多模式预测气候变化及其对雪冰流域径流的影响

Predicting climate change and its impact on runoff in snow-ice basin with multi-climate models

冰川覆盖流域的雪冰融水对河川径流有重要的调节作用。气候变化影响雪冰融水过程和数量变化,河川径流过程和径流量相应变化,其程度与流域冰川情况相关。通过利用CMIP5气候模式输出气象数据驱动流域水文模型,模拟研究天山地区3个不同冰川覆盖率河流(库玛拉克河、玛纳斯河、库车河)的径流对气候变化的响应。结果表明:随着未来气温和降水的持续增加,3个流域的雪融水均有增加,冰融水变化受冰川覆盖面积的影响,在各个流域变化不一致。径流变化主要受降水增加和雪冰融水变化的综合影响,在未来情景下各流域径流均有增加,分别增加了5.8%~14.3%(库车河)、2.9%~11.4%(玛纳斯河)、12.9%~47.1%(库玛拉克河),且冰川覆盖率越大的流域,预估径流不确定性变化区间受冰融水影响越大。预估3个流域的径流、雪冰融水年内分布变化表明,各河流的春季融雪时间提前和融雪量增加使得流域春季径流量较历史时期增大;在夏季,受雪冰融水变化的影响库车河、玛纳斯河夏季径流峰值量减小,而库玛拉克河径流峰值量增加,且预估的各流域夏季径流变化不确定性区间明显大于其它季节。

The snow-ice melt water in glacier-covered basins plays an essential role in regulating runoff.The impact of climate change on the snow-ice melting process and quantity change,river runoff process and quantity change,which is related to the glacier area in the basin.Using climate models’meteorological data of CMIP5 driven watershed hydrological model,simulated runoff response to climate change in Tianshan areas(Kumaric River,Manas River,and Kuqa River,Xinjiang,China).The results show that with the temperature and precipitation increasing in the future,three river basins’snow melt water is both increasing,but ice melt water changes affected by glacier coverage.The change of runoff was mainly affected by the increase in precipitation and the change in snow and ice melt water;the runoff increased by 5.8%-14.3%(Kuqa River),2.9%-11.4%(Manas River),and 12.9%-47.1%(Kumaric River)under three representative concentration pathways(RCPs).It was estimated that the variation range of runoff uncertainty was affected by ice melting.From the projected intra-annual distribution of runoff,the snow and ice melt of the three basins,the spring runoff of the river basins increased compared with the historical period due to the snow melt time ahead and snow melt volume.In the summer,the peak runoff of the Kuqa River and Manas River decreased due to ice melt water,whereas the peak value of runoff in Kumaric River increased.In addition,the estimated uncertainty range of summer runoff in the study basins in the summer season is significantly larger than those of other seasons.