Characteristics of rainfall over Brazil: Annual variations and connections with the Southern Oscillation

Rao, V. Brahmananda; Hada, Kioshi

doi:10.1007/bf00868215

Cited by 273 publications

(220 citation statements)

References 21 publications

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“…The austral winter (June to August) and spring (Septem ber to November) rainfall over the Amazon accounts for considerably smaller seasonal percentages. These results are consistent with previous findings on the climatological distribu tion of the Amazon rainfall (Rao and Hada, 1990;Quadro et al, 1996).…”

Section: Introductionsupporting

confidence: 93%

On the influences of the El Niño, La niña and Atlantic Dipole Paterni on the Amazonian Rainfall during 1960-1998

et al. 2000

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-The influence of the large-scale climatic variability dominant modes in the tropical Atlantic present values (magnitude and sign) consistent with those found in previous works on the relationship between Amazon rainfall variations and the SST anomalies in the tropical Pacific and Atlantic. However, austral summer and autumn composites for the years with tropical Atlantic show negative precipitation anomalies extending eastward over the Key words: Seasonal rainfall, ENSO, Amazon, SST anomalous north-south dipole in the Atlantic. Sobre a Influência do El Niño, La Niña e Padrão De Dipolo do Atlântico na precipitação da amazônia durante 1960-1998RESUMO -A influência dos modos de variabilidade climática dc grande escala dominantes no Pacifico e Atlântico nas chuvas da Amazônia é investigada. A técnica de compósitos das anomalias de precipitação na Amazônia é usada neste trabalho. Os anos base destes compósitos são aqueles do período 1960-1998 com ocorrências de extremos na Oscilação Sul (El Niño ou La Niña) e de padrão de dipolo norte/sul quente (ou frio) nas anomalias de TSM no Atlântico tropical. Dipolo quente (frio) significa anomalias positivas (negativas) no Atlântico tropical Norte e negativas (positivas) no Atlântico tropical Sul. Compósitos de verão e outono austrais para extremos na Oscilação Sul (El Niño ou La Niña) e independente para padrão de dipolo norte/sul (quente ou frio) de anomalias de TSM no Atlântico tropical, apresentam valores (magnitude e signal) consistentes com aqueles encontrados em trabalhos anteriores sobre a relação entre as variações de precipitação na Amazônia e anomalias de TSM no Pacífico e Atlântico tropicais. No entanto, compósitos dos verões e outonos austrais para os anos com ocorrências simultâneas dc El Niño e dipolo quente norte/sul de anomalias de TSM no Atlântico tropical mostram anomalias negativas de precipitação estendendo-se para leste sobre a Amazônia centro-leste. Este resultado indica o importante papel desempenhado pelo Atlântico tropical na distribuição anômala de precipitação na Amazônia.Palavras-chave: Chuva sazonal, ENOS, Amazônia, Dipolo norte-sul de anomalias de TSM.

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Section: Introductionsupporting

confidence: 93%

On the influences of the El Niño, La niña and Atlantic Dipole Paterni on the Amazonian Rainfall during 1960-1998

et al. 2000

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“…The influence of PAC SSTs on Nordeste and Amazon rainfall, as well as the Pacific-Atlantic relationships and the local conditions that provide rainfall anomalies, have been described in various papers (Hastenrath and Heller, 1977;Kousky et al, 1984;Rao and Hada, 1987;Aceituno, 1988;Rogers, 1988;Marengo, 1992;Marengo and Hastenrath, 1993;Moron et al, 1995;Nobre and Shukla, 1996;Enfield and Mayer, 1997;Roucou, 1997;Marengo et al, 1998;Uvo et al, 1998;Liebmann and Marengo, 2001;Pezzi and Cavalcanti, 2001;Molinier et al, in press).…”

Section: Introductionmentioning

confidence: 97%

Interannual rainfall variability in the Amazon basin and sea‐surface temperatures in the equatorial Pacific and the tropical Atlantic Oceans

