气候反馈对温度空间模态的依赖性:IPCC AR6解读

Dependence of climate feedbacks on temperature patterns:interpreting IPCC AR6

摘要:

依据政府间气候变化专门委员会(IPCC)第六次评估报告(AR6)第一工作组(WGI)报告第七章的内容,详细解读了气候反馈对温度空间模态的依赖性。与第五次评估报告(AR5)相比,AR6对于地表温度空间模态演变在驱动气候反馈变化中作用的理解已有了较大提升。AR6认为,在温室气体强迫下,北极在21世纪的增温幅度很可能大于全球平均水平,南极在百年时间尺度上的增温要强于热带地区;同时,在百年时间尺度上热带太平洋东部的变暖幅度大于西部,即热带太平洋东-西向海表温度梯度减弱。极地放大效应(尤其是南半球)和热带太平洋东-西向海表温度梯度随时间的变化是影响未来气候反馈如何演变的关键因素。随着地表增温空间模态的演变,气候反馈(尤其云反馈)预计将在未来几十年的时间尺度上逐渐增加,对气候变化更多是起放大作用。

Abstract:

Based on the content of Chapter 7 from the Sixth Assessment Report (AR6) contributed by the Intergovernmental Panel on Climate Change (IPCC) Working Group I (WGI),this paper interprets the dependence of climate feedbacks on temperature patterns in detail.Compared with the Fifth Assessment Report (AR5),the understanding of the relationship between transient changes in climate feedback and evolving spatial patterns of surface temperature has been greatly improved in AR6.The assessments show that under greenhouse gas forcing,it is very likely that the warming in the Arctic will be more pronounced than on global average over the 21st century.On centennial timescales,the Antarctic will warm more than the tropics and the tropical Pacific Ocean east-west sea surface temperature (SST) gradient will weaken,with greater warming in the east than the west.AR6 identifies changes in the degree of polar amplification over time,particularly in the Southern Hemisphere,and changes in the tropical Pacific Ocean east-west SST gradient over time as key factors affecting how climate feedbacks may evolve in the future.Climate feedbacks,particularly from clouds,are expected to become less negative (more amplifying) on multi-decadal timescales as the spatial pattern of surface warming evolves.