No abstract

In this paper, the impacts of the convective activities in the western Pacific warm pool on the interannual and intraseasonal variations of the summer monsoon in East Asia are analyzed by using the observed data for 12 summers from 1978 to 1989. The analyzed results show that both interannual and intraseasonal variabilities of the East Asian summer monsoon are greatly influenced by the convective activities in the warm pool. Generally, the monsoon rainfall is below normal in East Asia and the abrupt change of the monsoon circulation is obvious in the summer of strong convective activities around the Philippines.The impacts of the convective activities in the warm pool on the summer monsoon in East Asia and the East Asia/Pacific teleconnection pattern of summer circulation anomalies due to the convection are discussed by using the theory of planetary wave propagation and the numerical modelling by the IAP-GCM, respectively.

[1] The interdecadal modulation of the Pacific Decadal Oscillation (PDO) upon the impact of the El Niño-Southern Oscillation (ENSO) on the east Asian winter monsoon (EAWM) is investigated. When the PDO is in its high phase, there is no robust relationship between ENSO and EAWM on the interannual timescale. When the PDO is in its low phase, ENSO exerts strong impact on the EAWM, with robust and significant low-level temperature changes occurring over east Asia. The contrast in ENSO's influence between the two phases of the PDO is quite remarkable, which urges that the phase of the PDO should be taken into account in the ENSObased prediction of wintertime climate over east Asia. This modulation may be accounted for by the change in the lowlatitude Pacific-east Asian teleconnection and in the response of midlatitude geopotential height to ENSO over Northwest Pacific.