Saharan dust long-range transport across the Atlantic studied by an airborneDoppler wind lidar and the MACC model

摘要

A huge amount of dust is transported every year from north Africainto the Caribbean region. This paper presents an investigation of thislong-range transport process based on airborne Doppler wind lidar (DWL)measurements conducted during the SALTRACE campaign (June–July 2013), aswell as an evaluation of the ability of the MACC (MonitoringAtmospheric Composition and Climate) global aerosol model toreproduce it and its associated features. Although both the modeled windsfrom MACC and the measurements from the DWL show a generally good agreement,some differences, particularly in the African easterly jet (AEJ) intensity,were noted. The observed differences between modeled and measured wind jetspeeds are between 5 and 10 m s. The vertical aerosol distributionwithin the Saharan dust plume and the marine boundary layer is investigatedduring the June–July 2013 period based on the MACC aerosol model results andthe CALIOP satellite lidar measurements. While the modeled Saharan dustplume extent shows a good agreement with the measurements, a systematicunderestimation of the marine boundary layer extinction is observed.Additionally, three selected case studies covering different aspects of theSaharan dust long-range transport along the west African coast, over theNorth Atlantic Ocean and the Caribbean are presented. For the first time,DWL measurements are used to investigate the Saharan dust long-rangetransport. Simultaneous wind and backscatter measurements from the DWL areused, in combination with the MACC model, to analyze different featuresassociated with the long-range transport, including an African easterly wavetrough, the AEJ and the intertropical convergence zone.