气候变化对中国西北地区山区融雪径流的影响

Impact of Climate Change on Snowmelt Runoff in the Mountainous Regions of Northwest China

选择祁连山黑河流域作为中国西北地区山区积雪流域的典型代表 ,分析了 195 6— 1995年 40a以来气候、积雪变化的状况和特点以及春季融雪径流的波动趋势 .利用融雪径流模型 (SnowmeltRunoffModel SRM)和卫星遥感数据模拟气温上升框架下的融雪径流变化情势 .结果表明 :中国西北地区山区的气候变化主要表现在年平均气温的缓慢上升而降水基本平稳 ,年内气温的上升幅度以 12月份比较强烈 ,而 36月融雪期的气温并没有大的变化 ,导致融雪期在时间尺度上的扩大 ,融雪径流呈慢增加趋势且受径流周期变化控制 。

Snow cover is an indicator for global warming. Climate change influences the distribution of glaciers and snow. Thus, air temperature rising results in changing of distribution of seasonal snow cover and regime of snowmelt runoff in Northwest China. Heihe Basin is a typical snow cover region with an area of 10 009 km 2 in Northwest China, where snowmelt runoff is the main supply for water resources. It is found that an impact of climate change on snowmelt runoff in mountainous regions is clear in the basin. So in this paper, the Heihe Basin was sampled to analysis the impact in mountainous regions of Northwest China. The impact of snowmelt runoff was simulated by using Snowmelt Runoff Model——SRM and satellite remote sensing data under air temperature rising. By analyzing the climatic and hydrological data sets derived from 46 observation stations for 40 years(1956—1995), an air temperature rising trend since 1956 is seen, together with a stable precipitation. The annual mean air temperature has increased about 0 7~1 4 ℃. Temperature mainly rises in January and February, but less rises in the spring. Meanwhile, in the test area, variation in rainfall and snowfall has a small effect. When air temperature increasing in winter is the main variation of climate change, snowfall will increase correspondingly. Based on statistics, snowfall increasing due to air temperature rising reaches 7%~10%. Snowmelt runoff regime changes with climate changing temporally and spatially. The curves of different coefficient of discharge show a change of monthly mean discharge contribution from the middle ten days of April to the middle ten days of October. The snowmelt period stretches with the shifted advance 10 days. While the discharge increases, the peak of runoff also advances to May.