长江上游降水特征及时空演变规律

基于长江上游1960年-2014年80个国家气象站的降水量资料,统计分析了长江上游降水量特征,并且通过绘制空间分布图,采用Mann-Kendall法、Pettitt法、Morlet小波分析法检验降水量时间序列,综合分析了长江上游降水量的时空演变特征。结果表明,长江上游1960年-2014年多年平均降水量为900.8mm,平均年降水总量为8 925.1m~3,降水量年际变化大,年降水量极值比为1.5,冬季极值比达3.9,降水量年内分布很不均匀,汛期占80%以上;空间上,长江上游降水量呈现东南部降水量大,西北部小的分布特征;时间上,长江上游年降水量总体上呈现显著的下降趋势,年降水量在1985年发生了突变,长江上游年降水量变化周期由强到弱依次为28a、13a、8a,各分区变化周期以28a为主。

Characteristics of precipitation in upper reaches of the Yangtze River and its temporal and spatial evolution

Study on the characteristics of precipitation and its temporal and spatial evolution is of an important guiding significance for the development and utilization of water resources in the basin. Based on the precipitation data (1960-2014) from 80 meteorological stations in upper reaches of the Yangtze River, we studied the characteristics of precipitation. Besides, the temporal and spatial evolution was analyzed by drawing the spatial distribution map and using Mann-Kendall test, Pettitt test, Morlet wavelet analysis method. The results showed that, during 1960 to 2014, the mean annual precipitation depth of upper reaches of the Yangtze River was 900.8 mm and the mean annual precipitation volume was 8925.1 m3, the annual variation of precipitation was great, the ratio of extreme annual precipitation was 1.5 and reached 3.9 in winter, monthly and the seasonal mean precipitation was very uneven, and the precipitation in flood season accounted for more than 80%; spatially, precipitation was large in southeast and small in northwest; temporally, significant negative trend was detected in annual precipitation in upper reaches of the Yangtze River, and the abrupt change took place in 1985, the primary period of precipitation in upper reaches of the Yangtze River was 28a, 13a, 8a in the descending order of strength, and the period of precipitation in the partitions was mainly 28a.