| To further study the causes of El Ni? events Extended Associate PatternAnalysis (EAPA) is adopted again with monthly sea surface wind stress andprecipitation besides sea level pressure (SLP) and sea surface temperature(SST) in or over the Pacific and related seas in present paper sine 1979 inpresent paper. The results show that El Ni? events mean a SST redistributioncovering almost the whole Pacific that needs a huge amount of energy providedby air-sea interaction in the most Pacific regions; It is the west burst andwind convergence, coming from meddle latitudes directly, instead of Kelevinwaves that produce the strong SST warm signal in Nino regions; Two negativeSLP anomalies in middle of the North and South Pacific, most likely producedby the average air pressure decreasing effect of explosive cyclones throughprecipitation, and the positive SLP anomaly over the Asia-Australia landbridge, coming mainly from the south hemisphere with a little influence fromthe Asian continent, are the three major causes for El Ni? onset, they worktogether to produce the west bursts, wind convergence in Nino regions andanomalous westerly in the middle Pacific that results in a warm tongue andcold pincers gearing together; Basically, during its early stage the oceanis forced by the atmosphere, while during its late stage the atmosphere isforced by the ocean. |
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