根据湄公河干流清盛、琅勃拉邦、穆达汉、上丁 4 个代表性水文站 1960 - 2012 年的实测日径流资料, 采用 M ann2kendall 趋势检验法、Pettitt 突变检验法和不均匀系数 CV , 分析了年径流、汛期和枯期径流、月径流和极值径 流等水文要素的演变特征。结果表明, 清盛、琅勃拉邦、上丁三站年径流呈下降趋势, 穆达汉站年径流为上升趋势, 其中穆达汉站年径流在 1994 年发生显著突变; 各站汛、枯期径流比值均呈下降趋势, 汛、枯期径流分配差异趋于减 小; 各站年内分配不均匀系数 CV 均为下降趋势, 其中清盛站和上丁站下降趋势达显著水平, 各站径流年内分配过 程趋于均匀; 清盛、穆达汉、上丁三站流量波动区间逐渐减小, 琅勃拉邦站流量波动区间逐渐增大。整体上, 湄公河 流域产水能力的空间差异较大, 50 多年来不同河段的径流变化趋势呈现增减相间的格局。

This study evaluat es the hy dr olo gical char act eristics such as annual r unoff, r uno ff in flood and dr y seaso n, monthly runo ff and ext reme r uno ff using daily measured runo ff data of Chiang Saen, Luang Pr abang, Mukdahan and Stung Treng hydro2 log ical stat ions in the mainstream of M eko ng River fr om 1960 to 2012. For this purpose, t he Mann2Kendall trend test, the Pettitt mutation test, and the coefficient o f variance ( CV ) w ere used to analyze the evo lution characteristics. . The results show ed t hat the annual runoff of Chiang Saen, Luang Pr abang , and Stung Tr eng statio ns ex hibited dow nw ar d tr end, w hile the annual runo ff of Mukdahan stat ions show ed upw ard tr end. Among them, the annual runo ff o f Mukdahan statio n had a sig nificant chang e in 1994. The runo ff r atio show ed a dow nw ar d trend, w hile the difference in runo ff distribut ion during the flo od season and dry sea2 son tended to decrease. Furthermor e, the CV of each station showed decreasing trend. The declining tr end o f Chiang Saen and St ung T reng stations w as signif icant, and the runoff distributio n o f each statio n w as distributed w ithin the y ear. The f low fluc2 tuatio n range of t hr ee stat ions ( Chiang Saen, Mukdahan, and Stung Tr eng ) w as g radually decr eased, w hile the flow fluctuatio n range o f Luang Prabang statio n increased gr adually. On the w ho le, the runoff change t rend show ed an incr eased and decreased patter n at differ ent riv er sect ions in the past 50 years which rev ealed that the spat ial differ ence of w ater pro ductio n capacity of the Mekong Riv er Basin is quite lar ge.

国家重点研发计划( 2016YFA0601602) ; 国家自然科学基金项目( 91747103; 51679145; 51779146) ;中央级公益性科研院所基本科 研业务费专项( Y518007)