EP43A-0953
Surprises from the field: Novel aspects of aeolian saltation observed under natural turbulence
Thursday, 17 December 2015
Poster Hall (Moscone South)
Raleigh L. Martin, University of California Los Angeles, Los Angeles, CA, United States, Jasper F Kok, University of California Los Angeles, Atmospheric and Oceanic Sciences, Los Angeles, CA, United States and Marcelo Chamecki, Pennsylvania State University Main Campus, Department of Meteorology, University Park, PA, United States
Abstract:
The mass flux of aeolian (wind-blown) sediment transport – critical for understanding earth and planetary geomorphology, dust generation, and soil stability – is difficult to predict. Recent work suggests that competing models for saltation (the characteristic hopping of aeolian sediment) fail because they do not adequately account for wind turbulence. To address this issue, we performed field deployments measuring high-frequency co-variations of aeolian saltation and near-surface winds at multiple sites under a range of conditions. Our observations yield several novel findings not currently captured by saltation models: (1) Saltation flux displays no significant lag relative to horizontal wind velocity; (2) Characteristic height of the saltation layer remains constant with changes in shear velocity; and (3) During saltation, the vertical profile of mean horizontal wind velocity is steeper than expected from the Reynolds stress. We examine how the interactions between saltation and turbulence in field settings could explain some of these surprising observations.
