publications

In prep.

1. Hydrographic climatology of the South Brazil Bight continental shelf and slope

   Sasaki, Dalton K., Silva, Danilo A., Junio, Sergio R. D. G., Dottori, Marcelo, Silveira, Ilson C. A. da S., Belo, Wellington C., and Martin, Renato P.

   Theoretical and Applied Climatology 2024
2. The Brazilian Continental Shelf

   Dottori, M., Sasaki, Dalton K., Silva, Danilo A., Birocchi, Paula, and Nascimento, Rafaela do

   2022

2023

1. Multidisciplinary scientific cruises for environmental characterization in the Santos Basin–methods and sampling design

   Moreira, Daniel L, Dalto, Adriana G, Figueiredo Jr, Alberto G, Valerio, Aline M, Detoni, Amalia, Bonecker, Ana CT, Signori, Camila N, Namiki, Cláudia, Sasaki, Dalton K, Silva, Danilo A., and others,

   Ocean and Coastal Research 2023

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2. Implementation of simple models to estimate the discharge through rainfall data from MERGE

   Birocchi, Paula, Sasaki, Dalton K., Silva, Danilo A., and Dottori, Marcelo

   Theoretical and Applied Climatology 2023

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3. An inventory of salty and warm subsurface intrusions in the South Brazil Bight

   Silva, Danilo A., Sasaki, Dalton Kei, Dottori, Marcelo, da Silveira, Ilson Carlos Almeida, Belo, Wellington Ceccopieri, and Martins, Renato Parkinson

   Continental Shelf Research 2023

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   Subsurface intrusions of salty and warm waters onto the shelf can potentially impact the thermodynamics and biogeochemistry of these relatively shallow water environments. Such thermohaline intrusions are usually associated with double diffusive processes and can enhance the vertical and lateral fluxes. In this work, we characterized subsurface intrusions of Tropical Waters (TW) at the South Brazil Bight (SBB) - a mid-latitude continental shelf, which were detected based on salinity vertical profiles from a historical dataset. We found the intrusions tend to follow the pycnocline and are relatively common year-round, occurring at 27% of the dataset, with a maximum salinity highly correlated with the maximum stratification. Intrusions have different along-shelf characteristics, varying with the shelf width and depth. North of São Sebastião Island (SSI) – at the central portion of the SBB –, intrusions were thicker, saltier, and shallower than the ones found at the south of SSI. These differences could be related to the variations of the Coastal Water (CW) and South Atlantic Central Water (SACW) volume along the shelf and throughout the year. We found that intrusions’ thickness presents an inverse correlation with stratification, resulting in thinner intrusions in more stratified environments. This inverse correlation suggests double-diffusively driven intrusions. We apply the Turner Angle method to investigate whether the environment is susceptible to double diffusive processes. This analysis suggests that thermohaline intrusions in the SBB might not be primarily double diffusive. However, the dominance of different double diffusion processes - diffusive convection (salt fingering) at the upper (lower) layer - suggests that these processes influence intrusion growth, steady-state, and erosion. Nonetheless, the mechanism responsible for the initial density perturbation remains unknown and further studies are needed to explore the relationship between the Brazil Current dynamics and thermohaline warm and salty subsurface intrusions.

4. Hydrographic structure of the continental shelf in Santos Basin and its causes: The SANAGU and SANSED campaigns (2019)

   Dottori, Marcelo, Sasaki, Dalton K., Silva, Danilo A., Del–Giovannino, Sergio R., Pinto, Andressa P., Gnamah, Magnim, Santos, Arian D., Silveira, Ilson C. A. da, Belo, Wellington C., Martins, Renato P., and al.,

   Ocean and Coastal Research 2023

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2022

1. Seascape genetics in a polychaete worm: Disentangling the roles of a biogeographic barrier and environmental factors

   Mendes, Cecili B., Cortez, Thainá, Santos, Cinthya S. G., Sobral-Souza, Thadeu, Santos, Arian Dielactaquiz, Sasaki, Dalton Kei, Silva, Danilo A., Dottori, Marcelo, and Andrade, Sónia C. S.

   Journal of Biogeography 2022

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2021

1. The atmospheric blocking influence over the South Brazil Bight during the 2013–2014 summer

   Silva, Danilo A., and Dottori, Marcelo

   Regional Studies in Marine Science 2021

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   The 2013–2014 summer in the Southeast Brazil region set records for negative precipitation anomalies and the highest sea surface temperatures. Such event was attributed to the anomalous presence of atmospheric blocking, which prevented the propagation of a cold front towards the Equator and the establishment of the South Atlantic Convergence Zone, two phenomena that regulate the precipitation regime in this area. These blocking episodes are relatively important to the climate in mid-latitudes, but the feedback of the coastal ocean is still poorly understood under these anomalous conditions. This paper investigates, from a numerical perspective, the impacts on the thermohaline properties and circulation in the South Brazil Bight (SBB). We found that enhanced shortwave radiation leads to intense surface heating and that the presence of northeasterly winds strengthens the coastal upwelling nearby Cabo Frio. The South Atlantic Coastal Waters, transported into the SBB, regulate the extreme heating in the northern half of the domain, while, in the southern half, the absence of cold waters leads to the development of a warm-water pool. The final thermohaline structure induced an enlargement and intensification of the northwestward currents south of São Sebastião Island. Between Ubatuba and Cabo Frio, in the northern half, the northeasterly winds developed an intense surface advection towards offshore, and in the northern region, compensated by an opposite advection, towards the coast. We conclude that the coastal ocean feedback could present extreme anomalous conditions during atmospheric blocking events, leading to impacts upon the thermodynamical properties. Further studies are needed to understand the impacts of these events on biogeochemical properties.

2019

1. Anomalous wind driven circulation on the south Brazil Bight during the 2014 summer

   Silva, Danilo A.

   2019

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   The 2014 summer, on the Brazilian southeast region, was marked by a long period of precipitation deficits and strong income of solar radiation. Such event was attributed to the anomalous presence of an atmospheric blocking, that prevented the propagation of southerly cold fronts in the region. In a single event, northeasterly winds influenced the South Brazil Bight for 24 days in a row. Using numerical modeling, this work aims to understand how this events can impact the coastal circulation, mainly in the inner and mid shelves, of the South Brazil Bight. Therefore, the hydrodynamical module from the Estuarine, Coastal and Ocean Model (ECOM) was implemented, forcing numerical simulations with reduced estuarine discharge, heat flux, reanalysis derived winds and climatological thermohaline fields. It was indentified a small advance of South Atlantic Central Water (SACW) at the bottom, being thermally blocked by the intense heating at the inner shelf. However, with the influence of northeasterly winds, the SACW filled in the water column, forcing Tropical Waters (TW) towards offshore. In the rest of the domain, the Ekman transport was identified as the main mechanism to force TW retraction in the surface layers, also inducing a small increase in the subsurface intrusion of TW. Density gradient variations on the inner shelf intensified the northeastward currents, between Cananéia and São Sebastião, also creating an enlargement of this feature. North of the São Sebastião Island, however, it was observed a weakening of this current, due to the divergence closest to the coast, caused by the offshore transport. At the end of the blocking event, the South Brazil Bight was occupied with warmed Coastal Waters (CW) and SACW, with intensified currents all over the domain and changes in the horizontal features in specific areas.