Contact: Randee Exler FOR IMMEDIATE RELEASE
(301)713-0622 10/19/94
Recent atmospheric and oceanic trends indicate the El Nino phenomenon associated with abnormally warm water episodes is developing in the tropical Pacific.
The Commerce Department's National Oceanic and Atmospheric Administration reported today climate conditions similar to those in September 1991 and September 1992 that were followed by El Nino/Southern Oscillation (ENSO) conditions during early 1992 and early 1993. During ENSO conditions, positive sea surface temperature anomalies dominate the tropical and subtropical Pacific Ocean east of the date line and water temperatures exceed 30 degrees Celsius (86 degrees F) near the equator at the date line.
During El Nino episodes, abnormally low pressure is observed in the eastern tropical Pacific and abnormally high pressure is found over Indonesia and northern Australia. The normal pattern of tropical cloudiness and precipitation is also disrupted. Rainfall that normally falls over Indonesia shifts eastward over the abnormally warm ocean waters of the central equatorial Pacific. The recent pattern of drought over Indonesia and eastern Australia, where warm episodes are often first noticed, indicates this shift in precipitation.
Since early 1990, the surface waters in the tropical Pacific have averaged warmer than normal, and ENSO conditions have been common. The period 1992 through 1993 had one of the longest periods of continuous warm episode conditions observed during the last 100 years. After a brief return to near normal conditions in early 1994, warm episode conditions have gradually redeveloped in the tropical Pacific.
Major advances during the past ten years in predicting ocean surface temperatures in the tropical Pacific allow scientists to predict that abnormal warmth in the central equatorial Pacific will continue into early 1995. Scientists cannot, however, predict the exact magnitude of the warmth nor the degree to which certain regions of the world will be impacted. NOAA's Climate Analysis Center will continue to closely monitor the ENSO condition and provide updates as the conditions warrant.
At an average of every three to five years, ocean surface temperatures in the equatorial central and eastern Pacific become abnormally warm. The abnormal warming in the eastern Pacific often begins in mid to late December and peaks during the northern spring. The term El Nino (or "The Child," referring to the Christ Child) was coined in Ecuador and Peru to denote these episodes of abnormally warm water that have been recorded since the days of the Conquistadors.