气候变化下长江黄河上游源区径流丰枯遭遇研究

Study on runoff abundance and depletion encounters in the upper reaches of the Yangtze and Yellow Rivers under climate change

摘要

【目的】长江黄河上游源区位于青藏高原东部，是其主要产水区和水源涵养区，分析气候变化对位于该区域的跨流域调水工程水源区和受水区来水丰枯遭遇概率影响，进而对提高工程规划设计与调度运行的效益提供理论支撑。【方法】利用二维Copula函数构建了径流丰枯遭遇概率计算模型，分析了过去40年长江黄河上游源区径流丰枯遭遇概率的特征。利用分布式水文模型与气候模式，预估了到本世纪中和到21世纪末长江黄河上游源区径流丰枯遭遇概率的变化趋势及利于调水概率对气候变化的响应特征。【结果】研究区流域历史期(1978—2020年)年径流量总体呈增加趋势，夏秋两季径流量波动较大(-3.29~11.78 m³·s^-1·a^-1),具有明显季节特征，其中金沙江流域夏秋径流量增加速率最大，总体高于黄河源径流量变化趋势(-2.3~0.73 m³·s^-1·a^-1),符合调水需求。年尺度、汛期尺度径流量丰枯同步频率总体上大于丰枯异步频率，非汛期尺度则小于异步频率，利于调水概率均在68%~75%间，保障了供水的可能性。未来整体上年、汛期利于调水概率总体上高于历史时期(3.53%~5.44%),非汛期尺度SSP245预估期、SSP585近期利于调水概率则低于历史期(-1.57%~-0.91%)。【结论】从SSP245情景过渡到SSP585情景，径流量丰枯异步概率逐渐增大，说明未来极端气候条件下可能导致水资源空间分布差异性变大，时空差异更加明显。平均利于调水概率在71.2%~73.2%,能进行补偿调度的概率较大，对南水北调西线工程的实施是非常有利的，且可在不同时间阶段汛期、非汛期进行补偿调水。

Abstract

[Objective] The upper reaches of the Yangtze and Yellow Rivers, located in the eastern Qinghai-Xizang Plateau, serve as major water production and conservation areas. The study aims to analyze the impact of climate change on the probability of runoff abundance and depletion encounters in the water source and receiving regions of inter-basin water diversion projects in this area, thereby providing theoretical support for improving project planning, design, and operational efficiency. [Methods] A bivariate Copula function was employed to construct a runoff abundance and depletion encounter probability model, analyzing the characteristics of these probabilities in the upper reaches of the Yangtze and Yellow Rivers over the past 40 years. Distributed hydrological models and climate scenarios were used to predict changes in runoff abundance and depletion encounter probabilities by the mid-21st century and the end of the 21st century, as well as the response characteristics of diversion-favorable probabilities to climate change. [Results] During the historical period(1978—2020) in the study area, an overall increasing trend in annual runoff was observed. Significant fluctuations in runoff were recorded during the summer and autumn seasons(-3.29~11.78 m³·s^-1/a), reflecting distinct seasonal characteristics. The highest rate of increase in summer-autumn runoff was found in the Jinsha River Basin, which was generally higher than the runoff change trend in the Yellow River source region(-2.3~0.73 m³·s^-1/a), aligning with the requirements for water diversion. On an annual and flood season scale, the synchronous frequency of runoff abundance and depletion was generally higher than the asynchronous frequency, while on a non-flood season scale, it was lower. The probability of diversion-favorable conditions ranged from 68% to 75%, ensuring water supply feasibility. Future projections indicate that annual and flood season diversion-favorable probabilities will generally exceed historical values(3.53%~5.44%), whereas probabilities during the non-flood season under SSP245 and early SSP585 scenarios will fall below historical levels(-1.57%~0.91%). [Conclusion] Transitioning from SSP245 to SSP585 scenarios, the probability of asynchronous runoff abundance and depletion encounters is projected to increase, indicating that extreme climate conditions may lead to greater spatial differences in water resource distribution and more pronounced temporal-spatial variations. The average probability of diversion-favorable conditions is estimated to range from 71.2% to 73.2%, suggesting a high likelihood of compensatory water regulation. This finding is highly favorable for the implementation of the Western Route of the South-to-North Water Diversion Project, enabling compensatory water diversion during both flood and non-flood periods at different time stages.

关键词

径流演变 / 丰枯遭遇 / Copula函数 / 气候变化 / 青藏高原 / 黄河 / 长江流域 / 南水北调西线工程

Key words

runoff evolution / abundance and depletion encounters / Copula function / climate change / Qinghai-Xizang Plateau / Yellow River / Yangtze River Basin / Western Route of South-to-North Water Diversion Project

基金资助

雅鲁藏布江中游自然资源西藏自治区野外科学观测研究站开放基金项目(2024YJZKF006)

第二次青藏高原综合科学考察研究项目(2019QZKK0207-02)

中国大坝工程学会青年人才资助项目(WR110199A0012024)

重庆市技术创新与应用发展专项重点项目(CSTB2023TIAD-KPX0086)

2022 年度中国科协科技智库青年人才计划(20220615ZZ07110156)

青海省中央引导地方科技发展资金项目(2022ZY020)

国家自然科学基金项目(51909275)

国家自然科学基金项目(42172267)