Meteorological predictions for the Mars Pathfinder lander

The NASA Ames Mars general circulation and boundary layer models are used as guides to forecast the meteorological environment of the Pathfinder lander site. Based on these models we predict that for a Viking-like atmospheric dust loading, significant vertical wave structure will be seen in the entry temperature profile above 50 km. Temperatures in this region will oscillate by up to 30 K about a mean value of similar to 145 K. At the surface during the primary mission, winds are expected to rotate clockwise during the day at 2-10 m/s, while air temperatures will range from overnight lows in the mid 180s K to daytime highs near 250 K. If the atmosphere is dust free at arrival, as appears possible from recent Earth-based observations, then we expect a cooler upper atmosphere (130-140 K) with less wave structure during entry, weaker surface winds, and a slight increase in near surface air temperatures. Regardless of dust loading, we predict that the daily averaged surface pressure will reach its annual minimum about 15-20 sols after landing. During the extended mission, the basic character of Pathfinder's meteorology will change from that of a summertime quasi-regular regime to that of a wintertime highly variable regime. This transition is predicted to occur by sol 60. The strongest winds (30 m/s) and lowest daily-averaged temperatures (similar to 200 K) will be recorded during early winter.