Winter and spring evolution of northern seasonal deposits on Mars from OMEGA on Mars Express

Appere, T.; Schmitt, B.; Langevin, Y.; Doute, S.; Pommerol, A.; Forget, F.; Spiga, A.; Gondet, B.; Bibring, J.P. (2011). Winter and spring evolution of northern seasonal deposits on Mars from OMEGA on Mars Express. Journal of geophysical research, 116(E5) Washington, D.C.: American Geophysical Union 10.1029/2010JE003762

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The OMEGA visible/near-infrared imaging spectrometer on Mars Express has observed the retreat of the northern seasonal deposits during Martian year 27–28 from the period of maximum extension, close to the northern winter solstice, to the end of the retreat at Ls 95°. We present the temporal and spatial distributions of both CO2 and H2O ices and propose a scenario that describes the winter and spring evolution of the northern seasonal deposits. During winter, the CO2-rich condensates are initially transparent and could be in slab form. A water ice annulus surrounds the sublimating CO2 ice, extending over 6° of latitude at Ls 320°, decreasing to 2° at Ls 350°, and gradually increasing to 4.5° at Ls 50°. This annulus first consists of thin frost as observed by the Viking Lander 2 and is then overlaid by H2O grains trapped in the CO2-rich ice layer and released during CO2 sublimation. By Ls 50°, H2O ice spectrally dominates most of the deposits. In order to hide the still several tens of centimeters thick CO2 ice layer in central areas of the cap we propose the buildup of an optically thick top layer of H2O ice from ice grains previously embedded in the CO2 ice and by cold trapping of water vapor from the sublimating water ice annulus. The CO2 ice signature locally reappears between Ls 50° and 70°. What emerges from our observations is a very active surface-atmosphere water cycle. These data provide additional constraints to the general circulation models simulating the Martian climate.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute

UniBE Contributor:

Pommerol, Antoine

ISSN:

0148-0227

Publisher:

American Geophysical Union

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:28

Last Modified:

05 Dec 2022 14:08

Publisher DOI:

10.1029/2010JE003762

Web of Science ID:

000290625000002

BORIS DOI:

10.48350/10258

URI:

https://boris.unibe.ch/id/eprint/10258 (FactScience: 216116)

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