未来气候变化对赣江上游区极端径流影响预估

受气候变化影响,近年来赣江上游区洪旱灾害频发,但缺少综合评估未来气候变化情景下赣江上游区极端径流演变特性。采用IPSL-CM5A-MR气候模式模拟的RCP 2.6、RCP 4.5、RCP 8.5排放情景下的气候数据经统计降尺度,驱动栅格型新安江水文模型,预估未来气候变化情景下赣江上游区极端径流的演变趋势。结果表明,栅格型新安江水文模型能合理地模拟赣江上游峡山站的历史日流量过程和极端径流;3种排放情景下极端高流量较基准年呈显著的增大趋势,RCP 2.6情景最为明显;3种排放情景下极端低流量较基准年明显减小,RCP 4.5情景极端低流量减幅最大。结果可为适应气候变化的水资源管理提供依据。

Projection of Future Climate Change Impacts on Extreme Runoff in the Upper Reaches of Ganjiang River Basin

Affected by climate change, floods and droughts have occurred frequently in the upper reaches of Ganjiang River basin in recent years. However, previous studies have not yet comprehensively assessed the evolution characteristics of extreme runoff in the upper reaches of Ganjiang River under future climate change scenarios. In this paper, the climate data under the emission scenarios of RCP 2.6, RCP 4.5, and RCP 8.5 simulated by the IPSL-CM5A-MR climate model were used to drive the grid-based Xinanjiang hydrological model through statistical downscaling and to predict the trend of extreme runoff in the upper reaches of Ganjiang River basin under future climate change scenarios. The results show that the grid-based Xinanjiang hydrological model is able to reasonably simulate the historical daily flow process and extreme runoff at the Xiashan hydrological station in the upper reaches of the Ganjiang River. Under three future emission scenarios, the extreme high flow shows a significant increase trend compared with the baseline period. The RCP 2.6 scenario is the most obvious increase of extreme high flow. The extreme low discharge under three emission scenarios is significantly lower than that in the baseline period, and the RCP 4.5 scenario shows the most obvious decrease trend of extreme low flow. The results can provide a basis for water resources management to adapt to climate change.