1,721,002 research outputs found
Evidências da recirculação da corrente do Brasil na costa sudeste brasileira através de imagens termais
No full textAs imagens de TSM revelam feições e estruturas de diferentes escalas como frentes termais, vórtices e meandros, que por sua vez constituem a manifestação de fenômenos físicos importantes do oceano. A estrutura dinâmica ligada à recirculação da CB ainda é pouco conhecida. Não se tem conhecimento de trabalhos que a tenham evidenciado em imagens termais. O presente trabalho tem como objetivo buscar evidências da recirculação da CB próxima ao Cabo Frio e ao Cabo de São Tomé, através de mapas diários de TSM do sensor orbital GOES-8
Evolução da formação do vórtice de Cabo Frio nos anos de 2006 a 2009
No full textA Corrente do Brasil (CB) é caracterizada por apresentar uma intensa atividade de mesoescala na região leste e sudeste da costa brasileira. Característica responsável pela formação de meandros que, em muitos eventos, se fecham em vórtices. Um dos maiores e mais recorrentes meandros é o formado na região de cabo frio (23°) RJ, sendo frequente a sua evolução para um vórtice ciclônico. Este trabalho caracterizou o Vórtice de Cabo Frio (VCF) e avaliou na sua formação dos seus ciclos completos. Tais objetivos foram alcançados através da análise dos vórtices emitidos pela CB, digitalizados a partir de imagens orbitais
Frente térmica e núcleo de velocidade da corrente do Brasil na costa sudeste brasileira
No full textSurface Thermal Fronts (TF) in the southeastern brazilian coast, were examined in order to validate its utility in the identification of te symmetry axis of the Brazil Current's main flux. The spatial variability of the position of TF was initially charecterized in the GOES-8 diary termal data for 2006/2007, in maps which has free cloud cover for the region
Reconstrução dos dados faltantes em imagens orbitais de temperatura da superfície do mar para a região Sudoeste do Atlântico Sul
No full textDisponível em meio físico e digital..Bibliografia: p.216-219.Um método baseado em Função Ortogonal Empírica foi utilizado para reconstrução de imagens de Temperatura da Superfície do Mar (TSM). Foram adotadas abordagens univariada, utilizando somente dadps TSM, e multivariada, combinando TSM e Mapas de Anomalia da.An empirical orthogonal function-based technique was used to reconstruct missing data of Sea Surface Temperature (SST) images. Sea surface temperature data was used to assess the benefits of a univariate reconstruction, and the combination of both SST and
Detecção de feições oceanográficas a partir de dados orbitais: validação de modelos numéricos
No full textBibliografia: p.2
Captura sinótica de um vórtice de mesoescala da corrente do Brasil através de dados de XBT coletados por aeronave ao largo de Arraial do Cabo – RJ
No full textBibliografia: p.4
Numerical simulation of M2 internal tides in the south Brazil Bight and their interaction with the Brazil currente
No full textA fully three-dimensional nonlinear primitive equation ocean model is applied tostudy the semidiurnal internal tide in the South Brazil Bight under summer conditions.Along the shelf break and upper slope of this region, the upper layer (0–600 m) isoccupied by the southward flowing Brazil Current. Several numerical experiments wereconducted to investigate the generation and propagation of the M2internal tide. Usinghorizontally homogeneous and vertically stratified density fields, internal tides weregenerated over the whole Bight with a clear signal on the continental shelf. When a morerealistic summer stratification was considered, a baroclinic jet, representative of the BrazilCurrent, developed and comparisons between current observations and modeled resultswere improved. This jet acts as a barrier to the coastward propagation of the internal tidegenerated over the slope, reflecting it back towards the open ocean. On the negativerelative vorticity side of the Brazil Current, located over the shelf, internal tides aretrapped, enhancing vertical current variability and, hence, tidally induced mixing. Theresults highlight the importance of considering background flows when investigating internal tides in regions of strong along-slope baroclinic flows such as western boundary currents
Variability of the upwelling system in the southeastern Brazilian margin for the last 110,000 years
No full textWestern boundary upwelling systems such as those found in the southeastern Brazilian margin (SBM) are promoted by special atmospheric and oceanographic interactionswith topography of the coastline. In order to investigate the evolution of the upwelling systemin SBMover the past 110 kyr, the abundance of Globigerina bulloides (a planktonic foraminiferal species typically associated with upwelling waters) from two marine cores was combined with estimates of upper water thermal structure derived from Modern Analog Technique based on planktonic foraminifera. High abundances (up to 35%) of large specimens of G. bulloides (=250 μm) associated with cooling subsurface waters reveal the occurrence of an intense coastal upwelling system between 110 kyr and 88 kyr. Changes in coastline orientation due to lower sea level stand (20-70 m lower than today) and a longer season of vigorous Brazil Current (BC) and prevailing northeasterly winds maintained permanently the cold and nutrient-rich South Atlantic Central Waters (SACW) over the shelf promoting the strongest upwelling system of the Brazilian coast over the past 110 kyr. At 88 kyr, a sharp reduction of 14% in abundance of G. bulloides and a 2.6 °C warming of the water column indicates an abrupt weakening of the coastal upwelling, probably caused by a disturbance in SACW formation. During the last glaciation, longer current winter-like conditions of prevailing southwesterly winds and a weakened Brazil Current suppressed the upwelling system in SBM. At this time, constant and relatively high abundance of G. bulloides (up to 10%) suggest that the coastal upwelling was restricted to a short period of months year-round, when the BC and northeasterly winds were relatively vigorous despite the glacial context. The predominance of warm and oligotrophic Tropical Waters due to the shutdown of coastal upwelling in northern SBM was inferred for the last 20 kyr. Despite vigorous northeasterly winds and BC strength, high sea level stand during the Holocene submersed the Abrolhos Bank (AB) leading to a new coastline configuration. Presently, the interaction between the AB and the BC generated a newoceanographic feature in SBM, the Vitória Eddy,with very limited efficiency in producing a strong upwelling such as the one recorded in the past
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