1960-2012年澜沧江-湄公河流域气候变化趋势及不同区间的径流响应

Variation trends of climate change and hydrological responses of individual regions in Lancang-Mekong River Basin from 1960-2012

气候变化是河川径流变化的主要驱动因素,分析流域气候变化及径流响应对有效适应气候变化具有重要意义。基于普林斯顿全球气象驱动数据集资料和澜沧江-湄公河(简称澜湄流域)干流8个水文站的实测径流资料,分析了澜湄流域不同区间气温、降水的演变趋势以及不同阶段降水-径流的响应关系。结果表明:1960-2012年期间,澜湄流域不同区间年气温呈现显著性升高趋势,其中,上游区间升温幅度较大,超过0.2℃/10a;同期,澜湄流域的8个区间只有"旧州-允景洪"区间年降水量呈现减少趋势,其余各区年降水量均为不同程度的增加趋势;此外,所有区间春季降水量均为增加趋势,冬季降水量大多为减少趋势;8个区间的年径流系数序列突变大多发生在20世纪60年代;澜湄流域不同区间降水-径流关系存在一定的差异,不同阶段降水-径流关系发生了不同程度的改变;相同降水条件下,"琅勃拉邦-穆达汉"区间在2000年以后的产流量大多高于前期,而"旧州-允景洪"区间和"清盛-琅勃拉邦"区间后期径流量大多低于第1阶段径流量。

Climate change is the principal driving factor for the changes of runoff in the rivers. Analyzing the climate change in the basin and the hydrological response of runoff is of great significance to the effective adaption of global warming. Using Princeton Global Forcing Database and the monitored runoff data of eight hydrological stations in the mainstream of Lancang-Mekong River Basin,variations of temperature and precipitation in different regions,and hydrological responses of runoff to climate change in different hydrological phases during 1960-2012 were investigated. Results show that the variation of annual temperature presented a significant rising trends during 1960-2012 for all of the eight regions in the basin exceeding > 0. 2 ℃/10 a. Meanwhile,annual precipitation in the region of Jiuzhou-Yunjinghong decreased while the rest of the seven regions increased to various degrees. At seasonal scale,spring precipitation increased for all of the eight regions while winter precipitation decreased for most regions. Abrupt changes in annual runoff coefficient series mainly occurred in the 1960s. The interaction between precipitation and runoff varied from region to region and phase to phase. Under the same condition of precipitation,runoff yield after 2000 was much higher than that in the previous phases for the region of Luang Prabang-Mukdahan;however,runoff yield in the later phase was mostly lower than that in the first phase for the regions of Jiuzhou-Yunjinghong and Chiang Saen-Luang Prabang.