气候变化对澜湄流域上下游水资源合作潜力的影响

Impact of climate change on water resource cooperation between the upstream and downstream of the Lancang-Mekong River basin

澜沧江-湄公河(澜湄)流域南北跨越了25个纬度,流域上下游气候差异明显。同时遭遇干旱或湿润通常不利于上下游水资源合作,而水文气象条件正常或上下游间的干湿条件不一样时有利于缓解流域内的竞争性用水状况。为探究气候变化对澜湄流域上下游水资源合作潜力的影响,基于普林斯顿降水数据集与全球气候模型预估数据,利用标准化降水指数(SPI)和Copula函数计算了历史时期(1985—2016年)与未来时期(2021—2090年)澜湄流域上下游同时面临干旱、湿润以及干湿存在差异的发生概率。基于典型浓度路径RCP4.5和RCP8.5情景的预估结果显示与历史时期相比,未来时期澜湄流域在RCP4.5与RCP8.5情景下具有相似的变化趋势,即:遭遇同期湿润的概率在逐渐增大(最大达到199.5%),遭遇同期干旱的概率则在逐渐减少(最小达到-35.9%),而遭遇干湿差异时期的概率在所有时段均大幅减少(-53.1%^-42.5%)。未来澜湄流域上下游同期湿润概率的增加和遭遇干湿差异概率的减少预计将加大上下游面临水资源竞争的可能性,从而对澜湄流域各国家之间的水资源合作产生不利影响。这一研究可以为澜湄流域水资源合作策略的制定提供科学参考和依据。

The Lancang-Mekong River basin flows southward across 25 degree of latitude with large climatic variations between the upstream and downstream.The concurrent drought and wet events will affect the water resources cooperation potential between upstream and downstream countries.Based on the Princeton precipitation dataset and global climate model data,the standardized precipitation index and Copula function were used to investigate the impacts of climate change on concurrent drought,concurrent wet and concurrence of different dry and wet conditions during the historical period(1982-2016)and future period(2021-2090)in the upstream and downstream of the Lancang-Mekong River basin.The results showed that compared with the historical period,the Lancang-Mekong River basin shows the similar change trend under the scenarios of RCP4.5 and RCP8.5 in the future period:the probability of concurrent wet will gradually increase(maximum 199.5%),and the probability of concurrent drought will gradually decrease(minimum-35.9%),and the probability of uneven water resource situation will greatly reduce in all periods(-53.1%--42.5%).The results indicate that water resources cooperation between the upstream and the downstream of the Lancang-Mekong River basin may be adversely affected by climate change,and there is an urgent need for adaptation strategy to address water resources cooperation in the Lancang-Mekong River basin.