Yun Xiaobo, Tang Qiuhong, Wang Jie, Li Jiabo, Li Yumei, Bao Hongjun
National Meteorological Centre, China Meteorological Administration, Beijing, China; China Meteorological Administration Hydro-Meteorology Key Laboratory, Beijing, China.
Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
Sci Total Environ. 2023 Oct 20;896:165297. doi: 10.1016/j.scitotenv.2023.165297. Epub 2023 Jul 3.
Hydrological extremes intensified by meteorological extremes are threatening water security in the Lancang-Mekong River Basin (LMRB), and reservoir operation may mitigate hydrological extreme through regulating hydrological processes during meteorological extreme. However, the capacity of reservoirs in modulating propagation from meteorological extremes to hydrological extremes has seldom been quantified. This study adopted the VIC-Reservoir hydrological model to assess the impact of reservoir operation on the propagation at multi-timescales in the LMRB. The Standardized Precipitation Index and Standardized Streamflow Index were adopted to characterize meteorological extreme and hydrological extreme, respectively, on a range of timescales. The results indicate that reservoir operation has effectively delayed the propagation from meteorological to hydrological extremes during the period of 2008-2016 with rapid reservoir development in the LMRB, compared with the period of 1984-2007 with natural condition. The transmission process of extreme events with a duration of no more than 6 months has been suppressed during the reservoir impact period. However, the influence of reservoir regulation on long-term extreme events that last more than 12 months is generally low. In the upstream basin where reservoir impact is largest, reservoirs can exert a weak mitigation effect on long-term dry extremes. This study provides quantitative assessment of the role of reservoirs in regulating propagation between meteorological and hydrological extremes in the LMRB, and facilitate decision making for the management of water hazards under changing environment.
由气象极端事件加剧的水文极端事件正威胁着澜沧江 - 湄公河流域（LMRB）的水安全，而水库运行可通过在气象极端事件期间调节水文过程来减轻水文极端事件的影响。然而，水库调节从气象极端事件到水文极端事件演变过程的能力很少被量化。本研究采用VIC - 水库水文模型来评估水库运行对LMRB多时间尺度演变过程的影响。分别采用标准化降水指数和标准化径流指数在一系列时间尺度上表征气象极端事件和水文极端事件。结果表明，与1984 - 2007年自然状态时期相比，在2008 - 2016年LMRB水库快速发展时期，水库运行有效地延迟了从气象极端事件到水文极端事件的演变。在水库影响期内，持续时间不超过6个月的极端事件的传播过程受到了抑制。然而，水库调节对持续时间超过12个月的长期极端事件的影响通常较小。在水库影响最大的上游流域，水库对长期干旱极端事件可发挥微弱的缓解作用。本研究对水库在调节LMRB气象极端事件和水文极端事件之间演变过程中的作用进行了定量评估，并有助于在变化环境下进行水灾害管理的决策。
