17B.5
Seasonal activity of the Madden-Julian Oscillation: A precursor of ENSO warm events?
Chidong Zhang, Univ. of Miami/RSMAS, Miami, FL
It has been an uncertain issue as whether the Madden-Julian Oscillation (MJO) can influence ENSO in a deterministic way. This study found that forcing of intraseasonal Kelvin waves in the equatorial Pacific Ocean by wind stress associated with the MJO shows a significant relationship with anomalous sea surface temperature (SST) of ENSO. An index was designed to measure seasonal activity of such forcing. During the1980-1999 time period, stronger seasonal forcing in the western Pacific precedes greater SST anomalies in the eastern Pacific associated with ENSO warm events by 6 - 12 months. This result suggests that seasonal activities of Kelvin-wave forcing by the MJO in the western Pacific provide a precursory signal to the amplitude of ENSO warm events. Possible mechanisms for this connection between the forcing and ENSO SST and potential applications of this precursory signal to ENSO prediction are discussed.
Session 17B, Intraseasonal Variability III (Parallel with Sessions 17A and 17C)
Friday, 3 May 2002, 11:00 AM-12:30 PM
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