The response of the South Brazil Bight to the passage of wintertime cold fronts

Stech, José; Lorenzzetti, João A.

doi:10.1029/92jc00486

Cited by 145 publications

(88 citation statements)

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“…The periods of wind and current energy concentration raging from 6 to 13 days coincide with the periodicity found for cold front air systems on the southeastern coast of Brazil (STECH;LORENZZETTI, 1992). Although no significant change is observed in wind direction, apparently the currents on the Brazilian Northeast Continental Shelf are somehow affected by frontal instabilities of mid-latitudes.…”

Section: Tide Wind and Currentmentioning

confidence: 95%

Hydrography and currents on the Pernambuco Continental Shelf

Domingues

Schettini

Truccolo

et al. 2017

RBRH

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The present study presents the seasonal hydrography and currents of the Brazilian Northeast Continental Shelf. The study area is located on the Brazilian tropical coast of the Atlantic Ocean between 7.5 and 9 °S. This continental shelf is narrow (~35 km wide) and shallow, with shelf break lying at a depth of 60 m. Salinity and temperature data were collected monthly by means of hydrographic surveys, conducted across the shelf in a single transect in the central part of the study area, between March 2012 and May 2013. Two further campaigns were also conducted to characterize the winter (August 2013) and the summer (January 2014), covering the whole study area (4,600 km 2 ). Water level and currents were measured using an array of Acoustic Doppler Current Profilers (ADCP) moored at mid-shelf in the central area. Seasonal temperature ranged from 26 °C in September to 29.5 °C in April, with a 2-month lag between the minimum and maximum air temperatures. Salinity did not present a clear seasonal pattern, fluctuating between 36.5 and 37.0 psu throughout the year. The mean temperature and salinity values obtained in the winter and summer campaigns were 26.5 and 27.6 °C and 37.1 and 36.7 psu, respectively. Tropical Water (TW) was predominant, accounting for 95% to 97%, with presence of Coastal Water (CW) limited to the inner part of the shelf. The mean flow velocity values in the water column in winter and summer were 0.11 and 0.06 m/s, respectively, similarly to the seasonal wind regime. Northward currents were observed predominantly in winter, with a short period of inverted southward current. These episodes were related to periods of wind relaxation and presented periodicity of 6-13 days, observed through wavelet analysis. This periodicity may be associated with atmospheric instabilities at higher latitudes. Summer currents were sluggish, when the tides accounted for 75 and 43% of the variance in the cross-and along-shelf current components, respectively. TW is the main water mass in the Pernambuco Continental Shelf (PCS) in summer and winter. Current intensity is weak and without direction in summer and stronger towards the north in winter.Keywords: Water masses; Circulation; Brazilian Northeast Shelf. RESUMOEste trabalho apresenta a descrição sazonal da hidrografia e hidrodinâmica de uma plataforma continental localizada na borda oeste do Atlântico tropical, a área de estudo encontra-se entre as latitudes de 7,5 e 9 °S, possui apenas 35 km de largura e 187 km de extensão, com a quebra de plataforma em 60m de profundidade. A salinidade e temperatura foram coletadas em campanhas hidrográficas mensalmente entre março de 2012 e maio 2013 por meio de transectos na região central da área de estudo. Também, duas campanhas foram realizadas, uma para caracterizar o inverno (Agosto de 2013) e outra o verão (janeiro de 2014) cobrindo toda a área de estudo (4600 km 2 ). O nível da água e correntes também foram coletados com um Perfilado Acústico por efeito Doppler (ADCP) fundeado na região central da área de estudo. A ...

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Section: Tide Wind and Currentmentioning

confidence: 95%

Hydrography and currents on the Pernambuco Continental Shelf

Domingues

Schettini

Truccolo

et al. 2017

RBRH

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“…Com base em cartas sinóticas e dados de estações costeiras, Stech & Lorenzzetti (1992) identificaram um intervalo médio de 7 dias entre passagens frontais no litoral sul-sudeste brasileiro.…”

Section: Estatística De Intervalos Entre Duas Passagens Frontais Consunclassified

“…Na plataforma sul-sudeste do Brasil, esses distúrbios atmosféricos podem provocar sobre-elevações do nível do mar (Stech & Lorenzzetti, 1992;Camargo & Harari, 1994; Castro e Lee, 1995, Innocentini & Caetano Neto, 1996Rocha et al 2004).…”

Section: Introductionunclassified

Climatologia de frentes frias no litoral de Santa Catarina

Rodrigues¹,

Franco²,

Sugahara

2004

Rev. Bras. Geof.

