State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an 710048, China.
State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an 710048, China.
Sci Total Environ. 2020 Apr 1;711:135189. doi: 10.1016/j.scitotenv.2019.135189. Epub 2019 Nov 22.
The Budyko parameter, which controls the shape of Budyko curve, represents the superimposed impact of various periodic factors (including climatic factors, catchment characteristics, large-scale climate patterns, solar activity and anthropogenic activity) on the watershed water-energy balance dynamics. However, this superimposition is not conducive to identifying the drivers of Budyko parameter dynamics at different time scales, and thus affects parameter estimation. Here we obtain the Budyko parameter ω in the Fu's equation (one form of the Budyko framework) for the Wei River Basin (WRB), and then adopt the Empirical Mode Decomposition method to reveal the relationships between factors and ω series at multiple time scales by considering the interplay among different influencing factors. Results indicate that (1) ω series are decomposed into 4-, 12-, 20-, exceeding 20-year time scale oscillations and a residual component with an significantly increasing trend in the mainstream of the WRB, a non-significantly decreasing trend in the Jing River Basin and Beiluo River Basin; (2) by analyzing the residual trend component, evaporation ratio, soil moisture and effective irrigated area are found to induce the significant increase of ω in the upstream of the WRB, whereas that in the middle and lower reaches is dominated by baseflow and Niño 3.4; (3) ω dynamics at the 4-year time scale is dominated by evaporation ratio, aridity index, baseflow and soil moisture; baseflow, Pacific Decadal Oscillation (PDO) and sunspots attribute to the dynamics at 12-year time scale; all the factors except baseflow and soil moisture contribute to the dynamics at 20- or exceeding 20-year time scales. The results of this study will help identify the connection between watershed water-energy balance dynamics and changing environment at multiple time scales, and also be beneficial for guiding water resources management and ecological development planning on the Loess Plateau.
博丢克参数控制着博丢克曲线的形状，它代表了各种周期性因素（包括气候因素、集水区特征、大尺度气候模式、太阳活动和人为活动）对流域水-能量平衡动态的综合影响。然而，这种叠加不利于识别不同时间尺度上博丢克参数动态的驱动因素，从而影响参数估计。在这里，我们获得了傅里叶方程（博丢克框架的一种形式）中渭河流域（WRB）的博丢克参数 ω，然后采用经验模态分解方法，通过考虑不同影响因素之间的相互作用，揭示了多时间尺度上因素与 ω 序列之间的关系。结果表明：（1）ω 序列在 WRB 主流中被分解为 4 年、12 年、20 年及以上时间尺度的振荡和一个呈显著增加趋势的剩余分量，在泾河流域和北洛河流域呈非显著减少趋势；（2）通过分析剩余趋势分量，发现蒸发比、土壤湿度和有效灌溉面积导致 WRB 上游 ω 的显著增加，而中下游则主要由基流和尼诺 3.4 主导；（3）ω 在 4 年时间尺度上的动态主要由蒸发比、干旱指数、基流和土壤湿度主导；基流、太平洋十年涛动（PDO）和太阳黑子与 12 年时间尺度上的动态有关；除基流和土壤湿度外，所有因素都有助于 20 年或 20 年以上时间尺度上的动态。本研究的结果将有助于识别流域水-能量平衡动态与多时间尺度变化环境之间的联系，也有利于指导黄土高原水资源管理和生态发展规划。
