Di Lorenzo, E., T. Xu, Y. Zhao, M. Newman, A. Capotondi,
S. Stevenson, D. J. Amaya, B.T. Anderson, R. Ding,
J.C. Furtado, Y. Joh, G. Liguori, J. Lou, A. J. Miller,
G. Navarra, N. Schneider, D. J. Vimont, S. Wu and H. Zhang, 2023:
Modes and mechanisms of Pacific decadal-scale variability.
Annual Review of Marine Science, 15, 249-275.
Abstract.
The modes of Pacific decadal-scale variability (PDV), traditionally defined
as statistical patterns of variance, reflect to first order
the ocean.s integration (e.g., reddening) of atmospheric forcing that
arises from both a shift and a change in strength of the
climatological (time-mean) atmospheric circulation. While
these patterns concisely describe PDV, they do not
distinguish among the key dynamical processes driving the evolution of PDV anomalies,
including atmospheric and ocean teleconnections and coupled
feedbacks with similar spatial structures that operate
on different timescales. In this review, we synthesize
past analysis using an empirical
dynamical model constructed from monthly ocean surface
anomalies drawn from several reanalysis products, showing that the
PDV modes of variance result from two fundamental low-frequency
dynamical eigenmodes: the North Pacific.central Pacific (NP-CP)
and Kuroshio-Oyashio Extension (KOE) modes. Both
eigenmodes highlight how two-way tropical.extratropical teleconnection
dynamics are the primary mechanisms energizing and synchronizing the basin-scale footprint of
PDV. While the NP-CP mode captures interannual- to
decadal-scale variability, the KOE mode is linked to the basin-scale
expression of PDV on decadal to multidecadal timescales,
including contributions from the South Pacific.
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