Great Dust Storms on Mars: What Have We Learned?

Great dust storms on Mars are dramatic episodes of dust-raising and widespread transport that may have climatic effects on intra-seasonal, inter-annual, and ultimately much longer (e.g., obliquity) timescales. This paper will address to what extent the unprecedented observational coverage of Mars in recent times from orbiting spacecraft has changed our understanding of regional dust storms and hazes. During this period two nearly global dust storm events have occurred, in 2001 and in 2007; these are considered within the historical context of such storms with emphasis on the frequency of occurrence and on the mechanisms involved in their onset and decay.