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Vortices ciclonicos da alta troposfera no Oceano Atlantico Sul
Abstract
A climatological study on upper tropospheric cycionic vortices based on satellite images is presented. Their formation is associated with the upper tropospheric anticyclonic flow over South America during the summer months. Vortices entering Brazil affect the distribution and intensity of the observed precipitation. Pages: 19-28
... A seguir são apresentados e discutidos os resultados da aplicação do SPI para os dados mensais de precipitação para a Microrregião de Sousa-PB. Na (Gan e Kousky, 1986;Ferreira e Mello, 2005). É perceptível que para a microrregião os valores do SPI-3 e SPI-6 oscilam em torno da linha da escala zero, retratando as condições alternadas de seca ao longo do período estudado. ...
A seca é um dos fatores mais complexo e prejudicial dos desastres naturais que influenciam e afetam os ecossistemas de diversas regiões do globo, em particular o nordeste do Brasil. O objetivo desde estudo foi determinar, quantificar e monitorar a periodicidade dos eventos secos e chuvosos numa microrregião do município de Sousa-PB. Para tal aplicou-se o índice climático bastante difundido denominado Standardized Precipitation Index (SPI), nas escalas de tempo de 3 e 6, para o período de 1962 a 2019. Os dados de precipitação mensal foram cedidos pela Agência Executiva de Gestão das Águas (AESA). Os resultados obtidos indicaram que os episódios de seca, diferiram na intensidade e magnitude nos anos estudados. As maiores concentrações de seca, nas escalas de tempo de 3 e 6 meses do SPI, não foi observada tendências temporais significativas. Com relação às frequências de ocorrências de secas leve as maiores probabilidades ocorreram nas escalas de 3 e 6 meses. Quanto a tendência úmida, a chuva leve foi a que apresentou a maior probabilidade de ocorrência.
... On the upper level, the BH is on average, and the NL is shifted to the east of the NEB (Fig. 4h). The NL has an important role in the NEB rainfall distribution, depending on position and movement, which could amplify rains or intensify droughts in the region (Gan and Kousky 1986;Chaves and Cavalcanti 2001;Reis et al. 2021). These outcomes explain the precipitation probability occurrence and wet day intensity in Fig. 3. Fig. 4 Average of wind velocity at 925 hPa (uv925, unit: ms −1arrows) and outgoing longwave radiation (OLR, unit: Wm −2 -colors and contours) having values of OLR less than 240 Wm −2 (a-d), and wind velocity at 200 hPa (uv200, unit: ms −1 -arrows) and geopoten-tial height at 200 hPa (Z200, unit: dm-colors) (e-h) corresponding to each hidden state. ...
A hidden Markov model (HMM) with four hidden states is used to describe the daily precipitation occurrence and wet day
intensities of a gridded precipitation dataset over the Northeast Brazil (NEB) for 35 austral summer seasons (1980/81–
2014/15). Results show that States 1 and 3 correspond to the wet versus dry conditions associated with the interplay between
the Intertropical Convergence Zone (ITCZ) and South American Monsoon System (SAMS). States 2 and 4 feature a southwest-northwest seesaw of precipitation occurrence, associated with antisymmetric conditions between the ITCZ and South
Atlantic Convergence Zone (SACZ). The Madden Julian Oscillation (MJO) seems to afect the development of the SACZ
in States 3 and 4. In State 4, the MJO infuenced the convection in the northwest NEB during phases 8-1-2. During easterly
Quasi-Biennial Oscillation (EQBO), the convective activity in the SACZ regions is intensifed in States 3 and 4 during MJO
phase 1, and weakened in State 4 during phases 1, 3, and 4. In the interannual timescales, States 1 and 3 are preconditioned
by a positive and a negative South Atlantic Ocean Dipole (SAOD), respectively. State 2 is modulated by a long and positive
El Niño-Southern Oscillation (ENSO) that triggered extratropical teleconnection patterns in both hemispheres. State 4 is
preconditioned by a negative ENSO that produces changes in the Walker and Hadley circulations. These fndings enhance
the understanding of the dynamic processes of summer rainfall over the NEB and their association with potentially predictable intraseasonal and interannual teleconnections on seasonal timescales.
... It is observed that the two regions (RH2 and RH3) over the years present similar behaviors, but with different pluviometric heights, although the oscillation of the signal occurs in a similar phase. In these regions the most important precipitations are associated with the displacement of the ITCZ to the South and the performance of the VCAN in the summer (Gan and Kousky, 1986;Uvo, 1989). ...
This study aims to make a diagnostic analysis of rainfall at different time scales in the rainfall homogeneous regions of the state of Pernambuco and associate them with weather systems operating in the region. The state was divided into three geographical regions (HR) of rainfall regime, according to Ward's clustering method. In each RH applied to Wavelet Transform (TO) time series of 1995-2015 precipitation. The results showed that in all regions the dominant scale is annual. It is also observed the interaction with the semi-annual and seasonal scales mainly in RH2 and RH3 regions. The TO showed that high levels of rainfall in the regions are associated with different weather systems.
