The interaction between the Atlantic Subtropical Cells and AMOC: variability from past to future

• Grant number: 25/05649-2
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: August 01, 2025
• End date: July 31, 2028
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Physical Oceanography
• Principal Investigator: Ilana Elazari Klein Coaracy Wainer
• Grantee: Laura Sobral Verona
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 20/14356-5 - The Santos Bifurcation: present and past, AP.PFPMCG.TEM

Abstract

The Atlantic Subtropical Cells (STCs) are shallow overturning circulations that connect subtropical subduction regions to equatorial upwelling zones. They are primarily driven by wind stress but are also influenced by interactions with the Atlantic Meridional Overturning Circulation (AMOC) and may modulate sea surface temperature (SST) variability (i.e. Atlantic Niño). Their variability, in turn, affects regional precipitation patterns, particularly over South America and West Africa. Despite their importance, many uncertainties remain regarding the long-term evolution of the STCs and their coupling with the AMOC, especially in the context of anthropogenic climate change. Observations suggest that the AMOC has weakened in recent decades, with climate models projecting further decline in the 21st century. However, the implications of this weakening for the STCs and their influence on equatorial SST variability remain poorly understood. The projected weakening of the Atlantic Niño further raises questions about the role of STCs-AMOC interactions in modulating equatorial upwelling and heat transport under future climate scenarios. This project aims to investigate the interplay between these processes across different climate states, from past warm climates to future projections, using a combination of single model large ensemble and paleoclimate simulations. Our main goal is to identify the key mechanisms connecting AMOC upper limb changes to the STCs and assess the STCs role as potential mediators of Atlantic Niño responses. By bringing past to future climate perspectives, this project will enhance our understanding of tropical climate variability, ocean circulation, and regional climate impacts under warming scenarios. (AU)