Dust rocket storms, gravity waves and their impact on the martian troposphere and thermosphere

Abstract : Background Recent studies have shed light on mesoscale phenomena in the Martian atmosphere, unresolved by global climate models [6]. A particular emphasis was put on near-surface circulations, less so on dynamical phenomena in the upper troposphere and mesosphere. This aspect is in need to be further investigated to better understand recent observations and, more generally, the martian climate. Gravity waves Many independent measurements have shown that extremely low temperatures ("cold pockets") are found in the Martian mesosphere. Recent observational achievements also hint at such cold pockets by revealing mesospheric clouds formed through the condensation of CO2 [e.g., 5]. Large-scale meteorological conditions are key factors to account. Dust rocket storms We use atmospheric mesoscale modeling with radiatively-active transported dust to predict the evolution of a local dust storm monitored by OMEGA onboard Mars Express [4]. In the afternoon, dust transport within storm is governed by deep convective motions (Figure 3). The vast majority of convective energy supply originates in the absorption of incoming sunlight by dust particles, mostly in the visible. What we propose to name a "dust rocket storm" subsequently forms and injects dust particles at high altitudes in the Martian troposphere (30 to 40 km above the surface). Combined to advection by horizontal winds, this contributes to form detached layers of dust reminiscent of those observed e.g. with instruments onboard Mars Reconnaissance Orbiter [3]. Such detached layers are stable over several days. We checked the robustness of our conclusions by performing sensitivity simulations without the radiative effect of transported dust, with various sizes and properties of dust disturbance and with lifting activated in a more realistic setting. Our conclusions (manuscript to be submitted to JGR planets) have strong implications for the Martian dust cycle and advocate for further studies of dust storms (including global dust storms) at finer scales than usually assumed in global climate models.
Type de document :
Communication dans un congrès
EPSC 2012 (European Planetary Science Congress), Sep 2012, Madrid, Spain
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https://hal.archives-ouvertes.fr/hal-00749778
Contributeur : Catherine Cardon <>
Soumis le : jeudi 8 novembre 2012 - 13:30:08
Dernière modification le : jeudi 11 janvier 2018 - 06:26:45

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  • HAL Id : hal-00749778, version 1

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A. Spiga, F. Gonzalez-Galindo, J. Faure, J.-B. Madeleine, F. Altieri, et al.. Dust rocket storms, gravity waves and their impact on the martian troposphere and thermosphere. EPSC 2012 (European Planetary Science Congress), Sep 2012, Madrid, Spain. 〈hal-00749778〉

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