On-line version ISSN 1852-7744
BERMAN, Ana Laura; COMPAGNUCCI, Rosa and SILVESTRI, Gabriel. Análisis en tiempo-frecuencia de la conexión entre la atmósfera y el océano Pacífico tropical. Geoacta [online]. 2011, vol.36, n.2, pp. 167-175. ISSN 1852-7744.
Relations between the Southern Oscillation Index (SOI) and the sea surface temperature (SST) in the tropical and subtropical South Pacific are explored in this paper for different bands of the time-frequency space using the wavelet transform. In the tropical central Pacific, results show that the widely know coupled system El Niño-Southern Oscillation (ENSO) characterized by simultaneous positive (negative) SOI anomalies and negative (positive) SST anomalies occurs in the entire range of frequency. However, these significant links with the SOI are interrupted in the western tropical ocean in oscillations around 8 yrs near the extensively described 1976/77 climate shift. In the largest periodicities, the SOI has a weak relation with the western tropical areas and it does not have connection with the eastern regions. The indexes of subtropical SST exhibit complex relationships with the SOI. The links are significant but non-stationary with the western regions, close connections only occur in specific periodicities in the central areas and they vanish to the east. The analysis performed for reconstructed series for pre-instrumental times reveals that the sporadic disconnections between the SOI and the tropical Pacific were usual during the last centuries.
Keywords : Southern Oscillations Index; El Niño events; Pacific Ocean surface temperature.