1961～2006年江淮流域极端降水事件变化特征

Temporal and Spatial Variation Characteristics of Extreme Precipitation Events in the Yangtze and Huaihe River Basin of China from 1961 to 2006

利用1961~2006年江淮流域降水资料,计算了6种极端降水指数,分析了江淮流域极端降水的时空变化特征。极端降水指数除了大于10 mm天数呈微弱下降趋势外,其他极端降水指数均为上升趋势,其中非常湿天降水量和极端湿天降水量上升趋势最明显。在年代际变化方面,极端降水出现了气候变得更加湿润的特点,但是这种增加趋势并不明显。在极端降水指数空间分布方面,极端降水指数在不同地区的变化情况并不相同,日最大降水日量和连续5 d最大降水量在江淮流域中部和西南部为增加趋势,在江浙的沿海和西北地区为减少趋势。降水日数在江淮流域的北部和西部地区均为减少趋势,而在长江中下游及以南地区为增加趋势。非常湿天降水量和极端湿天降水量则除了在河南和陕西部分地区是减少趋势外,其他地区呈一致的上升趋势。

Based on the daily precipitation data in the Yangtze and Huaihe River Basin from 1961 to 2006, six extreme precipitation indices in the Yangtze and Huaihe River Basin were calculated and the temporal and spatial characteristics of extreme precipitation events in the Yangtze and Huaihe River Basin were analyzed. Except the days with the rainfall of mere than 10 mm, other extreme precipitation indices all showed the rising trend. The rising trend of the rainfall of very wet day and the rainfall of extremely very wet day were most significaut. From the decadal change aspect, the extreme rainfall showed the characteristics of wet climate, but the increasing trend was not obvious. From the spatial distribution of extreme precipitation indices, extreme precipitation indices had different change situations in various regions. The daily maximum rainfall and maximum rainfall during the continuous five daysshowed an increasing tread in middle and southwest of Yangtze and Huaihe River Basin, but they were opposite in the coastal and northeast areas of Jiangsu and Zhejiang. The rainfall days in the north and west areas of Yangtze and Huaihe River Basin showed a decreasing trend and that in the middle, lower and south of Yangtze Region showed an increasing trend. Except Henan Province and part of Shanxi Province, the rainfall of very wet day and extremely wet day in other regions all showed a rising trend.