Modélisation des nuages de dioxyde de carbone (CO2) sur Mars : application aux nuages mésosphériques.

Constantino Listowski 1
1 IMPEC - LATMOS
LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales
Abstract : Carbon dioxide (CO2) ice clouds on Mars stem from the condensation of the main atmospheric component (95% CO2). Numerous theoretical studies suggest that these clouds may have an influence on Mars' current climate, and that they have played a significant role in its past evolution. Only recently, observational constraints on crystal sizes and opacities of these clouds have been obtained after their discovery in the mesosphere. In this context, we have focused on the modeling of these clouds, with the aim of characterizing the microphysics of a near-pure vapor condensing in a rarefied atmosphere. We have developed a growth rate model for crystals, taking into account the potentially high temperature difference between the crystal surface and the environment, which appears to be important for a near-pure vapor. A one dimensional microphysical model has then been developed for these clouds to simulate their formation in the mesosphere. Thanks to this model, we can now explain their short lifetime and their diurnal behavior. We show that it is possible to reproduce the cloud crystal sizes, but not their opacities, as long as clouds are supposed to form onto dust particles (regolith) lifted from the ground by storms. A meteoritic input has been used to simulate denser clouds, in agreement with observations. The new microphysical model is intended to be coupled to Mars' climate and meteorological models.
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Submitted on : Friday, July 11, 2014 - 6:48:06 PM
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  • HAL Id : tel-01023294, version 1

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Constantino Listowski. Modélisation des nuages de dioxyde de carbone (CO2) sur Mars : application aux nuages mésosphériques.. Planétologie et astrophysique de la terre [astro-ph.EP]. Université Pierre et Marie Curie - Paris VI, 2013. Français. ⟨tel-01023294⟩

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