qualitative relationships between permafrost distribution mapped with geophysical surveys and surface slope, aspect, and modeled solar radiation determined from high resolution digital terrain data. Vegetation biomass and vegetation type determined from remotely sensed data also show qualitative relationships to permafrost extent. Quantitative analysis show similar, albeit weaker, trends between permafrost distribution and each of these variables, likely because numerous variables impact permafrost at each study location. This study indicates that the combination of digital terrain, remote sensing, and geophysical data may provide a robust dataset for determining current extent of permafrost and estimating changes in extent with respect to future climate change scenarios.