Observations of the northern seasonal polar cap on Mars III: CRISM/HiRISE observations of spring sublimation

Pommerol, Antoine; Appéré, T.; Portyankina, Ganna; Aye, Klaus-Michael; Thomas, Nicolas; Hansen, C.J. (2013). Observations of the northern seasonal polar cap on Mars III: CRISM/HiRISE observations of spring sublimation. Icarus, 225(2), pp. 911-922. Elsevier 10.1016/j.icarus.2012.08.039

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We analyze a series of targeted CRISM and HiRISE observations of seven regions of interest at high latitudes in the Northern polar regions of Mars. These data allow us to investigate the temporal evolution of the composition of the seasonal ice cap during spring, with a special emphasis on peculiar phenomena occurring in the dune fields and in the vicinity of the scarps of the North Polar Layered Deposits (NPLDs). The strength of the spectral signature of CO2 ice continuously decreases during spring whereas the one of H2O ice first shows a strong increase until Ls = 50°. This evolution is consistent with a scenario previously established from analysis of OMEGA data, in which a thin layer of pure H2O ice progressively develops at the surface of the volatile layer. During early spring (Ls < 10°), widespread jet activity is observed by HiRISE while strong spectral signatures of CO2 ice are detected by CRISM. Later, around Ls = 20-40°, activity concentrates at the dune fields where CRISM also detects a spectral enrichment in CO2 ice, consistent with "Kieffer's model" (Kieffer, H.H. [2007]. J. Geophys. Res. 112, E08005. doi:10.1029/2006JE002816) for jet activity. Effects of wind are prominent across the dune fields and seem to strongly influence the sublimation of the volatile layer. Strong winds blowing down the scarps could also be responsible for the significant spatial and temporal variability of the surface ice composition observed close to the NPLD.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences

UniBE Contributor:

Pommerol, Antoine; Portyankina, Ganna; Aye, Klaus-Michael and Thomas, Nicolas

Subjects:

500 Science > 530 Physics
500 Science > 520 Astronomy
600 Technology > 620 Engineering

ISSN:

0019-1035

Publisher:

Elsevier

Language:

English

Submitter:

Cléa Serpollier

Date Deposited:

14 Aug 2014 10:11

Last Modified:

08 Oct 2015 09:29

Publisher DOI:

10.1016/j.icarus.2012.08.039

BORIS DOI:

10.7892/boris.46248

URI:

https://boris.unibe.ch/id/eprint/46248

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