Dynamical Forcing of Cap Edge Dust Lifting During the Onset of the 2018 Mars Global Dust Event
Abstract
The development of a global dust haze on Mars by June 20, 2018 appears to be the result of a succession of dust raising events that occur in different locations at different times but are ultimately linked to global and regional scale wind systems. Dust lifting along the edge of the retreating south polar cap appears to be one such system that may have a prominent role in the sequence of storm development. MARCI images, for example, show an abrupt increase in cap edge lifting near the prime meridian on June 6, 2018 that in subsequent sols expands eastward toward Hellas and westward toward Argyre. Quantification of the amount of dust contributed by cap edge lifting is difficult to determine at this time but the imaging data suggest it is significant. The abrupt turn-on of cap edge lifting suggests a dynamical forcing mechanism triggered by changes in atmospheric heating patterns associated with the evolving dust field. The possibilities include the "sea breeze" circulation generated by the sharp latitudinal temperature gradients at the edge of the cap, southern hemisphere frontal systems associated baroclinic eddies which are still possible at this season, and thermal tides pumped up by the buildup of tropical dust in the Chryse-Arabia-Meridiani longitude sectors. We assess these possibilities with a combination of MARCI imaging data, MCS temperature data, REMS pressure data, and modeling simulations with the Ames Mars Global Circulation Model. Our goal is to assess the relative importance of these systems to cap edge lifting, and to determine what role that lifting plays in driving the storm to truly global scale proportions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P43J3871H
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 6225 Mars;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 5405 Atmospheres;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 5445 Meteorology;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS