The Oscillation of Tropical Height Field and El Nino Events

The monthly SST data from the National Climate Data Center (U. S. A) during the 33 years periods of 1946—1978 and the monthly geopotential height data set from Monthly Climatic Data for the World (U. S. A) during the 21 years periods of 1964—1984 are utilized in this paper. It is found that the tropical monthly geopotential height values form 850 through 30 hPa in both South and North America and North Africa, as well as over the pacific Ocean appear the quasi-triennial oscillation and that one to three months after the El Nino events, tropical monthly isobaric height departures from 500 through 30 hPa change from negative to positive values, on the contrary, one to two months after the El Nino, from positive to negative values. The most sensitive region of the global tropical isobaric height field is at Tahiti station