The Regional Ocean Modeling initiatives at INPE: An overview of South Atlantic Ocean modeling and biochemical studies

Christina Schultz, Luciano P. Pezzi, Douglas F.M. Gherardi, D.F. Dias, Helena C. Soares
National Institute for Space Research (INPE) - Brasil

The Ocean Modeling Group at INPE-Brazil has been developing several studies aimed at improving our understanding of physical and biogeochemical oceanic phenomena. The studied area includes the Tropical South-Atlantic Ocean and Southern Ocean. This is part of an international cooperation, in which Brazil participates with studies using numerical modeling and statistical analysis of time series. These studies focus on the prediction of the impacts of extreme weather events over the Tropical South Atlantic Ocean as well as predict the occurrence of these events in the future. One such study is dedicated to the modeling of physical-biological interactions at the spawning area of the Brazilian Sardine, using both ROMS and an Individual Based Model (IBM).

Also, there is an ongoing investigation looking at the interannual climate variability along the Brazilian Large Marine Ecosystems (LMEs). This investigation has shown strong correlation with climate indices that represent ENSO, Antarctic Oscillation, and Tropical Atlantic Variability. The impacts of the Pacific Decadal Oscillation 1976/1977 regime shift is also evaluated. These statistical fields will be compared with NPZ (Nutrient, Phytoplankton and Zooplankton) experiments using the biogeochemical tools available within ROMS to address the biological consequences of the observed climatological patterns.

The South Atlantic Ocean was also investigated using ROMS with the Fennel biogeochemical model, in order to analyze the carbon fluxes and the area’s capacity as a carbon sink. The focus of the analyses is the influence of the La Plata River plume and the Brazil-Malvinas Confluence Region (BMC) on the ocean carbon balance. The oceanic circulation was well represented, as was the La Plata river plume. The chlorophyll blooms, however, showed a delay, happening mostly during the summer at the Patagonian Continental Shelf. The yearly carbon flux calculated was -1.42*106 mMol/m2.day, suggesting that this area is a powerful carbon sink.