近50a华东地区夏季极端降水事件的年代际变化

利用中国华东地区90站点1960--2009年夏季（6—8月）逐日降水资料，分析了近50a来华东地区各类极端降水事件的强度和发生频次的年代际变化。结果表明：华东地区极端降水事件年代际变化特征明显。近20a来，不论是极端降水事件的平均强度还是发生次数都要明显高于前30a；1990年代是极端事件多发且强度较强的年代；华东区域极端强降水过程事件的连续降水日数多在9d以下，而极端连续降水日数事件基本在9d以上；较之华东地区其他区域，福建地区存在更多的强度大、持续久的降水过程；华东地区最大极端降水量出现在江西北部与安徽南部的交界区域。极端降水事件频发带存在南北摆动的年代际变化，这一特征在极端日降水事件和极端强降水过程事件上表现得更为明显。同时，存在两个极端事件频发带，分别位于长江流域附近。在后3个年代，这两个频发带呈现出分一合一分的年代际变化特征。

Interdecadal changes of summertime precipitation extremes in East China in recent five decades

Using the daily rainfall data of 90 stations in East China from 1960 to 2009 ,the interdecadal changes of occurrence frequency and intensity of precipitation extremes in boreal summer （June-July- August） in East China in recent five decades are investigated. Results show that there are significant in- terdecadal changes of the precipitation extremes in the past 50 years. In recent 20 .years, the precipitation extremes occur more frequently than those in the earlier 30 years, and more and stronger extreme pre- cipitation events are observed in 1990s. In East China, the extreme events of precipitation processes last usually less than 9 days. However, the extreme events of continuous rainy days last usually more than 9 days. Relative to the other regions in East China, the more precipitation processes with higher persist- ence and stronger intensity occur in Fujian Province. The largest extreme rainfall appear in conjunction part of Jiangxi and Anhui provinces. Zones where the extreme events of precipitation occur more fre- quently moves interdecadally in meridional direction. The north-south shifts of the zones mentioned a- bove are also observed in the extreme events of daily precipitation and precipitation processes. Interest- ingly, there exist two frequent occurrence zones of precipitation extreme events over the south and north of Yangtze River, respectively. The two zones get closer to each other and even merge into one in some decades, and get distant from each other in other decades, which is observed in the last three decades.