The Atmospheric Drivers of the Major Saharan Dust Storm in June 2020

Abstract

This study investigates the atmospheric dynamics of the major dust storm that occurred in June 2020 over the Sahara and during which dust clouds associated with the highest-on-record aerosol optical depths were transported toward the America. An anomalous atmospheric circulation pattern in the mid-latitudes, linked to a circumglobal wavetrain, resulted in the development of a subtropical high-pressure system to the west of the Saharan heat low. This created a pressure dipole and generated anomalously strong northeasterlies over the Sahara, which caused continuous dust emissions over 4 days. Occurring along the northern fringes of the intertropical discontinuity, the dust was transported to higher altitudes (6 km) by the strong updraft in this region. This injected the dust at the African Easterly Jet (AEJ) altitudes and favored a rapid westward long-range transport. The AEJ was also anomalously strong, being strengthened by the anticyclonic circulation associated with the anomalous high.