Direct In-situ Measurement of Natural Dust Devil Sediment Loading and Flux

Introduction: Dust devils are an effective aeolian erosion mechanism of small-scale, substantially particle loaded convective vortices driven by insolation, common on both Earth and Mars. These vortices are highly turbulent flows with dust entrainment that is dictated by the surficial material over which they pass, the ambient wind that push them, and the pockets of hot air that power their " engine " , thus they fluctuate second-to-second laterally and vertically. On Mars, dust devil activity might support the persistent dustiness in the atmosphere [1], although spacecraft observations appear to rule out the possibility that Mars' global dust storms are triggered by dust devil activity [2,3,4]. This report offers field observations critical to such concerns. Understanding the climate influence of injecting fine particles into the upper atmosphere by dust devils requires data describing their size frequency distribution, and the amount of dust that they lift, yet few studies have attempted direct measurement of particle loading. Terrestrial LIDAR observations at ~100m height [5] show an ~10 3 enhancement compared to ambient dust loading, allowing an estimate of actual dust load of ~0.1gm