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.