Reduced European aerosol emissions suppress winter extremes over northern Eurasia
Reduced European aerosol emissions suppress winter extremes over northern Eurasia
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DOI：
10.1038/s41558-020-0693-4
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发表时间：
2020-02
影响因子：
30.7
通讯作者：
Yuan Wang;T. Le;Gang Chen;Y. Yung;H. Su;J. Seinfeld;Jonathan H. Jiang
中科院分区：
文献类型：
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作者：
Yuan Wang;T. Le;Gang Chen;Y. Yung;H. Su;J. Seinfeld;Jonathan H. Jiang
冬季极端天气事件因其严重的影响而受到广泛关注，但其年代际变化的主导因子尚未明确。在这里，我们表明，由于地球空间重新分布的人为气溶胶的辐射强迫主要决定了在北方半球冬季极端天气的空间变化在1970-2005年，一个独特的全球气溶胶强迫的过渡期。在此期间，当地的Rossby波活动和极端事件（前10%的波振幅）在高纬度地区，主要是在欧亚大陆北方表现出显着的下降趋势。长期观测数据和最先进的气候模型相结合，揭示了人为气溶胶在冬季急流、行星波活动和地面温度变化上的明确特征。特别是，欧洲气溶胶减少导致的变暖增强了急流极侧的纬向温度梯度，加强了纬向风，导致欧亚大陆北方极端事件的显著抑制。这些结果揭示了气溶胶强迫如何影响大尺度大气动力学，并说明了人为气溶胶及其时空变异在评估历史和未来气候中极端天气驱动因素方面的重要性。
Winter extreme weather events receive major public attention due to their serious impacts, but the dominant factors regulating their interdecadal trends have not been clearly established,. Here, we show that the radiative forcing due to geospatially redistributed anthropogenic aerosols mainly determined the spatial variations of winter extreme weather in the Northern Hemisphere during 1970–2005, a unique transition period for global aerosol forcing. Over this period, the local Rossby wave activity and extreme events (top 10% in wave amplitude) exhibited marked declining trends at high latitudes, mainly in northern Eurasia. The combination of long-term observational data and a state-of-the-art climate model revealed the unambiguous signature of anthropogenic aerosols on the wintertime jet stream, planetary wave activity and surface temperature variability on interdecadal timescales. In particular, warming due to aerosol reductions in Europe enhanced the meridional temperature gradient on the jet’s poleward flank and strengthened the zonal wind, resulting in significant suppression in extreme events over northern Eurasia. These results exemplify how aerosol forcing can impact large-scale extratropical atmospheric dynamics, and illustrate the importance of anthropogenic aerosols and their spatiotemporal variability in assessing the drivers of extreme weather in historical and future climate.