西江中游水沙序列的多时间尺度特征

小流域的水沙多时间尺度周期变化分析可为中长期水沙预测提供科学依据,为西江中游水沙序列的多尺度特征提供工程参考依据。选用红水河迁江站1957-2016年年径流和年输沙量数据资料,采用Mann-Kendall趋势检验、小波分析法和耦合关系模型,分析迁江站主要的水沙序列周期及其多时间尺度变化特征。结果表明:迁江站年水沙序列具有下降趋势,多尺度特征基本一致且存在主周期,人类活动、气候波动及水土保持措施等因素对水沙序列的变化有直接的影响。径流序列的第一主周期是25~30 a,第二主周期是13~24 a,第三主周期是3~12 a;输沙序列第一主周期是20~30 a,第二主周期是9~20 a,第三主周期是3~9 a。在5,16和28 a的时间尺度上,受生态环境及人类活动的影响,水沙序列产生较大紊乱,最终输沙序列相较于径流序列趋于稳定,其变化也滞后于径流序列。在耦合关系中,径流序列的R2为0.43,输沙序列的为0.71,输沙序列的显著性高于径流序列;且人类活动利用科学技术通过影响输沙系统,将原水沙系统的矛盾进行缓解乃至解决,使得西江中游水沙系统进入再生时期。

Multi-time-scale Characteristics of Water-sediment Series in the Middle Reaches of the Xijiang River

An analysis of multi-time-scale periodic changes of water and sediment in small watersheds can provide a scientific basis for medium and long-term water and sediment prediction,and provide an engineering reference for the multi-scale characteristics of water and sediment sequence in the middle reaches of the Xijiang River.The annual runoff and annual sediment transport data of the Qianjiang Station of the Hongshui River from 1957 to 2016 is selected,and the Mann-Kendall trend test,wavelet analysis and coupling relationship model are used to analyze the main water-sediment series cycle and its multiple time at Qianjiang Station Scale change characteristics.The results show that the annual water-sediment sequence at Qianjiang Station has a downward trend,the multi-scale characteristics are basically the same and the main cycle exists.Human activities,climate fluctuations and water and soil conservation measures have a direct impact on the changes of the water-sediment sequence.The first major cycle of the runoff sequence is 25~30 a,the second major cycle is 13~24 a,and the third major cycle is 3~12 a;the first major cycle of the sediment transport sequence is 20~30 a,and the second major cycle is 9~20 a,The third main period is 3~9 a.On the time scales of 5,16 and 28 a.Due to the influence of the ecological environment and human activities,the water-sediment sequence has become more turbulent,and the final sediment transport sequence tends to be stable compared to the runoff sequence,and its change is also lagging behind the runoff sequence.In the coupling relationship,R2 of the runoff sequence is 0.43,and the sediment transport sequence is 0.71.The significance of the sediment transport sequence is higher than that of the runoff sequence;and human activities use science and technology to alleviate the contradictions of the original water and sediment system by affecting the sediment transport system.Even the solution makes the water-sediment system in the middle reaches of the Xijiang River enter the regeneration period.