Characterizing the Modern-Day Aeolian Environment at Gale Crater, Mars
Abstract
Since landing on Mars in 2012, the Mars Science Laboratory Curiosity rover has accumulated a wealth of data regarding atmospheric processes on Mars. Hundreds of images collected as part of repeat imaging ("change detection") experiments have revealed an active aeolian surface environment despite Mars' tenuous atmosphere. These experiments have been conducted periodically over the entirety of the mission, which has allowed for a broad assessment of wind activity across a variety of geomorphic settings and during a range of environmental conditions (e.g., both within and outside organized dune fields, across all four seasons and amid a global dust storm). Within Gale crater, change detection images have confirmed the strong seasonality in wind that was previously suggested by models and orbital studies, with substantially higher levels of transport between Ls 200 to 360°. During this time of year, winds are regularly mobilizing aeolian populations on daily, or even hourly, timescales, which contradicts the idea that threshold conditions are rarely met on modern-day Mars; within the Bagnold Dune Field, impact ripples are seen to migrate centimeters per sol. Our understanding of Martian aeolian processes is further challenged by the mobilization of fine pebbles on landscapes surrounding the dunes, which indicate wind speeds unsupported by in situ measurements and models. When examined collectively, Curiosity change detection images reveal an active aeolian landscape that may be explained with a low-flux saltation model where preferentially exposed sand mobilized at sub-threshold values can generate full saltation downwind.
Repeat images have proved invaluable for characterizing the wind regime around the Curiosity rover (e.g., wind direction and magnitude), and have provided a means to test the accuracy of atmospheric models, particularly in lieu of robust and high frequency Remote Environmental Monitoring System (REMS) wind measurements. Understanding when, where, and how wind is mobilizing sand across Mars is fundamental for our scientific interpretation of the Martian rock record and paleoclimate, but is equally important for ensuring the success of future robotic and human missions to Mars (e.g., for engineering wind-resistant instruments, managing operational constraints, weather forecasting, and assessing the potential risk of microbial transport).- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMEP43A..08B
- Keywords:
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- 3322 Land/atmosphere interactions;
- ATMOSPHERIC PROCESSESDE: 1625 Geomorphology and weathering;
- GLOBAL CHANGEDE: 5210 Planetary atmospheres;
- clouds;
- and hazes;
- PLANETARY SCIENCES: ASTROBIOLOGY