Miller, A. J., and N. Schneider, 2000:
Interdecadal climate regime dynamics in the North Pacific Ocean:
Theories, observations and ecosystem impacts
Progress in Oceanography, 47,
Basin-scale variations in oceanic physical variables are thought to
organize patterns of biological response across the Pacific Ocean
over decadal time scales.
Different physical mechanisms can be responsible for the diverse basin-scale
patterns of sea-surface temperature (SST), mixed-layer depth,
thermocline depth, and horizontal currents,
although they are linked in various ways.
In light of various theories and observations,
we interpret observed basinwide patterns of
decadal-scale variations in upper-ocean temperatures.
Evidence so far indicates that large-scale perturbations
of the Aleutian Low generate temperature anomalies in the
central and eastern North Pacific due to the combined
action of net surface heat flux, turbulent mixing and
Ekman advection. The surface-forced temperature anomalies
in the central North Pacific
subduct and propagate southwestwards in the ocean thermocline
to the subtropics but apparently do not reach the equator.
The large-scale Ekman pumping due to changes of the
Aleutian Low forces western-intensified thermocline depth
anomalies that are approximately consistent with Sverdrup theory.
These thermocline changes are
associated with SST anomalies
in the Kuroshio/Oyashio
Extension that are of the same sign as
those in the central North Pacific, but lagged
by several years.
The physics of the possible feedback from the SST
anomalies to the Aleutian Low, which might close
a coupled ocean-atmosphere mode of decadal variability,
is poorly understood and is an area of active research.
The possible responses of North Pacific Ocean ecosystems to these complicated
physical patterns is summarized.