基于小波多尺度变换的渭河水沙演变规律研究

Evolution Law of the Runoff and Sediment Discharge of the Weihe River Based on Wavelet Multi-Scale Transform

关中平原地区是推动陕西省经济社会发展的引擎,其生产总值占陕西省的70%以上,但是水资源短缺、时空分布不均、河流含沙量高等问题严重制约其经济社会的发展。运用小波变换、滑动t检验、累积距平以及Yamamoto、Mann-Kendall等方法系统分析了1935~2011年渭河水沙序列演变规律。研究结果显示:77 a间除20世纪70年代、80年代外,其它年代渭河华县站水沙变化波动下降的匹配趋势均一致,其中径流量减流速度大于输沙量减沙速度;渭河水沙序列周期变化不一,径流量变化的主周期依次为38 a、14 a、4 a,输沙量变化的主周期依次为15 a、49 a、43 a、4 a;除输沙量49 a变化周期外,其他水沙变化周期大致相近;由于渭河输沙量变化所受气候及人类活动的影响远较径流量复杂,加之水沙异源,所以渭河华县站输沙量周期变化及突变点分布情况比径流量变化复杂,且其第一主周期变化呈现独特的变化态势。

Guanzhong Plain is the economic engine of Shaanxi Province, which contributed 70% GDP to Shaanxi Province, and however problems such as lower water resources per capita, uneven distribution, higher river sediment concentration restrict its economic and social development. In order to reveal the evolution law of multi-scale the runoff and sediment discharge of the Weihe River,to offer provide theoretical basis for comprehensive utilization of water resources, water and soil erosion for guanzhong area, the Weihe River Basin,and the Yellow River Basin. In this article, Morlet complex wavelet function was used to transform the sequence of runoff and sediment discharge of Huaxian country station during 1935-2011, and combined with the analysis of measured values of the runoffand sediment discharge, to know well periodic variation and catastrophe point of the runoff and sediment discharge of the Weihe River, the methods of moving t test, accumulative anomaly and Yamamoto was applied to detect catastrophe point. The findings of research indicate that the change of runoff and sediment discharge of the Weihe River have the fluctuating descending tendency from1935 to 2011, there are multi-time scales periodic variation of the runoff and sediment discharge of the Weihe River, the main cycles of runoff are 38 a,14 a and 4 a, apart from the 49 a cycle of sediment discharge, other main cycles are similar apporximately, while the main cycles of sediment discharge are 15 a,49 a,43 a and 4 a;catastrophe points of the runoff and sediment discharge in small-scale are much more than big-scale′ s, the amount and situation of catastrophe points of the runoff and sediment discharge in different scale are different;Because of climate and mankind activity the change of sediment discharge more complex than runoff, in addition to the sources of sediment and water are different, so the periodic variation and catastrophe points of sediment more complex than runoff, and the first main cycles of sediment discharge has unique change trend.