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Evolution of Mars' northern polar seasonal CO 2 deposits: Variations in surface brightness and bulk density
Author(s) -
Mount Christopher P.,
Titus Timothy N.
Publication year - 2015
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2014je004706
Subject(s) - mars exploration program , polar , astrobiology , environmental science , brightness , atmospheric sciences , surface brightness , geology , atmosphere of mars , martian , physics , astronomy , galaxy
Small‐scale variations of seasonal ice are explored at different geomorphic units on the Northern Polar Seasonal Cap (NPSC). We use seasonal rock shadow measurements, combined with visible and thermal observations, to calculate density over time. The coupling of volume density and albedo allows us to determine the microphysical state of the seasonal CO 2 ice. We find two distinct end‐members across the NPSC: (1) Snow deposits may anneal to form an overlying slab layer that fractures. These low‐density deposits maintain relatively constant densities over springtime. (2) Porous slab deposits likely anneal rapidly in early spring and fracture in late spring. These high‐density deposits dramatically increase in density over time. The end‐members appear to be correlated with latitude.