气候和下垫面要素对泾河流域径流变化的影响

Impacts of Climate and Underlying Surface Factors on Runoff Variation in Jinghe River Basin

定量评估河川径流的变异规律,开展其归因诊断分析是变化环境下制定应对策略与合理利用水资源的基础。以水资源匮乏的泾河流域为例,首先,采用3种潜在蒸发计算方法(Penman-Monteith方法、Priestley-Taylor方法和Hargreaves-Samani方法)评估径流对气象因素和下垫面因素的敏感性;其次,采用Bayesian突变检验方法识别径流序列的突变年份,以此将气候状态划分为天然期和变化期;最后,采用Budyko-Fu公式定量评估气候变化和人类活动在不同时段对径流改变量的贡献程度。结果表明:不同潜在蒸发计算方法得到的年潜在蒸发量之间差异显著,仅考虑气温和太阳辐射的Hargreaves-Samani方法不确定性影响最大;随着潜在蒸发量的增大,气象因子的弹性系数逐渐减小,而下垫面因子的弹性系数却显著增大;不同时段气候变化和人类活动对径流减小的贡献程度不同,气候变化和人类活动对径流减少的贡献分别为80%和20%左右。

Quantitative assessment of the variation law of river runoff and the analysis of its attribution diagnosis are the basis for formulating coping strategies and rational utilization of water resources in a changing environment.This article took the Jinghe River basin as an example,first,the Bayesian mutation test method was used to identify the location of the abrupt change point of runoff,so as to define the climate state as the natural period and the changing period;secondly,three potential evaporation calculation methods(Penman⁃Monteith method,Priest⁃ley⁃Taylor method and Hargreaves⁃Samani method)were used to compare and evaluate the difference in sensitivity of runoff to meteorological factors and underlying surface factors;finally,the Budyko⁃Fu formula was used to quantitatively evaluate the contribution of climate change and human activities to runoff change at different periods.The results show that the annual potential evaporation amount obtained by different potential evaporation calculation methods is significantly different,and the uncertainty of the Hargreaves⁃Samani method,which only consid⁃ers the temperature,has the greatest impact;as the potential evaporation increases,the elastic coefficient of meteorological factors gradually decreases,while the elastic coefficient of the underlying surface factor increases significantly;the contribution of climate change and human activities to the reduction of runoff in different periods is different,the contribution of climate change and human activities to the reduction of runoff is about 80%and 20%respectively.The research results are of guiding significance for the scientific and rational development of water resources development and utilization in river basins.