Variation characteristics of extreme precipitation in eastern China and its relationship with atmospheric stability

By using the daily precipitation data of 392 stations over eastern China from 1959 to 2008, which passed 5% quality control,the characteristics of extreme precipitation are studied. The studied time period is divided into 1948—1976 and 1977—2008,and the differences of MPV( moist potential vorticity) and atmospheric stability are discussed during the two periods. Results indicate that the significant south-north differences of extreme precipitation are found over eastern China. The extreme precipitation and its percentage decrease in north of eastern China,especially in east of North China,which increase in south of eastern China,especially in the middle and lower reaches of Yangtze River. MPV exhibits a reduction in north of eastern China and an increase in south of eastern China. Both the convective stability and the baroclinic stability weaken in the south and strengthen in the north. The siginificant variation of atmospheric property is a main reason of the change trend of the extreme precipitation over eastern China. The further study demonstrates that the temperature anomalies are negative at 300 hPa over the high latitudes after 1976,which leads to the difference of thermodynamic properties of upper air in eastern China and affects the convective stability. Meanwhile,the negative temperature anomalies make the decrease( in-crease) of west wind in the north( south) side of the cold center,and the baroclinic stability weakens( strengthens) accordingly.