永定河流域水循环特征及其对气候变化的响应

Water Cycle Characteristic and Its Responses to Climate Change of the Yongding River Basin

气候变化对我国各地区水资源时空格局的影响是气候变化影响评估的重要内容.本文以永定河流域为研究对象,采用线性回归法、Mann-Kendall非参数检验等方法,分析了1957—2001年的水文气象要素变化特征;基于数字高程模型、土地利用和土壤类型等资料,建立了SWAT分布式水文模型,验证了SWAT模型在该流域的适用性;根据IPCC第四次评估报告多模式结果,分析了IPCCSRES-A2、A1B、B1情景下2050年以前降水、气温、径流、蒸发的响应过程.结果表明1957—2001年永定河流域年均降水量呈递减趋势,气温呈缓慢上升的变化趋势,年均径流量呈缓慢减少趋势,蒸发量呈缓慢下降趋势,20世纪60年代为丰水期,90年代为枯水期.在IPCC SRES-A2、A1B、B1情景下永定河流域2050年以前气温将持续增高,年降水量将增加,径流量较基准期将出现先减少后增大的趋势,结果预示着永定河流域的水资源在21世纪前期将出现减少,21世纪中期才有可能增加.这对于经济发达、人口稠密、用水量大并且严重缺水的永定河流域而言,水资源危机将进一步加剧.

Assessment of climate change impacts on water resources of the temporal and spatial pattern in various regions is an important aspect of climate change impact studies in China. In this paper, the linear regression and Mann-Kendall non-parametric test methods were used to analyze the change characteristics of the hydro-climatic series in the Yongding River Basin during 1957--2001 firstly. Then the SWAT model was applied and validated based on the digital elevation model, land use and soil type etc. in the basin. Finally the responses of precipitation, temperature, runoff and evaporation to climate change were analyzed based on the IPCC AR4 multi-mode climate models under different GHG emission scenarios （SRES-A2 ,A1 B and B1 ）in the 21st century before 2050. The results show decrease trends for precipitation, runoff and evaporation ,while the temperature increases during 1957--2001. Under the different GHG emission scenarios in the 21st century, the precipitation, temperature will increase while runoff will reduce and then increase in the mid-21st century, which indicate that the water resources crisis may be aggravated in the early-21st century in the basin as the development of economy and large amount of water consumption.