Características projetadas da monção sul-americana para final do século XXI

Abstract

The projected changes in the South America Monsoon System (SAMS) related to the (1) expansion area; (2) terms of surface water and energy balances and (3) pressure at mean sea level (PMSL) patterns are shown for the end of the century (2080-2099), under Representative Pathway Scenario 8.5 (RCP8.5). For this reason, a set of Global Climate Models (GCMs) and projections of the Regional Climate Model version 4 (RegCM4) nested to these GCMs were analyzed. The analysis of balance terms are concentrated in four subdomains: Northern Amazon (NAMZ), Southern Amazon (SAMZ), La Plata Basin (LPB) and Southern Southeast Brazil (SSB). For the analysis, ensembles from the projections of the GCMs and RegCM4 were used. Both ensembles indicate a decrease in the monsoon area in the south of the Amazon and an expansion towards the Atlantic Ocean in the period 2080-2099 compared with 1995-2014. The trends in the water and energy balances, considering the wet period of the SAMS (November to March), show different signs in each subdomain. While in NAMZ and SAMZ, ensembles project dry conditions (i.e., decrease in the amount of precipitation, soil moisture and runoff), in LPB and SSB they project more wet conditions at the end of the century. In the four subdomains, an increase in air temperature is projected. The warmer conditions in the subdomains of the Amazon (NAMZ and SAMZ) are associated with changes in the energy balance terms (increased net radiation and sensitive heat flux on the surface and decreased latent heat flux on the surface), while in LPB and SSB are not directly associated with changes in the energy balance. The analysis of the pattern of PMSL was carried out using the principal component analysis technique. The results of this stage of the study indicate that for the future climate a change in the frequency of the patterns found in the present climate is projected. However, no significant changes in the acting of atmospheric systems are projected in the CPs of the future climate.