摘要
本研究基于第六次国际耦合模式比较计划(CMIP6)的末次间冰期模拟试验(lig127k)与工业革命前参照试验(piControl)数据,利用气候反馈响应分析方法,揭示了地球轨道参数改变引起的全球地表温度变化及其关键过程和机制。5个模式的分析结果表明:1)与piControl相比,lig127k试验中地球轨道参数的改变主要影响了大气层顶入射太阳辐射的季节性差异,其中北半球冬季大气层顶入射太阳辐射明显减少,全球平均为-19.60 W/m^(2),而夏季则显著增加,为20.42 W/m^(2),全年平均变化较小,仅为-0.06 W/m^(2);2)lig127k的地表温度也表现为冬季(夏季)显著的降低(升高),其中北半球冬季全球平均降温-0.61 K,夏季增温0.67 K;3)从物理过程分解来看,北半球冬季(夏季)的降温(增温)均主要来自大气层顶入射太阳辐射的贡献,其次来自水汽的正反馈贡献,而云辐射效应则抵消了大部分降温(增温);4)与工业革命前时期相比,在末次间冰期,海陆热力对比在北半球显著加强,而在南半球显著减弱,其中起正贡献的主要过程为陆地/海洋热输送和云辐射效应,而太阳辐射强迫效应和地表湍流热通量则是主要的负贡献项。
Understanding changes between paleo⁃and modern climate would enhance the understanding of how climate would response to external forcings and how to reduce uncertainty in future climate projection.In this study,by comparing the Last Interglacial experiment(lig127k)and preindustrial experiment(piControl),we have evaluated how global surface temperature would response to changes in orbital forcing and the key physical processes and mechanisms involved.The main findings based on five available models are as follows.Compared to piControl,a salient seasonal difference is found in top⁃of⁃the⁃atmosphere(TOA)downwelling shortwave radiation(rsdt).A significant increase in global⁃mean rsdt of 20.42 W/m^(2) is found for boreal summer,while boreal winter witnessed a significant decrease of-19.60 W/m^(2).Accordingly,prominent surface warming(cooling)anomaly,with a global⁃mean value of 0.67 K(-0.61 K),exists for boreal summer(winter).The overall anomaly in surface temperature is dominated by changes in rsdt,which is partly enhanced by the positive feedback from water vapor,while the most pronounced negative cloud feedback counteracted the majority of warming(cooling)effect in boreal summer(winter).Moreover,compared with piControl,in lig127k,the land⁃sea thermal contrast was significantly strengthened(weakened)over the Northern(Southern)Hemisphere,which is mainly attributed to the differences in the land/ocean heat transport and the cloud radiative effect,while differences in the TOA incoming solar radiation and the surface turbulent heat fluxes are main negative contribution terms.
作者
熊力
刘博
孙咏
XIONG Li;LIU Bo;SUN Yong(Department of Atmospheric Sciences,School of Environmental Studies,China University of Geosciences(Wuhan),Wuhan 430074,Hubei;State Key Laboratory of Tibetan Plateau Earth System,Environment and Resources(TPESER),Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101)
出处
《第四纪研究》
CAS
CSCD
北大核心
2023年第4期1010-1018,共9页
Quaternary Sciences
基金
国家自然科学基金青年基金项目(批准号:42005118)资助。
关键词
末次间冰期
地表温度变化
物理机制
气候反馈响应分析方法
地球轨道参数变化
海陆热力对比
last interglacial period
surface temperature change
physical mechanism
climate feedback response analysis method
orbital forcing chang
land⁃sea thermal contrast
