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The impact of the subtropical South Atlantic SST on South American precipitation

TASCHETTO, A. S.; WAINER, I.
Fonte: COPERNICUS PUBLICATIONS Publicador: COPERNICUS PUBLICATIONS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
86.18%
The Community Climate Model (CCM3) from the National Center for Atmospheric Research (NCAR) is used to investigate the effect of the South Atlantic sea surface temperature (SST) anomalies on interannual to decadal variability of South American precipitation. Two ensembles composed of multidecadal simulations forced with monthly SST data from the Hadley Centre for the period 1949 to 2001 are analysed. A statistical treatment based on signal-to-noise ratio and Empirical Orthogonal Functions (EOF) is applied to the ensembles in order to reduce the internal variability among the integrations. The ensemble treatment shows a spatial and temporal dependence of reproducibility. High degree of reproducibility is found in the tropics while the extratropics is apparently less reproducible. Austral autumn (MAM) and spring (SON) precipitation appears to be more reproducible over the South America-South Atlantic region than the summer (DJF) and winter (JJA) rainfall. While the Inter-tropical Convergence Zone (ITCZ) region is dominated by external variance, the South Atlantic Convergence Zone (SACZ) over South America is predominantly determined by internal variance, which makes it a difficult phenomenon to predict. Alternatively, the SACZ over western South Atlantic appears to be more sensitive to the subtropical SST anomalies than over the continent. An attempt is made to separate the atmospheric response forced by the South Atlantic SST anomalies from that associated with the El Nino - Southern Oscillation (ENSO). Results show that both the South Atlantic and Pacific SSTs modulate the intensity and position of the SACZ during DJF. Particularly...

Variabilidade climática do oeste paulista e suas ligações com a temperatura da superfície do mar dos oceanos Pacífico e Atlântico; Climatic variability at the western of São Paulo state and its relation to sea surface temperature on Pacific and Atlantic oceans

Ikefuti, Priscilla Venâncio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 22/06/2012 PT
Relevância na Pesquisa
106.22%
Vários estudos fornecem evidências de que os oceanos Atlântico e Pacífico desempenham papel significativo nas flutuações climáticas que ocorrem no Brasil. O objetivo desta pesquisa é avaliar a relação entre a temperatura da superfície do mar, TSM, dos oceanos Pacífico e Atlântico e a vazão de rios localizados no oeste do estado de São Paulo. Foram analisados 30 anos de dados, de 1979 a 2008. Os dados de vazão foram obtidos da Agência Nacional de Águas, os dados da temperatura da superfície do mar e radiação de onda longa emergente, do CDC/NOAA, e as variáveis climáticas (temperatura mínima, média e máxima, precipitação e umidade relativa) foram obtidos do INMET e referem-se aos dados observados na estação meteorológica da cidade de Presidente Prudente. Os resultados foram obtidos pela estimativa da correlação linear entre as séries mensais de vazão e dos dados climáticos com a temperatura da superfície do mar nos oceanos, com e sem defasagem temporal. Áreas com correlação alta e significativa foram encontradas no oceano Pacífico e Atlântico. Os padrões oceânicos obtidos para os quatro postos de vazão se assemelham entre si, sugerindo que a variabilidade climática dos postos é parecida. O padrão de ferradura no Oceano Pacífico Tropical está presente em todos os casos avaliados...

The annual cycle of satellite derived sea surface temperature on the western South Atlantic shelf

Lentini,Carlos A. D.; Campos,Edmo J. D.; Podestá,Guillermo G.
Fonte: Instituto Oceanográfico da Universidade de São Paulo Publicador: Instituto Oceanográfico da Universidade de São Paulo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2000 EN
Relevância na Pesquisa
86.23%
In this article, thirteen years of weekly sea surface temperature (SST) fields derived from NOAA Advanced Very High Resolution Radiometer global area coverage infrared satellite data, from January 1982 to December 1994, are used to investigate spatial and temporal variabilities of SST seasonal cycle in the Southwest Atlantic Oceano This work addresses large scale variations over the eastem South American continental shelf and slope regions limited offshore by the 1000-m isobath, between 42° and 22°S. SST time series are fit with annual and semi-annual harmonics to describe the annual variation of sea surface temperatures. The annual harmonic explains a large proportion of the SST variability. The coefficient of determination is highest (> 90%) on the continental shelf, decreasing offshore. The estimated amplitude of the seasonal cycle ranges between 4° and 13°e throughout the study area, with minima in August­September and maxima in February-March. After the identification and removal of the dominant annual components ofSST variability, models such as the one presented here are an attractive tool to study interannual SST variability.

