基于气象-水文-水动力耦合数值模型的三峡水库动库容调洪演算研究

The dynamic storage capacity calculation of the Three Gorges Reservoir under the changing environment has always been a key technical problem for the safe and stable operation of the Three Gorges Power Station and the safety of the middle and lower reaches of the Yangtze River. Aiming at the problem that the traditional lumped model is difficult to simulate the different rainfall effects of the Three Gorges Reservoir, a numerical weather prediction model suitable for the Three Gorges Reservoir interval is established, and the high-precision downscaling method from coarse grid to fine mesh is studied to carry out ensemble precipitation prediction of a parameterized scheme and different initial field. The high-precision grid rainfall prediction and the distributed hydrological model are coupled to simulate the flow generation process in the basin. At the same time, because the Three Gorges Reservoir is a typical large-scale river-type reservoir, the floods are scattered into the reservoir from the periphery of the reservoir. The wedge-shaped reservoir capacity formed by the backwater above the reservoir level plays an important role in regulating the flood. By considering the influence of dynamic storage capacity, the hydrological-hydrodynamic coupling numerical model of the Three Gorges Reservoir is established to quantitatively analyze the coupling relationship between reservoir water inflow, inflow and outflow, and water level in front of the dam, and further reveal the dynamic reservoir capacity and the response mechanism of the water level in front of the dam. The high-precision prediction and warning of the water level in front of the reservoir dam further enhances the operation and management level of the Three Gorges Reservoir and safeguards the Yangtze River.

变化环境下的三峡水库动库容调洪演算一直是三峡电站安全稳定运行、保障长江中下游安澜的关键技术难题。针对传统的集总式模型难以模拟三峡水库不同降雨落区带来影响的问题，建立适用于三峡水库区间的数值天气预报模式，研究从粗网格到细网格的高精度降尺度方法，进行不同初始场和参数化方案的降水集合预报，将高精度网格降雨预报和分布式水文模型耦合，进行三峡水库区间产汇流过程精细化模拟。同时，由于三峡水库属于典型的大型河道型水库，洪水从水库周边分散汇入水库，水库水平面以上回水形成的楔形库容对洪水起着重要的调节作用，通过考虑动库容影响，建立三峡水库水文水动力学耦合数值模型，定量分析水库雍水、出入库流量和坝前水位的耦合关系，揭示动库容与坝前水位的响应机理，进行三峡水库坝前水位的高精度预测预警，进一步提升三峡水库运行管理水平，保障长江安澜。

三峡水库动库容调洪演算一直是三峡水库安全稳定运行、综合效益持续发挥的关键技术难题。河道型水库的动库容演算涉及到气象预报、水文预报、水动力学模拟等多门学科，现有的三峡水库八段动库容演算方法缺乏准确模拟库区降雨径流时空演变过程的能力，气象、水文、水动力相互割裂，难以满足水库精细化调度的需要，迫切需要从新的模型、方法和技术层面开展进一步研究。.围绕三峡水库动库容调洪演算面临的关键技术问题，本项目主要从三峡库区数值天气模式、分布式水文模型建模、水动力模型建模、气象水文水动力耦合模型及动库容特性研究等方面开展相关研究，主要在以下两个方面取得了创新性成果：（1）优选了三峡库区数值天气预报模式参数化组合方案和分布式水文模型参数，研究了气象模式与水文模型不同时空网格间的高精度降尺度和高效率匹配方法，建立了耦合数值天气模式的三峡库区分布式水文模型。（2）考虑动库容影响，研究了水动力模型与水文模型无缝嵌套方法，建立了三峡水库水文水动力学耦合数值模型，定量了分析水库雍水、出入库流量和坝前水位的耦合关系，进一步揭示了动库容与坝前水位的响应机理。.本项目研究成果可以直接应用于指导三峡水库调度运行，提高三峡电站精细化调度水平，具有显著的社会经济效益，而且本项目针对的是水库动库容调洪演算的共性问题，建立的相关模型具有较好的通用性，在获取长江上游其他大型水库少量数据情况下，即可完成对目标区域的建模，具有较好的推广潜力与前景。