Resumo Os Vórtices Ciclônicos de Altos Níveis (VCAN) são um dos principais sistemas que provocam alterações no tempo durante a pré-estação chuvosa do The Upper-Tropospheric Cyclonic Vortexes (UTCV) are one of the main synoptic systems that provoke alterations in
the weather during the pre-rainy season over Northeastern Brazil (BNE). The main objective of the study is to understand
the UTCV configuration that was developed during 26 days in January 2016 through synoptic and thermodynamic
analysis. In addition to the vortex, systems of different spatial and temporal scales such as the South Atlantic Convergence
Zone (SACZ), Madden-Julian Oscillation (OMJ) were configured simultaneously, along with the El Niño that
had been active since 2015. The connection between these systems caused a large increase in rainfall over the BNE. The
UTCV configuration together with the SACZ being driven by the propagation of the MJO determined the excess of
rainfall during the days analyzed. The western periphery of the vortex was positioned close to the BNE east coast, causing
a change in the convergence pattern of large-scale moisture transport, which began to converge on the BNE,
increasing precipitation rates in some states. The evaluation of the UTCV vertical structure through vertical sections
indicated upward movements only in the western periphery, the eastern periphery was characterized by strong convective
inhibition.
O presente estudo teve por objetivo avaliar o desempenho da estimativa de precipitação gerada pelo CHIRPS em relação aos dados observacionais de postos pluviométricos da Fundação Cearense de Meteorologia e Recursos Hídricos (FUNCEME) distribuídos pelas regiões Pluviometricamente Homogêneas do Estado do Ceará, no período de 1981 a 2020. Para isso foi realizado o levantamento de dados CHIRPS pelo USGS e de postos pluviométricos representativos das regiões pela FUNCEME. Os dados foram submetidos a testes estatísticos de avaliação de dados como correlação de Pearson (r), coeficiente de determinação (r²), erro sistemático (BIAS), e Erro Médio Quadrático (RMSE), e foram especializados através do SIG ArcGIS 10.8 utilizando o método de interpolação IDW. Os testes de correlação e determinação comprovaram a relação direta entre as variáveis orbitais e de superfície, apresentando valores acima de 0.98 em todas as regiões do estado.Os testes de correlação e determinação indicam a possibilidade de haver uma relação entre as variáveis orbitais e de superfície em todas as regiões do estado. Já os testes de erros sistemáticos demonstraram que o maior erro sistemático foi identificado no litoral se destacou como a região com, uma média de 30%, enquanto as regiões de Jaguaribana, Ibiapaba e Baturité foram as com menor porcentagem de erro (Jaguaribe com 1% de superestimativa e Tianguá com -2% de subestimativa). A espacialização confirmou a validação dos dados orbitais CHIRPS para utilização em estudos de cunho ambiental e climatológico, tendo em vista a alta correlação e erro médio.
The objective was to identify the climatology of precipitation (PRP) in Dom Eliseu-PA and assess whether there is a trend that can be considered as evidence of climate change, using data from the National Oceanic and Atmospheric Administration (NOAA), through the Climate Prediction Center (CPC), with a resolution of 0.5°x 0.5°, from 1979 to 2020, from the point -3.25°S and -47.25°W. To evaluate the trend, the Mann-Kendall test was applied to the annual PRP data and six more variables of the number of days in the year with PRP greater than or equal to 1 mm, 10 mm, 20 mm, 30 mm, 40 mm, and 50 mm. The results showed that the climatology of PRP showed two distinct periods: from December to May the rainy season and from June to November the dry season, with an annual average of 1640 mm. In addition, about 43% of the days of the year there was an occurrence of PRP, with a greater number of days with records in the rainy season. Both the annual PRP and the number of days with PRP in the year showed a significant tendency to decrease, and can be considered as evidence of climate change. A strong variation was also verified, with great amplitude in the series analyzed, which were mainly linked to the mode of interannual variability of the sea surface temperature of the Pacific and Atlantic Oceans, except for the extreme daily values, which also seem to be influenced by other modulating mechanisms of PRP.
A relação entre a Zona de Convergência do Atlântico Sul (ZCAS) e o Vórtice Ciclônico de Altos Níveis (VCAN) foi analisada durante 34 verões austrais, de acordo com as fases positivas, negativas e neutras do El Niño Oscilação Sul (ENOS). Anomalias das componentes zonais e meridionais do vento, foram calculadas com base na climatologia de 1979-2013 no nível de 200 hPa, e submetidos ao filtro de Lanczos nas bandas temporais de 20-90 dias e 200 dias passa baixa, com a intenção de destacar as variabilidades intrassazonal e interanual, através da análise observacional de três composições médias de ZCAS referentes às fases positiva, negativa e neutra do ENOS. As composições filtradas nas bandas intrassazonal e interanual revelam a intensificação do VCAN tanto para os casos de ZCAS-El Niño e de ZCAS-Neutras, enquanto que a variabilidade interanual durante eventos de ZCAS sob anos de La Niña inibem a ação do VCAN próximo do continente a partir de uma circulação anticiclônica na região.