The Role of Ocean Dynamics in the Optimal Growth of Tropical SST Anomalies

Zanna, Laure; Heimbach, Patrick; Moore, Andrew M.; Tziperman, Eli
Fonte: American Meteorological Society Publicador: American Meteorological Society
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
86.27%
The role of ocean dynamics in optimally exciting interannual variability of tropical sea surface temperature (SST) anomalies is investigated using an idealized-geometry ocean general circulation model. Initial temperature and salinity perturbations leading to an optimal growth of tropical SST anomalies, typically arising from the nonnormal dynamics, are evaluated. The structure of the optimal perturbations is characterized by relatively strong deep salinity anomalies near the western boundary generating a transient amplification of equatorial SST anomalies in less than four years. The associated growth mechanism is linked to the excitation of coastal and equatorial Kelvin waves near the western boundary following a rapid geostrophic adjustment owing to the optimal initial temperature and salinity perturbations. The results suggest that the nonnormality of the ocean dynamics may efficiently create large tropical SST variability on interannual time scales in the Atlantic without the participation of air–sea processes or the meridional overturning circulation. An optimal deep initial salinity perturbation of 0.1 ppt located near the western boundary can result in a tropical SST anomaly of approximately 0.45°C after nearly four years...

Interannual variability in sea-surface temperature at one location along the Central California coast

Breaker, L. C.; Lewis, Peter A. W.; Orav, Endel John
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Relatório
EN_US
Relevância na Pesquisa
96.12%
Sea surface temperature (SST) since March 1, 1971 at Granite Canyon, just north of Pt. Sur, California, are examined for interannual variability. Each of four El Nino episodes occurring over the past 13 years can be easily detected in the raw data. Annual mean temperatures are significantly higher during the El Nino years. The 1982-83 El Nino episode was more intense than the previous episodes; temperatures were as much as 5C above normal during the episode and it lasted for about 20 months. Major abrupt decreases in SST were frequently observed during the spring. These events are identified as the spring transition to coastal upswelling and appear to be most intense following El Nino episodes. Empirical Orthogonal Function analysis of the data indicates that maximum variability in SST's occurs between October and February and that it coincides with the four El Nino episodes occurring over the past 13 years.; Prepared for: Chief of Naval Research Arlington, VA; http://archive.org/details/interannualvaria00brea; N0001484WR24004; NA

At-sea distribution of female southern elephant seals relative to variation in ocean surface properties

Bradshaw, C.; Higgins, J.; Michael, K.; Wotherspoon, S.; Hindell, M.
Fonte: Academic Press Ltd Elsevier Science Ltd Publicador: Academic Press Ltd Elsevier Science Ltd
Tipo: Artigo de Revista Científica
Publicado em //2004 EN
Relevância na Pesquisa
86.35%
We examined the relationships between physical oceanography (sea surface temperature – SST, sea surface height anomaly – SSH, ocean colour – OC, bathymetry – BA, sea-ice concentration – SI, and their associated gradients) and the foraging distribution (time at sea) of female southern elephant seals using generalized linear and generalized additive models (GLM and GAM). Using data from 28 separate foraging trips (22 unique individuals) over two years, we found that during the post-lactation trips (summer), the best GLM demonstrated a negative relationship between time at sea and SST and BA, but a positive relationship with SST gradient and SSH. During the post-moult (winter) trips, there was a negative relationship with OC gradient, SSH, and BA. The best post-lactation GAM identified a positive relationship with OC gradient, negative relationships with OC and SST gradient, and a non-linear relationship with SST. For the post-moult trip there was a negative relationship with OC, SST, BA and BA gradient, and a positive relationship with SST gradient. The relationship between the predicted time and observed time at sea was significant only for the post-lactation GAM, although predictability was low. That SST and its gradient predicted a small...

