ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-9-6767-2009 A comparison study of regional atmospheric simulations with an elastic backscattering Lidar and sunphotometry in an urban area Landulfo E. 1 Freitas S. R. 2 Longo K. M. 2 Uehara S. T. 1 Sawamura P. 1 Instituto de Pesquisas Energéticas e Nucleares – IPEN, São Paulo, Brazil Centro de Previsão do Tempos e Estudos Climáticos – CPTEC, Cachoeira Paulista, Brazil 18 09 2009 9 18 6767 6774 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/9/6767/2009/acp-9-6767-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/6767/2009/acp-9-6767-2009.pdf

We describe a comparison study of Aerosol Optical Thickness (AOT) from numerical simulations using a regional atmospheric model with an elastic backscattering lidar operating at 532 nm and a sunphotometer belonging to the AERONET network at São Paulo (23° S 46° W) city, Brazil, a very populated urban area. The atmospheric model includes an aerosol emission, transport and deposition module coupled to a radiative transfer parameterization, which takes the interaction between aerosol particles and short and long wave radiation into account. A period of one week was taken as case study during the dry season (late August) when intense biomass burning activities occur at remote areas in South America, and meteorological conditions disfavor the pollution dispersion in the city of São Paulo. The situation presented here showed how smoke from biomass burning in remote areas is transported to the south-east part of Brazil and affects the optical atmospheric conditions in São Paulo. The numerical simulations are corroborated by in situ measurements of AOT obtained by lidar and sun photometry.

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