Abstract:By using the NOAA precipitation data, the Southern Oscillation Index(SOI) and Niño3 index, the monthly mean data from NCEP/NCAR Reanalysis, the monthly mean sea surface temperature data from Hadley Center over the period of 1960-2016, we have investigated the interdecadal variation characteristics of relationship between summer precipitation and ENSO in the Maritime Continent(MC) region of the northern hemisphere through correlation analysis and regression analysis. When SOI is positive(negative), precipitation anomaly over MC is positive(negative), too. Results show that the correlation between SOI and summer precipitation over MC area has significantly weakened since 1998. The reason for this phenomenon is that the correlation of SOI and Sea Surface Temperature(SST) is negative in the central Pacific. The negative correlation center has shifted eastward and manifested as CP-type SSTA after 1998. This type of SSTA corresponds to the center of apparent heat source anomalies located in the central Pacific, which induces the Gill-type response of atmosphere, leading to an anomalous anticyclonic circulation in the lower troposphere east of the Philippines, thus strengthening the divergence there. This causes the precipitation over area north of equator to significantly decrease, canceling the precipitation increase over southern part of the MC, making the relationship between the precipitation and SOI loose.