Temporal And Spatial Characteristics Of Interannual And Interdecadal Abnormalities In The Tropical Pacific Ocean-Atmosphere System And The Influence To Summer Precipitation Over Eastern China

By using 1980-2009 GODAS monthly various elements, NCEP/NCAR reanalysis 850hPa winds (V850) and 160-station monthly precipitation data in China,the seasonal interannual and decadal characteristics of subsurface sea temperature(ST),sea surface height(SSH), mixed layer depth(MLD),etc. are studied over the tropical Pacific.The time-lagged correlations between every sea element in previous autumn, previous winter, spring, summer and summer precipitation are discussed. Using of the SVD analysis method shows its relationship with East Asia atmosphericcirculation and summer precipitation in China,the main results are as follows:(1)The analysis of ST abnormlity and its relationship with 850hPa wind field and summer precipitation in China indicate:1)when the ST is warmer and takes on El Nino pattern, it can be predicted that the precipitation will be significantly more than normal value over the south of the Yangtze River, especially Dongting Lake and Poyang Lake region, Sichuan basin and Yangtze-Huai River Valley, and less than normal over the areas from North China to He Tao, the North of Zhejiang, the coastal of South China and south part of Yunnan in the coming year summer.2)From the overall trend of 30a, Obvious inter decadal variability of ST over the tropical Pacific has been found, with "sudden change" taking Place in the middle 1990's and confirmed that "decadal ENSO" really exists.3)Before 1990's, the warm phase of PDO weaken gradually from winter to summer with influencing atmospheric circulation in previous winter, spring and summer, which generated a strong abnormality of cyclonic circulation from Mongolia to Northeast China advantageous to enhance vortex in northeast China.The eonvective activities are intensified from the area around the PhiliPPines to the Indo-China Peninsula through the South China Sea,the western Paeifie subtroPical high may shift nortbward,the summer rainfall may be below normal in the Yangtze River valley and theHuaihe River valley and it may be below normal in Northern China.(2)The analysis of SSH abnormlity and its relationship with 850hPa wind field and summer precipitation in China indicate:1)when the tropic Pacific SSH is of ENSO-pattern anomaly in the previous winter, it can be predicted that the precipitation will significantly be more than normal over the south of the Yangtze Riv-er, especially Dongting Lake and Poyang Lake region, eastern Qinghai-Tibet Plateau, Yangtze-Huai River Valley, eastern part of Neimen and less than normal over the southern South China, the North China and loop area in the coming year summer. The mechanism to forming the rainfall distribution is similar to ST.2)From the overall trend of 30a, temporal and spatial characteristics of SSH shows a resemblance to ST. SSH's over the tropical Pacific relationship with East Asia atmosphericcirculation and summer precipitation in China are discussed further and obtain results analogous to ST.(3)The analysis of MLD abnormlity and its relationship with 850hPa wind field and summer precipitation in China indicate:1)when El Nino event occurs in autumn and winter, the precipitation will significantly be more than normal over the south of the Yangtze River, especially south of, Dongting Lake and Poyang Lake, and less than normal over the southern South China in the coming year summer when is the decay period of the El Nino. The mechanism to forming the rainfall distribution is similar to ST and SSH.2)From the overall trend of 30a, temporal and spatial characteristics of MLD shows a resemblance to ST and SSH. MLD'S ove the tropical Pacific relation-ship with East Asia atmosphericcirculation and summer precipitation in China are discussed further and obtain results analogous to ST and SSH.