Abyssal Transport between the Southern Ocean and the South Atlantic from High-resolution Simulations

• Grant number: 25/08283-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: December 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Physical Oceanography
• Principal Investigator: César Barbedo Rocha
• Grantee: Marina Romann Tambelli
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 24/09961-8 - Variability of the Transports by the Deep Waters in the South Atlantic, AP.R

Abstract

Almost all the knowledge of abyssal transport between the South Atlantic and the Southern Ocean is based on conceptual models that generalize bottom transport as a flow northwards, carrying the Antarctic Bottom Water mainly from the Weddell Sea and Prydz Bay. However, the increased resolution in simulations, combined with advances in the representation of topography and mesoscale processes, as well as the increase in deep ocean observations, suggest that local specificities influence the pathways of abyssal transport.. Among these factors, channels stand out, whose presence can significantly modify the zonal mean transport. Our working hypothesis is that although the integrated abyssal transport is predominantly northward in the South Atlantic, high-resolution simulations can represent counter-flows that are important for the determination of zonally distributed thermohaline properties.To test this hypothesis, this study aims to quantify and characterize abyssal transport along the 34.5°S section using high-resolution numerical simulations. Estimates from the Southern Ocean State Estimate (SOSE) for 2013-2023, climatologies from the World Ocean Atlas, and observational data from the Deep Argo Program will be analyzed. The 34.5°S section was strategically chosen as it is the southernmost boundary of the Atlantic, where it is possible to calculate zonally integrated volume transport. Different methodologies for computing abyssal transport and its relationship with thermohaline properties will also be evaluated. This research will contribute to characterizing bottom water flows in the South Atlantic. (AU)