Overview of Climate-Vegetation Interactions in Amazonia: From the Last Glacial Maximum to the Climates of the Future
Carlos
Afonso
Nobre, CPTEC-INPE, nobre@cptec.inpe.br
(Presenting)
LBA research on Physical Climate aspects of Amazonia is uncovering novel features of the interaction of vegetation and the atmosphere in many spatial and temporal scales. The question of the importance of the Amazonian heat source for the global circulation of the atmosphere will be reviewed to establish likely remote climate changes due to Amazonian deforestation via atmospheric teleconnection patterns. Regionally, the question of the heterogeneity of deforestation patterns will be discussed. High resolution model simulations tend to indicate an increase of rainfall over the intensely deforested areas of Rondonia through the so-called “forest breeze” effect. However, a review of raingauge and satellite-derived observations of cloudiness and rainfall over Rondonia do not show, as yet, an increase of rainfall in either the dry of the wet season. The dynamics of the main circulation features associated with the heat source, namely the continental tropical convection in Amazonia, the South Atlantic Convergence Zone (SACZ) and the Inter-Tropical Convergence Zone (ITCZ), and their association to remote forcing from the Tropical Pacific and Atlantic Oceans, will be addressed and alterations of these large scale features due to land use change will be summarized. Next, a discussion of paleoclimate vegetation reconstructions from the Last Glacial Maximum (LGM) 20 kaBP to the present will be assessed in light of our current knowledge of biome-climate stability. Finally, a consideration will be given to likely scenarios of ecosystems changes in Amazonia due to scenarios of future climate change.