Large-Scale Common Features of Sub-Tropical Convergence Zones (the Baiu Frontal Zone, the SPCZ, and the SACZ) Part II : Conditions of the Circulations for Generating the STCZs

Kodama, Y.

doi:10.2151/jmsj1965.71.5_581

Cited by 189 publications

(166 citation statements)

References 66 publications

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“…Whether or not this relationship is representative for Baiu precipitation, which covers a restricted but variable window of the summer, is not fully clear. At least, our analyses confirm that the July interannual variations of the atmospheric circulation accompanying the coupled mode-such as the anomalous extension of the subtropical high, and the variations in the lower tropospheric moisture flux-are very similar to those of the Baiu, as described in the literature (e.g., Ninomiya and Akiyama, 1992;Kodama 1992Kodama , 1993.…”

Section: Discussionsupporting

confidence: 85%

“…Later, other physical processes-such as convective storms, and eventually the early visit of tropical cyclones-contribute to summer precipitation. Dynamically, the East-Asian rain-belt is understood as a subtropical convergence zone fed by the southwesterly low-level flow arising between the South Asian continental monsoon heat low and the Pacific subtropical high (e.g., Ninomiya 1984;Kodama 1992Kodama , 1993. The essential characteristics of the eastern sections of this rainband, referred to as the Baiu front, are: a strong meridional gradient of equivalent potential temperature aligned with the upperlevel subtropical jet, a narrow low-level jet, and a thick layer of moist near-neutrally stratified air (Ninomiya and Akiyama 1992;Yoshikane et al 2001).…”

Section: Introductionmentioning

confidence: 99%

“…The essential characteristics of the eastern sections of this rainband, referred to as the Baiu front, are: a strong meridional gradient of equivalent potential temperature aligned with the upperlevel subtropical jet, a narrow low-level jet, and a thick layer of moist near-neutrally stratified air (Ninomiya and Akiyama 1992;Yoshikane et al 2001). The large-scale flow of the lower troposphere between the continental heat low and the subtropical high has a frontogenetic effect on, and provides a convergent moisture flux into, the Baiu front (e.g., Akiyama 1975;Kodama 1993;Ninomiya and Kobayashi 1999). Precipitation along the front is organised in meso-a-scale convective systems, which themselves are embedded in larger-scale frontal disturbances (e.g., Ninomiya and Akiyama 1992).…”

Section: Introductionmentioning

confidence: 99%

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Interannual Covariance between Japan Summer Precipitation and Western North Pacific SST

Fukutome

Frei

Schär

2003

Journal of the Meteorological Society of Japan

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A statistical analysis is conducted of the covariance between summer precipitation in Japan and concurrent variations of sea surface temperature (SST) in the Western North Pacific (WNP;. To this end, a singular value decomposition (SVD) is applied to observed monthly anomalies of the two fields for the period 1961-1998 (38 summer seasons).The first coupled mode of the SVD explains as much as 71% of the total cross-covariance between WNP SST and Baiu precipitation. It is characterized by a zonally elongated dipole in the SST anomaly with opposite loadings on either side of about 30 N and a precipitation anomaly with its maximum in southern Japan. The patterns indicate a negative correlation between Japan's summer precipitation and the sea surface temperature in the East China Sea, Japan Sea and Kuroshio-Oyashio extension. Simpler composite analyses confirm the robustness of the coupling. In a linear regression analysis, the score of the WNP SST explains 30% of the domain mean summer precipitation variance, which is larger than the variance accounted for by lagged and concurrent ENSO-indices.Composites related to the mode's precipitation score were found to support both directions of the atmosphere-ocean interaction. On the one hand, the anomalies in radiation and evaporation at the sea surface would be sufficiently large to induce the observed temperature variations in the northern pole of the SST pattern. On the other hand, the possibility for an atmospheric response to the SST is supported by the consistency of anomalies in lower-tropospheric baroclinicity and moisture flux divergence with the underlying SST distribution.

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Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Interannual Covariance between Japan Summer Precipitation and Western North Pacific SST

Fukutome

Frei

Schär

2003

Journal of the Meteorological Society of Japan

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“…Em campos de radiação de onda longa emergente (ROLE) média mensal é caracterizada por uma banda de ROLE mínima ligada à Amazônia, onde há intensa convecção (Ninomiya, 2007). Em imagens de satélite é destacada por uma extensa banda de nebulosidade com orientação noroeste-sudeste, que se estende do sul da Amazônia ao sudeste do Brasil e sudoeste do Atlântico Sul (Casarin e Kousky, 1986;Kodama, 1992Kodama, , 1993Ferreira et al, 2004).…”

Section: Introductionunclassified

“…Carvalho et al (2004) mostraram que a(s) fase(s) quente (fria e neutra) do ENOS favorece (favorecem) a ocorrência de ZCAS oceânica (continental). Já Liebmann et al (2001) destacaram que, durante o verão austral, a quantidade de eventos extremos interanuais de precipitação no Estado de São Paulo é positivamente correlacionada com as anomalias de temperatura da superfície do mar (TSM) no Pacífico equatorial.…”

Section: Introductionunclassified

Impacto da temperatura da superfície do mar na simulação da Zona de Convergência do Atlântico Sul

Tomaziello

Gandú

2013

Rev. bras. meteorol.

