1. Towards Quantitative Evaluation of Ocean Tracer Model Simulations J. C. Orr 1, K. G. Caldeira 2, K. E. Taylor 3 and the OCMIP Group* 1 LSCE/CEA/CNRS and IPSL (France) 2 LLNL 3 PCMDI / LLNL 34 th International Liège Colloquium Tracer Methods in Geophysical Fluid Dynamics 6 May 2002 http://www.ipsl.jussieu.fr/OCMIP

2. OCMIP-2 Group AWI ( Bremerhaven, Germany ): R. Schlitzer, M.-F. Weirig CSIRO ( Hobart, Australia ): R. Matear IGCR/CCSR ( Tokyo, Japan ): Y. Yamanaka, A. Ishida IPSL ( LSCE, LODyC, Paris, France ): J. Orr, P. Monfray, O. Aumont, J.-Cl.Dutay, P. Brockmann LLNL ( Livermore, CA, USA ): K. Caldeira, M. Wickett MIT ( Boston, USA ): M. Follows, J. Marshall MPIM ( Max Planck Institut fuer Meteorologie – Hamburg, Germany ): E. Maier-Reimer NCAR ( Boulder, CO, USA ): S. Doney, K. Lindsay, M. Hecht NERSC ( Bergen, Norway ): H. Drange, Y. Gao PIUB ( Bern, Switzerland ): F. Joos, K. Plattner PRINCEton ( Princeton, USA ): J. Sarmiento, A. Gnanadesikan, R. Slater, R. Key SOC ( Southampton Oceanography Centre/ Hadley Center, UK ): I. Totterdell, A. Yool UL ( University of Liege/University Catholique de Louvain, Belgium ): A. Mouchet, E. Deleersnijder, J.-M. Campin PMEL/NOAA ( Seattle, USA ): J. Bullister, C. Sabine PSU (Penn. State, USA): R. Najjar, F. Louanchi UCLA (Los Angeles, USA ): N. Gruber, X. Jin

3. The OCMIP-2 models differ Resolution Seasonality Boundary conditions Sub-grid mixing Mixed Layer Sea-ice Model Offline/Online

4. How Good is a Model? Relative to data Relative to other models Skill assessment depends on –Our Objectives (e.g., mean state vs. variability) –Our Vision Rose colored glasses Dark Sunglasses Clear glasses? –Local, Qualitative Analysis –Global, Quantitative Analysis

5. Tracers –CFC-11 and CFC-12 –Natural C-14 and Bomb C-14 –He-3 and He-4 Carbon –Preindustrial: Abiotic Common Biogeochemistry (∑CO 2, Alk, PO 4, O 2, DOM) –Preindustrial to Present –Future (two IPCC scenarios: IS92a, S650) –Sequestration (7 sites, 3 depths, 2 scenarios) OCMIP-2 Simulations 3-

6. Global Ocean Annual Mean Sea-Air CO 2 Flux in 1995 (mol m -2 yr -1 )

7. Some Summary Statistics Standard deviations –reference –model Correlation Coefficient R: Centered Pattern RMS error: Overall Bias: Law of Cosines: * Taylor, K.E., J. Geophys. Res., 106, D7, 7183-7192, 2001 Key relationship: A Useful Diagram*

8. Taylor Plot: Sea-Air CO 2 Flux (1995 Annual Mean, Global Map)

9. Taylor Plot: Sea-Air CO 2 Flux (1995 Full Global Space-Time Distribution)

10. Basin Zonal Integrals Annual Mean Sea-Air CO 2 Flux in 1995 (Pg C yr -1 deg -1 )

11. Global Seasonal Zonal Integral Sea-Air CO 2 Flux in 1995 (Pg C yr -1 deg -1 )

12. Sea-Air CO 2 Flux: Pacific Ocean North Pacific: 22 o N-70 o N Equatorial Pacific: 22 o S-22 o N

13. Conclusions: Total CO2 validation Taylor* Diagram: graphical evaluation of 5 global summary statistics ( σ data, σ model, r, R.M.S., Bias) –Provides quick, global roadmap –Motivates further evaluation –Not mechanistic Air-sea CO2 flux –OCMIP-2 models succeed in terms of zonal mean –OCMIP-2 models fail in terms of zonal and seasonal anomalies * Taylor, K. E., J. Geophys. Res., 106, D7, 7183-7192, 2001

14. Taylor Plot for Deep  14 C (below 1000 m)

15. Natural  14 C (West Atlantic, GEOSECS Section) Some models over-predict  14 C Some models under-predict  14 C

16. Pacific Ocean WOCE P16  14 C Some models under-predict  14 C Some models over-predict  14 C Data

17. CFC-11 in the South Atlantic Dutay et al., Ocean Modell., 2001 Ajax Data Some models under-predict CFC uptake Some models over-predict CFC uptake

