Impact of industrial versus biomass burning aerosols on the Atlantic Meridional Overturning Circulation
Impact of industrial versus biomass burning aerosols on the Atlantic Meridional Overturning Circulation
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DOI：
10.1038/s41612-024-00602-8
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发表时间：
2024-03
影响因子：
9
通讯作者：
Robert J. Allen;Claire Vega;Eva Yao;Wei Liu
中科院分区：
文献类型：
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作者：
Robert J. Allen;Claire Vega;Eva Yao;Wei Liu
海洋的主要环流系统，大西洋经向翻转环流（AMOC），正在放缓。这种减弱与温室气体增加导致的变暖以及最近工业气溶胶污染的减少是一致的。然而，生物质燃烧气溶胶对AMOC的影响仍未得到研究。在这里，我们使用社区地球系统模型版本1大型Ensemble来量化两种气溶胶类型对AMOC的影响。尽管北大西洋生物质燃烧气溶胶的变化相对较小，但发生了显着的AMOC演变，包括从1920年到1970年的减弱，然后是AMOC加强。这些变化在很大程度上与工业气溶胶下相应的AMOC演变不同步。AMOC响应是由短波辐射改变引起的海面密度通量的热变化引起的。另一个涉及北大西洋海平面压力梯度的动力学机制在生物质燃烧气溶胶下很重要。AMOC引起的海洋盐度通量辐合起着正反馈的作用。我们的研究结果表明，生物质燃烧气溶胶加强了20世纪初与温室气体相关的AMOC减弱，也部分静音工业气溶胶对AMOC的影响。最近野火的增加表明，生物质燃烧气溶胶可能是未来AMOC变化的重要驱动因素。
The ocean’s major circulation system, the Atlantic Meridional Overturning Circulation (AMOC), is slowing down. Such weakening is consistent with warming associated with increasing greenhouse gases, as well as with recent decreases in industrial aerosol pollution. The impact of biomass burning aerosols on the AMOC, however, remains unexplored. Here, we use the Community Earth System Model version 1 Large Ensemble to quantify the impact of both aerosol types on the AMOC. Despite relatively small changes in North Atlantic biomass burning aerosols, significant AMOC evolution occurs, including weakening from 1920 to ~1970 followed by AMOC strengthening. These changes are largely out of phase relative to the corresponding AMOC evolution under industrial aerosols. AMOC responses are initiated by thermal changes in sea surface density flux due to altered shortwave radiation. An additional dynamical mechanism involving the North Atlantic sea-level pressure gradient is important under biomass-burning aerosols. AMOC-induced ocean salinity flux convergence acts as a positive feedback. Our results show that biomass-burning aerosols reinforce early 20th-century AMOC weakening associated with greenhouse gases and also partially mute industrial aerosol impacts on the AMOC. Recent increases in wildfires suggest biomass-burning aerosols may be an important driver of future AMOC variability.