Ronchail¹,

Cochonneau²,

Molinier³

et al. 2002

Intl Journal of Climatology

218

188

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Rainfall variability in the Amazon basin is studied in relation to sea-surface temperatures (SSTs) in the equatorial Pacific and the northern and southern tropical Atlantic during the 1977-99 period, using the HiBAm original rainfall data set and complementary cluster and composite analyses.The northeastern part of the basin, north of 5°S and east of 60°W, is significantly related with tropical SSTs: a rainier wet season is observed when the equatorial Pacific and the northern (southern) tropical Atlantic are anomalously cold (warm). A shorter and drier wet season is observed during El Niño events and negative rainfall anomalies are also significantly associated with a warm northern Atlantic in the austral autumn and a cold southern Atlantic in the spring. The northeastern Amazon rainfall anomalies are closely related with El Niño-southern oscillation during the whole year, whereas the relationships with the tropical Atlantic SST anomalies are mainly observed during the autumn. A time-space continuity is observed between El Niño-related rainfall anomalies in the northeastern Amazon, those in the northern Amazon and south-eastern Amazon, and those in northern South America and in the Nordeste of Brazil.A reinforcement of certain rainfall anomalies is observed when specific oceanic events combine. For instance, when El Niño and cold SSTs in the southern Atlantic are associated, very strong negative anomalies are observed in the whole northern Amazon basin. Nonetheless, the comparison of the cluster and the composite analyses results shows that the rainfall anomalies in the northeastern Amazon are not always associated with tropical SST anomalies.In the southern and western Amazon, significant tropical SST-related rainfall anomalies are very few and spatially variable. The precipitation origins differ from those of the northeastern Amazon: land temperature variability, extratropical perturbations and moisture advection are important rainfall factors, as well as SSTs. This could partially explain why: (a) the above-mentioned signals weaken or disappear, with the exception of the relative dryness that is observed at the peak of an El Niño event and during the dry season when northern Atlantic SSTs are warmer than usual; (b) rainfall anomalies tend to resemble those of southeastern South America, noticeably at the beginning and the end of El Niño and La Niña events; (c) some strong excesses of rain are not associated with any SST anomalies and merit further investigation.

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“…O Rio Grande do Sul, situado no extremo meridional do Brasil, pertence à chamada Região Sudeste da Amé-rica do Sul (Sul do Brasil, Nordeste da Argentina, Uruguai e Sul do Paraguai), que apresenta forte sinal do fenômeno El Niño Oscilação Sul (ENOS), especialmente em relação à precipitação pluvial (Ropelewski & Halpert, 1987;Rao & Hada, 1990;Studzinski & Diaz, 1994;Diaz et al, 1998;Grimm et al, 1998;Montecinos et al, 2000). O ENOS é um fenômeno de interação oceano-atmosfera, que ocorre no Oceano Pacífico tropical, e é considerado como a principal causa da variabilidade climática em diversas regiões do Globo.…”

Section: Introductionunclassified

Associação entre El Niño Oscilação Sul e a produtividade do milho no Estado do Rio Grande do Sul

Berlato

Farenzena

Fontana

2005

Pesq. agropec. bras.

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Resumo -A alta variabilidade interanual da produtividade de milho, no Rio Grande do Sul, é determinada, principalmente, pela variabilidade da precipitação pluvial, e esta, em grande parte está associada ao fenômeno El Niño Oscilação Sul (ENOS). A disponibilidade, hoje, de previsões sazonais do ENOS faz vislumbrar a possibilidade de uso dessas informações para minimizar prejuízos e maximizar a produtividade. Há necessidade, porém, de se avaliar a vulnerabilidade da produtividade do milho a esse fenômeno. O objetivo deste trabalho foi quantificar a associação entre a produtividade de milho e a variabilidade da precipitação pluvial, causada pelo ENOS. Para a análise, foram tomadas séries históricas de produtividade, de precipitação pluvial mensal, de ocorrência das fases do ENOS (El Niño e La Niña), de Temperatura da Superfície do Mar (TSM) no Pacífico equatorial, e do Índice de Oscilação Sul (IOS). Há forte tendência do El Niño em favorecer a cultura do milho, o que dá oportunidade à alta produtividade, ao passo que em anos de ocorrência de La Niña há alta freqüência de baixa produtividade. A precipitação pluvial mais associada à produtividade do milho é a integrada de outubro a março. Essas informações são úteis para decisões quanto a alternativas de manejo da cultura, frente a uma previsão de El Niño ou La Niña.Termos para indexação: Zea mays, La Niña, precipitação pluvial. Association between El Niño Southern Oscillation and corn yield in Rio Grande do Sul StateAbstract -The high interannual variability of corn yield in Rio Grande do Sul State is determined mostly by the variability of rainfall, which is mainly associated to El Niño Southern Oscillation (ENSO). Current availability of seasonal ENSO forecasts shows the possibility of using this information to minimize losses and maximize yield. However, it is necessary to assess the vulnerability of corn yield to this phenomenon. The objective of this work was to quantify the association between corn yield and rainfall variability due to ENSO. In order to perform the analysis, historical series of yields, monthly rainfalls, ENSO (El Niño and La Niña) phases, Sea Surface Temperature (SST) in equatorial Pacific, and the Southern Oscillation Index (SOI) were used. Results show that there is a strong trend for El Niño to favor corn crops, providing opportunities for high yields, while in years when La Niña occurs there is a high frequency of low yields. The rainfall most associated with corn yields is the integrated one from October to March. This information is useful for decision making as to crop management alternatives when there is a forecast of El Niño or La Niña.

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Characteristics of rainfall over Brazil: Annual variations and connections with the Southern Oscillation

Cited by 273 publications

References 21 publications

On the influences of the El Niño, La niña and Atlantic Dipole Paterni on the Amazonian Rainfall during 1960-1998

On the influences of the El Niño, La niña and Atlantic Dipole Paterni on the Amazonian Rainfall during 1960-1998

Interannual rainfall variability in the Amazon basin and sea‐surface temperatures in the equatorial Pacific and the tropical Atlantic Oceans

Associação entre El Niño Oscilação Sul e a produtividade do milho no Estado do Rio Grande do Sul

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