Relevance and modeling of intermittency in wind-driven sediment transport

Abstract:

Aeolian sediment transport drives dune development and dust emission from soils and is thus of fundamental importance for geomorphology and climate of numerous planetary bodies. Even though sediment transport is driven by nonstationary turbulent winds, and is thus inherently intermittent, current mass flux parameterizations in atmospheric models assume stationary winds and continuous transport. We draw on extensive field-based sand transport measurements to show that neglecting transport intermittency causes biases in the timing and intensity of predicted fluxes. We present a simple parameterization that accounts for transport intermittency and substantially improves the agreement against measurements during periods of low wind speed. We further analyze 35 years of hourly wind speed data from climate simulations to show that accounting for intermittency leads to significantly different predictions of sand mass fluxes throughout the year. These insights have potential implications for dust emission on Earth and Mars and could help explaining the formation of dunes against the prevailing circulation on Titan.