气候变化背景下滇中引水工程水源区与受水区 降水丰枯遭遇分析

基于历史实测降水数据与全球气候模型预估数据,使用 Morlet 小波方法分析滇中引水工程水源区与受水区 降水序列的周期变化和未来的降水趋势。同时,采用 Copula 函数计算历史时期（1960—2021 年）与未来时期 （2022—2100 年）水源区与受水区降水丰枯异步或丰枯同步的概率。结果表明：1960—2021 年降水序列存在 26~39?a、18~25?a、4~7?a 的 3 类时间尺度的周期变化,2022—2100 年降水序列存在 38~55?a、18~30?a、5~12?a 的 3 类时间尺度的周期变化,降水量呈现“多—少—多”的循环交替,预计未来 10~20?a 将持续处于降水较多的时期; 过去 62?a,水源区和受水区降水丰枯异步频率 36.4%,同期丰水年频率为 25.3%,同期枯水年频率小于 30%,水源区 和受水区具有水量互补的引水条件,两区域之间存在着水量补偿特征;与历史丰枯遭遇对比,未来降水量丰枯同 步频率均呈现减小的趋势,丰枯异步呈现增加的趋势,同枯和源枯受丰的频率减少,未来有利于调水的降水丰枯 组合概率平均增加 3.75%;在近、中、远期预估中,从 SSP1-2.6 情景过渡到 SSP5-8.5 情景,SSP5-8.5 情景下降水量 丰枯异步频率比 SSP1-2.6 情景大,说明水源区与受水区的降水区域差异变大,降水时空差异更加显著。通过对滇 中引水工程水源区与受水区降水量丰枯遭遇的综合分析、定量评估和模拟预测,为滇中引水工程水资源调度协同 一体化提供数据支撑及参考依据。

Synchronous-asynchronous encounter probability of high-low precipitation between the water source and water receiving area in the Water Transfer Project in Central Yunnan under climate change

The analysis of synchronous-asynchronous encounter probability of high-low precipitation between the water source and water receiving area is an important basis for regulation of water resources project and rational water resources allocation. The inter-annual precipitation variation cycles and trends were analyzed by Morlet wavelet analysis of water source and receiving area of the Water Transfer Project in Central Yunnan (WTPCY) from 1960 to 2021. A Copula function was used to construct a joint distribution model of precipitation between the water source and the receiving area of WTPCY based on the historical measured and the shared socio-economic path (SSP1-2.6 and SSP5-8.5) of the International Coupled Model Comparison Program Phase 6 (CMIP 6) precipitation data from 2022 to 2100 . The probability of asynchronous or synchronous precipitation was calculated in the two regions. The results show that: (1) annual precipitation in the water source area of the WTPCY was larger than that in the receiving area, the inter-annual variation of precipitation was relatively small and the intra-annual distribution was more uniform than that in the receiving area. The precipitation sequence from 1960 to 2021 had periodic changes on three time scales of 26 ~39 a, 18~25 a and 4~7 a, respectively, and the precipitation sequence from 2022 to 2100 has periodic changes on three time scales of 38~55 a, 18~30 a and 5~12 a. The precipitation showed a cycle of "more-less-more" alternately. It is expected that the next 10~20 a will continue to be a period of high precipitation. (2) In the past 62 years, the precipitation asynchronous encounter probability between the water source area and the water receiving area was 36.4% and the precipitation synchronous encounter probability of high precipitation years was 25.3%. The precipitation synchronous encounter probability of low precipitation years was less than 30%, and the WTPCY have complementary water transfer conditions. (3) Compared with the baseline, the probability of precipitation synchronous encounters will decrease but asynchronous encounters will increase by different degrees in the SSP1-2.6 and SSP5-8.5 scenarios. Especially, the precipitation synchronous encounter probability of low precipitation years showed a decreasing trend, and the water source area had low precipitation years but the water receiving area had high precipitation years and encounter probability showed a decreasing trend. In summary, the probability conducive to water transfer of synchronous-asynchronous encounter probability about the WTPCY will increase obviously by 3.75%. (4) With the increase in economic development and intensity of human activities, it will lead to climate instability and more uneven spatial and temporal distribution of precipitation. In the near, medium, and long-term projections, the transition from the SSP1-2.6 scenario (sustainable development model) to the SSP5-8.5 scenario (high-intensity development model), the probability of precipitation asynchronous encounter under the SSP5-8.5 scenario may larger than SSP1-2.6 scenario, indicating that the regional differences in precipitation between the water source area and the water receiving area become larger and the spatial and temporal differences in precipitation become more significant. In the future, the precipitation and the probability conducive to water transfer of synchronous-asynchronous encounter probability about the WTPCY will increase obviously. These characteristics are conducive to the operation of the WTPCY. Through comprehensive analysis, quantitative assessment, and simulation prediction of the synchronous-asynchronous encounter probability about the WTPCY under climate change, it provides data support and a reference basis for the synergistic integration of water resources regulation in the WTPCY.