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RESUMODurante o verão austral, diversas regiões do Brasil são afetadas por precipitação intensa, geralmente associada à Zona de Convergência do Atlântico Sul (ZCAS). O objetivo geral deste trabalho foi investigar a influência da resolução espacial e temporal dos dados de temperatura da superfície do mar (TSM) na simulação da precipitação associada à ZCAS. Foram realizadas simulações com o modelo BRAMS (Brazilian developments on the Regional Atmospheric Modeling System) para dois eventos de ZCAS, ocorridos em 1998 (El Niño) e 1999 (La Niña). A quantidade de precipitação acumulada na parte oceânica da ZCAS foi maior nos experimentos com TSM mais quente. Índices estatísticos foram utilizados para verificação do desempenho do modelo na simulação de precipitação nas regiões que compõem a ZCAS (oceânica, costeira e amazônica), com diferentes dados de TSM. A resolução espaço-temporal dos dados de TSM influencia de forma pouco significativa na representação da ZCAS pelo modelo BRAMS. O modelo é mais eficiente em identificar a ocorrência/não ocorrência de chuva do que em localizar núcleos mais intensos e seu desempenho foi superior (inferior) na região amazônica (oceânica) da ZCAS. Palavras-chave: modelagem numérica, ZCAS, TSM, precipitação.ABSTRACT: IMPACT OF SEA SURFACE TEMPERATURE IN THE SIMULATION OF SOUTH ATLANTIC CONVERGENCE ZONE During austral summer, several regions of Brazil are affected by intense precipitation, generally associated with the South Atlantic Convergence Zone (SACZ). The general aim of this work was to investigate the influence of spatial and temporal resolution of sea surface temperature (SST) data in simulating precipitation associated with SACZ. Simulations with the model BRAMS (Brazilian developments on the Regional Atmospheric Modeling System) were performed for two SACZ events, occurred in 1998 (El Niño) and 1999 (La Niña). The amount of accumulated precipitation in oceanic SACZ was larger in experiments with warmer SST. Statistical indices were used in order to verify the model's performance in the simulation of precipitation in the regions that compound SACZ (oceanic, coastal and amazon), with different SST datasets. Different time-space resolution of the SST data set does not have significant influence on the SACZ simulated with the BRAMS model. The model is more efficient in identifying occurrence/non-occurrence of rain than in localizing more intense nuclei, and its performance was better (worse) in amazon (oceanic) region of SACZ. Keywords: numerical modeling, SACZ, SST, precipitation.geralmente associada à chamada Zona de Convergência do Atlântico Sul (ZCAS), que normalmente localiza-se sobre a Região Sudeste, norte do Paraná, sul da Bahia, e Brasil Central (Carvalho e Jones, 2009), provocando chuvas intensas e persistentes devido à sua manutenção durante vários dias sobre essas regiões.

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Tropical-midlatitude exchange of air masses during summer and winter in South America: climatic aspects and examples of intense events

2000

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Meridional transport of air masses between the tropics and midlatitudes in South America are the most intense in the entire Southern Hemisphere, mainly due to the presence of the Andes. The incursions of tropical air into midlatitudes occur on the eastern side of the Andes in two preferred regions. The first is located in the tropical latitudes, close to the mountains between 20°and 30°S, and the second is a function of the position of the South Atlantic Convergence Zone (SACZ). All year long, the two preferred regions maintain their behaviour, with only small variations of their position or relative importance in different seasons of the year. The variability of the meridional transport is larger on the eastern side of the Andes, due to the presence of the mountain barrier, which favours baroclinic activity and allows an active exchange of air masses in both senses, especially during winter. The importance of the air mass transport is evident in the precipitation and surface temperature fields. During summertime, the Chaco Low (25°S and 65°W) intensifies due to the positive net radiation, favouring the transport of tropical air masses towards the south and the presence of strong convective activity, which is fed by moisture from tropical regions. During winter, the penetration of tropical air towards higher latitudes is more sporadic. The displacement of midlatitude air towards tropical latitudes occurs on both sides of the Andes. On the western side, the air associated with the subtropical Pacific anticyclone flows northward channelled by the Andes. On the eastern side, incursions of polar air towards lower latitudes are linked to cold fronts whose trajectory and movement is also favoured by the presence of the Andes. In particular, during wintertime the cold fronts are more intense and faster, and sometimes even reach tropical and equatorial latitudes which produces freezes in subtropical regions, such as the coffee growing areas in southeastern Brazil. In contrast, the incursions of cold air are notably weaker and less frequent in summer, and during these events the active cold fronts move northwards merging with the SACZ, which becomes more intense.

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Large-Scale Common Features of Sub-Tropical Convergence Zones (the Baiu Frontal Zone, the SPCZ, and the SACZ) Part II : Conditions of the Circulations for Generating the STCZs

Cited by 189 publications

References 66 publications

Interannual Covariance between Japan Summer Precipitation and Western North Pacific SST

Interannual Covariance between Japan Summer Precipitation and Western North Pacific SST

Impacto da temperatura da superfície do mar na simulação da Zona de Convergência do Atlântico Sul

Tropical-midlatitude exchange of air masses during summer and winter in South America: climatic aspects and examples of intense events

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