Ocean-atmosphere processes in response to Climate Change in the tropical South Atlantic
northward heat transport, AMOC, Precipitation, ENEB
The Atlantic Meridional Overturning Circulation (AMOC) is responsible for transporting large amounts of heat in the ocean, which affects the Intertropical Convergence Zone position, with further consequences on weather and climate. This work investigates the historical and climate projections variability of AMOC heat transport and its impacts on the precipitation in the Eastern Northeast of Brazil (ENEB).
The analyses were applied considering greenhouse gas increase by using extended global-warming simulations of the Coupled Model Intercomparison Project Phase 5 and 6 (CMIP5, CMIP6) under the scenarios of Representative Concentration Pathways (RCPs) 2.6, 4.5, 6.0, and 8.5 and Shared Socioeconomic Pathways (SSPs) 126, 245, 460 and 585, respectively. The latitudinal analyses of the difference in zonal mean ocean temperature in the Tropical South Atlantic from the CMIP5 and CMIP6 simulations and historical data, show an increase in the following years. The temperature projections show a positive temperature trend in the upper ocean due to the AMOC weakening.
By comparing the AMOC heat transport from the CMIP5 and CMIP6 simulation with historical AMOC from ORAS4, it is possible to identify a decrease in the heat transport induced by the weakening of the AMOC.
The cross-wavelet analyses indicate a co-variability between the AMOC heat transport and the continental precipitation over ENEB, mainly in the annual timescale and some weaker interannual relationship.