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1. 2. 1 Mantua et al. (1997), 2 Lagerloef (1995). OCEANIC AND ATMOSPHERIC EVIDENCE FOR A PACIFIC DECADAL OSCILLATION (PDO) PHASE SHIFT AFTER 1998. Gary S. E. Lagerloef , Earth and Space Research, Seattle, WA, USA Patrick Cummins, Institute of Ocean Sciences, Sidney BC, Canada
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1 2 1Mantua et al. (1997), 2Lagerloef (1995) OCEANIC AND ATMOSPHERIC EVIDENCE FOR A PACIFIC DECADAL OSCILLATION (PDO) PHASE SHIFT AFTER 1998 Gary S. E. Lagerloef, Earth and Space Research, Seattle, WA, USA Patrick Cummins, Institute of Ocean Sciences, Sidney BC, Canada Jeffrey Polovina, NOAA/NMFS, Honolulu, HI, USA Gary T. Mitchum, University of South Florida, St. Petersburg, FL, USA G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
P G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
P G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
Tide Gage Network Data, G. Mitchum, USF mm mm G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
J. Polovina, NMFS CTD Transect Data G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
Dynamic Height contours (altimeter anomalies plus mean Levitus) before and after 1998. G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
h is pycnocline depth WE is Ekman pumping velocity -1 is the dissipation time scale; ~1.5-2 years Cummins and Lagerloef, JPO, (2002) Freeland et al., DSR, (1997) Ekman Pumping Model of the Pycnocline Hasselmann (1976), Frankignoul and Hasselmann (1977) G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
Ekman Pumping Pycnocline Displacement Topex/Poseidon Sea Level EOF1 EOF1 EOF2 EOF2 Anomaly EOF Patterns G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
SST Anomaly EOF1 G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
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A Few Concluding Remarks • Observed sea level, SST, wind stress and SLP anomalies all show an abrupt transition to the ‘cold phase’ of the PDO during 1998. • The modeled pycnocline depth variability, along with the altimeter data, indicate large scale upper ocean changes persisting to the present. • The ‘cold phase’ weakened during the 2002 El Nino and now appears to be gaining strength again in 2003. • South Pacific variations show the basin-wide inter-hemisphere pattern. • Will this phase persist for the next decade or two or three….. Who wants to wager?? G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum
Freeland, H. et al. (1997) Deep- Sea Res., 44, 2117- 2129.Hasselmann, K. (1976) Tellus, 28, 473- 485.Lagerloef, G. (1995) J. Phys. Oceanogr., 25, 2242- 2258.Mantua, N. J. et al. (1997) Bull. Am. Met. Soc., 78, 1069- 1079. G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum