Investigating inter-annual dust redistribution at the surface of Mars with planetary climate model simulations

Global dust events (GDEs), occurring every few Martian years, are certainly the most impressive wheather phenomena on Mars and have been investigated by numerous studies. The reasons why GDEs occur in some Mars years, and not in others, remain challenging to unveil and many hypotheses have been set up, including that dust reservoirs need to be replenished after a GDE before the next one can occur. However, to our knowledge, the question of whether surface dust redistribution on Mars follows such a cyclic behavior was not adressed by mutli-year modeling studies yet.

In order to follow the time evolution of dust emission and deposition fluxes at the surface of Mars, we use the Mars Planetary Climate Model in its newest version 6 (Mars PCM6) (Bierjon et al., 2022), where dust injection is prescribed by observations, while transport and sedimentation freely follow the model winds. For prescribing dust injection, the Mars PCM6 uses daily global maps from observations of the Column Dust Optical Depth (CDOD) (Montabone et al., 2015). We further complete these maps with daily dust storm obervations from the Mars Dust Storm Sequences Database (MDSSD) (Wang et al., 2023), to take into account the intense dust storm activity near the Martian polar caps.

We thus obtain maps of the surface dust redistribution in the time frames covered by these observations (MY24-35 for the CDOD maps and MY28-33 for the MDSSD). We validate our modeling results with surface dust redistribution patterns from the literature, derived from remote-sensing observations of the Martian surface. Finally, we will analyse whether we find a periodic redistribution pattern of surface dust, in order to test the hypothesis of replenishing dust reservoirs between GDEs. This will utlimately help improving our understanding of Martian GDEs, on the road towards reliable weather prediction on Mars.

 

References

A. Bierjon, E. Millour, F. Forget, Finalization of the GCM version 6 - Improving the Dust Cycle, Laboratoire de Météorologie Dynamique, CNRS, IPSL, Paris, France, 2022, https://www-mars.lmd.jussieu.fr/esa/contract2020_2022/deliverables/MS3/D2.1_dust_cycle.pdf

L. Montabone, F. Forget, E. Millour, R.J. Wilson, S.R. Lewis, B. Cantor, D. Kass, A. Kleinböhl, M.T. Lemmon, M.D. Smith, M.J. Wolff, Eight-year climatology of dust optical depth on Mars, Icarus, Volume 251, 2015, doi:10.1016/j.icarus.2014.12.034

H. Wang, M. Saidel, M.I. Richardson, A.D. Toigo, J.M. Battalio, Martian dust storm distribution and annual cycle from Mars daily global map observations, Icarus, Volume 394, 2023, doi:10.1016/j.icarus.2022.115416