基于模型联用评估气候变化对径流特征的影响

Influences of Climate Change on Streamflow Characteristics Estimated by Model-Linkage

应用流域模型与气象发生器模型联用的方法,评估了未来气候变化对泾河源头流域径流量的影响。使用泾川水文站2006—2014年的实测月流量资料,校准并验证了通用流域污染负荷模型(GWLF)的水文传输参数集。使用崆峒气象站1955—2014年逐日气象资料,对气象发生器(LARSWG 5)模型参数进行了率定与评估。基于HADCM3气候模式结果,针对IPCC定义的A1B、A2、B1三种温室气体排放情景,使用校准后的LARSWG 5模型进行降尺度分析,生成反映研究区域21世纪50年代和21世纪80年代气候状态的日降水与气温序列,并将其作为输入数据代入校准后的GWLF模型,分析对应时间段流域径流特征的响应变化。结果表明:未来气候变化会显著影响泾河源头流域径流过程,流域蒸散发作用会随气温升高而显著增强,水体经由地表径流进入河道的通量会增大,而经由浅层地下潜流的通量会减小,未来流域水量的增大主要集中在秋冬季节。

A linkage of watershed model and weather generator were used to estimate the impact of future climate change on streamflow in the source of Jinghe River watershed. The observed monthly streamflow records from 2006 to 2014 in Jingchuan Hydrological Station were used to calibrate and validate the transport parameters of General Watershed Load Function( GWLF) model. Based on the series daily weather data records from 1955 to 2014 in Kongtong Weather Station,the parameters of Long Ashton Research Station Weather Generator( LARSWG 5)were estimated. Facing the three main further emissions scenarios of A1 B,A2 and B1 proposed by Intergovernmental Panel on Climate Change( IPCC),the calibrated LARSWG 5 was used to downscale the results of HADCM3 general circulation model to generate synthetic daily precipitation and temperature series reflecting the weather status in 2050 s and 2080 s of the studied area,which were further used as the input data of GWLF to estimate the responses of streamflow property. The results indicate that there will be significant impacts of future climate change on hydrologic process in the source of Jinghe River watershed. The evapotranspiration will greatly increase together with the rise of temperature and there will be more runoff but less groundwater flow to compose the streamflow,the increase of which will mainly focus on autumn and winter.