Ultrafast Arctic amplification and its governing mechanisms
Ultrafast Arctic amplification and its governing mechanisms
复制标题
DOI：
10.1088/2752-5295/ace211
复制
发表时间：
2023-07
期刊：
影响因子：
--
通讯作者：
Tyler P. Janoski;M. Previdi;G. Chiodo;Karen L. Smith;L. Polvani
中科院分区：
文献类型：
--
作者：
Tyler P. Janoski;M. Previdi;G. Chiodo;Karen L. Smith;L. Polvani
北极放大（AA），定义为与全球平均水平相比北极变暖的增强，是历史观测和未来气候模拟的一个强大特征。尽管许多研究调查AA机制，其相对重要性仍然存在争议。在这项研究中，我们研究了这些机制的不同时间尺度，以提高我们对AA的根本原因的理解。我们使用社区地球系统模型v1，大包围配置（CESM-LE），产生2年的模拟受到瞬间翻两番的CO2的大合奏。我们表明，AA出现几乎立即（天内）CO2增加之前，任何重大损失的北极海冰已经发生。通过对大气柱的详细能量收支分析，我们确定了模拟期间AA机制随时间变化的贡献。此外，我们还研究了这些机制对CO2翻两番季节的依赖性。我们发现，由CO2强迫驱动的北极和全球平均水平之间的不同潜热通量异常导致的地表热吸收，是短（1个月）时间尺度上最重要的AA贡献者。我们的研究结果证实了AA是一个固有的快速大气响应辐射强迫，揭示了一个新的AA机制。
Arctic amplification (AA), defined as the enhanced warming of the Arctic compared to the global average, is a robust feature of historical observations and simulations of future climate. Despite many studies investigating AA mechanisms, their relative importance remains contested. In this study, we examine the different timescales of these mechanisms to improve our understanding of AA’s fundamental causes. We use the Community Earth System Model v1, Large Ensemble configuration (CESM-LE), to generate large ensembles of 2 years simulations subjected to an instantaneous quadrupling of CO2. We show that AA emerges almost immediately (within days) following CO2 increase and before any significant loss of Arctic sea ice has occurred. Through a detailed energy budget analysis of the atmospheric column, we determine the time-varying contributions of AA mechanisms over the simulation period. Additionally, we examine the dependence of these mechanisms on the season of CO2 quadrupling. We find that the surface heat uptake resulting from the different latent heat flux anomalies between the Arctic and global average, driven by the CO2 forcing, is the most important AA contributor on short (1 month) timescales. Our results confirm that AA is an inherently fast atmospheric response to radiative forcing and reveal a new AA mechanism.