Auad, G., J. P. Kennett and A. J. Miller, 2003:
The North Pacific Intermediate Water response to a modern climate shift
Journal of Geophysical Research, 108, 3349, doi:10.1029/2003JC001987.
Abstract.
Oceanic observations and an isopycnal ocean model simulation are
used to investigate the response
of North Pacific Intermediate Water (NPIW)
to atmospheric forcing associated with the well known
1976-77 climate regime shift to a warm regime.
The model reproduces numerous features of NPIW
including distribution, depth, temperature and salinity.
Changes in NPIW associated with the
climate shift in the California coastal region were
strongly influenced by an anomalous poleward
flow at depth (300-1100m).
This current transports old, high salinity, low oxygen intermediate
waters from the northern tropics to the midlatitudes.
For depths below the mixed layer, the
model reproduces observed changes in salinity,
nitrates and to some extent oxygen, thus suggesting
that advective/diffusive processes are dominant in determining
their concentrations below
300m, isolated from the surface effects of
direct atmospheric forcing and biological processes.
These changes are structurally similar to those induced
by much larger, abrupt climate changes
at the end of the last glacial episode.
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