全球增温1.5℃和2.0℃对淮河中上游径流影响预估

Projection of the Impacts of Global Warming of 1.5℃ and 2.0℃ on Runoff in the Upper-Middle Reaches of Huaihe River Basin

论文应用第5次耦合模式比较计划(Coupled Model Intercomparison Project Phase 5,CMIP5)中5个全球气候模式(Global Climate Models,GCMs)和3种典型浓度路径(Representative Concentration Pathways,RCPs)在全球增温1.5℃和2.0℃下的预估结果,分析了淮河中上游地区未来的气候变化特征。进一步基于SWAT(Soil and Water Assessment Tool)水文模型定量预估了气候变化对该区域径流量的影响,并量化了预估结果的不确定性。结果表明:SWAT模型在淮河中上游对月径流量具有较好的模拟能力。在全球增温1.5℃和2.0℃下,淮河中上游年平均气温分别较基准期(1986—2005年)增加1.1℃和1.7℃;年降水量较基准期分别相应增加4%和7%;基于SWAT模型预估的年径流量较基准期分别增加5%和8%。未来气候变化不会改变月径流分布特征,年内径流仍集中在盛夏和初秋(6—9月)。预估的月丰水流量明显增加,尤其当全球增温达到2.0℃后,出现洪涝的风险明显增大。未来降水量和径流量预估都存在较大的不确定性,不确定性主要来源于GCMs,在全球增温2.0℃下预估的不确定性更大。

The climate change in the upper-middle reaches of Huaihe River Basin was projected in scenarios of 1.5 ℃ and 2.0 ℃ global warming using five General Circulation Models(GCMs) of the Coupled Model Intercomparison Project Phase 5(CMIP5) and three Representative Concentration Pathways(RCPs). Then the hydrological responses to climate change were simulated using hydrological model SWAT(Soil Water Assessment Tool), and the uncertainties of the results were estimated and compared quantitatively. This study draws following conclusions: 1) The simulation results of SWAT model are in agreement with discharge observations very well in both calibration period and validation period, so it is feasible to apply SWAT model in estimating the impacts of climate change. 2) The annual average temperature in the upper-middle reaches of Huaihe River Basin will rise by 1.1 ℃ and1.7 ℃ compared to the baseline(1986-2005). The annual precipitation will increase by 4% and7% in scenarios of 1.5 ℃ and 2.0 ℃ global warming respectively. The ensemble mean(MME)annual runoff simulated based on SWAT will increase by 5% and 8% in scenarios of 1.5 ℃ and2.0 ℃ global warming respectively. 3) The projected monthly runoff distribution will not change, and runoff will be concentrated in midsummer and early autumn(from June to September). Global warming will increase monthly high runoff dramatically, especially 2.0 ℃global warming. As a result, the risk of flooding would increase obviously in the future,especially by 2.0 ℃ global warming. 4) There are big uncertainties in projected precipitation and runoff, and the uncertainty comes mainly from GCMs structure, especially in the scenario of 2.0 ℃ global warming.