集合CMIP6多气候模式的南水北调中线工程水源区径流预估

Runoff Projection in Water Source Area of South-to-North Water Diversion Middle Route Project Based on CMIP6 Multiple Climate Models

南水北调中线工程是我国水资源开发利用的国策,评估气候变化下南水北调中线工程水源区的径流响应对调水工程的可靠运行具有重要意义。为此,采用第六次耦合模式比较计划中5个气候模式模拟的3种共享社会经济路径情景下(SSP 1-2.6、SSP 2-4.5、SSP 5-8.5)2021~2100年的气候数据,经贝叶斯模型平均法集合后驱动栅格型新安江模型,预估南水北调中线工程水源区未来径流的演变情势。结果表明,多模式集合后基准期(1961~2000年)月降水、气温模拟精度高于各气候模式;栅格型新安江模型在研究区具有较好的适用性;未来3种SSP情景下水源区各分区年径流深总体高于基准期,2021~2060年期间径流增幅小于2061~2100年。未来水源区的径流增幅低于调水规模的增幅,可能会给调水工程的高效运行带来挑战。

The South-to-North Water Diversion Middle Route Project is a national policy of development and utilization of water resources in China, and it is of great significance to evaluate runoff response to climate change in the water source area for reliable operation of the water diversion project. The climate data in the period of 2021 to 2100 under three shared socio-economic pathways(SSP 1-2.6, SSP 2-4.5, and SSP 5-8.5)simulated by five climate models from the Coupled Model Intercomparison Project Phase 6 were ensembled with the Bayesian model averaging(BMA) method. The ensembled climate data were used to drive the grid-based Xin’anjiang model to predict future runoff change in the water source area of the South-to-North Water Diversion Middle Route Project. The results show that the monthly precipitation and temperature data ensembled by the BMA method in the baseline period of 1961-2000 were more accurate than those simulated by single climate models. The grid-based Xin’anjiang model was feasible for runoff simulations in the study area. In general, the annual runoff under three future scenarios in each region of the water source area was projected to be higher than that in the baseline period, and the magnitude of runoff increase in the period of 2021-2060 was lower than that in the period of 2061-2100. The increase of runoff volume in the water source area was lower than the increase of the planned scale of water diversion in the future, which might pose challenges to the efficient implementation of the water transfer project.