Assessment of Extreme Current Events on the Santos Basin Continental Slope

• Ano de defesa: 2025
• Autor(a) principal: Gabel, Victor Schneider
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Agulhas Rings; Anéis das Agulhas; anticiclones remotos; Bacia de Santos; Brazil Current; Cape Frio Eddies; Corrente de Contorno Intermediária; Corrente do Brasil; correntes extremas; eventos extremos; extreme currents; extreme events; IFORM; Intermediate Western Boundary Current; remote anticyclones; Santos Basin; Vórtices de Cabo Frio
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/21/21135/tde-02092025-143246/

The Brazil Current (BC) and the Intermediate Water Boundary Current (IWBC) are the main currents present in the Santos Basin, a region where oil exploration takes place. Oil platform accidents are not uncommon in nearby areas, as evidenced by the incident in the Campos Basin in 2011. Despite this, studies on extreme current events in this region are scarce. The primary objective of this thesis is to investigate extreme currents on the continental slope of the Santos Basin, while also evaluating statistical techniques to estimate profiles and maps of extreme currents. To achieve this objective, we used synthetic moorings (time series from a grid point of GLORYS, considering all depths), validated with in situ data. Our results indicate that the mechanism with the highest potential for intensification of the BC on the slope is the interaction of the current jet with remote anticyclones, while for the IWBC, the main mechanism involves the interaction of the current jet with cyclonic eddies. Two of the involved anticyclones were classified as belonging to the Agulhas Rings Eddy Network (AREN), one of zeroth order and the other of fourth order. The involved cyclones were classified as Cape Frio eddies. Considering the three synthetic moorings and a return period of 100 years, the results obtained by the Inverse First Order Reliability Method showed that, on average, once per century, velocities equal to or greater than 1.09 m s-1 at the BC level and equal to or greater than 0.71 m s-1 at the IWBC level will occur. Extreme current maps indicated that, for the same return period, extreme currents at the BC level during winter tend to be weaker than in other seasons, while autumn presents an area beyond the slope with greater intensification potential. For the IWBC level, little seasonal variation was observed, with the average location of the jet showing the highest velocity intensity for the Santos Basin at this depth level.