Influence of the Solar Cycle on the North Atlantic Oscillation
Influence of the Solar Cycle on the North Atlantic Oscillation
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DOI：
10.1029/2021jd035519
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发表时间：
2022-01-16
影响因子：
4.4
通讯作者：
Gray, Lesley
中科院分区：
文献类型：
--
作者：
Kuroda, Yuhji;Kodera, Kunihiko;Gray, Lesley
应用滞后回归分析、194年的历史观测和165年的地球系统模型模拟，研究了太阳活动周期对北大西洋涛动(NAO)从平流层上层到地面路径的影响。太阳信号的传播可以很好地用自上而下的机制来解释，但这种机制受到海气耦合的强烈影响。太阳信号首先出现在副热带平流层上层，作为温度信号。然后，相关的纬向风信号向下传播到地面，以响应平流层的可变性，称为极夜急流振荡。NAO信号往往出现在太阳活动高峰期的2月份。太阳信号被进一步调制，使得正的NAO信号往往在冬季出现得更早，随着与NAO相关的SST信号的出现，太阳活动高峰之后的年份越来越多。太阳-NAO信号也存在50年尺度的波动和幅度调制，但随着NAO相关SST幅度的增大，NAO幅度有增大的趋势，这表明年代际海洋动力对这些调制有很大影响。
We examine the influence of the solar cycle on the North Atlantic Oscillation (NAO) on its pathway from the upper stratosphere to the surface by applying lagged regression analyses to recent observations, historical observations covering 194 years, and an Earth system model simulation covering 165 years. The propagation of the solar signal can well be explained by a top-down mechanism, but one that was strongly affected by air-sea coupling. The solar signal first appears in the subtropical upper stratosphere as a temperature signal. The associated zonal wind signal then propagates downward to the surface in response to stratospheric variability known as the Polar-night Jet Oscillation. The NAO signal tends to appear in February during years of peak solar activity. The solar signal is further modulated such that positive NAO signals tend to appear earlier in winter with increasing years after peak solar activity associated with the appearance of the NAO-related SST signal. There are also 50-year scale fluctuations and amplitude modulations of the solar-NAO signal, but the tendency of increasing NAO amplitude with increasing NAO-related SST amplitude suggests a strong influence of decadal ocean dynamics on these modulations.