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非线性是现代水文学研究的重要前沿问题之一,对揭示水文系统变化规律及其复杂性具有重要意义。基于开都河源流区气象和水文站1960-2012年实测数据,采用集合经验模态分解方法,对研究期内开都河年径流时间序列进行多尺度分析,并探讨其在不同时间尺度上的非线性变化特征及其对气候因子的多尺度响应。研究结果表明:(1)近50年来,开都河年径流整体上呈现出显著的非线性增加趋势,且其变化在年际尺度上表现出准2~3a和准4~5a的周期性波动,在年代际尺度上表现出准10~11a和准26~27a的周期性变化;(2)各周期分量的方差贡献率表明,年际振荡在径流长期变化中占据主导地位,年代际尺度在径流变化过程中也起着重要作用;(3)重构的径流年际变化能够较为详细地描述原始径流序列在整个研究时段的波动状况,二者在变化趋势上基本是一致的;重构的径流年代际变化则有效揭示了开都河径流量在1995年出现了由负距平到正距平的转折;(4)在重构的年际尺度和年代际尺度上,降水与径流的相关性都强于气温、潜在蒸发与径流的相关性,说明降水是影响开都河径流变化的决定性因素;而在年代际尺度上降水、气温和潜在蒸发的相关性都要明显强于年际尺度,表明年代际尺度是评价该区径流对气候波动响应过程的较佳尺度。
Nonlinearity is one of the most important frontier issues in the study of modern hydrology and is of great significance for revealing the changing laws and complexity of hydrological systems. Based on the measured data of meteorological and hydrological stations in the basin from 1960 to 2012 in the catchment area, a set empirical mode decomposition method was used to analyze the multi-scale annual runoff time series of the Kaidu River during the study period, Nonlinear variation and its multi - scale response to climatic factors. The results show that: (1) In the recent 50 years, annual runoff in Kaidu River shows a significant nonlinear increase trend, and its variation shows periodic fluctuations of 2 ~ 3a and 4 ~ 5a on the interannual scale (2) The contribution rate of variance of each periodic component shows that the interannual oscillation dominates in the long-term variation of runoff, and the decadal scale is in the range of (3) The reconstructed interannual variation of runoff can describe the fluctuation of the original runoff sequence in a more detailed way throughout the study period, and both of them are basically consistent in the trend of change. The reconstructed Interdecadal variation of runoff effectively revealed the turning of negative anomaly to positive anomaly in the flow of the Kaidu River in 1995. (4) On the reconstructed interdecadal and interdecadal scales, the correlation between precipitation and runoff Both of them are stronger than temperature and the correlation between potential evaporation and runoff shows that precipitation is the decisive factor affecting runoff change in Kaidu River. On the interdecadal scale, the correlation between precipitation, temperature and potential evaporation is obviously stronger than inter-annual scale , Indicating that the decadal scale is to evaluate this Runoff preferred scales climatic fluctuations in response process.