GRAIN-SIZE DEPENDENCE OF EOLIAN SALTATION LENGTHS DURING SNOW DRIFTING

Eolian saltation, a primary process in the transport of fine granular material by wind, produces a variety of geophysical effects on Earth a nd other planetary surfaces. Wind-tunnel experiments were carried out to investigate the dependence of saltation on grain size. The saltatio n length of snow particles was estimated at size intervals of 0.05 mm in diameter by measuring local vertical mass fluxes in 17 snow collect ors arrayed at the lee end of the snow surface. The measured mean salt ation length of snow particles of 0.01 - 1 mm in diameter ranged from 0.1 to 1.0 m at wind velocities of 5 - 10 m/s. Mean saltation length d ecreased with increasing diameter and decreasing wind speed. We sugges t that the probability of the saltation length of a particle at each d iameter is described by a monotonically decreasing distribution functi on, that is, the shorter the saltation length, the higher the frequenc y of its occurrence. One ramification of this distribution is that the mean saltation length does not imply the dominance of saltating parti cles of this length.