Investigating Future Arctic Sea Ice Loss and Near‐Surface Wind Speed Changes Related to Surface Roughness Using the Community Earth System Model
Investigating Future Arctic Sea Ice Loss and Near‐Surface Wind Speed Changes Related to Surface Roughness Using the Community Earth System Model
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DOI：
10.1029/2023jd038824
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发表时间：
2023-09
期刊：
影响因子：
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通讯作者：
A. DuVivier;S. Vavrus;M. Holland;L. Landrum;Christine A. Shields;Rudradutt Thaker
中科院分区：
文献类型：
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作者：
A. DuVivier;S. Vavrus;M. Holland;L. Landrum;Christine A. Shields;Rudradutt Thaker
为了应对不断变化的温室气体，北极正在经历显着而快速的转变，包括海冰范围和厚度的减少。预计北极近地表风也会增加。这项研究探讨了不同北极地区和季节的表面粗糙度和/或稳定性变化如何驱动风趋势，这一点尚未得到彻底研究。我们分析了来自社区地球系统模型版本 2 (CESM2) 大型集合体的 50 个实验，以及使用 CESM2 进行的 5 个实验，其中人工降低了海冰粗糙度以匹配公海的粗糙度。我们发现，在秋季、冬季和春季，表面越光滑，平均风速越高，平均冰速越慢。人为降低的表面粗糙度也强烈影响秋季和冬季的风速趋势，我们发现大气稳定性变化也是两个实验中驱动风趋势的重要因素。与对风的明显影响相反，海冰的平均状态和趋势在统计上无法区分，这表明近地表风并不是北极海冰消失的主要驱动因素。这项工作的两个主要结果是：（a）近地表风趋势是由表面粗糙度和近地表大气稳定性的变化驱动的，而这些变化本身又因海冰损失而变化；（b）海冰平均状态和趋势是由温室气体排放增加导致的总体变暖趋势驱动的，并且不受与地表风的耦合反馈的显着影响。
The Arctic is undergoing a pronounced and rapid transformation in response to changing greenhouse gasses, including reduction in sea ice extent and thickness. There are also projected increases in near‐surface Arctic wind. This study addresses how the winds trends may be driven by changing surface roughness and/or stability in different Arctic regions and seasons, something that has not yet been thoroughly investigated. We analyze 50 experiments from the Community Earth System Model Version 2 (CESM2) Large Ensemble and five experiments using CESM2 with an artificially decreased sea ice roughness to match that of the open ocean. We find that with a smoother surface there are higher mean wind speeds and slower mean ice speeds in the autumn, winter, and spring. The artificially reduced surface roughness also strongly impacts the wind speed trends in autumn and winter, and we find that atmospheric stability changes are also important contributors to driving wind trends in both experiments. In contrast to the clear impacts on winds, the sea ice mean state and trends are statistically indistinguishable, suggesting that near‐surface winds are not major drivers of Arctic sea ice loss. Two major results of this work are: (a) the near‐surface wind trends are driven by changes in both surface roughness and near‐surface atmospheric stability that are themselves changing from sea ice loss, and (b) the sea ice mean state and trends are driven by the overall warming trend due to increasing greenhouse gas emissions and not significantly impacted by coupled feedbacks with the surface winds.