1. On one year adjoint/Argo estimates Gael Forget MIT, EAPS Sept 23, 2008 ECCO2 Gael Forget MIT, EAPS Sept 23, 2008 ECCO2 Forget, Ferron, Mercier 08 (Oc. Mod.) Forget, Mercier, Ferron 08 (Oc. Mod.) Forget 09 (JPO, in rev.) Maze, Forget, Buckley, Marshall 09 (JPO, in rev.) Forget, Maze, Buckley, Marshall 09 (to be subm.)

2. Period of interest: Argo rich period, from ~2004  much consolidated data base for those recent years  room for better understanding of ocean behavior. Incentive for GCM-interpolation: complement obs. constraints with dyn./atm. constraints and extend interpretation of observations. Objection to GCM-interpolation: errors in dyn./atm. may prevent close fit to obs.  a basic matter of balance amongst the various constraints.

3. What is the trade-off in 1 year adjoint estimates: + rather large data base over one year + relatively easy to achieve close fit to obs. + (-?) GCM dynamics imposed up to seasonal cycle - (+?) adjustments to dynamics for longer time-scales Some success with 1 degree resolution, global, over 2004-5-6. close fit to obs. extended interpretation of observation … eddying follow on.

4. achieving a close fit to Argo

5. ECCO2-Argo WOA01-Argo Misfit to Argo T, 300m, 2004-2006

6. ECCO2-Argo ECCO1.3-Argo Misfit to Argo T, 300m, 2004-2006

7. OCCA-Argo ECCO1.3-Argo Misfit to Argo T, 300m, 2004-2006

8. Extended interpretation of observations

9. EDW layer at the surface 17 19 18 Sept March 17 19 18

10. 19 17 GCM-interpolated profiles | 04 | 05 | 06 | EDW layer below the surface 19 17 ARGO profiles | 04 | 05 | 06 | 0 200 400 600 800

11. Air-Sea Heat FluxOcean Mixing Divergent Flow Volume Change EDW layer volume budget

12. … eddying follow on

13. From Green’s function to Adjoint: practical for large dimension problem well-adjusted to both regional & global fitting 1 year, global, 1/6 degree: manageable computational cost fairly close fit, water mass studies, etc.

14. Components in practice Adjointok for cube sphere Line Searchok offline Controls ok for Init./forcing/mixing Observationssame as for 1 degree (?) Error covariances same as for 1 degree (?) first guess/spin-up start from 1 degree results

16. year X-X mean

17. 13 years 5000 m ECCO1.2

18. 3 years OCCA

19. 13 years 3 years ECCO1.2OCCA

21. year X-X mean

22. 13 years 3 years ECCO1.2OCCA

24. EDW layer17<T<19°C

25. EDW layer in Argo profiles

26. EDW layer in model profiles