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TOMS Executive committee

Community Terrain-Following Ocean Modeling System (TOMS) An overview of the collaboration between the modeling communities of Princeton (Ezer) and Rutgers (Arango) to:.

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TOMS Executive committee

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  1. Community Terrain-Following Ocean Modeling System (TOMS)An overview of the collaboration between the modeling communities of Princeton (Ezer) and Rutgers (Arango) to: Develop, test and improve numerical schemes for terrain-following ocean models in an effort to build an expert, advanced modeling system for wide range of applications. Provide support for the terrain-following ocean modeling community and coordinate the interaction between developers, users and forecasters.

  2. TOMS Executive committee ONR Modeling & Prediction Core model development groups Feedback From testers Feedback From intercomparisons with other models Coordinators TOMS testers Others (HYCOM/MICOM, MOM, POP, MIT…) Princeton (POM, NCOM, ECOM) Rutgers/UCLA (SPEM, SCRUM, SEOM, ROMS/TOMS) Users communities

  3. Workshops • First joint terrain-following ocean models users meeting- Bar Harbor, ME, 9/1999 • motivated the TOMS/ONR initiative & need for collaboration • Second joint terrain-following ocean models users meeting- NCAR, CO, 8/2001 • Inaugural TOMS developers workshop – 8/2001 • Second TOMS developers workshop – 7/2003 • Third joint terrain-following ocean models users meeting- PMEL, Seattle, WA, 8/2003

  4. Web-based support: communication with the terrain-following ocean modeling community • Improve web-based information at both Princeton (http://www.aos.princeton.edu/htdocs.pom/) and Rutgers (http://marine.rutgers.edu/po/) • Launch generic Ocean-Modeling web site (http://www.ocean-modeling.org)

  5. Why is this collaboration useful? • Benefit from several developing groups specializing in different areas (numerics, assimilation, sub grid scale parameterizations, etc.) • New schemes can be tested by many different applications running on different computer architectures (and compared with existing models). • Immediate impact on the ocean modeling community.

  6. A few examples from recent research to evaluate new numerics and parameterizations:… and how users may be affected (e.g., model stability and advanced time stepping schemes)

  7. Sensitivity to internal (DTI) & external (DTE) time steps (Ezer, Arango & Shchepetkin, 2002) ROMS UNSTABLE STABLE TDI/DTE POM CFL=13s

  8. While larger time step is possible in ROMS/TOMS, users should be aware of possible oscillatory behavior for small time step

  9. A recent paper:A possible explanation for ocean model instability occurring for small time stepsB. Heimsund & J. Berntsen, 2003try to explain this numerical instability and suggests a method to evaluate the stability using a simple shallow water equations on a 3-cell grid

  10. Pressure Gradient Schemes

  11. Structure ofV (cm/s) in ROMS for different PG schemes (medium seamount case) R-DJ (Vmax=3.7) R-PJQ (Vmax=0.03) R-FPJ (Vmax=30) R-DJC (Vmax=0.06) R-WDJ (Vmax=0.3)

  12. PG errors- moderately steep seamount

  13. Testing TOMS parallel code (MPI or OpenMP) for different computerarchitectures

  14. The cost of saving output and global averaging is much higher for the MPI code (for the shared-memory SGI machine)

  15. Related research areas (Princeton group) that can contribute to the TOMS development • Parameterization of vertical mixing and modification to the M-Y turbulence scheme: 1. Mixing due to internal waves (Ezer, 2000; Mellor, 2001) 2. Surface mixing due to breaking waves (Mellor, 2003; Mellor & Blumberg, 2003) 3. Bottom mixing and BBL (Ezer & Mellor, 2003) Various turbulent mixing schemes in TOMS (Brunt-Vaisala, M-Y-2.5, KPP, Canuto, Kantha-Clayson) need to be evaluated in view of new research on turbulence mixing.

  16. Generalized coordinate systems (Mellor et al., 2002; Ezer & Mellor, 2003)  help to evaluate future hybrid coordinate systems • Estuarine, tides, sediment transport, etc.  Experience with POM-related models may help in the development and testing of schemes like wetting-drying. • Pressure gradient schemes  Need to sort the many available schemes • Operational forecasting systems  Experience in developing such systems with POM at NOAA & Navy labs can help in the transformation of TOMS

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