Was the MY 34 Equinoctial Global Dust Event Predictable? A Study Using MACDA and EMARS Reanalyses
Abstract
Orbiters have now observed two equinoctial Global Dust Events (GDEs) almost exactly nine Martian years apart (both events occurred around solar longitude LS 185°). The Mars Global Surveyor (MGS) provided atmospheric observations in 2001 during the MY 25 GDE, while several orbiters (including the Mars Reconnaissance Orbiter, MRO) are mapping the evolution of the current MY 34 GDE. For the current GDE there even exist "ground truth" data from NASA's rovers "Curiosity" and "Opportunity" (at least until the latter entered safe mode). Are we any close to being able to forecast such events on Mars?
There is no operational data assimilation framework in place for weather forecasting on Mars yet, and even if there was, we expect much work would need to be done to improve the accuracy of the dust cycle in current Mars Global Climate Models (MGCMs), before reliable forecasts for dust storms could be attempted. Nevertheless, data assimilation can be used to compare the state of the atmosphere in several Martian years at a specific time, e.g. at the onset of the equinoctial GDEs in MY 25 and MY 34. This comparison can highlight whether the atmosphere was "primed" differently in MY 34 at LS 185° with respect to any other previous year, including MY 25. Could possible precursors have helped to predict the MY 34 equinoctial GDE, and if so, how much time ahead of its onset or early development? We seek to address these questions by using the assimilation of MGS/TES and MRO/MCS observational datasets, which are the most extensive ones currently available and publicly accessible. This study makes specific use of the sequential Analysis Correction scheme to assimilate orbiter observations into a version of the MGCM maintained at The Open University and the University of Oxford in the UK, which includes physical packages developed at the Laboratoire de Météorologie Dynamique/Sorbonne Université in France (MACDA reanalysis). We consider that reanalyses inter-comparison is a necessary step towards obtaining reliable results on the determination of the atmospheric state at a given time on Mars. We therefore use the EMARS reanalysis (based on the Local Ensemble Transform Kalman Filter applied to the Geophysical Fluid Dynamics Laboratory MGCM), which is produced at the Penn State University, USA, to compare and complement the results of the MACDA reanalysis.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P34A..08M
- 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