A Study of the Coupling Relations Between East Asia Winter Monsoon and ENSO Cycle

摘要

(1) There is closely asynchronous coupling relation between the 500hPa geopotential height field in winter half year and SST field in El Nino region in autumn. The first modes derived from SVD indicate the key time-space correlation characteristics of the two fields. (2) When East Asia winter monsoon is stronger (weaker) in the previous winter half year, El Nino(La Nina) event will occur. East Asia winter monsoon has an important effect on ENSO cycle. (3) When El Nino (La Nina) event appears, East Asia winter monsoon will be weaker (stronger) in following winter half year. ENSO cycle has also very important effect on East Asia winter monsoon. And it is stronger than the effect of previous East Asia winter monsoon on ENSO. (4) The conceptual model of their interaction is that stronger (weaker) East Asia winter monsoon→ El Nino (La Nina) event→ weaker (stronger) East Asia winter monsoon→ La Nina (El Nino) event→ stronger (weaker) East Asia winter monsoon, which forms a closed air-sea cycle process with two-year period. The anomalous variation of East Asian winter monsoon and the effect of ENSO cycle are an important mechanism for the occurrence and development of the other party of the two parties, respectively. (5)A way of phase space analysis based on SVD is presented. It can not only analyze the varying processes and anomalous feature of fields themselves but also reveal their internal interrelation on the basis of coupling relation of the two fields.