CLouds and Aerosol Radiative Interaction and Forcing Initiative

The CLouds and Aerosol Radiative Interaction and Forcing Investigation (CLARIFI) project is part of ESA’s Changing Earth Science Network Initiative and aims at quantifying the radiative effect of UV-absorbing aerosol layers above cloud layers, using space-based instruments and radiative transfer modelling. We focus on clouds and smoke from biomass burning in Southern Africa. It appears that clouds that exist in the presence of smoke aerosols have a typical reflectance spectrum, with a lower reflectance in the UV and visible than clouds without smoke. This lower reflectance is caused by the light absorption by smoke aerosols above the clouds, which is strongly wavelength-dependent. From integration of the measured reflectance spectrum of these smoke-polluted clouds over the SCIAMACHY wavelength range, we obtain a direct estimate of the shortwave absorption of polluted clouds. In this paper the first results of project are presented.