A record-breaking trans-Atlantic African dust plume associated with atmospheric circulation extremes in June 2020

ABSTRACT:

High concentrations of dust have adverse impacts on society and human health, yet our understanding of extreme dust events is still limited. A record-breaking trans-Atlantic African dust plume degraded air quality over large areas of the Caribbean and U.S. in June 2020. We found this extreme dust event is associated with enhanced dust emissions over western North Africa and atmospheric circulation extremes that favor dust long-range transport. An exceptionally strong African easterly jet and associated wave activities export African dust across the Atlantic toward the Caribbean, while a westward extension of the North Atlantic subtropical high and an extremely enhanced Caribbean low-level jet further transport the dust layer onto the U.S.  Over western North Africa, enhanced dust emissions are associated with extremely enhanced surface wind speeds over dust source regions and reduced vegetation coverage in the western Sahel.  While there are large uncertainties associated with future variations in African dust emissions, model projected atmospheric circulation changes generally favor long-range transport of African dust to the Caribbean Basin and the U.S. in a warmer future.