The Mars Dust Activity Database (MDAD): A comprehensive statistical study of dust storm sequences

A comprehensive Mars Dust Activity Database (MDAD) over 8 Mars years (MY 24, L-s = 150 degrees to MY 32, L-s = 171 degrees) is compiled from Mars Daily Global Maps. A total of 14,974 dust storm instances are cataloged with area >10(5) km(2) that are visually distinguishable from the surface. A dust storm instance is identified as a dust storm member over multiple sols if storm movement can be tracked. Dust storm sequences are collections of members that have a coherent trajectory from their origination areas over three or more sols. There are 228 sequences, with 125 originating in the northern hemisphere. Sequences primarily originate in Acidalia, Utopia, and Arcadia Planitiae in the northern hemisphere and Aonia-Solis-Valles Marineris and Hellas Basin in the southern hemisphere. Many northern hemisphere originating sequences flush into the southern hemisphere. The primary season for non-global dust events occurs during L-s = 140 degrees-250 degrees, with secondary seasons in L-s = 300 degrees-360 degrees in the northern hemisphere and L-s = 10 degrees-70 degrees in the southern hemisphere. Sequences are classified into three types. Main Member sequences have one dominant member; Continuous Development sequences have many smaller members; and Sequential Redevelopment sequences have repeating, medium-sized members. "Major" sequences have a maximum area >10(7) km(2), influence the zonal-mean global opacity, and exhibit flushing behavior. Major sequences occur over a narrower temporal range and are distinguished from other sequences by the larger size and duration distributions of their constituent members. Major sequences have unique antecedent conditions, with steadily increasing dust storm area in the 6 preceding sols that is significantly distinct from conditions preceding minor sequences.