INTERDECADAL TRANSITIONS AND TWO EXCEPTIONAL YEARS OF JUNE PRECIPITATION OVER SOUTH CHINA

An analysis of high-resolution precipitation data for 1978-2006 indicates that the precipitation over southern China in June experienced a low-value period in 1980-1989 and a high-value period in 1992-2001.It also reveals that exceptional heavy(light) precipitation occurred in June 2005(2004) since 1951.For these variations on both interdecadal and interannual timescales,fairly uniform anomalies of precipitation appeared over Vietnam,southern China,and southeastern China.Corresponding to positive(negative) precipitation anomalies,anomalous southeasterly(northwesterly) flow at 850 hPa reached Vietnam and anomalous southwesterly(northeasterly) flow expanded to the coastal regions of southern and southeastern China.Precedent to the positive(negative) precipitation anomalies during 1992-2001(1980-1989),positive(negative) anomalies of sea surface temperature appeared over the extratropical northwestern Pacific in the winter and spring seasons,associated with a strong(weak) extension of the warm Kuroshio Current that affects the coastal region of eastern China.The above-normal precipitation in June 2005 was associated with the pseudo-ENSO event in the previous winter,and the below-normal precipitation in June 2004 was associated with negative anomalies of sea surface temperature over the equatorial central Pacific and positive anomalies over the equatorial western and eastern Pacific.

An analysis of high-resolution precipitation data for 1978-2006 indicates that the precipitation over southern China in June experienced a low-value period in 1980-1989 and a high-value period in 1992-2001. It also reveals that exceptional heavy （light） precipitation occurred in June 2005 （2004） since 1951. For these variations on both interdecadal and interarmual timescales, fairly uniform anomalies of precipitation appeared over Vietnam, southern China, and southeastern China. Corresponding to positive （negative） precipitation anomalies, anomalous southeasterly （northwesterly） flow at 850 hPa reached Vietnam and anomalous southwesterly （northeasterly） flow expanded to the coastal regions of southern and southeastern China. Precedent to the positive （negative） precipitation anomalies during 1992-2001 （1980-1989）, positive （negative） anomalies of sea surface temperature appeared over the extratropical northwestern Pacific in the winter and spring seasons, associated with a strong （weak） extension of the warm Kuroshio Current that affects the coastal region of eastern China. The above-normal precipitation in June 2005 was associated with the pseudo-ENSO event in the previous winter, and the below-normal precipitation in June 2004 was associated with negative anomalies of sea surface temperature over the equatorial central Pacific and positive anomalies over the equatorial western and eastern Pacific.