SST changes in the South Atlantic driven by intense cyclones

Barbosa, Edson Luiz Shoitchi Yatabe; Camargo, Ricardo de
Fonte: Sociedade Brasileira de Meteorologia; Florianópolis Publicador: Sociedade Brasileira de Meteorologia; Florianópolis
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
86.21%
The identification and analysis of the effects of intense cyclone activity over the South Atlantic is the main focus of the current work. Using databases distributed by NCEP/NOAA of daily sea level pressure (SLP) and daily sea surface temperature (SST), the intense cyclones were detected through objective criteria of SLP fall, and the correspondent SST changes were investigated. The satellite measurements of daily SST changes are very noisy, which makes very difficult to identify the effect of the atmospheric system. In some interesting situations, it's possible to verify the relevance of horizontal advection and Ekrnan pumping processes to drive SST anomalies, but additional quantitative investigations are still necessary to understand the different processes and their correspondent scales.; Título: V SIC: Interação oceano-atmosfera: impactos climáticos no presente e cenários futuros. Eventos simultâneos ao V SIC: Encontro Sul Brasileiro de Meteorologia, 5. Florianópolis, Brasil, 2013; Congresso Latino-Americano e Ibérico de Meteorologia da FLISMET, 15. Florianópolis, Brasil, 2013.

Sea surface temperature records in the northern South China Sea from mid-Holocene coral Sr/Ca ratios

Wei, Gangjian; Deng, Wenfeng; Yu, Kefu; Li, Xian-hua; Sun, Weidong; Zhao, Jian-xin
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
106.06%
Three mid-Holocene sea surface temperature (SST) records spanning more than 30 years were reconstructed for the northern South China Sea using Sr/Ca ratios in Porites corals. The results indicate warmer than present climates between circa 6100 yr B.P. and

Abrupt temperature changes in the Western Mediterranean over the past 250,000 years

Martrat Sotil, Belén; Grimalt, Joan O.; Lopez-Martinez, Constancia; Cacho, Isabel; Sierro, Francisco Javier; Flores, José Abel; Zahn, Rainer; Canals, Miquel; Curtis, Jason H.; Hodell, David A.
Fonte: American Association for the Advancement of Science Publicador: American Association for the Advancement of Science
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
Relevância na Pesquisa
96.16%
5 pages, 2 figures.-- PMID: 15576615 [PubMed].-- Supporting information available at: www.sciencemag.org/cgi/content/full/306/5702/1762/DC1; A continuous high-resolution Western Mediterranean sea surface temperature (SST) alkenone record spanning the past 250,000 years shows that abrupt changes were more common at warming than at cooling. During marine isotope stage (MIS) 6, SST oscillated following a stadial-interstadial pattern but at lower intensities and rates of change than in the Dansgaard/Oeschger events of MIS 3. Some of the most prominent events occurred over MISs 5 and 7, after prolonged warm periods of high stability. Climate during the whole period was predominantly maintained in interglacial-interstadial conditions, whereas the duration of stadials was much shorter.; This work was supported by the Pole-Ocean-Pole (EVK2-2000-00089) and Coordinated European Surface Ocean Palaeoestimation (EVRI1-2001-00009) projects funded by the European Union.; Peer reviewed

Reconstruction of sea surface temperature variations in the Arabian Sea over the last 23 kyr using organic proxies (TEX86 and U37K′)

