早全新世与未来10 ka后东亚区域气候变化对比:自然强迫和人类活动的影响  

A comparative study of climate change in East Asia during the Early Holocene and 10000 years after present:Roles of natural forcing and human activities

作　　者：李新周[1,2] 刘晓东[1,3] Li Xinzhou;Liu Xiaodong(State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi'an 710061,Shaanxi;CAS Center for Excellence in Tibetan Plateau Earth Sciences,Chinese Academy of Sciences,Beijing 100101;University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]中国科学院地球环境研究所,黄土与第四纪地质国家重点实验室,陕西西安710061 [2]中国科学院青藏高原地球科学卓越创新中心,北京100101 [3]中国科学院大学,北京100049

出　　处：《第四纪研究》2020年第6期1611-1621,共11页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:41991254和41690115);中国科学院(B类)战略性先导科技专项项目(批准号:XDB26000000)共同资助。

摘　　要：以准两万年周期为特征的地球岁差参数变化所引起的太阳辐射变动是造成万年尺度亚洲季风气候变化的主要驱动力。现代地球近日点时间出现在冬季12月份,但在约1万年(10 ka)前的早全新世和未来10 ka后的未来,近日点时间均出现在夏季6月份,因而对北半球气候施以最强的岁差强迫。未来10 ka后气候除了受轨道改变引起太阳辐射变化强迫外,主要受人类活动排放温室气体影响。文章利用一个全球气候模式完成了早全新世、未来10 ka和现代(包括工业革命前)这3个时间段的一系列敏感性试验,对比检查了自然强迫和人类活动对东亚区域气候的可能影响。模拟结果表明:在仅有自然强迫时,与工业革命前相比,岁差引起的太阳辐射变化可造成早全新世及未来10 ka后东亚区域夏季变暖,冬季变冷,东亚夏季风和冬季风均显著增强。早全新世东亚区域夏季降水也明显增加,但因自然强迫下未来10 ka后温室气体浓度偏低,导致夏季降水出现减少现象。未来人类活动带来的温室气体浓度增加将引起地表温度显著增温,使东亚夏季风增强而冬季风减弱。在同时考虑自然强迫和人类活动影响后,东亚夏季降水进一步增加,未来10 ka后东亚夏季降水将较工业革命前增加9.87%,而早全新世只增加了2.66%。同时,在自然和人类共同作用下10 ka后东亚冬季风将减弱,而在仅有自然强迫的早全新世东亚冬季风却是增强的。这一研究说明,虽然未来10 ka后是岁差强迫最强盛时期,但人类活动可能会扰乱岁差尺度上东亚区域气候的自然演变规律,在未来气候预估中必须综合考虑自然强迫和人为因子共同影响。It is generally accepted within the scientific community that within the glacial-interglacial cycles of the Quaternary,over 100 ka cycles,the colder glacial period generally lasts 70 ka to 90 ka.In contrast,the relatively warm interglacial period between two glacial periods usually lasts 10 ka to 30 ka.The Last Glacial Maximum appeared at approximately 21 ka before present(B.P.),after which the Earth's climate entered the deglacial period and Holocene.From the pattern of the glacial-interglacial cycle,it is clear that the Earth's climate is currently entering or should soon enter the next glacial period.However,observations and numerical simulations in recent decades have confirmed that human-induced dramatic increases in the concentrations of greenhouse gases in the atmosphere since the Industrial Revolution is the dominant driver of global warming.The Earth's climate system may be undergoing a process of transition from a system subject to a single natural forcing to a system subject to both natural and human-related drivers.Human-related drivers may even have a more significant effect on the global climate compared to natural factors,and this effect will continue for a long time.The effects of polar ice sheets on the global climate have gradually diminished since the Early Holocene,and variations in solar radiation resulting from variations in the Earth's precession parameters characterized by a quasi ca.20 ka cycle is the main driving force of the changes to the Asian monsoon on a 10 ka time scale.Although the Earth's perihelion currently falls in December,during the Early Holocene and by 10 ka after present,the perihelion is in June,representing the strongest precession forcing on the climate of the Northern Hemisphere.Over the next 10 ka,it is generally accepted that emissions of greenhouse gases from human activities in combination with a change in solar radiation resulting from the Earth's orbital forcing will be the main drivers of the global climate.Under natural conditions,changes in atmospheric greenh

关 键 词：人类活动 自然强迫 岁差尺度 东亚季风区 

分 类 号：P532[天文地球—古生物学与地层学] P534.632[天文地球—地质学]