Estimation of annual heat flux balance at the sea surface from sst (NOAA-satellite) and ships drift data off southeast Brazil

The objective of this work is to study the possibility of estimating the heat flux balance at the sea surface from GOSSTCOMP (Global Ocean Sea Surface Temperature Computation) developed by NOAA/NESS, USA, and sea surface current data based from ships drift information obtained from Pilot Charts, published by the Diretoria de Hidrografia e Navegação (DHN, Brazilian Navy). The annual mean value of the heat flux balance at the sea surface off southeast Brazil for 1977, is estimated from data on the balance between the heat transported by the currents and that transported by eddy diffusion for each volume defined as 2º x 2º (Lat. x Long.) square with a constant depth equivalent to an oceanic mixed layer, 100 m thick. Results show several oceanic areas where there are net flows of heat from atmosphere towards the sea surface. In front of Rio de Janeiro the heat flow was downward and up to 70 ly day-1 and is probably related to the upwellirug phenomenon normally occurring in that area. Another coastal area between Lat. 25ºS to 28ºS indicated an downward flow up to 50 ly day-1; and for an area south of Lat. 27ºS, Long. 040ºW - 048ºW an downward flow up to 200 ly day-1, where the transfer was probably due to the cold water of a nortward flux from the Falkland (Malvinas) Current. Results also show several oceanic areas where net flows of heat (of about -100 ly day-1) were toward the atmosphere. In the oceanic areas Lat. 19ºS - 23ºS and Lat. 24ºS - 30ºS, the flows were probably due to the warm water of a southward flux of the Brazil Current. The resulting fluxes from the warm waters of the Brazil Current when compared with those from warm waters of the Gulf Stream and Kuroshio, indicate that the Gulf Stream carries about 3.3 times and the Kuroshio 1.7 times more heat than the Brazil Current. These values agree with those of data available on the heat fluxes of the above mentioned Currents calculated by different methods (Budyko, 1974)

Variações em escala média da temperatura e da salinidade do mar na região entre a Baía de Guanabara e Cabo Frio (17/08 a 26/08/1971)

Um aspecto importante a ser apontado no presente trabalho ê o fato de se ter acompanhado de um modo ininterrupto, durante 10 dias, as anomalias nas distribuições das propriedades físicas da água do mar. Os resultados experimentais obtidos na região costeira a oeste de Cabo Frio durante esse pe ríodo mostraram a preponderância dos processos advectivos e difusivos que alteram a distribuição da temperatura e da salinidade na superfície do mar. Essa anomalia pode ser indicada por nuvens do tipo cúmulos formada por convecção penetrante, fato verificável pela comparação dos dados térmicos de superfície, com fotografias obtidas pelo satélite ERTS.It should be pointed out that this paper reports observations conducted ininterruptdly during a 10 day period on anomalous distribution of physical properties of sea water. The experimental results obtained on the coastal region west off Cabo Frio (RJ), during the mentioned period showed the dominance of advectives and difusal processes causing changes in the distribution of temperature and salinity on sea surface layer. The anomaly recorded may be indicated by clouds of the "cumulus" type formed by penetrating convection, a fact which may be confirmed by comparing photographic data obtained by ERTS satellite

Geostrophic transport in the Brazil current region north of 20°S

Geostrophic volume transports in the upper 500 m are computed from historical hydrographic data for the area off the Brazilian coast west of 30°W and between 7° and 20°S. On the basis of water mass distributions, potential density surfaces of σθ = 27.05 kg m−3 (360–670 m) and σθ = 27.6 kg m−3 (∼1200 m) are used for referencing the meridional and zonal components of the geostrophic shears, respectively. Near 15°S a northwestward flow of 8 Sv crosses 30°W. This current reaches the shelf near 10°S in February and March, the only two months for which observations are available near that latitude along the coast; of the 8 Sv, about 4 Sv continue towards the northwest into the North Brazil Current while another branch also carrying 4 Sv turns southward as the beginning of the Brazil Current. Between 10° and 20°S the Brazil Current does not appear to strengthen appreciably, but because of the likely existence of flow on the shelf these transport values represent lower limits to the actual ones. At 30°W, another westward flow of approximately 8–10 Sv enters the area near 10°S and serves to strengthen the North Brazil Current. The total transfer of 12 Sv or more from the South Equatorial Current into the North Brazil Current and later to other currents and the northern hemisphere may be an important factor contributing to the well-known weakness of the Brazil Current in its more northerly latitudes

Distribuição da temperatura na superfície do mar obtida através do uso de sensores remotos na área compreendida entre Itanhaém e a Ilha de São Sebastião (SP)

