The Mars Daily Global Maps compiled from pole-to-pole image swaths taken by the Mars Reconnaissance Orbiter (MRO) Mars Color Imager (MARCI) are used to analyze the development histories of large Martian dust storms. Large Martian dust storms can significantly influence the opacity and circulation of the Martian atmosphere. They usually form through dust storm sequences that follow identifiable trajectories, with many covering areas beyond their origination zones. In this study, we identified and studied the development histories of 59 large-scale dust storms during MY 28–32. Of these dust storms, 40 originated in the northern hemisphere (called ‘northern sequences', predominantly during Ls = 210-240° and Ls = 300-330°) and 19 originated in the southern hemisphere (called ‘southern sequences’, primarily during Ls = 150–210°). Northern sequences generally originated in Acidalia, Utopia, or Chryse. These sequences tended to travel southward down confined longitudinal channels to the southern hemisphere, though a portion of northern sequences remained within their plain of origin. Southern sequences originated in Argyre-Solis-Valles Marineris (ASV), Hellas basin and Cimmeria-Sirenum. The majority of southern sequences remained near their origination zones, however northeastward and eastward trajectories were frequent for ASV and Cimmeria-Sirenum sequences respectively. The majority of dust storm sequences studied achieved peak areas towards the end of their trackable lifetimes. Parallel development and subsequent merging of dust storm sequences were found to be efficient ways through which Martian dust storms grew.
M. Saidel is supported by the SAO REU program which is funded in part by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant no. AST-1852268, and in part by the Smithsonian Institution. H. Wang is funded by NASA’s PDART grant 80NSSC20K1056 and MDAP grant 80NSSC17K0475.