利用英国东英格利亚大学CRU(Climatic Research Unit)逐月气温、日本高分辨率亚洲陆地降水数据集APHRODITE (Asian Precipitation-Highly-Resolved Observational Data Integration Towards Evaluation)逐日降水资料以及耦合模式比较计划CMIP5(Coupled Model Intercomparison Project phase 5)多模式集合逐月气温、降水格点数据,评估了CMIP5多模式集合对包括印度河、恒河、湄公河、萨尔温江、伊洛瓦底江和布拉马普特拉河全区域(简称南亚大河流域)气候变化的模拟能力,并对流域20162035、2046-2065和20812100年气候变化可能趋势进行了预估。结果表明:CMIP5多模式集合对流域年平均气温的时间变化和空间分布特征有较强的模拟能力,时间空间相关系数都达到0.01的显著性水平,尤其对夏季气温的模拟要优于其他季节;对降水而言,模式对其也有较好的模拟能力,尤其是降水的季节性波动。预估结果表明:RCP2.6、4.5、8.5情景下,相对于基准期(19862005年),21世纪前期(20162035年)、中期(20462065年)和末期(2081 2100年)全流域年平均气温都有上升,且上升增幅随排放情景增大而增大,流域高海拔地区增幅较大;降水除21世纪前期RCP4.5、8.5情景下的增长趋势较小外,全流域年降水量都将增大;未来上述三段时期夏季持续升温将引起北部高海拔地区冰川的进一步消融;春季降水未来将持续增加,对全区水资源的贡献将增加;流域冬季降水的少量增加有助冰川累积和高海拔地区水资源的增加;三段时期夏季降水都有增长,洪涝发生的风险加大,极端降水事件可能增多。
英文摘要:
Based on monthly temperature and precipitation grid datasets from CRU (Climatic Research Unit), APHRODITE (Asian Precipitation-Highly-Resolved Observational Data Integration Towards Evaluation) and CMIP5 (Coupled Model Inter-comparison Project phase 5) models,the simulation ability of CMIP5 models in the South Asian River Basin is evaluated for the period 1961-2005. The projected changes of the climate change under RCP2.6、4.5和8.5 scenarios are analyzed in the South Asian River Basin during 2016-2035,2046-2065 and 20812100 subsequently. The results show that the CMIP5 multi-model ensemble can capture the temporal variation and the spatial distribution characteristics of annual mean temperature quite satisfactory, with spatial correlation between the CMIP5 and CRU data have reached the significant level of 0.01,and summer temperature simulation results are obviously better than other months. On the other hand, CMIP5 ensembles can also reproduce annual precipitation and seasonal variation of precipitation well. Based on the results,it was projected that the annual averaged temperature over the whole basin will increase under RCP2.6,4.5, 8.5 scenarios during 20162035,20462065 and 20812100 relative to the 19862005,with the largest increasing scope in the upstream area. Annual precipitation will also increase at the same time with the exception of weak decreasing trend during early-21st century under RCP4.5 and 8.5 scenarios. The persistent rising of summer temperature might accelerates melting of glaciers, and impacts the local freshwater availability. The contribution of spring precipitation to the water resources in middle and high altitude area will be enhanced. Winter precipitation in northern high altitude area will contribute to glacier accumulation and the increase of water resources,while the slight rising of winter precipitation in eastern high altitude area will increase the water resources. Summer precipitation almost increases over the whole Basin during 2016-2035, 2046-2065 and 20812100. It will increase the risk of the flood disaster. And it was projected warm events and heavy rainfall events may increase in South Asian River Basin as well.