Huguet, Carme; Kim, Jung-Hyun; Sinninghe Damsté, Jaap S.; Schouten, Stefan
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2006 ENG
Relevância na Pesquisa
106.34%
Two sediment cores from the western Arabian Sea, NIOP905 and 74KL, were analyzed to determine sea surface temperature (SST) variations over the last 23 kyr. Two organic molecular SST proxies were used, the well-established U37K′ based on long-chain unsaturated ketones synthesized by haptophyte algae and the newly proposed TEX86 derived from the membrane lipids of Crenarchaeota. Comparison of NIOP905 and 74KL core top data with present-day SST (0–10 m) values indicates that both proxies yield temperatures similar to local annual mean SSTs. However, TEX86 and U37K′ SST down-core records derived from the same cores differ in magnitude and phasing. The alkenone SST record of NIOP905 shows small changes in SST (∼0.5°C) over the last 23 kyr, while that of core 74KL shows a ∼2°C increase from the Last Glacial Maximum (LGM) (23–19 calendar (cal) kyr B.P.) through the Holocene (the last 11.5 cal kyr B.P.) synchronous with changes in the Northern Hemisphere. In contrast, the TEX86 records of both cores show a large increase in SST from 22°–23°C in the LGM to 28°–30°C during Termination I (19–11.5 cal kyr B.P.), decreasing to present-day annual means of ∼26°C. A cold phase between 14.5 and 12 cal kyr B.P. that may correspond to the Antarctic cold reversal is also observed. This implies a Southern Hemisphere control on tropical SST reconstructed by the TEX86...

Interannual variability of the onset of the South China Sea summer monsoon

Luo, Ming; Leung, Yee; Graf, Hans-F.; Herzog, Michael; Zhang, Wei
Fonte: Wiley Publicador: Wiley
Tipo: Article; accepted version
EN
Relevância na Pesquisa
86.27%
This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/joc.4364; This article investigates the year-to-year variability of the onset of the South China Sea summer monsoon (SCSSM) and the possible influences exerted by the surface temperature anomalies over land and sea. Early and late monsoon onsets are related to the temperature anomalies in different regions. It is found that an early onset follows negative sea surface temperature (SST) anomalies in the central tropical Pacific (CP) Ocean during the preceding winter and spring, corresponding to a CP La Ni?a. In contrast, a late onset is preceded by the negative surface air temperature anomalies over land in the central Asian continent. Negative SST anomalies in the central-eastern equatorial Pacific Ocean and the associated warming in the western Pacific induce an anomalously enhanced Walker circulation. This anomalous Walker cell leads to an increase in convection, causing more latent heat release and a subsequent decrease of surface pressure. The anomalous Walker cell and the enhanced latent heat release weaken the Western North Pacific subtropical high and the Philippine Sea anticyclone, favouring a westerly flow from the Indian Ocean...

Examining water temperature proxies in Porities corals from the Great Barrier Reef: a cross-shelf comparison

Fallon, Stewart; McCulloch, Malcolm; Alibert, C
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
86.27%
Cores from colonies of the coral species Porites sp. were collected from inshore, mid-shelf, and outer reef localities (central Great Barrier Reef) to test the robustness of the major elemental sea surface temperature (SST) proxies (B/Ca, Mg/Ca, Sr/Ca, U/Ca) to the influence of inshore processes. Time series analyses of Sr/Ca, U/Ca, B/Ca, and Mg/Ca are compared to sea surface temperature (SST) in order to provide calibrations for these elements. This study shows that there are significant variations between the corals with respect to some of the proxies. In some cases, variations of ∼6°C are observed for a single U/Ca value. This magnitude of variation is also seen in the Mg/Ca proxy and, to a smaller extent, in the B/Ca-SST relationship. In two of the corals, both Mg/Ca and U/Ca do not follow a seasonal signal. The Mg/Ca and U/Ca ratios for two inshore corals are significantly different than the offshore corals (lower and higher, respectively). The other two proxies (B/Ca and Sr/Ca) do not display any inshore vs. offshore variations except for one inshore site that did not have a clear seasonal signal for either of these proxies. The Sr/Ca-SST relationship is the most robust, with a temperature variation of ∼2°C for a single Sr/Ca value...

