近40 a重庆地区夏季降水的气候特征

CLIMATE FEATURES OF SUMMER PRECIPITATION IN CHONGQING REGION DURING 40 a

利用重庆地区34个测站,1960～2000年6～8月降水量资料,采用EOF,REOF,小波分析及突变分析等方法,对重庆地区夏季降水量的空间分布特征和时间演变规律进行了诊断分析研究.结果表明:重庆地区夏季降水的空间分布既有整体一致的性质,也存在南部和北部及东部和西部相反变化的差异,并且可以把整个重庆地区划分为四个主要的降水分布型:渝西北区、渝东北区、渝东南区及渝西南区.各分布型代表站资料反映出近40 a来,重庆地区夏季降水有增加趋势,并且存在着22 a、14 a、及2～4 a的周期变化.

Using 1960-2000 a summer （Jun. -Aug. ） precipitation data over 34 stations of Chongqing region, the temporal and spatial variability features are studied by applying the methods of EOF, REOF, wavelet analysis. The results indicate that the summer precipitation distribution exhibits the common features as well as the spatial differences, which can be classified into four types as Northwest, Northeast, Southeast and Southwest Chongqing. There exists wetter trend over Chongqing region in the last 40 years. Generally, summer precipitation presents upward tendency and the periods of 22 a, 14a and 244 a. The abrupt change occurred in about 1988-1989.