Ocean-atmosphere processes in response to climate change in the western tropical South Atlantic : impacts on Eastern Northeast Brazil

Abstract

The Atlantic Meridional Overturning Circulation (AMOC) is one of the major drivers of meridional heat transport in the Atlantic from the southern to the northern hemisphere. The AMOC upper branch in the South Atlantic has an east- to-west path characterized by the southern branch of the South Equatorial

Current (sSEC), which transports heat to the Southwestern Atlantic Warm Pool (SAWP). The SAWP provides Latent Heat Flux that the southeast trade winds carry into Eastern Northeast Brazil (ENEB), which induces heavy precipitation in the coastal region of ENEB and causes landslides and flash floods. This study investigates the long-term changes of the AMOC, Tropical Atlantic (TA) sea surface temperature (SST), and mean and extreme precipitation over ENEB for historical and future projections of the CMIP6 under the 585 and 245 SSP scenarios. Changes in the upper TA SST patterns and the SAWP projection are expected to be warmer according to the CIMP6 output models due to the AMOC weakening effect on heat transport, increasing extreme precipitation patterns in the ENEB. The precipitation in ENEB is positively correlated with SST from the southeastern TA to the southwestern SAWP offshore of Brazil.