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Improvement of Mars Surface Snow Albedo Modeling in LMD Mars GCM With SNICAR
Author(s) -
Singh D.,
Flanner M. G.,
Millour E.
Publication year - 2018
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2017je005368
Subject(s) - albedo (alchemy) , snow , mars exploration program , environmental science , atmospheric sciences , shortwave , cryosphere , martian , climatology , martian surface , meteorology , radiative transfer , geology , sea ice , geography , astrobiology , physics , art , quantum mechanics , performance art , art history
The current version of Laboratoire de Météorologie Dynamique (LMD) Mars GCM (original‐MGCM) uses annually repeating (prescribed) CO 2 snow albedo values based on the Thermal Emission Spectrometer observations. We integrate the Snow, Ice, and Aerosol Radiation (SNICAR) model with MGCM (SNICAR‐MGCM) to prognostically determine H 2 O and CO 2 snow albedos interactively in the model. Using the new diagnostic capabilities of this model, we find that cryospheric surfaces (with dust) increase the global surface albedo of Mars by 0.022. Over snow‐covered regions, SNICAR‐MGCM simulates mean albedo that is higher by about 0.034 than prescribed values in the original‐MGCM. Globally, shortwave flux into the surface decreases by 1.26 W/m 2 , and net CO 2 snow deposition increases by about 4% with SNICAR‐MGCM over one Martian annual cycle as compared to the original‐MGCM simulations. SNICAR integration reduces the mean global surface temperature and the surface pressure of Mars by about 0.87% and 2.5%, respectively. Changes in albedo also show a similar distribution to dust deposition over the globe. The SNICAR‐MGCM model generates albedos with higher sensitivity to surface dust content as compared to original‐MGCM. For snow‐covered regions, we improve the correlation between albedo and optical depth of dust from −0.91 to −0.97 with SNICAR‐MGCM as compared to the original‐MGCM. Dust substantially darkens Mars's cryosphere, thereby reducing its impact on the global shortwave energy budget by more than half, relative to the impact of pure snow.