涪江流域径流变化趋势及其对气候变化的响应

Variation Trend of Runoff in Fujiang River Catchment and Its Responses to Climate Change

采用Mann-Kendall非参数检验方法分析了涪江流域实测径流量的变化趋势,根据假定的气候变化情景和HADCM3预估的气候情景,利用考虑融雪的水量平衡模型(SWBM模型)分析了径流对气候变化的响应。结果表明:涪江流域径流量总体呈现递减趋势,但非汛期的个别月份有增加趋势,实测年径流变化主要是由于气候要素变化引起的,流域内的水电开发对径流量的季节分配存在一定的影响。SWBM模型对涪江流域月流量过程具有较好的模拟效果,实测与模拟径流量总体较为吻合,只有个别年份峰值模拟误差相对较大。气温变化固定的情况下,降水变化与径流变化之间的关系接近线性;在降水变化相同的情况下,单位气温变幅引起的径流量变化幅度也基本相当。尽管不同排放情景下涪江流域径流量的变化有一定差异,但总体来看,未来水资源可能以偏少为主,特别是2030年以后,多年平均偏少量将可能超过5%。

Variation of runoff in the Fujiang River catchment was analyzed with Mann-Kendall method. Based on hypothetical scenarios and projections of HADCM3, responses of runoff to climate change were simulated using a simple water balance model. The results indicate that the recorded runoff in the Fujiang River catchment presented decreasing trend during 1955-2000, which mainly resulted from climate change. Although human activities across the catchment did put much effect on annual runoff amount, it altered seasonal distribution of runoff to some extent. The adopted monthly water balance model performed well for discharge simulation. The recorded and simulated discharges match well in general, except a little bit underestimation for some peak discharges. Relationship between changes in precipitation and changes in runoff under the fixed temperature change is a linear approaching. Under the same changes in precipitation, a unite change in temperature will result in an approximate change in runoff. Although projected runoffs under the different emission scenarios are different, water resources in the Fujiang River catchment will likely undergo decreasing trend, especially during the period after 2030, the decreasing range could beyond 5% as comparing to baseline in 1961-1990.