Enhanced Super-Rotation Before and During the 2018 Martian Global Dust Storm

Super-rotation affects-and is affected by-the distribution of dust in the martian atmosphere. We modeled this interaction during the 2018 global dust storm (GDS) of Mars Year 34 using data assimilation. Super-rotation increased by a factor of two at the peak of the GDS, as compared to the same period in the previous year which did not feature a GDS. A strong westerly jet formed in the tropical lower atmosphere, with strong easterlies above 60 km, as a result of momentum transport by thermal tides. Enhanced super-rotation is shown to have commenced 40 sols before the onset of the GDS, due to dust lifting in the southern mid-latitudes and tropics. The uniform distribution of dust in the tropics resulted in a symmetric Hadley cell with a tropical upwelling branch that could efficiently transport dust vertically; this may have significantly contributed to the rapid expansion of the storm.

Automated summary

During the global dust storm on Mars in 2018, super-rotation significantly increased, leading to a strong westerly jet in the lower atmosphere and strong easterlies above 60 kilometers. The enhancement of super-rotation began 40 sols before the storm, primarily due to dust lifting in the southern mid-latitudes and tropics.