基于不同气候变化情景的东江流域水资源量预测研究

摘要

The East River basin is the principle source of water supply for megacities in/in the vicinity of the Pearl River Delta.In this study,water resources during 2020 -2070 are evaluated under different climate scenarios based on outputs of 5 GCMs. The climate scenarios are RCP8.5 , RCP4.5 and RCP2.6.Besides,downscaling procedure was done based on observed data covering the period of 1960-2000.The period of 1960-2000 was taken as the base period.HSPF model was used in hydrological modeling.The results indicate that:① The HSPF model performs well in the hydrological simulation practice with NASH coefficient of over 0.81,PBIAS and RSR less than 10% and 0.45.The scenarios can well mirror the annual distribution of meteorological variables.② The precipitation and evaporation during 2020-2070 under the RCP2.6 and RCP4.5 scenarios increase and evaporation decrease under RCP8.5 scenario.③ The period of 2020 -2070 will witness increasing monthly streamflow and also high/low flow regimes.Besides,when compared to the base period,the period of 2020-2070 will wit-ness increasing flooding days .Flood risk will be significantly enhancing.%采用半分布式水文模型HSPF，结合1978－1998年东江流域实测气象数据和5个气候模式在3种RCP气候情景（RCP8.5，RCP4.5，RCP2.6）下基准期（1960－2000年）和未来时期（2020－2070年）降水、蒸发情景模拟结果，在对东江流域径流模拟检验基础上，对2020－2070年东江流域水资源量做了深入分析。结果表明，HSPF模型能很好模拟东江流域年、月径流以及洪水期径流变化，博罗站的NASH系数均超过0.81，PBIAS低于10％，RSR低于0.45；所选取气候模式能很好的反映研究流域气象数据在年内分布情况。对未来气候和东江流域水资源量模拟结果表明：①2020－2070年不同气候变化情景下东江流域降水及蒸发量在 RCP2.6和RCP4.5情景下均呈上升趋势，而在RCP8.5情景下，东江流域蒸发量则呈现下降趋势；②未来东江流域多年月均径流量呈增加趋势；③未来东江流域不同频率下的洪水和枯水流量均呈不同程度的增长。相对于基准期，未来时期的洪水天数呈增长趋势，洪水灾害有加剧态势。