Aerosol characterization and direct radiative forcing estimation over the ocean from satellite observations

Aerosol direct and indirect effects on the Earth’s climate are widely recognized but have yet to be adequately quantified because of the very high spatial and temporal variability of aerosols, which is the major cause of uncertainties in quantifying the atmospheric radiative forcing. A method to exploit the synergy between the Global Ozone Monitoring Experiment (GOME) onboard the ERS-2 polar orbiting satellite and the METEOSAT geostationary system was proposed (Costa et al., 2002), with the intent of merging the opportunities offered by both kinds of sensors for aerosol studies: 1) fairly good spectral resolution from polar based sensors increasing the accuracy of the aerosol characterization, and 2) suitable space and temporal resolution from geostationary satellites for monitoring the optical thickness and direct aerosol radiative forcing. Results are presented for a relevant transport event of aerosol from biomass burning over the South Atlantic Ocean on 6-13 September 2000. Retrieved aerosol optical properties are combined with radiative transfer calculations to assess the short-wave aerosol radiative forcing in the area of the event.