An assessment of the Sr/Ca ratio in shallow water hermatypic corals as a proxy for sea surface temperature

Marshall, Jerry; McCulloch, Malcolm
Fonte: Pergamon-Elsevier Ltd Publicador: Pergamon-Elsevier Ltd
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
86.24%
The high precision measurement of the Sr/Ca ratio in corals has the potential for measuring past sea surface temperatures at very high accuracy. However, the veracity of the technique has been questioned on the basis that there is both a spatial and temporal variation in the Sr/Ca ratio of seawater, and that kinetic effects, such as the calcification rate, can affect the Sr/Ca ratio of corals, and produce inaccuracies of the order of 2-4 °C. In the present study, a number of cores of the massive hermatypic scleractinian coral Porites, from the central Great Barrier Reef, have been analyzed for Sr/Ca at weekly to monthly resolution. Results from a 24 year record from Myrmidon Reef show an overall variation from 22.7 °C to 30.4 °C. The record shows a warming/cooling trend with maximum warming centred on the 1986-1987 summer. While some bleaching was reported to have occurred at Myrmidon Reef in 1982, the Sr/Ca record indicates that subsequent summer temperatures were much higher. The 4.5 year record from Stanley Reef shows a maximum SST of 30 °C during the 1997-1998 El Niño event. The calibrations from Myrmidon and Stanley Reefs are in excellent agreement with previously published calibrations from nearby reefs. While corals do not calcify in equilibrium with seawater due to physiological control on the uptake of Sr and Ca into the lattice of coralline aragonite...

Reconstruction of Sea-Surface Temperatures from Assemblages of Planktonic Foraminifera: Multi-Technique Approach Based on Geographically Constrained Calibration Data Sets and its Application to Glacial Atlantic and Pacific Oceans

Kucera, Michal; Weinelt, Mara; Kiefer, T; Pflaumann, U; Hayes, Angela; Weinelt, Martin; Chen, Min-Te; Mix, Alan C.; Barrows, Timothy; Cortijo, E; Duprat, Josette; Juggins, Steve; Waelbroeck, Claire
Fonte: Pergamon-Elsevier Ltd Publicador: Pergamon-Elsevier Ltd
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
106.25%
We present a conceptual framework for a new approach to environmental calibration of planktonic foraminifer census counts. This approach is based on simultaneous application of a variety of transfer function techniques, which are trained on geographically constrained calibration data sets. It serves to minimise bias associated with the presence of cryptic species of planktonic foraminifera and provides an objective tool for assessing reliability of environmental estimates in fossil samples, allowing identification of adverse effects of no-analog faunas and technique-specific bias. We have compiled new calibration data sets for the North (N=862) and South (N=321) Atlantic and the Pacific Ocean (N=1111). We show evidence that these data sets offer adequate coverage of the Sea-Surface Temperature (SST) and faunal variation range and that they are not affected by the presence of pre-Holocene samples and/or calcite dissolution. We have applied four transfer function techniques, including Artificial Neural Networks, Revised Analog Method and SIMMAX (with and without distance weighting) on faunal counts in a Last Glacial Maximum (LGM) data set for the Atlantic Ocean (748 samples in 167 cores; based on the GLAMAP-2000 compilation) and a new data set for the Pacific Ocean (265 samples in 82 cores) and show that three of these techniques provide adequate degree of independence for the advantage of a multi-technique approach to be realised. The application of our new approach to the glacial Pacific lends support to the contraction and perhaps even a cooling of the Western Pacific Warm Pool and a substantial (>3°C) cooling of the eastern equatorial Pacific and the eastern boundary currents. Our results do not provide conclusive evidence for LGM warming anywhere in the Pacific. The Atlantic reconstruction shows a number of robust patterns...

Sea-surface Temperatures Around the Australian Margin and Indian Ocean During the Last Glacial Maximum

