Characteristics and circulation background of extreme precipitation over East China.

Using the observed daily precipitation data across East China, this paper analyzes spatiotemporal changes of annual and seasonal extreme precipitation indices during 1960–2015. Effects of changes in atmospheric circulation on seasonal extremes were also detected by using the singular value decomposition method. Results show that amount of annual, spring and summer extreme precipitation over East China showed a significant increase with a maximum changing rate of 7.2, 3.2 and 5.4 mm decade⁻¹, and the stations with upward tendency mainly located in the southern part of East China. Preceding sea surface temperature of the Indian Ocean and the Equatorial Pacific Ocean shows great influences on spring extreme precipitation over East China through modulating anomalous anticyclones and winds, especially over the downstream of the south of East China. Summer extreme precipitation is statistically significantly correlated with the western North Pacific subtropical high (WPSH) and positive anomalies of 500 hPa geopotential heights. Anomalously strong WPSH combining with two blocking highs in mid-latitude regions tends to trigger more extreme precipitation events in the Yangtze River Basin but less in the Yellow River Basin. [ABSTRACT FROM AUTHOR]