A influência do Cânion Submarino Watu Norte na ressurgência costeira da Plataforma Continental do Espírito Santo
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Data
2024-10-07
Autores
Brasileiro, Gabriela Corrêa
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Universidade Federal do Espírito Santo
Resumo
This study investigates the role of the Watu Norte Submarine Canyon in coastal upwelling on the Espírito Santo Continental Shelf (ESCS). A preliminary thermohaline characterization and water mass distribution investigation were conducted to understand the region. Unlike previous studies relying on numerical modeling, remote sensing, or sporadic in situ data, this stage of the work used temperature and salinity data collected from 2018 to 2023 during 40 oceanographic cruises. These data allowed an unprecedented seasonal description of the thermohaline structure and water mass distribution in the region. The analysis revealed distinct regions on the shelf, with seasonal thermal stratification and the presence of SACW to the south of the Doce River mouth throughout the year, while homogeneity prevailed to the north. To evaluate the canyon’s influence on the observed patterns, semi-idealized numerical simulations were conducted. These simulations indicated that the canyon significantly affects SACW distribution on the ESCS, enhancing water transport onto the shelf and facilitating the intrusion of colder waters into areas adjacent to the canyon. The canyon’s orientation and dimensions were crucial to these interactions. A dimensional analysis of Rossby numbers and the canyon’s length-to-width ratio suggested that the current over the canyon tends to break geostrophic balance, generating an intense flow toward the canyon head. Although this dynamic occurs during coastal upwelling events, the opposing current directions at the edges relative to the surface flow resulted in an anticyclonic circulation pattern, observed from the shelf break depth up to 30 meters above the canyon head. The circulation intensified as the flow compressed while moving toward shallower isobaths, crossing the canyon head. These findings highlight the importance of submarine canyons in coastal dynamics and the need for models that incorporate detailed bathymetry to capture flow-bathymetry interactions, which have implications for protected area management and oceanic pattern prediction
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Circulação costeira , Modelagem numérica , Fluxo-batimetria , Massas de água , Coastal circulation , Numerical modeling , Flow-bathymetry , Water masses