83rd Annual

Thursday, 13 February 2003: 4:15 PM
Evolution of El Nino conditions in the tropical Pacific during 200203
Michael J. McPhaden, NOAA/PMEL, Seattle, WA
The classic signatures of El Nino--warming sea surface temperatures, weakening trade winds, and shifts in Pacific rainfall patterns--were detected in the tropical Pacific in early 2002. These conditions developed erraticly, being modulated by episodic westerly wind events associated with the Madden-Julian Oscillation. In contrast to the onset of the 1997-98 El Nino, warming in 2002 was less intense and less rapid to develop. However, by mid-year, most ENSO forecast models predicted that warm conditions would be sustained in the tropical Pacific through early 2003. This presentation reviews the current status of evolving El Nino conditions using data from the TAO/TRITON array of moored buoys and other elements of the ENSO Observing System. Development of these conditions will be compared with previous El Ninos and interpreted in light of recent theories. Implications for our understanding of ENSO cycle dynamics will be discussed.

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