The Intermittency of Wind-Driven Sand Transport

Abstract

Wind-blown sand is the main driver of dune development and dust emission from soils and is thus of fundamental importance for geomorphology, ecology, climate, and air quality. Even though sand transport is driven by nonstationary turbulent winds, and is thus inherently intermittent, current parameterizations in atmospheric models assume stationary wind and continuous transport. We draw on extensive field measurements to show that neglecting saltation intermittency causes biases in the timing and intensity of predicted fluxes. We present a simple parameterization that accounts for saltation intermittency and produces substantially improved agreement against measurements. We investigate the implications of accounting for transport intermittency in atmospheric models by analyzing 35 years of hourly wind speed data from climate simulations. We show that accounting for intermittency leads to significantly different predictions of sand mass fluxes throughout the year, with potential implications for timing and intensity of dust emission.