Quantitative Evaluation of Wavelet Analysis Method for Turbulent Flux Calculation of Non‐Stationary Series
Quantitative Evaluation of Wavelet Analysis Method for Turbulent Flux Calculation of Non‐Stationary Series
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DOI：
10.1029/2022gl101591
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发表时间：
2023-03
影响因子：
5.2
通讯作者：
Yubin Li;Yujie Wu;Jie Tang;Ping Zhu;Zhiqiu Gao;Yuanjian Yang
中科院分区：
文献类型：
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作者：
Yubin Li;Yujie Wu;Jie Tang;Ping Zhu;Zhiqiu Gao;Yuanjian Yang
本文对涡度相关法和小波分析法计算湍流通量的不确定性进行了评估。首先，通过将模拟大涡旋、湍流不对称性和不对称性的周期波和随机扰动添加到观测的稳态数据集中来构造非稳态数据集，并使用理论上的“真实”通量来定量评估这些方法的准确性。结果表明，EC和Morlet小波在不同的非平稳等级下产生的偏差范围为“真实”值的50%-100%，而墨西哥帽（Mexhat）小波的偏差约为它们的一半。此外，Mexhat导出的通量与基准值有很高的相关性，通过添加校正系数，这两个值的回归斜率可以提高到接近1。结果表明，使用Mexhat小波方法在非平稳条件下以高精度计算湍流通量的潜力。
This study evaluates the uncertainties of turbulent flux calculation using eddy covariance (EC) and wavelet analysis (WA) methods. First, a non‐stationary data set is concocted by adding periodic waves and random perturbations which mimic the large eddies, turbulent intermittency, and asymmetry into an observational stationary data set, and the theoretical “true” fluxes are used to quantitatively evaluate the accuracy of these methods. Results show that EC and Morlet‐wavelet generate biases ranging 50%–100% of the “true” values at different non‐stationarity grades, whereas the Mexican hat (Mexhat) wavelet has a bias of about half of them. Furthermore, there is a high correlation of the Mexhat‐derived fluxes to the benchmark values, the regression slopes of the values of these two can be improved to almost 1 by adding a correction coefficient. The results suggest the potential of using the Mexhat‐wavelet method to calculate turbulent fluxes with high accuracy under non‐stationary conditions.