18. Anthropogenic CO 2 uptake is correlated with CFC-11 uptake and ∆ 14 C Global CFC-11 Inventory (1989)Mean ∆ 14 C below 1000 m

19. Data-based estimate Simulated 1995 anthropogenic CO 2 column inventories Some models take up little CO 2 in the Southern Ocean Some models take up a lot of CO 2 in the Southern Ocean Sabine et al., 2001

20. Global air-sea anthropogenic CO 2 flux (Pg C yr -1 )

21. Summary of OCMIP2 anthropogenic CO 2 simulations Some agreement on global historical CO 2 uptake by the ocean –For the 1980’s = 2.0 ± 0.4 PgC yr –1 –For the 1990’s –IS92a = 2.5 PgC yr –1 –adjusted IS92a = 2.2 PgC yr –1 Some disagreement on regional and future fluxes –1980’s and 1990’s +/-13% (about the mean) –Year 2100+/-20% (IS92a and S650) –Year 2300+/-35% (S650)

22. Rationale for CO 2 uptake estimate Observed natural ∆ 14 C values are within the range of model results. Modeled CO 2 uptake is correlated with modeled ∆ 14 C Observed CFC-11 concentrations are within the range of model results Modeled CO 2 uptake is correlated with modeled [CFC-11] Independently estimated anthropogenic CO 2 inventories are within the range of model results Therefore, anthropogenic CO 2 uptake by the real ocean is probably within the range of model results. Ocean CO 2 uptake for the 1980’s = 2.0 ± 0.4 PgC yr –1 –IS92a 1990’s = 2.5 PgC yr –1 –Adjusted IS92a 1990’s = 2.2 PgC yr –1

24. Back-up slides

25. Efficiency of deep CO 2 injection is also correlated with CFC-11 uptake and ∆ 14 C Global CFC-11 Inventory (1989) Mean ∆ 14 C below 1000 m

26. Global Sea-Air CO 2 Flux in 1995 (Zonal Integral, Annual Mean, Pg C yr -1 deg -1 )

27. Pacific Sea-Air CO 2 Flux in 1995 (Zonal Integral, Annual Mean, Pg C yr -1 deg -1 )

28. Anthropogenic CO2 vs. CFC-11 Gruber et al., 2001

29. Simulated 1995 cumulative CO 2 fluxes and inventory Large model differences in the Southern Ocean

30. US Groups are anticipating funding Inverse basis function simulations –Gruber et al. Automated Model Ocean Diagnosis (AutoMOD), companion to NOCES, focusing on NASA data products –Caldeira et al.

31. Next steps Special OCMIP2 section in Global Biogeochemical Cycles IGBP open workshop “Global issues in ocean biogeochemistry” –May or June 2002 –GAIM, CLIVAR, JGOFS, GLOBEC, LOICZ, SOLAS EurOCMIP3 project (NOCES) –Emphasis on interannual to interdecadal variability –A wide range of model types (5 global ocean models, 1 regional ocean model, 1 inverse atmospheric inverse model) US proposals expecting funding –Inverse basis function simulations (Niki Gruber) –Automated Model Ocean Diagnosis (Ken Caldeira)

32. Global Biogeochemical Cycles OCMIP2 Special Section An overiew and history of OCMIP –J. Orr and N. Gruber Comparison of model physics relevant to the carbon Cycle in OCMIP2 –K. Lindsay (NCAR) OCMIP2 evaluation of deep-ocean circulation deduced from 3 He and 4 He simulations –J. Dutay (LSCE) Efficiency of purposeful CO 2 injection in the deep ocean: comparison of the OCMIP2 models –J. Orr (LSCE) Air-sea fluxes and north-south ocean transport of CO 2 and O 2 : results from OCMIP2 –P. Monfray (LSCE) Comparison of new and export production from the OCMIP2 models –R. Najjar (Penn State) Simulations of historical and future anthropogenic CO 2 uptake from OCMIP2 models –J. Orr (LSCE) Comparisons of model- and data-based estimates of anthropogenic CO 2 in the oceans –C. Sabine (PMEL)

33. Proposed IGBP open workshop TITLE: Global Scale Issues in Ocean Biogeochemistry WHERE: Ispra in Italy, (host N.Hoepffner at JRC) WHEN: May or June 2002 DURATION: 4 days at least (to give time for plenary discussion) SIZE: 60 (?) with 20 invited CO-ORGANIZERS: R.Schlitzer & P.Monfray ? PURPOSES : –Address big questions in global scale ocean biogeochemistry based on recent data, process modeling, and synthesis –Bridge the gaps between physics, biogeochemistry, and biology –Bridge the gap between people working on observations, process modeling, and global modeling –Stimulate strong concerted action in global scale research TARGET COMMUNITIES: –CLIVAR, JGOFS, GLOBEC, LOICZ and SOLAS