Air temperature is an important factor affecting the changes in ice conditions in rivers and canals, and water diversion projects located in high latitudes must consider the safety and efficiency of water transfer in winter. They often adopt the method of reducing water flow to suppress the ice jam risk, but it also causes the temporal and spatial loss of water transfer benefits, aggravating the water shortage dilemma in winter. Taking the Middle Route of the South-to-North Water Diversion Project as an example, an ice prediction model based on the actual characteristics of the project is established by the numerical simulation method. This paper uses the model to display the ice condition evolutions in the project under different short-term air temperature changes and reveal the law of the freezing range of the canal system under the coupling of air temperatures, water temperatures, and water flows. Finally, a mode for improving the water transfer benefits in winter based on the short-term air temperature forecast is proposed. The study results indicate that the initial water temperature and 7-day air temperature probability are inversely proportional to the freezing range and ice cover thickness of the canal system, and the 7-day air temperature changes in the project can form an ice cover with a maximum thickness of 0.17 m, which is 8.5 times the thickness of the ice cover under actual air temperature conditions. The larger the water transfer flow in the canal system, the shorter the freezing range, but it may increase the risk of ice jam formation. The model can predict future ice development by inputting the current hydraulic data of the project and the future short-term air temperature forecast data, and the errors are acceptable. Combined with the mode for improving the water transfer benefits, the flexibility, safety, and comprehensive benefits of the project operation in winter can be effectively improved.

中文翻译：

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南水北调工程中线冰期气温短期变化对调水调度的影响分析


气温是影响河流和运河冰况变化的重要因素，位于高纬度地区的引水工程必须考虑冬季调水的安全性和效率。他们经常采用减少水流的方法来抑制冰塞风险，但这也造成了调水效益的时空损失，加剧了冬季缺水困境。以南水北调工程中线为例，采用数值模拟方法建立了基于工程实际特征的冰预测模型。本文利用该模型展示了不同短期气温变化下工程中的冰况演变，并揭示了气温、水温和水流耦合下运河系统冰冻范围的规律。最后，提出了一种基于短期气温预报的冬季调水效益提升模式。研究结果表明，初始水温和 7 d 气温概率与运河系统的冰冻范围和冰盖厚度成反比，工程中 7 d 气温变化可形成最大厚度为 0.17 m 的冰盖，是实际气温条件下冰盖厚度的 8.5 倍。运河系统中的输水流量越大，冻结范围越短，但可能会增加形成冰塞的风险。该模型可以通过输入项目当前水力数据和未来短期气温预报数据来预测未来的冰发展，误差是可以接受的。 结合提高调水效益的模式，可有效提高冬季工程运行的灵活性、安全性、综合效益。