Changes in polar amplification in response to increasing warming in CMIP6

Abstract

The climate in polar regions has experienced an obvious warming amplification due to global warming. In this study, the changes in polar amplification are analyzed in response to feedback mechanisms (including Planck, lapse rate, cloud, water vapor, albedo feedback, CO2 radiative forcing, ocean heat uptake, and atmospheric heat transport) under three warming scenarios in CMIP6—namely, SSP1-2.6, SSP2-4.5, and SSP5-8.5. The results show that, by quantifying the warming contribution of different feedback mechanisms to surface air temperature with the “radiative kernel” method, Arctic amplification (AA) is stronger than Antarctic amplification (ANA), mostly resulting from the lapse rate feedback, followed by the albedo and Planck feedbacks. Furthermore, ocean heat uptake causes stronger polar warming in winter than in summer. During winter, the lapse rate feedback causes a larger AA than ANA. The intermodel spread for both AA and ANA decrease with increasing strength of global warming from SSP1-2.6 to SSP5-8.5, and the dominant mechanisms are the Planck, lapse rate, albedo, and ocean heat uptake feedbacks. These findings help to enhance our understanding of polar regions’ responses to different strengths of global warming.摘要由于全球变暖, 极地地区的气候经历了明显的变暖放大.在本项研究中, 我们根据CMIP6模式的三种变暖情景 (SSP1-2.6,SSP2-4.5和SSP5-8.5) 下, 极地放大变化对各个反馈机制 (包括普朗克,温度递减率,云,水蒸气,反照率反馈,CO2强迫,海洋热吸收和大气热传输) 的响应进行了分析.结果表明, 通过用"辐射核"方法量化不同反馈机制对地表温度的增温贡献, 北极放大 (AA) 强于南极放大 (ANA) , 由温度递减率反馈主导, 其次是反照率和普朗克反馈.此外, 海洋的热吸收导致冬季比夏季有更强的极地变暖.在冬季, 温度递减率反馈主导了AA大于ANA.AA和ANA的模式间差异随着全球变暖的增强而减小.