气候变化对玛纳斯河的径流量影响预测模拟分析

山区积雪和冰川融水径流是内陆干旱区的重要水资源, 研究全球变暖情景下温度对融雪径流的影响具有重要意义. 以典型的内陆河玛纳斯流域上游为例, 利用基于度-日因子算法的SRM(Snowmelt Runoff Model)融雪径流模型, 根据当前变化趋势和年内分配模拟出20种假定来模拟未来气候情景(气温上升1 ℃、 2 ℃、 3 ℃、 4 ℃和降水变化率为0、 ±10%、 ±20%的随机组合情况)下的河道径流量, 从而计算出径流量的变化率, 分析了温度和降水变化对径流量的影响. 结果表明: 对于以雪冰融水为主要补给的玛纳斯河, 随着温度和降水的增加, 径流量也会增加, 并会使融雪径流提前. 假定降水量不发生大的变化, 温度增高1 ℃, 径流量增大13%~16%; 在气温一定时, 降雨量增加10%, 径流量增加2%左右, 说明气温和降水都对干旱区内陆河山区径流形成具有重要影响. 该研究对制定气候变化情景下的水资源适应对策具有重要指导意义.

A Simulation Analysis of the Impact of Climate Change on Runoff in the Manas River

Climate change has significant influence on the hydrologic cycle. Snowmelt runoff is the main of water resources in the arid regions. So, there is great significance to study the influence of climate change on snowmelt runoff. The upper stream of the Manasi River, a typical inland river basin, was selected as the study area in this paper. The studied climate change scenarios were determined based on the changing trend of climate in the study area and global climate modeling (GCM). The runoff has been simulated under 20 climate changing scenarios (random assortment of ΔT=1 ℃, 2 ℃, 3 ℃, 4 ℃ and ΔP=0, ±10%, ±20%) using SRM model, which based on semi-distributed physical structure. The runoff change rate and the effect of temperature and precipitation on runoff were analyzed according to the simulation. The results show that the annual mean air temperature and annual precipitation had increased during the period from 1971 to 2007. The runoff in the Manasi River would increase with the temperature and rainfall. The snow melting-time would be ahead of time. If temperature raises 1 ℃, the runoff would increase by 13%~16%; if the rainfall increases by 10%, the runoff would increase by 2%. This indicates that temperature and rainfall play important role to the surface runoff of inland rivers. The study is helpful for regional water resources planning under the condition of climate change.