Spatial distribution and optical properties of Saharan dust observed by airborne high spectral resolution lidar during SAMUM 2006

Abstract

Airborne measurements of pure Saharan dust extinction and backscatter coef- ficients, the corresponding lidar ratio and the aerosol optical thickness (AOT) have been performed during the Saharan Mineral Dust Experiment 2006 with a high spectral resolution lidar. Maximum AOT values at 532 nm encountered during the DLR Falcon research flights were 0.50-0.55. A significant horizontal variability of the AOT south of the High Atlas mountain range was observed even in cases of a well mixed dust layer. High vertical variations of the dust lidar ratio of 38-50 sr were observed in cases of stratified dust layers. The variability of the lidar ratio was attributed to dust advection from different source regions. The aerosol depolarization ratio was about 30 % at 532 nm during all measurements and showed only marginal vertical variations. The dust layers were found to range from ground up to 4-6 km above sea level (ASL).