Estudo do impacto dos aerossóis na espessura óptica da atmosfera na região sul do Brasil

Abstract

Aerosols are solid or liquid particles suspended in the atmosphere which can be originated either by anthropogenic or natural sources. They are important on the radiative balance due to their capacity of absorb or scatter radiation. Consequently they affect the climate system, cooling or heating surface temperature. According to the characteristic of each aerosol particle, it is possible to quantify their effect on the atmosphere, as well as their type. Nowadays, there are several ways of studying some of the characteristics and/or proprieties of the aerosols. One of them is by analyzing the Atmospheric Optical Thickness (AOT), which quantifies the radiation attenuation in an optically active medium. Based on that this work aims to analyze the different types of aerosols present in southern Brazil. By analyzing the percentile 99 (P99) it will be possible to know where the regions with high values of AOT are. This will be done by AOT data from MODIS sensor (Moderate-resolution Imaging Spectroradiometer), in the 0,55μm wavelength from 2002 to 2011. It was observed that the predominant type of aerosol in the region is characterized as slightly radiation attenuators, with low AOT (AOT <1,0). Besides this, it was observed that the periods with high AOT was winter and spring, especially in northeast of Southern Brazil. By the studies cases it was possible to notice that the large- scale circulation pattern, for example the subtropical high, aids in the transport of these particles from other regions to the Southern Brazil.