Barrows, Timothy; Juggins, Steve
Fonte: Pergamon-Elsevier Ltd Publicador: Pergamon-Elsevier Ltd
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
106.24%
We present new last glacial maximum (LGM) sea-surface temperature (SST) maps for the oceans around Australia based on planktonic foraminifera assemblages. To provide the most reliable SST estimates we use the modern analog technique, the revised analog method, and artificial neural networks in conjunction with an expanded modern core top database. All three methods produce similar quality predictions and the root mean squared error of the consensus prediction (the average of the three) under cross-validation is only ±0.77°C. We determine LGM SST using data from 165 cores, most of which have good age control from oxygen isotope stratigraphy and radiocarbon dates. The coldest SST occurred at 20,500±1400 cal yr BP, predating the maximum in oxygen isotope records at 18,200±1500 cal yr BP. During the LGM interval we observe cooling within the tropics of up to 4°C in the eastern Indian Ocean, and mostly between 0 and 3°C elsewhere along the equator. The high latitudes cooled by the greatest degree, a maximum of 7-9°C in the southwest Pacific Ocean. Our maps improve substantially on previous attempts by making higher quality temperature estimates, using more cores, and improving age control.

Variabilidade da vazão de regiões homogêneas da bacia hidrográfica amazônica brasileira: teleconexões com a temperatura da superfície do mar (TSM) de 1976 - 2010; Streamflow variability of homogeneous subregions in the Brazilian Amazon basin: teleconnections with sea surface temperature (SST) of 1976-2010

Limberger, Leila
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/09/2015 PT
Relevância na Pesquisa
126.37%
A variabilidade climática é um objeto característico da Geografia já que anomalias positivas ou negativas de seus elementos, principalmente precipitação e temperatura, podem afetar de forma significativa a vida da população atingida. Na presente pesquisa, a variabilidade da vazão na bacia amazônica brasileira para o período de 1976 a 2010 é estudada por meio de técnicas estatísticas, tais como correlação linear, regressão linear simples e múltipla, análise de agrupamento e análise de ondeletas. Campos de componentes atmosféricos são apresentados para a compreensão da circulação atmosférica anômala que leva a anomalias de vazão. O objetivo é compreender com mais profundidade possíveis associações entre a variabilidade da vazão fluvial e da temperatura da superfície do mar, TSM, em regiões oceânicas específicas, reconhecendo-se para isso o acoplamento oceano-atmosfera que modula a variabilidade climática global. Este estudo compreendeu o uso de dados de vazão e precipitação do sistema Hidroweb/ANA, dados de TSM, radiação de onda longa e vento do conjunto de dados da Reanálise I, do NCEP/NCAR, e dados de precipitação do Global Precipitation Climatology Project, GPCP. A maior parte das análises considerou o tratamento de dados na escala mensal. O estudo verificou que há variabilidade espacial para a resposta da correlação linear entre a TSM e a vazão na bacia amazônica brasileira...

The annual cycle of satellite derived sea surface temperature on the western South Atlantic shelf

Lentini, Carlos A. D.; Campos, Edmo J. D.; Podestá, Guillermo G.
Fonte: Universidade de São Paulo. Instituto Oceanográfico Publicador: Universidade de São Paulo. Instituto Oceanográfico
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 01/01/2000 ENG
Relevância na Pesquisa
86.23%
Neste artigo, treze anos de imagens semanais da temperatura da superfície do mar (TSM) obtidas através do sensor infravermelho Advanced Very High Resolution Radiometer a bordo dos satélites NOAA, de janeiro de 1982 a dezembro de 1994, são utlilizadas para investigar as variabilidades espacial e temporal do cicIo sazonal de TSM no Oceano Atlântico Sudoeste. Este trabalho objetiva as variações de larga escala sobre a plataforma continental e o talude leste da América do Sul limitados ao largo pela isóbata de 1000 metros, entre 42°5 e 22°S. As séries temporais de TSM são ajustadas aos .harmônicos anual e sem i-anual para descrever a variação anual das temperaturas da superfície do mar. O harmônico anual explica a maior parte da variabilidade da TSM. O coeficiente de determinação é alto (>; 90%) sobre a plataforma continental, decrescendo em direção ao largo. A amplitude estimada do cicIo sazonal varia entre 4° e l30e na região de estudo, atingindo mínimas temperaturas em agosto-setembro e máximas em fevereiro-março. Após identificação e remoção das componentes dominantes da variabilidade da TSM, modelos como o apresentado aqui são uma ferramenta atrativa para o estudo da variabilidade inter-anual da TSM.; In this article...

On the annual cycle of the sea surface temperature and the mixed layer depth in the Gulf of México.

