Figure 14 Results from
two regime shift analyses
of a composite of the 100
environmental time series
in the North Pacific. The
step passes through the
mean standard deviate
within each regime. The
standard error of the 100
time series is illustrated for
each year
observed in the last century: 1890—1924 (cool), 1925—1946 (warm), 1947—1976
(warm) and 1976—at least mid-1990s (cool).
PDO cycles unleash a number of oceanic processes that cause dramatic regime
shifts in the productivity of the North Pacific.
—
Using Principal Component
Analysis to identify temporally coherent changes in 100 physical and biological
time series of the North Pacific and Bering Sea, two regime shifts in 1977 and 1989
were identified (Figures 14 and 15). They concluded that independent analyses
of climate-only and biology-only data matrices point to the 1977 changes being
pervasive throughout the Pacific climate and marine ecosystems. The shift
included an intensification of the wintertime Aleutian Low, a year-round cooling
of the Central North Pacific Ocean, and a year-round warming of the coastal
Northeast Pacific Ocean and Bering Sea (Figure 15). Exemplary consequences
are the decrease in zooplankton abundance off California, decreases in Alaskan
shrimp populations and most west coast salmon populations, and increases in
most Alaskan salmon populations. A second shift was observed in 1989,
particularly based on biological data. Climatically there was a winter cooling of
the coastal waters in the northern Gulf of Alaska and the Bering Sea, a winter
warming of the Central North Pacific Ocean, and intensification of the winter
S. R. Hare and N. J. Mantua, Prog. Oceanogr., 2000, 47, 103—145.
R. J. Beamish, D. J. Noakes, G. A. MacFarlane, L. Klyashtorin, V. V. Ivanov and V. Kurashov,
Can. J. Fish. Aquat. Sci., 1999, 56, 516—26.
T. L. Hayward, Tree, 1997, 12, 150—154.
M. Barange
74
two regime shift analyses
of a composite of the 100
environmental time series
in the North Pacific. The
step passes through the
mean standard deviate
within each regime. The
standard error of the 100
time series is illustrated for
each year
observed in the last century: 1890—1924 (cool), 1925—1946 (warm), 1947—1976
(warm) and 1976—at least mid-1990s (cool).
PDO cycles unleash a number of oceanic processes that cause dramatic regime
shifts in the productivity of the North Pacific.
—
Using Principal Component
Analysis to identify temporally coherent changes in 100 physical and biological
time series of the North Pacific and Bering Sea, two regime shifts in 1977 and 1989
were identified (Figures 14 and 15). They concluded that independent analyses
of climate-only and biology-only data matrices point to the 1977 changes being
pervasive throughout the Pacific climate and marine ecosystems. The shift
included an intensification of the wintertime Aleutian Low, a year-round cooling
of the Central North Pacific Ocean, and a year-round warming of the coastal
Northeast Pacific Ocean and Bering Sea (Figure 15). Exemplary consequences
are the decrease in zooplankton abundance off California, decreases in Alaskan
shrimp populations and most west coast salmon populations, and increases in
most Alaskan salmon populations. A second shift was observed in 1989,
particularly based on biological data. Climatically there was a winter cooling of
the coastal waters in the northern Gulf of Alaska and the Bering Sea, a winter
warming of the Central North Pacific Ocean, and intensification of the winter
S. R. Hare and N. J. Mantua, Prog. Oceanogr., 2000, 47, 103—145.
R. J. Beamish, D. J. Noakes, G. A. MacFarlane, L. Klyashtorin, V. V. Ivanov and V. Kurashov,
Can. J. Fish. Aquat. Sci., 1999, 56, 516—26.
T. L. Hayward, Tree, 1997, 12, 150—154.
M. Barange
74