金沙江中上游流域未来径流模拟研究

为了探究金沙江中上游流域未来径流变化趋势，为流域防洪规划提供依据，基于SWAT水文模型，选用CMIP5数据集建立未来时段的全球气候模式，从时间和空间尺度解析研究区2022—2050年径流变化趋势。结果表明：流域2022—2050年降水量和平均气温均高于基准期，并且呈现上升趋势，其中流域南部降水量增幅较大，流域北部气温增幅较大。在RCP2.6、RCP4.5、RCP8.5 3种气候情景下，2022—2050年年径流量均呈现增大趋势，变化率分别为5.79×10⁸、5.53×10⁸、2.99×10⁸ m³/a。相较于基准期，未来春季和秋季径流量呈现减少趋势，夏季和冬季径流量呈现增加趋势，冬季径流量增幅达到了10%。流域产流量呈现从西北到东南依次增加的特点，相较于基准期，流域南部产流量均呈现增加趋势。未来径流量呈现增加趋势，冬季径流量增幅较大，可能会发生冬汛等极端水文事件，流域南部受洪水威胁的可能性进一步增大。

Simulation of future runoff in the middle and upper reaches of Jinsha River Basin

The change trend of future runoff in the middle and upper reaches of Jinsha River Basin was investigated to provide some technical support for the planning of flood control in the basin. Based on the SWAT hydrological model, the CMIP5 data set was selected to establish a global climate model for the future period of 2022-2050, and the runoff change trend in the study area was analyzed from the temporal and spatial scales. The results show that the precipitation and temperature in the basin from 2022 to 2050 are both higher than those in the base period, and show an upward trend, with a large increment in rainfall in the south of the basin and a large increment in temperature in the north of the basin. Under the three scenarios of RCP2.6, RCP4.5 and RCP8.5, the runoff from 2022 to 2050 all show an upward trend, and the change rates are 579×10⁶ , 553×10⁶ and 299×10⁶ m³/a, respectively. Compared with the base period, the future spring and autumn runoff show an downward trend, whereas the summer and winter runoff show an upward trend, with the largest increment in winter, reaching 10%. The runoff yield increases sequentially from northwest to southeast; compared with the base period, the runoff yield in the south of the basin presents an increasing trend. The results indicate that the runoff will show an increasing trend in the future, with a greater increment in winter, and extreme hydrological events such as winter floods may occur; in the future, the threat of floods in the southern basin may further aggravate.