A Mechanism for Pacific Interdecadal Resonances
A Mechanism for Pacific Interdecadal Resonances
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DOI：
10.1029/2018jc013752
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发表时间：
2018-09
期刊：
影响因子：
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通讯作者：
J. Skákala;J. Bruun
中科院分区：
文献类型：
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作者：
J. Skákala;J. Bruun
太平洋年代际变率（PIV）是一种重要的大尺度气候现象。越来越多的证据表明PIV包含三种光谱共振：十年（13 ± 1年）光谱峰值、二十年（20 ± 5年）共振和十五年（60 ± 10年）共振。虽然已经澄清了很多关于PIV背后的机制，仍然有许多悬而未决的问题，这些共振模式（特别是十五模式）的起源。我们描述的动态在太平洋盆地的玩具（延迟振荡器）模型，揭示了这些共振峰的性质。该模式表明，与由热带外大气-海洋局部耦合引起的双十年共振不同，十五年共振和可能的十年共振是由热带外和热带之间的大气和海洋遥相关引起的。我们表明，通过海洋隧道的热带外和热带之间的微小耦合足以触发太平洋海盆的十五年振荡。我们的模型还解释了（a）观测到的双十模和十五模之间的三周期锁定和（B）热带中东部和北太平洋中部的异常同步，相对符号相反。我们的结论是海洋遥相关的作用可能是低估了目前的PIV文献。
Pacific interdecadal variability (PIV) is an important large‐scale climate phenomenon. There is growing evidence that PIV contains three spectral resonances: a decadal (13 ± 1‐year) spectral peak, bidecadal (20 ± 5‐year) resonance, and a pentadecadal (60 ± 10‐year) resonance. Although much has been clarified about mechanisms behind PIV, there are still many open questions about the origin of these resonant modes (especially the pentadecadal mode). We describe dynamics in the Pacific basin by a toy (delayed oscillator) model that sheds light on the nature of these resonant peaks. The model suggests that unlike the bidecadal resonance, which results from local atmosphere‐ocean coupling in the extratropics, the pentadecadal and possibly also decadal resonances result from atmospheric and oceanic teleconnections between the extratropics and tropics. We show that a tiny coupling between extratropics and tropics through the ocean tunnel is sufficient to trigger the pentadecadal oscillation in the Pacific basin. Our model also explains (a) the observed three‐period locking between the bidecadal and pentadecadal modes and (b) the synchronization of anomalies in the central eastern tropics and central North Pacific with the opposite relative sign. We conclude that the role of oceanic teleconnections is probably underestimated in the current literature on PIV.