Recent Ice Ages on Mars: The role of radiatively active clouds and cloud microphysics
Abstract
Global climate models (GCMs) have been successfully employed to explain the origin of many glacial deposits on Mars. However, the latitude-dependent mantle (LDM), a dust-ice mantling deposit that is thought to represent a recent "Ice Age," remains poorly explained by GCMs. We reexamine this question by considering the effect of radiatively active water-ice clouds (RACs) and cloud microphysics. We find that when obliquity is set to 35°, as often occurred in the past 2 million years, warming of the atmosphere and polar caps by clouds modifies the water cycle and leads to the formation of a several centimeter-thick ice mantle poleward of 30° in each hemisphere during winter. This mantle can be preserved over the summer if increased atmospheric dust content obscures the surface and provides dust nuclei to low-altitude clouds. We outline a scenario for its deposition and preservation that compares favorably with the characteristics of the LDM.
Additional Information
© 2014 American Geophysical Union. Received 20 JUN 2014; Accepted 25 JUN 2014; Accepted article online 1 JUL 2014; Published online 23 JUL 2014. Very helpful and constructive advice regarding the text was provided by the Editor and an anonymous reviewer. We express our gratitude to Kat Scanlon for useful discussions and to the team of the Center for Computation and Visualization (CCV) of Brown University for their support. We acknowledge financial assistance from the NASA Mars Data Analysis Program grant NNX11AI81G to J.W. Head. The LMD Mars GCM is developed with the support of Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), and Centre National d'Études Spatiales (CNES) in collaboration with the AOPP (Atmospheric, Oceanic, and Planetary Physics laboratory, Oxford University) and IAA (Instituto de Astrofisica de Andalucia, Granada) groups. The Editor thanks an anonymous reviewer for his/her assistance in evaluating this paper.Attached Files
Published - Madeleine_et_al-2014-Geophysical_Research_Letters.pdf
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Additional details
- Eprint ID
- 72455
- Resolver ID
- CaltechAUTHORS:20161130-135441128
- NNX11AI81G
- NASA
- Centre National de la Recherche Scientifique (CNRS)
- European Space Agency (ESA)
- Centre National d'Études Spatiales (CNES)
- Created
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2016-11-30Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field