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Gravity-driven grainflows in natural environments
Topics: Coastal and Marine
, Geomorphology
, Religion and Belief Systems
Keywords: aeolian, avalanche, barchan, slipface Session Type: Virtual Paper Abstract Day: Monday Session Start / End Time: 2/28/2022 03:40 PM (Eastern Time (US & Canada)) - 2/28/2022 05:00 PM (Eastern Time (US & Canada)) Room: Virtual 39
Authors:
Douglas J Sherman, University of Alabama
Pei Zhang, University of Alabama
Jon Pelletier, University of Arizona
Jean Ellis, University of South Carolina
bailiang Li, Xi'an Jiatong Liverpool University
Eugene Farrell, National University of Ireland Galway
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Abstract
Gravity-driven grainflows on aeolian dunes are important agents of sand transport on Earth and Mars but have been the focus of few field studies. We present results from the first comprehensive field study to evaluate hypotheses posed by previous studies concerning the influence of sand transport rates on grainflow frequency and magnitude and the relationship between grainflow area and speed. The slipface of a barchan was monitored with a terrestrial laser scanner and video camera, with coincident measurements of wind speed and sand transport rate. More than 1609 grainflows were detected and measured. Analysis of time-averaged data supports the first hypothesis, refutes the second hypothesis, and supports the third hypothesis. We also found that grainflow speeds measured in laboratory studies are substantially slower than those found in the field, and the grainflow speed and area relationships found for field and laboratory data are significantly different.
