乌江流域降雨和径流的周期变化

Periodic Changes of the Precipitation and Runoff in Wu River Watershed

开展乌江流域降雨和径流实测序列的多尺度时频分析,对乌江流域水资源的合理利用以及解决该地区的季节性干旱具有一定的意义。本文采用小波变换方法对乌江流域年均降雨量和径流量变化的周期性进行分析,研究结果为:乌江流域1956—2000年降雨量和径流量均具有中等程度的变异,且径流量的增加速率大于降雨量;降雨和径流存在明显的年际和年代变化,且降雨量和径流量的变化周期具有同步性;降雨量的主周期依次为41年、25年、11年和5年,而25年尺度的周期具有全局性;径流量的变化周期大致为40年、25年、16年和6年,而25年尺度的周期具有全局性。

This study made an analysis of the periods of annual precipitation and annual natural runoff in Wu river area by using morlet wavelet transform.The results showed that from 1956 to 2000,the rainfall and runoff of Wu river area changed moderately,but the increasing rate of runoff was larger than that of the rainfall.Both rainfall and runoff had obviously periodic patterns.The major periods of rainfall change were about 41 years,25 years,11 years and 5 years,25 year period was general.The periods of runoff change were about 40 years,25 years,16 years and 6 years,25 year period was also general.The results were tested by wavelet variance and found mainly affected by solar activity.The results are helpful to rational use of water resources and resolution of seasonal drought in Wu river area.