Snow–Ground Interface Temperatures in the Kuparuk River Basin, Arctic Alaska: Measurements and Model

Abstract

Air and snow?ground interface temperatures were measured during two winters at 33 stations spanning the 180-km-long Kuparuk basin in arctic Alaska. Interface temperatures averaged 7.5°C higher than air temperatures and varied in a manner that was more complex, and on a spatial scale more than 100 times smaller, than the air temperature. Within the basin, two distinct thermal regimes could be identified, with the division at the boundary between coastal and uplands provinces. When each station was classified into one of three snow exposure classes (exposed, intermediate, or sheltered), accounting for variations in snow depth and thermal properties, 87% of the variation in the average interface temperature could be predicted from air temperature. Individual station interface temperature records were fit using a beta curve that captured the slow decrease in autumn and the rapid rise in spring. Beta curves were specified by three parameters (α, ?, and ?) that could be predicted if province and snow exposure class were known. A model based on the beta curves was developed and applied over the basin to predict interface temperatures in both time and space. Tests of the model against data from within the domain and from arctic Alaskan locations outside the domain suggest an accuracy of ±2°C when simulating average winter interface temperatures, and ±3°C when simulating daily interface temperatures.