VARIATIONS OF PRECIPITATION OVER THE EQUATORIAL PACIFIC AND EL NINO EVENTS

The variations of precipitation in the western and central equatorial Pacific were investigated by using the three-month (October to December) data set for the period from 1899 to 1982.The EOF analysis of precipitation shows great contrary between the areas of 20°N-10°S and north or south to it.The coefficients of first eigenvector of precipitation are closely correlated with the sea surface temperature in the eastern equatorial Pacific (correlation coefficient 0.75).The composite sea level pressure anomaly charts show that the equatorial low moves to the east near the dateline,the subtropical high weakens in the southern Pacific and the high pressure predominates over Australia,when plentiful precipitations are observed in the central Pacific.It is noted that the 1982-1983 E1 Nino event is not unusual,in the sense of the precipitation anomalies and the atmospheric circulation anomalies,but its intensity might be the strongest one in the last several decades.