Este livro agrega informações que subsidiam o entendimento da oceanografia da Baía de Todos os Santos. Propicia o embasamento científico para a interpretação de sua situação atual com vistas ao planejamento de futuros projetos de pesquisa e de ações gerenciais que venham a garantir a recuperação e a preservação de sua riqueza natural, como recifes de corais, estuários, manguezais, bem como a promoção da qualidade de vida das populações do Recôncavo Baiano.
An analysis of subtropical 200 mb cyclones is made for the South Atlantic. The cyclones are observed to occur primarily during the summer months and generally form near the axes of the mid-oceanic troughs. The relationship between cyclone formation and the presence of 200 mb anticyclones over the continental areas is discussed. Proposed mechanisms for cyclone formation are considered. The cyclones are characterized by a cold core and a direct thermal circulation—the cold air sinking and warm air on the periphery rising. The cloud pattern associated with the cyclones is found to depend on the direct thermal circulation, the vortex location and its direction of movement. The effects of South Atlantic 200 mb cyclonic vortices on Brazilian weather are discussed. DOI: 10.1111/j.2153-3490.1981.tb01780.x
The establishment of a thermally direct local circulation which has its ascending branch at about 10 deg N and its descending branch over northeast Brazil and the adjoining oceanic region is proposed as a possible mechanism for the occurrence of severe droughts over this Brazilian region. The driving for this anomalous circulation is provided by enhanced moist convection due to the effect of warmer sea surface anomalies over the northern tropical Atlantic and cooling associated with colder sea surface temperature anomalies in the southern tropical Atlantic. A simple primitive equation model is used to calculate the frictionally-controlled and thermally-driven circulation due to a prescribed heating function in a resting atmosphere, and a series of numerical experiments are carried out to test the sensitivity of the Goddard Laboratory's model to prescribed sea surface temperature anomalies over the tropical Atlantic.
Two sources of kona-storm development in the eastern Pacific are
studied, together with factors leading to storm intensification.
Vertical structure of this subtropical cyclone is considered in terms of
sounding data from Hawaiian stations during the storms of February and
March 1951.The kona cyclone initially possesses cold-core
characteristics, with winds and rainfall amounts increasing with
distance from the low-pressure center and reaching a maxima at a radius
of 200 to 500 mi. However, with intensification, this cyclone may
develop warm-core properties, with rainfall and wind profiles bearing
marked resemblance to those of the tropical cyclone.
RAINFALL in Ceará is correlated with sea surface temperature in the south Atlantic Ocean. Knowledge of sea surface temperature makes possible a useful rainfall forecast before the rainy season begins. The mechanism may be that sea temperature affects the height of the trade wind inversion, and thus the height of the moist layer. The data also suggest in association between below normal sea temperatures in the south Atlantic and the E1 Niño in the Pacific.
Includes bibliographical references. Partially sponsored by the National Science Foundation Partially sponsored by the National Science Foundation FACFATMS100073BLUE
INPE-789-TPT/017).. CASARIN, D.P. Um estudo obsewacional sobre sistemas de bloqueios no hemisfério sul. Dissertação de Mestrado em Meteorologia
- São José Dos Campos
São José dos Campos, INPE, 1975 (INPE-789-TPT/017)..
CASARIN, D.P. Um estudo obsewacional sobre sistemas de bloqueios no hemisfério sul. Dissertação de Mestrado em Meteorologia. São José dos Campos, INPE, 1983 (INPE-263&TDL/
114).
Dynarnic of clirnatic hezards i n Northeast Brazil
- S Hasten-Rath
- L Heller
HASTEN-RATH, S.; HELLER, L. Dynarnic of clirnatic hezards i n
Northeast Brazil. Quarterly Journal of the Royal
l
Society, 103(1) : 77-92.1 977.
A quasi-lagrangian analysis of the rnass and angular rnornenturn balance of an upper troposphere vortex over eastern Brazil
- D R Johnson
- J S Snook
JOHNSON, D.R.; SNOOK, J.S. A quasi-lagrangian analysis of the
rnass and angular rnornenturn balance of an upper
troposphere vortex over eastern Brazil. In: INTERNATIONAL
CONFERENCE ON SOUTHERN HEMISPHERE METEO-ROLOGY, 1. São Jos6 dos Campos, Brazil. Preprints. Boston,
MA, Arnerican Meteorological Society, 1983, p. 21 0-21 4.