Many small martian craters contain windblown sediments asymmetrically positioned on the floor which could indicate the prevailing winds. However, wind pattern and deposition appear to be functions of crater geometry. Two end-member cases could result in opposite sites of deposition; #1) raised rim craters with deep floors result in deposition on the upwind floor as a result of flow stagnation and/or flow reversal and #2) low-rimmed or rimless shallow craters conversely lack flow stagnation and wind reversal, with deposits "banking" against the downwind part of the floor. We propose to determine the "cross-over" in crater geometry between the end members, based on wind tunnel simulations in which the crater geometry is systematically varied. Wind tunnel results will be assessed through field work on full-scale craters at Amboy lava field, Calif. Results from simulations and field studies will be applied to the analysis of deposits in the Gusev and Meridiani areas using MER and HiRISE images. The types, dimensions, and locations of the deposits with respect to crater geometry (rim, floor, and location) will be determined for each candidate crater. The flow-field model as a function of crater geometry will be applied to the data set and compared to the inferred wind direction derived from the wind streaks and wind tails seen in the zones adjacent to (but not within) the craters to assess consistency. The overall wind directions derived from the synthesis will then be compared to predictions of wind patterns as a function of time of day and season based on models of the atmosphere for regional scales. If the analysis is successful, then the proposed technique of using the location of aeolian deposits in small craters has the potential for application to the many areas of Mars images by HIRISE to infer local wind patterns.
|Effective start/end date||3/15/10 → 3/14/15|
- NASA: Goddard Space Flight Center: $409,000.00