Update of ECCO-GODAETony Lee

NASA Jet Propulsion Lab, California Institute of Technology

IGST-XII meeting, St. John’s, Newfoundland, Aug. 7-9, 2007

In-situ observations Satellite data

Recent activities for the MITGCM adjoint-based reanalysis system

• Update of almost all input data & error estimates (e.g., weekly to daily SST).

• Injection of new data (e.g., time-varying GRACE, elephant-seal data).

• Extension through 2006.

• Replacement of surface-flux control with bulk forcing & atmos. State control.

• Inclusion of full thermodynamic/dynamic sea-ice model.

• Downscaling: e.g., Southern-Ocean eddy-permitting adjoint-based estimation.

• Fully global lat-long-polar cap grid.

• Mass-conserving (non-Boussinesq) option.

• OpenAD: a new open-source tool for automatic differentiation.

• New ECCO web site.

• …(not inclusive)

• ECCO Kalman filter/RTS smoother ported to MOM4 successfully.

• Core dynamics of MOM4 adjoint code completed.

• Downscaling: tropical Indian Ocean & Gulf of Mexico.

• Proposed transfer of ECCO-GODAE systems to PO.DAAC at JPL and to sustain the production and distribution.

Near real-time Kalman filter smoother system

Example of recent ECCO activities: eddy-permitting adjoint assimilation

before assimilation after 27 iterations of optimization

Model-data (SSM/I) misfit in sea-ice concentration

Sea Mammal Research Unit,

University St. Andrews, UK,

British Antarctic Survey

Courtesy M. Meredith

Example of new input data: CTD-type observations from seals in SO

1. MIT Darwin Project (Follows et al.); drive biogeochemical model offline (N. Gruber).– marine ecosystem modeling; ocean biogeochemical cycle

2. CLIMODE: CLIvar MOe Water Dynamic Experiment (Marshall et al.)– Investigation of sub-tropical 18o mode water formation dynamics

3. CODAE: Central California ODAE (C. Edwards, UCSC)– Study of the Monterey Bay & Central California coast circulation

4. Sub-polar North Atlantic gyre & tropical Pacific circulation (F. Schott, Geomar, Kiel)5. Long-term biogeochemical tracer calculations (S. Khatiwala, LDEO)

1. Transport matrix (Jacobian) approach6. Mean Dynamic Topography uncertainties (F. Fossepoel, IMAU, Utrecht)

– Uncertainty estimate in preparation of the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite mission

7. Ocean circulation magnetic field signals (Manoj et al., GFZ, Potsdam)

8. “Liming” the ocean inceases CO2 absorption (D. Harvey, U. Toronto)

1. Uses upwelling velocities to investigate pCO2 inceases in response to CaCO3

9. Thermodynamic analysis of ocean circulation (N. Wienders, FSU; J. Nycander, MISU, Sweden)1. Streamfunction-based calculations of MOC energetics

• Ocean mass changes and Earth rotation (B. Gross et al., IERS/SBO & JPL)• Global instability calculations (Shafer Smith, NYU)• Global gravitational model development (N. Pavlis, SGT)

1. Sponsored in part by GRACE and National Geospatial Intelligence Agency (NGA)1. Vortex calculations (P. Poncet, INSA, Toulouse)2. Use of ocean mixed layer depths (N. Cassar, Princeton University)3. Initializing climate prediction (Cazes-Boezio et al. 2007, Yulaeva et al., 2007)4. …

Examples of applications by external users

• Ponte, R. M., C. Wunsch and D.Stammer, 2007: Spatial mapping of time-variable errors in Jason-1 and TOPEX/POSEIDON sea surface height measurements. JAOT, in press.

• G. Forget and C. Wunsch, 2007: Global hydrographic variability and the data weights in oceanic state estimates. J. Phys. Oceanogr., in press.

• D. Stammer and A. Koehl and C. Wunsch, 2007: Impact of the GRACE geoid on ocean circulation estimates. JAOT, in press.

Error/uncertainty estimates and updates remain crucial, for new observations and model representation

Examples of recent work:

New ECCO web page: much more streamlined, better documentation, more complete products.

Various ECCO products (including input data, surface forcing, and T/S budget output).

Ongoing effort to develop an open-source automatic differentiation tool: Open AD