赣江流域未来降雨径流变化模拟预测

Simulation and Prediction of Future Precipitation and Runoff Change in the Ganjiang Basin

本文采用BCC-CSM1.1全球气候模式,在IPCC5推荐的三种代表性浓度路径RCP2.6、RCP4.5和RCP8.5情景下,应用SDSM统计降尺度技术将GCM输出进行降解,并作为分布式两参数月水量平衡模型的输入,模拟预测赣江流域未来的降雨径流变化。结果表明:在三种浓度路径下,2020s和2050s时期年径流量均比近期减少,2080s时期则存在差异:RCP2.6和RCP4.5浓度两种路径下的年径流量与近期基本持平,而RCP8.5浓度路径下相对近期有明显的增加。同时,未来主汛期径流减少,非汛期径流呈现不同程度的增加,气候变化在一定程度上有可能减轻赣江流域未来汛期的防洪压力和枯水期的供水压力。

The SDSM statistical downscaling technique was adopted to degrade the output of BCC-CSM1.1 model under three representative concentration pathways: RCP2.6, RCP4.5 and RCP8.5 scenarios recommended by IPCC5. Future precipitation and temperature series were as inputs of distributed two-parameter monthly water balance model to simulate and predict future runoff change in the Ganjiang basin. The results show that under three representative concentration pathways, simulated annual runoff volumes of 2020s and 2050s are both less than the reference value in the recent period, but there are differences for 2080s period: under RCP2.6 and RCP4.5 concentration pathways, the simulated annual runoff volumes are almost equal to the recent reference value, while more than the recent reference value under RCP8.5 concentration pathways. Meanwhile, future runoff volume decreases in the main flood season and increases in dry season, which implies that climate change is likely to alleviate flood control pressure during flood season and water supply pressure during dry season to some extent in the Ganjiang basin.