Publication Date:
2016-07-19
Description:
252 transient drops in atmospheric pressure, likely caused by passing convective vortices, were detected by the REMS instrument during the first Martian year of the Mars Science Laboratory (MSL) landed mission. These events resembled the vortex signatures detected by the previous Mars landers Pathfinder and Phoenix, however the MSL observations contained fewer pressure drops greater than 1.5 Pa and none greater than 3.0 Pa. Apparently these vortices were generally not lifting dust since only one probable dust devil has been observed visually by MSL [Moores et al., 2015]. Since ample dust seems to be present on the surface [Arvidson et al., 2014], the obvious explanation for this is the smaller number of strong vortices with large central pressure drops. The annual variation in the number of detected convective vortices followed approximately the variation in Dust Devil Activity (DDA) predicted by the MarsWRF numerical climate model. This result does not prove, however, that the amount of dust lifted by dust devils would depend linearly on DDA, as is assumed in several numerical models of the Martian atmosphere, since dust devils are only the most intense fraction of all convective vortices on Mars, and the amount of dust that can be lifted by a dust devil depends on its central pressure drop. Sol-to-sol variations in the number of vortices were usually small. However, on one sol a sudden increase in vortex activity, related to a dust storm front, was detected.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
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