New 3D Climate Model for Mars

The first paper describing our newest climate model for Mars has just gone live at the journal Icarus as a paper-in-press.  You can access the paper here.  The model simulates the global Martian atmosphere – but unlike all prior full general circulation models for Mars (Mars GCM), it does so with a novel numerical approach and a novel (cube-sphere) computational grid.  The upshot of the improved numerics is much better treatment of things like dust and water vapour that are blown around in the atmosphere.  As the crucial elements of the Martian climate system, getting the transport of these systems right is central to proper simulation of the climate.  In the paper, we “calibrate” the model with Mars Odyssey Orbiter Gamma Ray / Neutron Spectrometer and Mars Exploration Rover Alpha Proton X-ray Spectrometer measurements of argon.  Argon is a really useful “tracer” as it has no chemical or physical sources or sinks – it is merely enriched or diluted by “freeze distillation” of the CO2 that makes up the majority of the Martian atmosphere.  The good news is that the new model does much better than all prior Mars GCMs.  The bad news is that the model still under-predicts argon in the southern polar winter.  There’s still obviously work to be done before we properly understand transport in the Martian atmosphere.

As with the WRF model that we also run at Ashima Research, the core MITgcm is primarily used for study of the Earth’s climate addressing crucial questions of atmospheric and oceanic circulation, regional and global climate, and climate change.

The figure, below, shows Martian topography and albedo (reflectivity) on the native cube-sphere grid.  The full globe can be constructed by “folding” the edges of the domain together.  The major advantage over standard grid-point models is the absence of two “convergence” points at the poles.

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