Global analysis of aerosol properties above clouds

Abstract

Abstract The seasonal and spatial variability of Aerosol Above Cloud (AAC) properties are derived from passive satellite data for the year 2008. A significant amount of aerosols are transported above liquid water clouds on the global scale. For particles in the fine mode (i.e., radius smaller than 0.3 µm), including both clear‐sky and AAC, retrievals increase the global mean aerosol optical thickness by 25(±6)%. The two main regions of originated anthropogenic AAC are the tropical Southeast Atlantic, for biomass‐burning aerosols, and the North Pacific, mainly for pollutants. Man‐made AAC are also detected over the Arctic during the spring. Mineral dust particles are detected above clouds within the so‐called “dust belt” region (5–40° N). AAC may cause a warming effect and bias the retrieval of the cloud properties. This study will then help to better quantify the impacts of aerosols on clouds and climate.