Description of the University of Auckland global Mars mesoscale meteorological model

Abstract

The University of Auckland global Mars mesoscale meteorological model (GM4) is a numerical model of the martian atmosphere that has been developed through the conversion of the Penn State University/National Center for Atmospheric Research fifth generation mesoscale model (MM5). The model is initialized in this paper through the implementation of a ‘base-state’ atmosphere. Continual boundary condition input from a GCM is unnecessary as the global domains of the model are self consistent and form a continuous domain around the entire planet. A description of the model and its basic underlying physical principles as applicable to the atmosphere of Mars is outlined. Comparison between ASI/Met data collected from Mars Pathfinder during its 1997 mission and simulated conditions using GM4 is given. Diurnal temperature variation as predicted by the model shows very good correspondence with the measured surface data, to within 5 K for the majority of the diurnal cycle. Mars Viking I surface meteorological data is compared to the GM4 model, yielding similar results. To assess the vertical structure of the atmosphere, simulations have also been compared with Mars Global Surveyor Radio Science temperature–pressure profiles. As a further test for the model, various seasonal comparisons of surface and vertical atmospheric structure are performed with the European Space Agency AOPP/LMD Mars Climate Database. Agreement between the two models is reasonable, though polar regions are not very well represented by the GM4 model at present. As an experimental case study, mountain flow over Olympus Mons is simulated using this new mesoscale modeling system, showing results in good agreement with similar model simulations and observational data.