Global analysis of aerosol properties above clouds

F. Waquet (1) , F. Peers (1) , F. Ducos (1) , P. Goloub (1) , S. Platnick , J. Riedi (1) , D. Tanré (1) , F. Thieuleux (1)

1 LOA - Laboratoire d’Optique Atmosphérique - UMR 8518

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.

Keywords: aerosol; climate; cloud; satellite; global

Domains: Sciences of the Universe [physics]

F. Waquet, F. Peers, F. Ducos, P. Goloub, S. Platnick, et al.. Global analysis of aerosol properties above clouds. Geophysical Research Letters, 2013, 40, pp.5809-5814. ⟨10.1002/2013GL057482⟩. ⟨insu-03620880⟩