SEASONAL SAND FLUX VARIATIONS ON MARS: NEW MEASUREMENTS AND MODELING AT MEROE PATERA AND GALE CRATER AEOLIAN FIELDS
Our sand flux measurements are partitioned into two measurement types: ripple-derived flux and whole-dune-derived flux. For the former, the automated algorithm COSI-Corr produces ripple displacement maps which we further optimize using principal component analysis (PCA). For the latter measurement, we manually compare the dune slip face positions in the first and last images in a series to derive a whole-dune flux averaged over the time period. These two measurement types further constrain the ratio of ripple to total sand flux and can inform the mechanisms of bedform evolution.
Similar to Nili Patera (Ayoub et al., 2014), ripple flux measurements at Meroe Patera show a seasonal variation in ripple sand flux from ~0.5-4 m3/m/Earth-year (average of 1.57) with lowest fluxes near Mars’ aphelion orbital position (i.e., furthest from the Sun) and maximum fluxes near perihelion (closest solar distance). For Meroe Patera dunes, the time-averaged, whole dune-derived fluxes average 11.3 ± 5.7 m3/m/Earth-year with the lowest fluxes furthest downwind, consistent with previous measurements (Runyon et al., 2017a). The resulting ratio of total-to-ripple flux of ~7 is comparable to the value of ~5 measured at Nili Patera (Bridges et al., 2012).
We will also present initial results from the MarsWRF modeled winds with the predicted sand fluxes.