DPS Meeting, Madison, October 1998
Session 11P. Mars Atmosphere I, II, III, IV
Contributed Poster Session, Monday, October 12, 1998, 4:10-5:30pm, Hall of Ideas

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[11P.15] Mixing height of the Martian ABL - preliminary model results

A.-M. Harri (Finnish Meteorological Institute), A. Petrosyan (Russian Space Research Institute)

The mixing height of the Martian atmospheric boundary layer (ABL) is a key parameter in both dust and volatile transportation. The diagnostic expressions for mixing height evaluation based on Bulk Richardson number are likely to give increased values and need to be revised. In our presentation we discuss a few prognostic models of the Mars mixing height and predict its diurnal evolution for Pathfinder and Viking landing sites.

In our mixing height modeling for Mars we assume that in the morning the mixing layer is nearly neutrally stratified. Hence the height of shear driven turbulent boundary layer is used as the initial condition in solving the prediction equations of the mixing height. The applicability of two Earth-based prognostic models for growth of the daytime mixed layer to Mars are discussed.

The main model assumption of the first model is that development of an unstable boundary layer is governed by the same kind of similarity relations that are also applicable at the surface layer with new dimensionless parameters connected to the mixing height. The model has the capability of accounting for the complex Martian surface orography, as well as for extending to the stable static stability conditions in nighttime.

The second model includes the effect of convective and mechanical turbulence in the entrainment process which is characteristic of strong wind conditions.

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