A CHARACTERIZATION OF THE AEOLIAN ENVIRONMENT AT OXIA PLANUM, MARS

Oxia Planum, Mars, is the landing site for the European Space Agency’s ExoMars Rosalind Franklin rover. In preparation for the nominal mission, we undertook extensive surveys of aeolian features to characterize the aeolian environment of the landing site.

Multiple methods of data acquisition and analysis were used to characterize the landscape in and around the proposed rover landing site. Machine learning, manual mapping, and change detection techniques were first used to identify, map, and determine the migration, morphometrics, distribution, and orientations of 10,733 transverse aeolian ridges (TARs) and periodic bedrock ridges (PBRs), as well as dust devils, dust devil tracks, and windstreaks in HiRISE, CTX, CaSSIS, and HRSC images. We then evaluated global circulation models (GCMs) at multiple obliquities over several Martian years to qualify and quantify the best possible representation of the Martian atmosphere and wind regime at Oxia Planum and compared these outputs to our landscape-level data.

Overall, we found evidence for at least three distinct atmospheric epochs. The oldest winds are recorded in the crestline orientations of PBRs and connote winds from the N-NNE or S-SSW (180° ambiguity). Geologically recent winds responsible for the orientation of TARs originated in the NW-NNW and blew towards the SE-SSE. Contemporary winds and/or wind gusts, as recorded by active dust devils and dust devil tracks/windstreaks, is primarily oriented in a WNW-ESE direction (180° ambiguity), with a secondary orientation from NNE-SSW (180° ambiguity). These landscape-level observations do not align with modelled GCM winds.

This work was the first to comprehensively evaluate the aeolian environment at Oxia Planum using granular bedform, bedrock landforms, inferred near-surface winds, and GCMs.