Funding was provided by the Portuguese Foundation for Science and Technology under Grant POCTI/CTA/42917/2001. One of the authors (VL) acknowledges support by the Italian Space Agency under the grant Sinergia GERB-SEVIRI nello studio del bilancio radiativo a scala regionale e locale. The senior author was supported by the Subprograma Ciência e Tecnologia do 2° Quadro Comunitário de Apoio. Meteosat imagery was kindly made available by EUMETSAT. AERONET data are available online (http://aeronet.gsfc.nasa.gov/;) thanks to NASA, CNES, and CNRS. AERONET investigators and their staff deserve special thanks for establishing and maintaining the sites where the data used in this investigation were obtained. POLDER aerosol parameters are products derived from the data of the CNES POLDER instrument on board NASDA's ADEOS. MODIS data are courtesy of NASA Earth Science Enterprise and the official algorithms were developed by the MODIS Science Teams. They were processed by the MODIS Adaptive Processing System (MODAPS) and Goddard Distributed Active Archive Center (DAAC), the latter being in charge of archiving and distribution. CERES data were provided by the Atmospheric Sciences Data Center at NASA Langley Research Center. Three anonymous reviewers significantly contributed to the improvement of the manuscript and are gratefully recognized.
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