MENDOZA,V. M.; VILLANUEVA,E. E.; ADEM,J.
Fonte: Centro de Ciencias de la Atmósfera, UNAM Publicador: Centro de Ciencias de la Atmósfera, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2005 EN
Relevância na Pesquisa
106.25%
Using an integrated mixed layer model we carry out a simulation of the annual cycle of the sea surface temperature (SST) and of the mixed layer depth (MLD) in the Gulf of México. We also compute the annual cycle of the entrainment velocity in the deepest region of the Gulf of México. The model is based on the thermal energy equation and on an equation of mechanical and thermal energy balance based on the Kraus-Turner theory; both equations are coupled and are vertically integrated in the mixed layer. The model equations are solved in a uniform grid of 25 km in the Gulf of México, the northwestern region of the Caribbean Sea and the eastern coast of Florida. The surface ocean current velocity and the atmospheric variables are prescribed in the model using observed values. We show the importance of the Ekman pumping in the entrainment velocity. We found that the upwelling plays an important role in increasing the entrainment velocity, producing an important reduction in the SST and diminishing the depth of the mixed layer in the Campeche Bay. In the rest of the Gulf of México the downwelling tends to reduce the entrainment velocity, increasing the SST and the MLD. Comparison of the computed annual cycle of the SST and the MLD with the corresponding observations reported by Robinson (1973)...

Sea surface temperature and mixed layer depth changes due to cold-air outbreak in the Gulf of Mexico

VILLANUEVA,E. E.; MENDOZA,V. M.; ADEM,J.
Fonte: Centro de Ciencias de la Atmósfera, UNAM Publicador: Centro de Ciencias de la Atmósfera, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 EN
Relevância na Pesquisa
106.19%
The impact of a cold-air outbreak (CAO) on the mixed layer in the Gulf of México (GoM), during the period 18-23 October 1999, is shown in this work. A numerical model, based on the thermal energy equation and the balance equation between the thermal and mechanical energies, is used for computing both, the sea surface temperature (SST) and the sea mixed layer depth (MLD) changes due to atmospheric forcing before and during the CAO. The importance of the contributions to the temperature tendency by thermal forcing at the surface, the vertical entrainment of cold water from the thermocline, the horizontal transport of thermal energy by ocean currents and by turbulent eddies in the mixed layer are analyzed, as well as the contributions to the entrainment velocity by deepening of the mixed layer and the Ekman's pumping velocity. During the passage of the CAO on the GoM the SST changes were markedly influenced by the increase in the surface wind speed. At the end of the period the experiments show that the vertical entrainment turned out to be the most determining process in the cooling of the mixed layer, even overhead of the latent and sensible heat fluxes and the horizontal transport by ocean currents and by turbulent eddies.

Factors that modulate the seasonal variability of the sea surface temperature of the Eastern Tropical Pacific

Flores-Morales,A. L.; Parés-Sierra,A; Marinone,S. G.
Fonte: Instituto de Geofísica, UNAM Publicador: Instituto de Geofísica, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2009 EN
Relevância na Pesquisa
106.18%
Seasonal variability of the sea surface temperature (SST) in the Eastern Tropical Pacific were studied. For this purpose the following data were analyzed: SST and wind data from the Comprehensive Ocean-Atmosphere Data Set from 1978 to 1997, temperature and salinity fields from the LEVITUS climatology and sea surfac heights from TOPEX/Poseidon from 1993 to 2002. Various locally important factors that modulate this variability were identified: (1) the influence of the Gulf of California with the seasonal variability of the California Current, which extend about 200 km from the mouth towards the south and west, and about 300 km from the peninsula's west side toward the north; (2) the influence of the Gulfs of Tehuantepec and Papagayo where, due to the behavior of the winds, a local cooling of the surface during winter is generated; (3) upwelling at the Equator, off Cabo Corrientes, and off the west coast of Baja California; (4) spatial and temporal variation of the Inter-Tropical Convergence Zone and its relation with the thermal equator; (5) remote propagating signals in the zone; and (6) seasonal variations of the Equatorial Current System.