Effects of Global Dust Storm in MY28 and Roles of Unresolved Waves on the General Circulation of Mars

Abstract The changes in the meridional circulation in MY28 owing to the global dust storm (GDS) event are quantitatively investigated using a reanalysis data set. During the GDS, a horn‐like high temperature anomaly up to 56 K relative to the climatology is observed around the north pole between 200 and 0.5 Pa. The high temperature anomaly is maintained by the downward flow approximately five times stronger than that of climatology. Below the 5 Pa level around 45°N, the dynamic mechanism for downwelling intensification is attributed to the latitudinal expansion of the angular‐momentum conserving Hadley‐like cell. Above the 5 Pa level, the downwelling is attributed to the much stronger wave‐driven meridional flow extending to the north pole. Estimation of the wave forcing due to unresolved waves in the reanalysis data, including subgrid‐scale gravity waves, reveals that the strong meridional flow is driven by the unresolved waves rather than large‐scale resolved waves.