Di Lorenzo, E., N. Schneider, K. M. Cobb, P. J. S. Franks, K. Chhak, A. J. Miller,
J. C. McWilliams, S. J. Bograd, H. Arango, E. Curchitser, T. M. Powell and P. Riviere, 2008:
North Pacific Gyre Oscillation links ocean climate and ecosystem change.
Geophysical Research Letters, 35, L08607, doi:10.1029/2007GL032838.
Abstract.
Decadal fluctuations in salinity, nutrients, chlorophyll, a variety of zooplankton
taxa, and fish stocks in the Northeast Pacific are often poorly correlated with the
most widely-used index of large-scale climate variability in the region - the Pacific
Decadal Oscillation (PDO). We define a new pattern of climate change, the North
Pacific Gyre Oscillation (NPGO) and show that its variability is significantly
correlated with previously unexplained fluctuations of salinity, nutrients and
chlorophyll. Fluctuations in the NPGO are driven by regional and basin-scale
variations in wind-driven upwelling and horizontal advection . the fundamental
processes controlling salinity and nutrient concentrations. Nutrient fluctuations
drive concomitant changes in phytoplankton concentrations, and may force similar
variability in higher trophic levels. The NPGO thus provides a strong indicator of
fluctuations in the mechanisms driving planktonic ecosystem dynamics. The NPGO
pattern extends beyond the North Pacific and is part of a global-scale mode of
climate variability that is evident in global sea level trends and sea surface
temperature. Therefore the amplification of the NPGO variance found in
observations and in global warming simulations implies that the NPGO may play an
increasingly important role in forcing global-scale decadal changes in marine
ecosystems.
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