The Relationships between Tropical Pacific and Atlantic SST and Northeast Brazil Monthly Precipitation

ABSTRACT The monthly patterns of northeast Brazil (NEB) precipitation are analyzed in relation to sea surface temperature (SST) in the tropical Pacific and Atlantic Oceans, using singular value decomposition. It is found that the relationships between precipitation and SST in both basins vary considerably throughout the rainy season (February-May). In January, equatorial Pacific SST is weakly correlated with precipitation in small areas of southern NEB, but Atlantic SST shows no significant correlation with regional precipitation. In February, Pacific SST is not well related to precipitation, but south equatorial Atlantic SST is positively correlated with precipitation over the northern Nordeste, the latter most likely reflecting an anomalously early (or late) southward migration of the ITCZ precipitation zone. During March, equatorial Pacific SST is negatively correlated with Nordeste precipitation, but no consistent relationship between precipitation and Atlantic SST is found. Time-lagged analyses show the potential for forecasting either seasonal mean or monthly precipitation patterns with some degree of skill. In some instances, individual monthly mean SST versus seasonal mean (FebruaryMay) precipitation relationships differ considerably from the corresponding monthly SST versus monthly precipitation relationships. It is argued that the seasonal mean relationships result from the relatively strong monthly relationships toward the end of the season, combined with the considerable persistence of SST in both oceans

Principais secas ocorridas neste século no estado do Ceará: uma avaliação pluviométrica

This paper shows analyses about sazonal rainfall distribution over Ceará State in the years of severe drougths on this century. The principais results were: there aren't a canonical configuration in sazonal rainfall distribution over State in this years. It is, for each drougth year differents areas are affected, and not always the "Sertão" areas present the worsts indexes of precipitation on the State. In general, in this severe drought years in great part of State the normalized rainfall deviations, to period February to May, present values less than -40% of climatology. RESUMO:Este artigo mostra análises da distribuição sazonal da precipitação no Estado do Ceará em anos de seca extrema ocorridas neste século. Os principais resultados foram: não há um padrão canônico de configuração na distribuição sazonal de chuva ao longo do Estado nestes anos. Isto é, para cada ano de seca diferentes áreas são afetadas, e não somente as áreas de Sertão apresentam os menores índices de precipitação no Estado. Em geral, em anos de secas severas em grande parte do Estado os desvios normalizados de precipitação, período de fevereiro a maio, apresentam valores inferiores a -40% da climatologia

Forecasts of Tropical Atlantic SST Anomalies Using a Statistical Ocean Model at CPTEC/INPE - Brazil

The Center for Weather Forecast and Climate Studies (CPTEC) located in Brazil, has recently developed and implemented a modeling system to predict tropical Atlantic sea surface temperature anomalies (SSTA). This system named SIMOC (Statistical Modeling System) produces skillful forecasts (better than persistence) for lead times up to six months in advance (Repelli and Nobre, 1998).Pages: 28-3