Resumo

AGOSTA, Eduardo Andres  e  COMPAGNUCCI, Rosa Hilda. Procesos atmosféricos/oceánicos de baja frecuencia sobre la cuenca sudoeste del Atlántico Sur y la variabilidad de la precipitación en el centro-oeste de Argentina. Geoacta [online]. 2008, vol.33, pp.21-30. ISSN 1852-7744.

Some authors find that the precipitation variability at diverse scales over subtropical Argentina can be linked to sea surface temperature (SST) conditions of the South Atlantic (Venegas et al., 1998, Robertson and Mechoso 1998, Doyle and Barros 2002). Particularly, summer precipitation in Central-West Argentina (CWA) shows relationship with the SSTs at mid-latitudes over southwestern South Atlantic (Compagnucci and Agosta 2006). SSTs variations over that oceanic area are modulated by surface air mass flow around 40ºS (Wainer and Venegas 2002). Therefore, the objective of this work is to study low-frequency processes in the atmosphere/ocean system over southwestern South Atlantic associated with summer precipitation in CWA. Results show that the atmospheric circulation has a center of action over southwestern South Atlantic around 45ºS/60ºW, associated with precipitation during the whole 20^th century that modules the quasi-18-year oscillation of CWA precipitation found by Compagnucci et al. (2002). This center of action is the common forcing between precipitation and the SST conditions over southwestern South Atlantic.

Palavras-chave : Climate change; Precipitation; Transition 1976/77; Teleconnections.

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