One of the things we’re working on with our global Mars atmosphere model (MarsWRF) is predicting martian dust storms. Dust storms on Mars can range anywhere in size from small local events a few kilometers in scale to events that fill the entire global atmosphere. In modeling them, we’re hoping to understand how they develop. The processes we consider in the model are: 1) dust lifting, 2) dust transport and mixing by the winds, 3) dust settling to the surface under gravity, and 4) the heating of the atmosphere as dust absorbs sunlight and interacts with thermal infrared radiation from the planet and atmosphere.
) – this is the same kind of model used to look at things like the large scale atmospheric circulation and climate change on the Earth. In this study, we took a look at how the simulation of the Martian atmosphere changes as the grid spacing (effectively the resolution) changes from about 5 degrees (about 300 km) down to 0.5 degrees (about 30 km). There were a number of interesting findings, including significant changes in the middle and upper atmosphere circulation. In the figure below, surface wind patterns and wind stresses are shown for a 2 degree and a 0.5 degree case. Wind stress is the lateral force (per unit area) felt by the surface due to wind blowing across it. When this stress becomes high enough, sand can get kicked around on the surface and dust lifted. Being a desert planet, dust storms of all sizes play across the Martian surface. A major science question revolves around how these storms form and grow. The resolution test was designed to examine whether there were significant changes in total wind stress with resolution (no) and whether the patterns changed significantly (yes – peak stresses became much sharper and more focused on topography). The paper can be found 
