Show simple item record Martin, Raleigh L. Barchyn, Thomas E. Hugenholtz, Chris H. Jerolmack, Douglas J. 2013-12-11T16:49:16Z 2013-12-11T16:49:16Z 2013-07-26
dc.identifier.citation Martin, R. L., T. E. Barchyn, C. H. Hugenholtz, and D. J. Jerolmack (2013), Timescale dependence of aeolian sand flux observations under atmospheric turbulence, J. Geophys. Res. Atmos., 118, doi:10.1002/jgrd.50687. en_US
dc.description.abstract The transport of sand in saltation is driven by the persistently unsteady stresses exerted by turbulent winds. Based on coupled high-frequency observations of wind velocity and sand flux on a desert dune during intermittent saltation, we show here how observations of saltation by natural winds depend significantly on the timescale and method used for determining shear stress and sand flux. The correlation between sand flux and excess shear stress (stress above a threshold value) systematically improves for longer averaging timescale, T, and is better for stress determined by the law-of-the-wall versus the Reynolds stress method. Fitting parameters for the stress-flux relationship do not converge with increasing T, which may be explained by the nonstationary nature of wind velocity statistics. We show how it may be possible, based on the scale-dependent statistics of stress fluctuations, to rescale saltation flux predictions for wind observations made at different timescales. However, our observations indicate hysteresis and time lags in thresholds for initiation and cessation of saltation, which complicate threshold-based approaches to predicting sediment transport at different timescales. en_US
dc.language.iso en_CA en_US
dc.publisher American Geophysical Union en_US
dc.subject Aeolian sand flux en_US
dc.subject Turbulent winds en_US
dc.subject Aeolian sediment transport en_US
dc.subject Aeolian sediment transport--Effect of wind on en_US
dc.subject Surface winds en_US
dc.subject Sand dunes--Effect of wind on en_US
dc.title Timescale dependence of aeolian sand flux observations under atmospheric turbulence en_US
dc.type Article en_US
dc.publisher.faculty Arts and Science en_US
dc.publisher.department Department of Geography en_US
dc.description.peer-review Yes en_US
dc.publisher.institution University of Lethbridge en_US

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