From: arXiv.org e-Print archive
Posted: Thursday, May 12, 2016
Adrian J. Brown, Wendy M. Calvin, Patricio Becerra, Shane Byrne
(Submitted on 11 May 2016)
A key outstanding question in Martian science is 'are the polar caps gaining or losing mass and what are the implications for past, current and future climate?' To address this question, we use observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of the north polar cap during late summer for multiple Martian years, to monitor the summertime water cycle in order to place quantitative limits on the amount of water ice deposited and sublimed in late summer.
We establish here for the first time the summer cycle of water ice absorption band signatures on the north polar cap. We show that in a key region in the interior of the north polar cap, the absorption band depths grow until Ls=120, when they begin to shrink, until they are obscured at the end of summer by the north polar hood. This behavior is transferable over the entire north polar cap, where in late summer regions 'flip' from being net sublimating into net condensation mode. This transition or 'mode flip' happens earlier for regions closer to the pole, and later for regions close to the periphery of the cap.
The observations and calculations presented herein estimate that on average a water ice layer ~70 microns thick is deposited during the Ls=135-164 period. This is far larger than the results of deposition on the south pole during summer, where an average layer 0.6-6 microns deep has been estimated by Brown et al. (2014).
Comments: This article is closely related and draws from arXiv:1501.02040
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1605.03487 [astro-ph.EP] (or arXiv:1605.03487v1 [astro-ph.EP] for this version)
From: Adrian Brown
[v1] Wed, 11 May 2016 15:53:06 GMT (3929kb)
// end //