Moisture Flows On Southeast Brazil: Present And Future Climate

The characterization of the moisture flows over South America, with a special focus on the Southeast Brazil (SEB), was performed through the analysis of 21 Earth System Models (ESMs) belonging to the Coupled Model Intercomparison Project Phase 5 (CMIP5) for the present climate (1971-2000) and projections for the late 21st century (2071-2100) using a scenario of high radiative forcing (RCP 8.5). The results show that the ESMs simulate well the spatial distribution of the flow and the divergence of moisture in the present climate, when compared with the 20CRv2c reanalysis, although some biases have been identified. In relation to the magnitude of the moisture flow, the models underestimate the moisture convergence mainly on the central, south and southeast regions of South America. On SEB, the simulations show that the main sources of moisture for the region come from the north and east edges, confirming the contribution of moisture from the Amazon Basin and the South Atlantic Ocean. Climate change projections indicate an increase in moisture flow across South America, and regions of moisture convergence (divergence) in the present climate are projected to be even more convergent (divergent) in the future climate. In addition, the moisture flow over the SEB also showed to be more intensified on all lateral edges, as well as the moisture balance. This result is consistent with some studies on projections of climate change towards the end of the 21st century, which indicate that there will be an intensification of meteorological systems such as the Low Level Jet and the South American Monsoon System, contributing to the increase of moisture transport to the SEB region.