Vertical profile and Horizontal Increase of Drift-Snow Transport

Abstract There are a number of published empirical formulae for drift-snow transport as a function of wind velocity. Comparing these formulae at the same wind velocity, however, results in considerable disagreement. It is hypothesized that the disparity arises from snow conditions and the various stages of development of drifting snow. The horizontal distribution of drift flux was measured with snow traps along a transect parallel with the wind, beginning at an up-wind boundary that served as the starting point of drifting snow. Results indicate that drift-snow transport cannot be defined uniquely unless the drifting snow attains equilibrium (i.e. the snow profile is saturated). Saltation of snow particles is thought to prevail near the snow surface. However, the vertical flux profile of saltating snow has never been measured. Vertical profiles of drift flux from the snow surface to a height of 30 cm were measured at nine levels, using snow traps composed of nine streamers (compartments). It appears that the saltation flux prevails up to a height of 7-9 cm above the surface, and the suspension flux gradually takes over as the drifting snow develops.