A utilização de sensores remotos em oceanografia tem sido amplamente aumentada principalmente devido aos aspectos sinópticos, ao aumento da precisão das informações bem como do aspecto econômico. Este trabalho apresenta as características e os resultados primários de alguns vôos executados sobre o mar na região próxima a Santos e Ilha de São Sebastião, na costa sudeste do Brasil. A técnica mostrou-se eficiente na verificação dos processos de circulação costeira, bem como em qualquer processo em que se utilize a temperatura como traçador. As correntes de maré parecem exercer grande influência na área próxima a baía de Santos, onde uma velocidade superficial média da ordem de 1,2 m/s foi estimada, e essa influência pode se estender à distância da ordem de 50 mn. Podemos observar também a possível divisão da área, pelo menos superficialmente, em duas sub-áreas, com comportamentos térmicos diferentes, cuja interface se desenvolve normalmente à costa em frente a Santos.The use of remote sensing in oceanography, has been largely increased, mainly because the synoptic look, the accuracy of the data as well as the economics aspects. This paper shows the features and the first results of some experiments performed in the offshore region near Santos Bay and São Sebastião Island, in the southeast coast of Brazil. The technique seems to be powerfull in coastal circulation studies, as well as, in every process that uses the temperature as a natural tracer. The tide currents seem to have large influence in the area near the Santos Bay, with a surface mean speed of about 1.2 m/s, which can reach distances of about 50 n.m. One can note that the area can be divided, at least in surface terms, in two subareas, with different thermal behaviours, with the interface standing normal to the coast in front of Santos

Note on the occurrence of saline fronts in the Ilha Grande (RJ) region

Registros contínuos da temperatura e da salinidade, em função de distâncias horizontais, foram obtidos para as águas de superfície existentes ao redor da Ilha Grande, em 21 de junho de 1975. Foi detectado um fluxo de água com baixa salinidade (S ~ 33,10º /oo) e temperatura ligeiramente maior do que a das águas adjacentes, na região entre a Ponta de Castelhanos e a Ponta Grossa da Marambáia. A interação entre este fluxo e as águas costeiras mais salinas (S ~ 35,4 a 35,6º /oo) se apresentou de forma visível, como uma frente salina. Os valores de salinidade, registrados à leste da Ilha Grande sugerem, que a origem dessa agua de baixa salinidade ê a descarga fluvial na Baía de Sepetiba.Continuous records of temperature and salinity were obtained on the surface waters as function of the horizontal distances around Ilha Grande region, on June 21, 1975; an outflow of less saline (S~33.10º /oo ) and slightly warmer water was detected throughout the region between Ponta de Castelhanos and Ponta Grossa da Marambaia and a visible manifestation of a saline front was observed in the interaction of this outflow with the coastal and more saline water (S~ 35.4 to 35.6º /oo). The recorded salinity values in the east region of Ilha Grande, suggest that the source of less saline water is the runoff in the Baia de Sepetiba

On the Variability of Southern Ocean Front Locations Between Southern Brazil and the Antarctic Peninsula

A 4-year expendable bathythermograph data set (1984–1987) from the area between southern Brazil and the Antarctic Peninsula provides information on the interannual variability of front locations. Two boundaries of subtropical water at different depths are identified north and south of the Brazil Current-Falkland (Malvinas) Current confluence zone. The northern Subtropical Front is displaced over a large part of the Argentine Basin from one observational period to the other. The shallow southern Subtropical Front appears fixed to the Falkland Escarpment. The Polar Front and Subantarctic Front locations do not vary much, except for one case where a cold core eddy in the Polar Frontal Zone causes a large northward displacement of the Subantarctic Front

Direct measurements of western boundary currents off Brazil between 20°S and 28°S

Current measurements from three moored arrays on the Brazilian continental slope between 20 degrees S and 28 degrees S are investigated for the existence and strength of western boundary currents from near the surface down to the North Atlantic Deep Water. The Brazil Current is found to deepen southward from 100 m to more than 670 m and to strengthen its volume transport to 16.2 x 10(6) m(3)/s. Antarctic Intermediate Water is transported in a well-developed boundary current southward at 28 degrees S and northward north of Cabo Frio (24 degrees S). This result supports earlier suggestions derived from the analysis of hydrographic data that Antarctic Intermediate Water enters the Brazil Basin from the east and bifurcates as it meets the continental break off Brazil. North Atlantic Deep Water is transported southward in a weakly developed boundary current that leads to lower estimates of volume transport than expected from earlier hydrographic data analysis