Snow Bedforms Create the Surface Roughness of Polar Snow

Abstract:

Polar snow surfaces are rough. The wind moves, piles up, and scours snow grains from the snow surface, and recombines them into various shapes also called bedforms. Individual bedforms may have shapes that can be readily described and perhaps understood, but one storm event after another generate a complex compound surface whose roughness is the sum of both deposition and erosion. Characterizing and understanding the origin of this bedform roughness is one key toward a better estimation of precipitation at a global scale from microwave remote sensing, and also a better understanding of two critical sea ice processes; the transfer of momentum from the atmosphere to ice floes, and the spatial distribution of melt ponds in springtime. During this presentation, we will describe the dynamics of snow bedform formation and we will explore how the basic palette of bedforms combined with a unique weather history can reveal the genesis of a rough snow surface. Detailed laser scanner maps of bedforms measured in Arctic Alaska will be used to illustrate these processes and forms.