Metrics for assessing snow surface roughness from Digital imagery

Abstract

Digital image profiles of snowpack surfaces were acquired concurrently with 1-cm resolution manual measurements. The manual measurements confirmed that unaltered digital images accurately represented a two-dimensional roughness profile of the snowpack surface. Roughness indices, such as random roughness, that have been used to represent soil surfaces were computed, and their utility for quantifying snowpack surface roughness is illustrated. Variogram analysis was used to determine the fractal dimension and scale break. Surface characteristics were a function of the scale, with a rough snow surface and graupel yielding similar results. A relatively smooth snow surface showed no crystal-scale features and had a fractal dimension approaching that of a random surface. © 2009 by the American Geophysical Union.