Caracterização ótica dos aerossóis sobre o Brasil

Abstract

Aerosols are solid or liquid particles suspended in the atmosphere, which can directly or indirectly influence the climate of a region, because they interfere with the energy balance. Analyzing their optical characteristics is necessary to understand their effects on the atmosphere. For the optical characterization we used data of Aerosol Optical Thickness (EOA) and Angstrom Exponent (AE) obtained through the AERONET solar photometer at eight sites (Alta Floresta, Campo Grande, Cuiabá, Ji Paraná, Rio Branco, Petrolina, São Martinho and São Paulo) with a period of at least seven years of observational data. The relationship between these two mentioned parameters makes it possible to identify how attenuating the atmospheric particles are and the dominance of the average particle size. To identify the dominant aerosol type at the analysis sites, the medians and distribution and frequency of EOA and AE were analyzed and the parameters greater than and less than 1.0 were adopted for EOA and AE less than or equal to 1.5 and between 1.5 and 2.0. The sites showed the characteristic dominant aerosol type being poorly attenuating and dominance of coarse particles, with the exception of Rio Branco which showed aerosols with poor attenuating characteristics of fine mode, so it can be associated with particles generated by burning, common in the surrounding region of the site analyzed. For the seasonality analysis, sites near the Amazon region showed higher values between August and September and in Petrolina and São Martinho did not show much seasonal variability.