Opportunity landing site weather simulations.

The latest landed missions to Mars - Mars Exploration Rovers (MERs) Spirit and Opportunity - have been successful. Although the MERs do not have actual meteorological instrumentation, they have observed using their Mini-TES the boundary layer diurnal temperature profiles and surface temperatures (Smith et al, Science 3 December 2004; 306:1750-1753).

We have developed the Mars Limited Area Model (MLAM) in co-operation between the Division of Atmospheric Sciences of University of Helsinki and the Finnish Meteorological Institute, to study Martian mesoscale weather phenomena. MLAM is the first European 3-dimensional limited area model for Mars.

MLAM is based on an operational forecast model, HIRLAM. As current HIRLAM, MLAM is a hydrostatic model. It uses sigma-vertical coordinate with approximately 30 levels in the vertical. The model includes a comprehensive physics package. The horizontal scale of the relevant phenomena is 10-1000 km.

Conversion for Mars has required, e.g., changing the Earth's constants to the Martian ones. The radiation scheme was rewritten for Martian conditions. We included the effects of dust in the parameterisations and validated them via comparisons with a multiple scattering high spectral resolution, i.e. line-by-line scheme. We modified also the soil scheme for Mars. Oxford University Mars group has provided us with the output of their Mars General Circulation Model with assimilation of thermal and dust observations, for using as initial and boundary conditions.

Here we have used MLAM to simulate weather at the Opportunity (MER B) landing site and compared the results to the in-situ observations.

This work was supported by University of Helsinki.