The Southern Brazilian Continental Shelf (SBCS) is one of the more productive areas for fisheries in Brazilian waters. The water masses and the dynamical processes of the region present a very seasonal behavior that imprint strong effects in the ecosystem and the weather of the area and its vicinity. This paper makes use of the Regional Ocean Modeling System (ROMS) for studying the water mass distribution and circulation variability in the SBCS during the year of 2012. Model outputs were compared to in situ, historical observations and to satellite data. The model was able to reproduce the main thermohaline characteristics of the waters dominating the SBCS and the adjacent region. The mixing between the Subantarctic Shelf Water and the Subtropical Shelf Water, known as the Subtropical Shelf Front (STSF), presented a clear seasonal change in volume. As a consequence of the mixing and of the seasonal oscillation of the STSF position, the stability of the water column inside the SBCS also changes seasonally. Current velocities and associated transports estimated for the Brazil Current (BC) and for the Brazilian Coastal Current (BCC) agree with previous measurements and estimates, stressing the fact that the opposite flow of the BCC occurring during winter in the study region is about 2 orders of magnitude smaller than that of the BC. Seasonal maps of simulated Mean Kinetic Energy and Eddy Kinetic Energy demonstrate the known behavior of the BC and stressed the importance of the mean coastal flow off Argentina throughout the year.

Oil spill detection and mapping (OSPM) is an extremely relevant issue from a scientific point of view due to the environmental impact on coastal and marine ecosystems. In this study, we present a new approach to assess scientific literature for the past 50 years. In this sense, our study aims to perform a bibliometric and network analysis using a literature review on the application of OSPM to assess researchers and trends in this field of science. In methodological terms we used the Scopus base to search for articles in the literature, then we used bibliometric tools to access information and reveal quantifying patterns in this field of literature. Our results suggest that the detection of oil in the sea has undergone a great evolution in the last decades and there is a strong relationship between the technological evolution aimed at detection with the improvement of remote sensing data acquisition methods. The most relevant contributions in this field of science involved countries such as China, the United States, and Canada. We revealed aspects of great importance and interest in OSPM literature using a bibliometric and network approach to give a clear overview of this field’s research trends.

Abstract. The Southern Brazilian Continental Shelf (SBCS) is an area with great ecological and economic importance to Brazil. In this region can be observed the recurrent passage of frontal systems and extra-tropical cyclones, which are more frequent during the winter months of the southern hemisphere. These systems act on the ocean surface layers as direct driving forces, which may change the thermohaline structure of the water column and induce sea level perturbations. This study used the coupled ocean-atmosphere regional model (COAWST) to evaluate the effect of the passage of a frontal system associated with an extra-tropical cyclone. The ROMS oceanic model was configured with two nested grids, in order to solve the hydrodynamic processes at different scales. The parent (20–40° S/40–60° W) and child (25–29.3° S/46.3–50° W) grid comprise the coastal region, with a horizontal resolution of 1/9° and 1/27°, respectively, with 32 vertical levels. The initial conditions are the Global Analysis Forecast from CMEMS and forcing files used the Climate Forecast System v.2 (CFSv2) data, from NCEP. This event took place on the continental shelf of the State of Santa Catarina, in September of 2016. The model results were compared to remote sensing data and to the tide gauges from the City of Imbituba (State of Santa Catarina, Brazil). The comparison showed a correlation higher than 78 % between sea level rise data and the model results. The filtering of sea level data made it possible to identify the meteorological component in the model results. The comparison between the tidal-gauge and the model output presented values under 25 cm. The model was capable of representing the sea level anomalies propagation associated with the passage of the atmospheric frontal system. The model output showed the presence of a sea level anomaly propagating northward along the continental shelf at 480 km day−1, probably associated with the presence of a coastal-trapped wave.

Coastal ocean observing and modeling systems (coastal observatories), connected with regional and global ocean systems, improve the quality of information and forecasts for effective management of safe and sustainable maritime activities. The public availability of systematic and long-term information of the ocean is an engine for the Blue Economy, boosting economic growth, employment, and innovation. An overview of some Brazilian initiatives is presented in this paper, involving universities, private companies, federal and state agencies, covering institutions from south to north of Brazil. Although these initiatives focus mainly on ocean physics, integrated efforts can extend the scope to include biogeochemistry and marine biodiversity, helping to address interdisciplinary problems. Existing initiatives can be connected, and new ones fostered, to fill in the gaps of temporal and spatial coverage of ocean monitoring in the vast oceanic area under Brazilian jurisdiction (nationally referred to as the Blue Amazon, in reference to the similar richness of the Amazon Forest). The alignment among national and regional initiatives, as well as with international programs, can be promoted if coordinated by a national-level organization, maximizing the return of public investment and socioeconomic benefits. In light of international examples, possible future institutional arrangements are discussed, leveraging from existing national public policies and international cooperation that Brazil is taking part. The United Nations Decade of Ocean Science for Sustainable Development is a timely opportunity to encourage an institutional arrangement to support and articulate an integrated network of coastal observatories in Brazil.

