“一带一路”区域未来气候变化预估

CMIP5 projected changes in mean and extreme climate in the Belt and Road region

利用耦合模式比较计划第5阶段(CMIP5)提供的18个全球气候模式的模拟结果,预估了3种典型浓度路径(RCP2.6、RCP4.5、RCP8.5)下“一带一路”地区平均气候和极端气候的未来变化趋势。结果表明:在温室气体持续排放情景下,“一带一路”地区年平均气温在未来将会持续上升,升温幅度随温室气体浓度的增加而加大。在高温室气体排放情景(RCP8.5)下,到21世纪末期,平均气温将普遍升高5℃以上,其中北亚地区升幅最大,南亚和东南亚地区升幅最小。对于降水的变化,预估该区域大部分地区的年降水量将增加,其中西亚和北亚增加最为明显,而且在21世纪中期,RCP2.6情景下的增幅要比RCP4.5和RCP8.5情景下的偏大,而在21世纪后期,RCP8.5情景下降水的增幅比RCP2.6和RCP4.5情景下的偏大。未来极端温度也将呈升高的趋势,增温幅度高纬度地区大于低纬度地区、高排放情景大于低排放情景。而且在高纬度区域,极端低温的增暖幅度要大于极端高温的增幅。连续干旱日数在北亚和东亚总体呈现减少趋势,而在其他地区则呈增加趋势。极端强降水在“一带一路”区域总体上将增强,增强最明显的地区位于南亚、东南亚和东亚。

In this study,based on the simulation results from 18 CMIP5 models,the future changes of the mean and extreme climate in the Belt and Road under three representative concentration pathways(RCP2.6,RCP4.5 and RCP8.5)are projected.The results show that the annual temperature in the Belt and Road would continue to rise in the future as a response to the continuous emission of greenhouse gases,and in addition the rising amplitude tends to increase with the enhancement of greenhouse gas emission.Under the high emission(RCP8.5)scenario,the increase of annual temperature would generally exceed 5℃by the end of the 21st century,with the greatest warming occurring in West Asia and North Asia,and the smallest in South Asia and Southeast Asia.The annual precipitation is projected to increase over most of the region,particularly in West Asia and North Asia,where the projected increases under the RCP2.6 scenario is greater than that under the RCP4.5 and RCP8.5 scenarios by the middle of the 21st century,while the case is reversed with larger increase in the RCP8.5 scenario than in the RCP2.6 and RCP4.5 scenarios by the end of the 21st century.Extreme temperature is also projected to increase in the future,with the warming amplitude in the high latitudes being greater than in the low latitudes,and that under the high emission scenario greater than under the low emission scenario.Moreover,the increase in the extreme low temperature is greater than that of the extreme high temperature over the high latitudes.The number of consecutive dry days is projected to decrease in North Asia and East Asia,while increasing in other regions.The projected extreme precipitation tends to intensify in the Belt and Road,and the greatest intensification appears in South Asia,Southeast Asia and East Asia.