华南前汛期极端降水气候变化特征及其与太平洋海温相关关系研究

Characteristics of Extreme Precipitation During the Pre-rainy Season in Southern China and Their Correlations with the Pacific SST

利用国家气象信息中心提供的89个华南代表气象站的1969—2013年逐日降水资料及NOAA重构延长的逐月海表温度(SST)资料,研究了华南前汛期极端降水的时间变化特征,以及太平洋海表温度与华南前汛期极端降水年际异常的相关关系,并定义了对华南前汛期极端降水具有指示意义的海表温度异常指数。主要结论:1)华南前汛期极端降水存在显著的年际变化以及年代际变化。20世纪90年代以来,华南前汛期发生极端旱涝的情况增多,此外,华南前汛期极端降水存在2个显著的突变年份。除降水强度外,其他各个极端降水指数在1977年存在一个突变,极端降水由多变少;在21世纪初存在另外一个极端降水由少到多的突变(除总降水量外)。2)定义的前冬太平洋海温异常指数与华南前汛期极端降水具有显著相关关系,该指数与El Ni觡o事件关系密切,当前冬该指数为正(负)或者发生El Ni觡o(La Ni觡a)现象时,则可预测次年华南前汛期极端降水异常也偏强(弱)。

Based on the 1969—2013 daily precipitation data of the 89 representative stations in Southern China provided by the National Meteorological Information Center, as well as the NOAA extend reconstruction monthly SST （sea surface temperature） data, the temporal variations of extreme precipitation during the pre-rainy season in Southern China and their correlations with Pacific SST were studied. Also, the SST anomaly index related to extreme precipitation during the pre-rainy season in Southern China was defined. The main conclusions were： 1） extreme precipitation during the pre-rainy season in Southern China presented significant inter annual and decadal variations. Since 1990s, the extreme precipitation cases increased significantly. There were two significantly sudden change periods of extreme precipitation in Southern China. The other extreme precipitation indexes presented mutation with less extreme precipitation cases in 1977. Another precipitation mutation year from less to more mutations was in the early 2000s. 2 ） there were significantly correlations between the SST anomaly index and extreme precipitation during the pre-rainy season in Southern China. The indexes were closely related to El Nino events. When SST showed the El Nino （La Nina） phenomenon, the indexes of the preceding winter were positive（negative）, which can be used to predict the enhanced （weakened） extreme precipitation in the next year.