On the mechanisms of decadal variability of the North Pacific Gyre Oscillation over the 20th century
On the mechanisms of decadal variability of the North Pacific Gyre Oscillation over the 20th century
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DOI：
10.1002/2014jc010660
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发表时间：
2015-09
影响因子：
--
通讯作者：
Daling Li Yi;Liping Zhang;Lixin Wu
中科院分区：
文献类型：
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作者：
Daling Li Yi;Liping Zhang;Lixin Wu
利用简单海洋资料同化（SODA）再分析的长期积分资料，研究了20世纪世纪北太平洋环流振荡（NPGO）的年代际变化。NPGO反映的第二个主导模式的海面高度（SSH）的变化在SODA，与北南偶极子结构在东北太平洋。该地区的SSH异常表现出明显的年代际变化，在18年左右出现一个显著的频谱峰值。上层海洋热量收支表明，这种偶极子结构与NPGO主要是由于异常Ekman泵和Ekman平流引起的地面风。SODA再分析中的NPGO模态来源于大气随机噪声（北太平洋涛动），该噪声具有双曲偶极子型，但没有优选的时间尺度。海洋行星波，特别是平流斜压模，大气随机噪声的集成导致了一个空间共振与首选的年代际时间尺度。最后，对现有研究的局限性进行了讨论。
The decadal variability of the North Pacific gyre oscillation (NPGO) over the 20th century is examined from a long-term integration of the Simple Ocean Data Assimilation (SODA) reanalysis. The NPGO is reflected by the second dominant pattern of sea surface height (SSH) variability in SODA, with a north-south dipole structure over the northeast Pacific. SSH anomalies in this region exhibit distinct decadal variability with a significant spectrum peak at approximately 18 years. The upper-ocean heat budget reveals that this dipole structure associated with the NPGO is predominantly due to the anomalous Ekman pumping and Ekman advection induced by the surface wind. The NPGO mode in SODA reanalysis originates from atmosphere stochastic noise (North Pacific Oscillation) which has a meridional dipole pattern but no preferred time scale. The oceanic planetary wave, particularly the advective baroclinic mode, integration of atmospheric stochastic noise leads to a spatial resonance with preferred decadal time scale. The limitation of current study is also discussed.