dust source (VIDEO) PNAS Nexus This video is under embargo. Please login to access this video. Caption Daily progression of Dust Aerosol Optical Depth over Southern Africa during the austral spring/summer of 2019/2020. Credit Gittings et al Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.