Hydrographic climatology of the South Brazil Bight continental shelf and slope

A regional climatology of the subtropical area along the South Brazil Bight is created to establish the seasonal average hydrographic conditions over the continental shelf and slope. A multiscale objective analysis with a potential vorticity constraint is used with historical hydrographic temperature and salinity profiles from different databases. Relative to the World Ocean Atlas 2018, the interpolation produced improved results, which were evaluated by comparing the surface fields with satellite data and sea surface elevation simulated with the Regional Ocean Model System (ROMS). ROMS three-dimensional currents showed that the temperature and salinity fields support the presence of both Brazil Current and its seasonal variability, the Intermediate Western Boundary current, along with recurrent features such as the Cape Frio (cyclonic) Eddy, and the signature of quasi-stationary anticyclonic vortices along São Paulo slope. Cape Frio Eddy structure favours the onshore transport of the South Atlantic Central Water (SACW) in the bottom layer along the northeastern area ( \(23^\circ \) ${23}^{\circ }$ S) of the shelf break. On the continental shelf, features such as the seasonal uplifting of SACW and midwater intrusions of Tropical Water beneath the Coastal Water (CW) are correctly described. CW is subdivided into spicy (austral summer/autumn) and minty (austral winter/spring) subgroups with the second being influenced by the Subtropical Shelf Water coming from the continental shelf along Argentina and Uruguay, where Rio de La Plata is diluted in the shelf waters.