Mapping snow distribution in the Alaskan Arctic using aerial photography and graphic relationships

A method is presented for mapping the end-of-winter snow distribution in the Arctic using vertical aerial photographs taken during the melt. The photos show a limited number of distinctive snowmelt patterns that arise reliably year after year. Data and results from an energy balance melt model indicate that the patterns are not caused by differential melt but instead represent areas of distinctive end-of-winter snow depth. A map of these snowmelt patterns-is thus a map of the end-of-winter snow distribution. Because wind transport of snow is common, the patterns are closely related to the topography. Rules based on this pattern-topography relationship are developed and used to map the snow cover directly from topographic maps for three areas covering similar to 220 km(2) of the Kuparuk Basin in northern Alaska. Analysis of the snow maps suggests that about 75% of the area was mapped correctly. Applicability, reliability, and limitations of this mapping approach are discussed.