Wang Shijie, Chen Feng, Hu Mao, Chen Youping, Cao Honghua, Yue Weipeng, Zhao Xiaoen
Yunnan Key Laboratory of International Rivers and Transboundary Eco-Security, Institute of International Rivers and Eco-Security, Yunnan University, Kunming 650500, China.
Yunnan Key Laboratory of International Rivers and Transboundary Eco-Security, Institute of International Rivers and Eco-Security, Yunnan University, Kunming 650500, China; Southwest United Graduate School, Kunming 650092, China; Key Laboratory of Tree-ring Physical and Chemical Research of the Chinese Meteorological Administration, Xinjiang Laboratory of Tree-ring Ecology, Institute of Desert Meteorology, Chinese Meteorological Administration, Urumqi 830002, China.
Sci Total Environ. 2024 Oct 15;947:174707. doi: 10.1016/j.scitotenv.2024.174707. Epub 2024 Jul 10.
The rapid development of the Greater Mekong Subregion (GMS) makes it essential to understand the major mechanisms controlling the streamflow, especially for the Lancang-Mekong River (abbr. Mekong River). We used instrumental annual streamflow data (1960-2007) from Chiang Saen hydrological station and several gridded hydroclimatic datasets to explore the hydroclimatic evolution of the Mekong River, together with its driving mechanisms. We found that changes in the Mekong streamflow are consistent with precipitation changes, and the Mekong is thus a precipitation-dominated river that is susceptible to the effects of ongoing climate change. The instrumental record of Mekong annual streamflow is closely related to hydroclimatic changes, especially those related to moisture, within the area from the Hengduan Mountains to the Chiang Saen Station. Based on these gridded records, we extended the Mekong annual streamflow record to cover 1891-2021 using nested multiple linear regression fitting. The fitted streamflow explained up to 57.6 % of the instrumental changes and it indicates that the major 2019 drought was not unique over the past century. Despite extremely low precipitation and high temperatures, it is likely that the effects of drought can be mitigated via hydraulic engineering regulation. Climatological analyses showed that the Mekong annual streamflow is driven by the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), which is consistent with observed quasi-interannual cycles of 3-4 years. A multi-model ensemble of CMIP6 revealed that the Mekong annual streamflow will experience an upward trend in the future, accompanied by the more extreme impacts of ENSO and the IOD.
大湄公河次区域（GMS）的快速发展使得了解控制河流流量的主要机制变得至关重要，特别是对于澜沧 - 湄公河（简称湄公河）而言。我们使用了清盛水文站1960 - 2007年的实测年径流量数据以及几个网格化的水文气候数据集，来探究湄公河的水文气候演变及其驱动机制。我们发现湄公河径流量的变化与降水量变化一致，因此湄公河是一条以降水为主导的河流，容易受到当前气候变化的影响。湄公河年径流量的实测记录与横断山脉至清盛站区域内的水文气候变化密切相关，尤其是与水分有关的变化。基于这些网格化记录，我们使用嵌套多元线性回归拟合将湄公河年径流量记录扩展至1891 - 2021年。拟合的径流量解释了高达57.6%的实测变化，这表明2019年的大旱在过去一个世纪并非独一无二。尽管降水极少且气温很高，但通过水利工程调控有可能减轻干旱的影响。气候分析表明，湄公河年径流量受厄尔尼诺 - 南方涛动（ENSO）和印度洋偶极子（IOD）驱动，这与观测到的3 - 4年准年际周期一致。CMIP6的多模型集合显示，湄公河年径流量未来将呈上升趋势，同时伴随着ENSO和IOD更极端的影响。
