HR: 1400h
AN: A23A-05    [Abstracts]
TI: Influence of the Inter-ENSO Extremes on the South American Moisture Transport during opposite PDO Phases
AU: Silva, G
EM: gyrlene@model.iag.usp.br
AF: Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Departamento de Ciências Atmosféricas , Universidade de São Paulo, Rua do Matão, 1226, Cidade Universitária, São Paulo, SP 05508-090, Brazil
AU: * Ambrizzi, T
EM: ambrizzi@model.iag.usp.br
AF: Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Departamento de Ciências Atmosféricas , Universidade de São Paulo, Rua do Matão, 1226, Cidade Universitária, São Paulo, SP 05508-090, Brazil
AB: The impact of the inter El Niño/Southern Oscillation (ENSO) variability on the atmospheric circulation and the moisture distribution over the South America according to the Pacific Decadal Oscillation (PDO) phases is investigated. Emphasis is done on the spring and austral summer. It was found that during the summer when weak El Niños (EN) and neutral ENSO events occur during cold PDO regime the moisture transport from the tropics to the subtropics, particularly around the South Atlantic Convergence Zone region, seems to be more important than in the warm PDO phase. When strong EN is in phase with warm PDO the feedback between them seems to favor an enhanced meridional moisture transport from tropical latitudes to the La Plata Basin. Substantial differences among the austral seasons have been found on the composites of the circulation anomalies for the extreme ENSO events that occur during warm PDO. These differences are more conspicuous when the atmosphere is influenced by the warm phase of the ENSO. In subtropical latitudes around the La Plata Basin region, the most significant difference from spring to the summer season during strong EN events is the increase on the intensity of the circulation anomalies over that region. On the other hand, during weak EN and La Niñas events circulation patterns from one season to another can have opposite signals in the same region. It is demonstrated that the intensity of an ENSO episode can modulate the moisture transport in the South American continent. This study contributes to the current knowledge about the South America circulation anomalies associated with the interannual variability taking into account the PDO phases. Some more detailed analysis and numerical experiments are currently been carried out and will be presented elsewhere.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly