Analysis of net radiation in Atlantic forest affected with anthropic intervention, in São Paulo, Brazil

Abstract

Forest ecosystems, such as the Atlantic forest in South America, have been removed to give rise to agricultural activities and human settlement. This situation may be causing changes in the absorption of solar energy on the earth's surface, modifying the consumption of net radiation, which in turn can influence air temperature. Therefore, this research aimed to evaluate the changes in the net radiation of the Sorocaba basin, analyzing how changes in the Atlantic forest, caused by agricultural areas and anthropic constructions, this is impacting on the net radiation and the repercussion in the regulation the local climate. For these purposes, the radiation balance in the basin and its biophysical components (NDVI, surface temperature, albedo and emitted radiation) were determined through the SEBAL model, using OLI / TIRS-Landsat 8 and ASTER (GDEM) images. The results revealed that the built areas, as well as those for agricultural use, present higher albedo and surface temperature values, when it is compared to the Atlantic forest. Thus, these areas present higher heat flux emitted into the atmosphere in the form of infrared radiation. Consequently, lower net radiation consumption was generated, which was 712.40Wm-2, 669.40Wm-2, 629.90Wm-2, 616.60Wm-2 and 524.40Wm-2, on average, for forest, agricultural areas, areas with pastures, bare soils and built areas, respectively. Thus, deforestation in the basin caused the net radiation to decrease and more heat was emitted into the atmosphere, which favors the greenhouse effect (the main cause of global warming), affecting the regulation of the air temperature.