A numerical model of the Martian polar cap winds

An investigation of the Martian polar cap winds and their response to a variety of factors is carried out by numerical experiments based on a zonally symmetric primitive equation model. The seasonal thermal forcing, mass exchange between polar caps and atmosphere, large-scale topography, and polar cap size are discussed, noting that topography has a small effect, but the circulation intensity increases with cap size. The model results show that surface winds near the edge of a retreating polar cap are enhanced, and that the surficial wind indicators near the south pole are formed during spring and those near the north pole during winter. It is suggested that the high-latitude dune fields in the northern hemisphere are formed when the terrain is covered by frost, and that the saltating particles are 'snowflakes' which formed by the mechanism proposed by Pollack (1976). The model results for the winter simulation compare favorably with general circulation model (GCM) calculations.