澜沧江-湄公河流域径流与气候因子变化的季节差异特征研究

Study on the seasonal different characteristics of streamflow and climate factors in the Lancang-Mekong River Basin

根据DELWARE温度和降水数据、GLDAS蒸散发数据和湄公河干流9个水文站的实测径流,采用回归分析、均值T检验和低通滤波,分析了该流域气候和径流在1950-2017年间的变化情况,经分析表明流域内气候和径流在研究时段内有较大变化,而且在不同的月份呈现不同的变化特征。流域年平均温度整体呈增加趋势,2008年后的平均温度相对2008年前平均温度有显著增加;流域年平均降水的变化幅度不大;流域平均蒸散发在12月-次年2月呈下降趋势,其他月份呈增加趋势,2008-2017年月平均蒸散发与1950-2007年月平均蒸散发相比大幅提升,尤其是在6-10月;湄公河流域年径流没有显著变化,但径流在12月-次年4月呈上升趋势,7-10月呈下降趋势,其中,上升趋势比下降趋势显著,1-4月径流上升趋势在2008年之后更为显著;最小径流在2008年后有显著增加趋势,最大径流在2008年后呈下降趋势;年流量逆转次数自20世纪90年代起有明显升高趋势。通过比较温度、降水、蒸散发和径流在不同时间段的变化情况,可以看出径流在2008年后变化趋势和气候自然变化关系不显著,但可能跟大坝蓄水能力显著提高等人为活动有较大关系。

In this study,based on DELWARE temperature and precipitation data,GLDAS evapotranspiration data,and measured streamflow from nine hydrological stations located along the mainstream of the Mekong River,the regression analysis,T test and low-pass filter were used to analyze the climate and streamflow changes in the basin during the periods of 1950-2017.The results show that the average temperature of the basin is increasing,and since 2008,the temperature has increased significantly,while the average precipitation in the basin has changed little.The average evapotranspiration in the basin shows a decreasing trend in December-January,and an increasing trend in other months.The average evapotranspiration in 2008-2017 has increased significantly compared with the average evapotranspiration in 1950-2007(June-October).The annual streamflow in the basin has not changed significantly,but since 2008 the streamflow shows an increasing trend in December-April,along with a decreasing trend in July-October.The increasing trend is more obvious than the decreasing trend,and the increasing trend in January-April is more significant after 2008.For the yearly minimum streamflow,there is a significant increasing trend after 2008,and the maximum streamflow shows a decreasing trend after 2008.The streamflow reversals have increased significantly since 1990.By comparing temperature,precipitation,evapotranspiration and streamflow changes in different time periods,it can be seen that the change of streamflow after 2008 is not significantly related to the changes of natural climate,but may be significantly related to the dams water storage capacities(human activities).