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ABSTRACT.A climatology of cold fronts at the coast of State do Santa Catarina, Brazil, is established based on 10-year period (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999) of NCEP-NCAR reanalysis data. The cold front passages were objectively identified taking into account the wind shifts to a southerly direction, as well as the persistence of southerly wind for at least one day, and a decreasing of air temperature. The results show that, on the average, 3 to 4 cold fronts reach coast of Santa Catarina, each month, with an interval of 8 days. The composite data analysis, using the date of days of cold front passages at Santa Catarina as reference, shows clearly a climatological pattern of evolution, with cold front moving typically from southwest to northeast. In terms of seasonal mean, during winter, one day before reaching coast of Santa Catarina (day -1) the cold front is observed at Rio Grande do Sul. After passing at Santa Catarina (day 0), it continues to move equatorward, reaching the coast of Rio de Janeiro one day later (day +1), until it reaches latitudes close to 20˚S (day +2), in the its stage of dissipation. In the third day, after the passage at Santa Catarina, the cold front is no more observed. Similar pattern of evolution is observed during summer, though the cold fronts are less intense and of slightly more rapid dissipation.Keywords: climatology of cold fronts, movement of cold fronts, cold fronts at the coast of Santa Catarina, Brazil. RESUMO. Uma climatologia de frentes friasé estabelecida para o litoral do Estado de Santa Catarina, com base nos dados de reanálises do NCEP-NCAR, do períodode 10 anos, de 1990 a 1999. As passagens de frentes frias foram objetivamente identificadas levando em conta o giro do vento para direção sul, persistência do vento de sul por pelo menos um dia, e uma queda de temperatura do ar simultânea ao giro do vento ou até dois dias depois. Os resultados mostram que, na média, de 3 a 4 frentes frias atingem a costa de Santa Catarina, mensalmente, com um intervalo de 8 dias. As análises da composição de dados, usando como referência os dias de passagens de frentes frias em Santa Catarina, mostram claramente um padrão climatológico de evolução com frente fria movendo-se tipicamente de sudoeste para nordeste. Em termos das médias sazonais, durante o inverno, um dia antes da passagem em Santa Catarina (dia -1), a frente friaé observada no Rio Grande do Sul, e depois de passar por Santa Catarina (dia 0), continua avançando para latitudes mais baixas, alcançando o litoral do Rio de Janeiro um dia depois (dia +1), até atingir posteriormente latitude de aproximadamente 20˚S (dia +2), já em fase de dissipação. No terceiro dia após a passagem por Santa Catarina, ela nãoé mais identificada.Padrão climatológico de evolução semelhanteé observado no verão, embora nessaépoca as frentes frias tenham menor intensidade e dissipação ligeiramente mais rápida.Palavras-chave: climatologia das frentes frias, movimento das frentes frias, frentes frias no litoral de Santa Catar...

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“…On the synoptic weather scale, meteorological disturbances, through mechanisms of ocean-atmosphere interaction, are sources of energy and movement especially in the shallow areas of the coastal zone (Castro, 1990). Among the disorders, the passage of frontal systems is the most relevant in determining the variability of the circulation pattern in SBCS, making the shear strength of the wind one of the most important low frequency mechanisms in the coastal circulation (Stech & Lorenzzetti, 1992).…”

Section: Discussionmentioning

confidence: 99%

Oceanographic Variability in the Inner Shelf of Paraná, Brazil: Spring Condition

Noernberg¹,

Alberti²

2014

Rev. Bras. Geof.

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ABSTRACT. The hydrographic and hydrodynamics data obtained from a 10 meters deep mooring (0.5 meter above the bottom) located in the Inner Shelf of Paraná, Brazil, from Oct/11/2006 to Dec/10/2006, were analyzed. The oceanographic variability was characterized by maximum values of 54.2 cm.s -1 for current, 2.9 m for height, and 10 s for wave period. The salinity ranged from 32 to 33.7 ups and temperature from 20.7 to 25.3 • C. The wind stress is the main force driving the oceanographic variability, especially during high-energy events, generating waves bigger than 2.5 m, which occur with periods of 7.6 days. The low frequency oscillations dominate the behavior of longshore currents. These currents also answer more effectively to the wind variability. The most important tidal components were the lunar and solar semi-diurnal, M 2 and S 2 , respectively. The temperature and salinity response to the wind effect is faster than circulation pattern response. However, the variability of temperature and salinity associated with the wind energy peaks still needs to be better understood. For this, we need a better understanding of the sources of heat and salt, both local and remote, as well as their variability. A tensão do ventoé a principal forçante que governa a variabilidade dos parâmetros oceanográficos, especialmente nos eventos de alta energia, gerando ondas maiores que 2,5 m, que ocorrem com períodos de 7,6 dias. As oscilações de baixa frequência dominaram o comportamento das correntes longitudinais. Estas correntes também respondem mais efetivamenteà variabilidade do vento. As componentes de maré de maior amplitude foram as componentes lunar e solar semidiurnas M 2 e S 2 , respectivamente. A resposta da temperatura e da salinidade em função da ação do vento ocorre de forma mais imediata que a resposta do padrão de circulação.Entretanto, a variabilidade da temperatura e salinidade associada aos picos de energia do vento ainda precisa ser mais bem compreendida. Para tal,é necessário um melhor conhecimento das fontes de calor e sal, tanto locais quanto remotas, bem como de suas variabilidades.

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The response of the South Brazil Bight to the passage of wintertime cold fronts

Cited by 145 publications

References 12 publications

Hydrography and currents on the Pernambuco Continental Shelf

Hydrography and currents on the Pernambuco Continental Shelf

Climatologia de frentes frias no litoral de Santa Catarina

Oceanographic Variability in the Inner Shelf of Paraná, Brazil: Spring Condition

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