Análise das componentes dos fluxos superficiais de massa e energia na região Sul do Brasil

Abstract

Ecosystems interact with the atmosphere through, mass and energy superficial fluxes, therefore understanding the properties of these fluxes in different ecosystems is very important for improving knowledge about biophysical processes that control them and the surface-atmosphere interaction. In South of Brazil, two important biomes are present: the Pampa biome and the Atlantic Forest biome, which have been undergoing a great anthropogenization of their areas. In this thesis an article was dedicated to study a typical ecosystem in each biome. In Pampa, in one of its soil uses, rice areas had their superficial fluxes monitored by eddy covariance technique (EC) for five years. So, this indicates, during the experiment, the ecosystem worked as carbon dioxide absorber. In terms of energy balance, the ecosystem showing low values of Bowen ratio. The Soil water evaporation was the dominant component of the evapotranspiration fluxes. Carbon dioxide flux seasonality is connected to leaf area index. Of its components, ecosystem respiration (RE) responds to temperature seasonality and gross primary production (GPP) depends to solar radiation variability. The second ecosystem monitored by EC technique was Araucaria forest which is part of Mata Atlantica biome. In this study, the forest was stratified in two levels, the overstory and the understory layers that present distinct contributions to total ecosystem fluxes. The ecosystem as a whole absorbed carbon dioxide during the experiment, in which the overstory was responsible by absorption via GPP and the understory was emitter of carbon dioxide via RE. Energy balance in this forest indicated that latent heat flux was the dominant component in energy balance, being the highest contribution to evapotranspiration fluxes from the overstory.