1. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum1 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 1 Mantua et al. (1997), 2 Lagerloef (1995) 1 2

2. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum2 P

3. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum3 P

4. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum4 mm Tide Gage Network Data, G. Mitchum, USF

5. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum5 J. Polovina, NMFS CTD Transect Data

6. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum6 Dynamic Height contours (altimeter anomalies plus mean Levitus) before and after 1998.

7. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum7 Ekman Pumping Model of the Pycnocline Cummins and Lagerloef, JPO, (2002) Freeland et al., DSR, (1997) Hasselmann (1976), Frankignoul and Hasselmann (1977) h is pycnocline depth W E is Ekman pumping velocity -1 is the dissipation time scale; ~1.5-2 years

8. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum8 Anomaly EOF Patterns Topex/Poseidon Sea Level EOF1 EOF2 Ekman Pumping Pycnocline Displacement EOF1 EOF2

9. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum9 SST Anomaly EOF1

10. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum10 P

11. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum11

12. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum12

13. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum13

14. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum14 A Few Concluding Remarks 1.Observed sea level, SST, wind stress and SLP anomalies all show an abrupt transition to the ‘cold phase’ of the PDO during 1998. 2.The modeled pycnocline depth variability, along with the altimeter data, indicate large scale upper ocean changes persisting to the present. 3.The ‘cold phase’ weakened during the 2002 El Nino and now appears to be gaining strength again in 2003. 4.South Pacific variations show the basin-wide inter- hemisphere pattern. 5.Will this phase persist for the next decade or two or three….. Who wants to wager??

15. IUGG-Sapporo JSP01 The Decadal to Centennial Variability of the Ocean and Atmosphere 30 Jun 2003G. Lagerloef, P. Cummins, J. Polovina, G. Mitchum15 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.