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Deciphering the Role of Ocean Dynamics in Equatorial Pacific Decadal Variability
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  • Yu Zhang,
  • Shi-Yun Yu,
  • Shang-Ping Xie,
  • Dillon J. Amaya,
  • Qihua Peng,
  • Yu Kosaka,
  • Xiaopei Lin,
  • Jun-Chao Yang,
  • Sarah M. Larson,
  • Arthur J. Miller,
  • Lei Fan
Yu Zhang
Ocean University of China
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Shi-Yun Yu
Ocean University of China
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Shang-Ping Xie
UCSD
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Dillon J. Amaya
University of Colorado Boulder
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Qihua Peng
SCSIO
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Yu Kosaka
University of Tokyo
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Xiaopei Lin
Physical Oceanography Laboratory, Ocean University of China

Corresponding Author:[email protected]

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Jun-Chao Yang
Ocean University of China
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Sarah M. Larson
North Carolina State University
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Arthur J. Miller
Scripps Institution of Oceanography
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Lei Fan
Ocean University of China
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Abstract

Equatorial Pacific decadal variability (EPDV) modulates global climate. Although EPDV is suggested to be generated by both air-sea thermodynamically coupled slab ocean models (SOM) and fully coupled dynamic ocean models (DOM), the reason of EPDV simulated by the two distinct hierarchies of models remains unclear. This ambiguity arises from a gap in the dynamical framework between SOM and DOM. To fill the gap, we conducted a novel experiment (Clim-tau) that retains only the effects of thermodynamic coupling and mean ocean current on EPDV (without anomalous ocean current). We showed that in Clim-tau, thermodynamic-driven EPDV as in SOM is largely damped by equatorial Pacific mean upwelling; whereas involving anomalous ocean current as in DOM, the damped EPDV will be further amplified. Finally, we discussed the role of ocean dynamics in the observed EPDV. Our study highlights that SOM may misinterpret the physical mechanisms in the regions where ocean dynamics is important.