Abstract:Based on the rotated empirical orthogonal function (REOF) method, the precipitation patterns during the “Dragon Boat Water” from 1961 to 2009 are analyzed. What’s more, the spatial and temporal characteristics are discussed by adopting linear tendency estimation, experimental mode decomposition (EMD), Morlet wavelet analysis and Mann Kendall test. The results show that there are three kinds preferred precipitation patterns in Southeast Coast, the North region and Southwest Coast, respectively, and all of them show 6-8 year periodic oscillations. Southeast Coast has decreasing trend in precipitation, while the North region and Southwest Coast share an increasing trend in the past 49 years. However, the precipitation “dragon boat water” has occurred more frequently in the North region since mid 1990s, and the rainfalls in Southeast and Southwest Coast have shown positive anomalies in recent several years. Two abrupt jumps occurred in mid 1970s and early 1990s in Southeast Coast and the North region, respectively, but there was no obvious change in Southwest Coast. Finally, the different atmospheric circulation features are compared from the aspects of Northwest Pacific subtropical high, blocking high, monsoon trough, low layer shear, vertical velocity speed and the total water vapor transport.