The Pacific Decadal Oscillation: Interdecadal Climate Variability and Ecosystem Impacts

1
The Pacific Decadal Oscillation Interdecadal
Climate Variabilityand Ecosystem Impacts

• Steven R. Hare
• International Pacific Halibut Commission
• hare_at_iphc.washington.edu

22 March 2001
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The first evidence Oregon coho and Alaska pink
salmon catches
Adapted from Francis and Sibley (1991). NW Env.
Journ. 7 295-307.
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The regime view
Francis and Hare (1994). Fish. Oceanogr.
3279-291 Hare and Francis (1995). CJFAS Spec.
Pub. 121 357-372
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Regime changes in SLP
Unit is millibars pressure, contour interval is 1
mb
From Hare (1996), Dissertation
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Changes after 1976/77 climate regime shift
Surface wind speed
Sea surface temperature
From Hare (1996), Dissertation
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Modes of Pacific climate variability
From Mantua et al. 1997. Bull. Amer. Soc. 78
1069-1079
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Coastwide salmon catches
From Hare et al. (1999), Fisheries 24 6-14
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Inverse Production Regimes
From Hare et al. (1999), Fisheries 24 6-14
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100 Ecosystem Indicators
From Hare and Mantua (2000), Prog. Oceanogr.
103-146
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The ecosystem footprint of the 1976/77 climate
regime shift
From Hare and Mantua (2000), Prog. Oceanogr.
103-146
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Gulf of Alaska Zooplankton Biomass
1956-1962
1980-1989
From Brodeur and Ware (1992) Fish. Oceanogr. 1
32-38
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Community reorganization in the Gulf of Alaska
following ocean climate shift
From Anderson and Piatt (2000) Mar. Ecol. Prog.
Ser 189 117-123.
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Changes in the abundance of Steller sea lions in
Alaska, 1956-1992
From Trites and Larkin (1996) Aquatic Mammals
22 153-166
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Changes in the onset of spring in the western
United States
From Cayan et al. (2001) Bull. Amer. Soc. 82
399-415
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Intensity and Location of the Aleutian Low
From Gargett Fish. Oceanogr. 6 109-117
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Conceptual model linking climate change and
salmon production
From Hare (1996), Dissertation
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The Optimal Stability Window
From Gargett (1997) Fish. Oceanogr. 6 109-117
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Conceptual Model of Climatically-Driven Ecosystem
Change
D
D
D
D
D
1 predators
forage
store
store
2 predators
store
store
2 production
From Francis et al. (1998), Fish. Oceanogr. 7
1-21.
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Halibut and salmon
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Biological changes in the halibut stock
Weight at age of Kodiak females
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Conclusions
Alaska and West Coast salmon stocks show a 70
year long pattern of inverse production Productivi
ty regimes last 20-30 years, matching the time
scale and phase reversals of the PDO Last phase
reversal occurred in 1976-77, may be in the early
stages of another Freshwater habitat must be
protected for stocks to survive poor productivity
ocean regimes
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North Pacific decadal variability since 1661
From Biondi et al. (2001) J. Climate 14 1-10.
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A (minor)1989 regime shift?
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A 1998 sea change?
SST
SLP
Summer
Winter
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PDO turns sharply negative in mid 1998