1. Observations of Mesoscale* Ocean Circulation: Present and Future Observations of Mesoscale* Ocean Circulation: Present and Future Bo Qiu Dept of Oceanography University of Hawaii Bo Qiu Dept of Oceanography University of Hawaii A UH profiling float was being deployed from R/V Revelle in Kuroshio Extension, May ‘05 Schematic of Satellite Altimetry * mesoscale = 10s~100s km

2. Altimeter-derived rms sea surface height variability (cm) Eddy “desert” Abundant mesoscale eddies

3. Altimeter-derived rms sea surface height variability (cm) Schematic of NW Pacific Ocean Circulation

4. Semi-monthly Kuroshio Extension paths (1.7m SSH contours) Stable yrs: 1993-94, 2002-04 Unstable yrs: 1996-2001, 2006-07

5. (a) Upstream KE path length (141-153°E) (b) Eddy kinetic energy (141-153°E, 32-38°N) Stable yrs: 1993-94, 2002-04 Unstable yrs: 1996-2001, 2006-07

6. Pacific Decadal Oscillations (Mantua et al. 1997) Center of action of wind forcing is in the eastern half of the N Pacific basin Positive (negative) phase of PDO generates – (+) local SSH through Ekman divergence (convergence)

7. Yearly SSH anomaly field in the North Pacific Ocean + -

8. 2004 stable 2005 unstable 20 floats 28 floats UH-KESS profiling float measurements 1500db 5 days Kuroshio Extension System Study Observing Array/Timeline

9. Distributions of semi-monthly profiling float T/S data (contours: SSH from satellite altimeters)

10. T(z) and PV(z) evolution in the KE recirculation gyre mixed layer depth subtropical mode water KESS period

11. PV values on 25.4 σ θ surface (~250m)

12. from mesoscale to submesoscale … What’s Next ? SSH snapshot from the NLOM model for 04/10/2006 Right: from the original 1/32°-resolution output Left: reduced to 1/2°-resolution (observable by current nadir-looking satellite altimeters)

13. SSH vs vorticity snapshot from the NLOM model for 04/10/2006 original 1/32°-resolutionreduced 1/2°-resolution

14. original 1/32°-resolution anticyclonic vorticity cyclonic vorticity PDF of modeled vorticity as a function of intensity Ratio of anticycl./cyclonic vorticities

15. Recommended to NASA by the NRC Decadal Survey for Oceanographic and Hydrological Applications: http://bprc.osu.edu/water 1.Point vs 200km- wide swath measurements 2.Repeat cycle: 10 days vs 3~5 days (at mid-high lat.) “Surface Water and Ocean Topography (SWOT)” Mission

16. Approximate Time and Space Scales of Oceanic Variability Chelton (2001)

18. center of PDO forcing L H L EKE levelSSHA along 34°NSSH fieldPDO index 145E165E155E135E

19. Yearly-mean sea surface height field

20. Kuroshio Extension System Study (KESS) is designed to study KE’s transition/impact from a stable to unstable state KESS period

21. T(z), S(z) and PV(z) evolution in the KE recirculation gyre mixed layer depth subtropical mode water

22. Altimeter-derived rms sea surface height variability (cm) Schematic of NW Pacific Ocean Circulation Eddy “desert” Abundant eddies