Precursors of ENSO beyond the tropical Pacific

Author(s): Yu, JY; Paek, H | Abstract: Precursors of the El Nino-Southern Oscillation (ENSO) are atmospheric or oceanic phenomena that often occur before the onset of ENSO events and offer the potential to predict ENSO events with significant lead times. Most of the well-known ENSO precursors identified, so far, occur within the tropical Pacific, such as the build-up of subsurface ocean heat content anomalies in the tropical western Pacific (e.g., Wyrtki 1985; Meinen and McPhaden 2000) and the appearance of westerly wind bursts in the tropical western-to-central Pacific (e.g., McPhaden 1999; Vecchi and Harrison 2000; Zhang and Gottschalk 2002). These precursors have been suggested to affect ENSO onset through fluctuations in thermocline depths in the equatorial Pacific, which are recognized as a central element of the ENSO generation mechanism.