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Seasonal activity of Polar Dunes on Mars (MarsDune)
Date du début: 1 sept. 2013, Date de fin: 31 août 2017 PROJET  TERMINÉ 

A significant finding of the data analysis from the High Resolution Imaging Science Experiment (HiRISE) on board the Mars Reconnaissance Orbiter is the confirmation of active surface processes under the current Martian climate. Many of these processes in the Polar Regions are linked to seasonal volatile and wind cycles, such as the migration of aeolian ripples and sand dunes, avalanches of carbon dioxide ice from polar cliffs and formation of new dune gullies and alcoves. The proposed research will quantify the geomorphic work of active surface aeolian process on annual timescales. We aim to constrain the rate, timing and volume of sediment transport by ripple and dune migration and by the newly identified cryo-venting process. Our work will focus on dunefield sites in the circumpolar region that reflect the range of latitudes, topographies, and dune morphologies. We will use HiRISE images, now available for three Mars years, to determine the migration rate of dunes and ripples. DTM models of dune fields will be used to characterize dune form, slopes and volume, from which bulk sediment transport will be estimated. High temporal resolution images will identify springtime wind direction variability in a novel use of cryo-venting fan deposits as wind vanes. The timing of seasonal ripple migration and seasonal ice sublimation will be constrained and locations of remnant ice patches on dunes identified. The recovery of changes in dune slipface morphology from cryo-aeolian and aeolian process will be assessed and relative sediment volume transport will be estimated from DTM’s. These combined analyses will advance our understanding of duneform evolution and move towards defining the aeolian system sediment state on Mars