Analysis of transport and mixing of generic trace gases in the martian atmosphere with MRAMS

The Mars Regional Atmospheric Modeling System (hereafter MRAMS, Rafkin & Michaels, [2019]) is used to simulate, via passive (inert) tracers, the 3-D atmospheric transport, dispersion and mixing of trace gases released at different locations from instantaneous releases, and to evaluate whether air masses could make it to specific locations. The objective is to study if circulation (mean or regional) is favorable for transport trace gases from any point of the planet to specific locations. With the corresponding caveats, our modeling results can be used to investigate transport and mixing of trace gases like water vapor or methane. In these MRAMS experiments, a total of 18 tracers are strategically placed quasi-globally in the computational mother domain. Tracers are placed in 30 degree latitude belts (-90->-60, -60->-30, -30->0, 0->30, 30->60, 60->90) and then at above ground levels from 0-10 km, 10-30 km, and 30 km-model top.  We can determine from which latitude belt air is coming/going and from what level in the atmosphere.  The tracers also provide the means to quantify atmospheric mixing, diagnosed by evaluating the fraction of a given tracer mixing ratio compared to the total as a function of time. Tracer experiments show that northern high latitude air masses can be transported with very little dilution to some lower latitude locations, including Hrad Vallis and Jezero Crater.  In other locations, source air masses are highly diluted.