从日波动到年水文周期：基于小波的塞内加尔河水电入流非平稳季节性分析
From Daily Fluctuations to Annual Hydrological Cycles: A Wavelet-Based Analysis of Nonstationary Seasonality in Senegal River Hydropower Inflows
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中文总结 AI 辅助
本研究结合傅里叶与小波分析的可复现框架，分析塞内加尔河三个站点近60年日入流的非平稳季节性，明确年周期对应D8细节层等关键结论，为水电入流情景生成提供可迁移方法。
中文摘要 AI 辅助
本研究提出了一种可复现的框架，结合傅里叶分析与小波分析，基于1961-2020年近60年间的65631条日观测数据，对塞内加尔河三个站点（巴芬马卡纳、费卢、古伊纳）的日入流季节性展开研究。研究采用谐波回归、韦尔奇谱分析、平稳小波分解、Morlet连续小波变换、趋势与变点检验及交叉小波相干性等方法，结果显示年周期主要对应D8细节层（约256-512天），而非4级近似层；在测试的四类小波中，Haar小波被选为最优拟合。D8分量占总能量的18.85%-19.89%，而傅里叶谐波模型可解释日入流变异性的73.3%-78.7%。平均季节峰值出现在9月（约第252-254天），且三个站点间的年相干性极高（0.988-0.999），表明区域水文周期高度同步。研究未发现季节性强度、振幅或峰值时间存在稳健的单调趋势，但Pettitt检验检测到1971-1976年前后振幅或平均入流存在统计显著的转变，与区域状态转变一致，不过需独立的降雨及大坝运行数据予以验证。该框架为在MOSSHOOS-Plan4RES中生成入流情景提供了透明基础，且可迁移至其他数据稀缺的水电系统。
英文摘要
This study presents a reproducible framework combining Fourier and wavelet analysis to examine the seasonality of daily inflows at three sites on the Senegal River (Bafing Makana, Felou, Gouina), based on 65,631 daily observations spanning nearly 60 years (1961-2020). Using harmonic regression, Welch spectral analysis, stationary wavelet decomposition, Morlet continuous wavelet transforms, trend and change-point tests, and cross-wavelet coherence, the authors show that the annual cycle corresponds mainly to the D8 detail level (roughly 256-512 days), rather than a level-4 approximation. The Haar wavelet was selected as the best fit among four families tested. The D8 component accounts for 18.85-19.89% of total energy, while Fourier harmonic models explain 73.3-78.7% of daily inflow variability. The average seasonal peak occurs in September (around days 252-254), and annual coherence across the three sites is exceptionally high (0.988-0.999), indicating a highly synchronized regional hydrological cycle. No robust monotonic trend was found in seasonality strength, amplitude, or peak timing. However, Pettitt tests detected a statistically significant shift in amplitude or mean inflow around 1971-1976, consistent with a regional regime transition, though confirming this would require independent rainfall and dam-operation data. The framework offers a transparent basis for generating inflow scenarios within MOSSHOOS-Plan4RES and is transferable to other data-scarce hydropower systems.
