Wind tunnel observations of weak and strong snow saltation dynamics

Theoretical considerations suggest that saltation dynamics is dominated by either aerodynamic entrainment or by a combination of ejection and rebound at a given time and location. Calling these two regimes weak and strong saltation, respectively, we have investigated high-resolution snow mass flux measurements by shadowgraphy in a cold wind tunnel to determine whether these two regimes can be experimentally reproduced. In this contribution, we first suggest that aerodynamic entrainment should lead to a negative correlation in the growth rates of horizontal versus vertical mass fluxes, while for the ejection regime, a positive correlation is plausible. Based on this criterion, we find evidence of weak and strong saltation in our data. Weak saltation is characterized by smaller peaks of horizontal mass flux; however, these peaks have a higher growth rate and therefore are typically narrow. The larger peaks are associated with strong saltation, are wider, and their frequency of occurrence increases with increasing overall saltation mass flux.

Published in:
Journal Of Geophysical Research-Earth Surface, 122, 9, 1589-1604
Washington, Amer Geophysical Union

 Record created 2017-11-08, last modified 2019-12-05

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