A set of open-source routines capable of identifying possible oil-like spills based on two random forest classifiers were developed and tested with a Sentinel-1 SAR image dataset. The first random forest model is an ocean SAR image classifier where the labeling inputs were oil spills, biological films, rain cells, low wind regions, clean sea surface, ships, and terrain. The second one was a SAR image oil detector named “Radar Image Oil Spill Seeker (RIOSS)”, which classified oil-like targets. An optimized feature space to serve as input to such classification models, both in terms of variance and computational efficiency, was developed. It involved an extensive search from 42 image attribute definitions based on their correlations and classifier-based importance estimative. This number included statistics, shape, fractal geometry, texture, and gradient-based attributes. Mixed adaptive thresholding was performed to calculate some of the features studied, returning consistent dark spot segmentation results. The selected attributes were also related to the imaged phenomena’s physical aspects. This process helped us apply the attributes to a random forest, increasing our algorithm’s accuracy up to 90% and its ability to generate even more reliable results.

Oil spills are one of most impactful sources of marine pollution. The damage caused requires knowing the behavior of oil in the marine environment, through studies of prevention, control and mitigation of oil spills. In this study, two climatological simulations were carried out for the Cumuruxatiba Basin, for summer and winter periods, using the MEDSLIK-II oil spill dispersion model. The region was chosen due to its closeness to the Abrolhos National Park and the high environmental risk associated with the oil industry in this region. The main objective was to analyze the impact of ocean circulation on possible oil spills near the Exclusive Economic Zone (EEZ) of Brazil. For this, simulations were performed using the outputs of the ROMS ocean model and atmospheric data from the ERA5 reanalysis, used to force the MEDSLIK, through a Lagrangean oils spill representation. The results show that in winter the ZCIT displacement occurs and the southern expansion of South Atlantic Subtropical High (SASH) causes, in the region, an intensification of the southeast trade winds. The increase in longitudinal oil transport is evidenced at the lower speeds of the Brazil Current (BC), in the winter months, increase the likelihood of spills reaching the northeastern Brazilian coast. For summer, the simulations showed that the trade winds and the greater BC transport act as a physical barrier preventing the oil from moving to the coast. Based on the results obtained, we believed that the methodology used may be essential for future studies of oil spills in coastal areas of the Brazilian coast.Keywords: Dispersion Modeling, Ocean Circulation, Oil Spill Simulação hidrodinâmica de um derramamento de óleo hipotético na Bacia de Cumuruxatiba (BA) com o modelo MEDSLIK-IIRESUMOOs derramamentos de óleo correspondem a uma das mais impactantes fontes de poluição marinha. Devido aos danos causados, conhecer o comportamento do óleo no ambiente marinho através de estudos de prevenção, controle e mitigação de derramamentos de óleo, é necessário. Neste estudo realizou-se duas simulações climatológicas para a região da Bacia de Cumuruxatiba, durante os períodos de verão e inverno, através do modelo de dispersão de óleo MEDSLICK-II. A região foi selecionada devido à sua proximidade com o Parque Nacional do Abrolhos e ao alto risco ambiental associado à indústria do petróleo na região. O objetivo foi analisar o impacto da circulação oceânica em possíveis derramamentos de óleo próximo à Zona Econômica Exclusiva do Brasil. Para isso foram realizadas simulações a partir das saídas do modelo oceânico ROMS e dos dados atmosféricos do modelo ERA-5, utilizados para forçar o MEDSLIK através de simulações lagrangeana da mancha. Os resultados mostram que nos períodos de inverno, o deslocamento da ZCIT e a expansão meridional da Alta Subtropical do Atlântico Sul (SASH) geram uma intensificação dos ventos alísios de sudeste aumentando o transporte zonal de óleo. Com menores velocidades da Corrente do Brasil (BC) no inverno, aumenta a probabilidade de derramamentos atingirem a costa Nordeste brasileira. Nos meses de verão, os ventos predominantes de nordeste e o maior transporte da BC atuam como uma barreira física impedindo o deslocamento do óleo para a costa. Assim, acredita-se que a metodologia usada possa ser de fundamental importância para aplicação em futuros estudos de derramamentos de óleo nas áreas costeiras do litoral brasileiro.Palavras-chave: Circulação Oceânica, Derramamento de óleo, Modelagem de dispersão.

No abstract

No abstract