THRESHOLDS AND FLUXES: NATHAN BRIDGE’S LEGACY AND RECENT MARSWIT AND HIRISE AEOLIAN SCIENCE

Nathan Bridges led a surge of interest and knowledge in planetary aeolian systems over the past two decades. Nathan’s willingness to bring others into his research group gave rise to an established network of planetary aeolian scientists who continue to collaborate as an aeolian team. Here, we present results from those collaborative efforts. Recent Martian Surface Wind Tunnel (MARSWIT) experiments examine thresholds for cascading saltation and find that the initiation of saltation that could trigger cascading saltation on Mars occurs at shear velocities 100-300% lower than traditional threshold models. These shear velocities match well with observations made by Nathan and others using Curiosity rover data. Inspired by Nathan’s pioneering use of Cosi-Corr to measure sand fluxes on Mars from orbital data, Cosi-corr measurements of sand fluxes in the north polar region of Mars show fluxes vary spatially away from the icecap. These measurements are used to estimate the erosion rate of the Basal Unit of further develop a model for the accumulation of aeolian deposits around the ice cap. These works build on Nathan’s contributions to aeolian systems research and orbital and rover mission operations and demonstrate his leadership bringing aeolian systems to the forefront of planetary science.