Dynamics of Air-Sea Interaction in the Southwest Atlantic Ocean: A Comparative Study with Focus on the Brazil-Malvinas Confluence and South-Southeast Brazil, Under Historical and Future Scenarios

• Ano de defesa: 2025
• Autor(a) principal: Loyola, Sebastian Andres Garcia
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Air-sea fluxes; Fluxos ar-mar; long-term variability; Oceano Atlântico Sudoeste; Southwest Atlantic Ocean; variabilidade de longo prazo
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/21/21135/tde-02092025-140939/

This thesis investigates oceanic and atmospheric processes in the Southwestern Atlantic (SWA), with emphasis on the Brazil-Malvinas Confluence (BMC) region and the South-Southeast coast of Brazil (SEB), over recent decades and under projected climate change scenarios. The study employs the highresolution regional model Coastal and Regional Ocean Community (CROCO), combined with reanalysis datasets and climate projections from the CMIP6 ensemble, considering different emission pathways through the end of the 21st century. The analysis focuses on key variables related to ocean dynamics and oceanatmosphere interactions, including sea surface temperature and salinity, wind fields, coastal circulation, and mesoscale processes, as well as indicators of energy variability and mass and heat fluxes. The results reveal complex seasonal, interannual, and decadal patterns, driven by both local and large-scale mechanisms, with particular emphasis on the influence of the South Atlantic Convergence Zone (SACZ), the major oceanic fronts of the Southwestern Atlantic especially the Brazil-Malvinas Confluence and the coastal upwelling systems along the southeastern Brazilian shelf. The findings indicate that the CROCO model effectively captures regional dynamic features such as the Cabo Frio upwelling, BMC variability, and coastalocean exchanges, outperforming global reanalyses and climate models in representing fine-scale regional processes. Multivariate statistical analyses highlight important linkages among wind patterns, heat fluxes, and ocean circulation, offering an integrated understanding of the regions dynamics. Future projections reveal contrasting trajectories between mitigation and high-emission scenarios. While intermediate scenarios suggest gradual changes in the thermal structure and regional circulation, high-emission pathways project significant transformations, with potential to intensify coastal processes, alter ix marine productivity, and increase risks related to sea-level rise and extreme events. This thesis contributes to advancing the understanding of regional responses of the Southwestern Atlantic to global climate change, emphasizing the importance of high-resolution modeling in assessing local impacts and informing adaptation strategies. By integrating different spatial and temporal scales, the study provides valuable insights for coastal management and for addressing the challenges posed by climate variability and long-term trends throughout the 21st century.