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NRL's coupled ice-ocean forecast system: Current capabilities and future plans

NRL's coupled ice-ocean forecast system: Current capabilities and future plans. Robert C. Rhodes, Ruth H. Preller, Pamela G. Posey, Alan J. Wallcraft, E. Joseph Metzger and Lucy F. Smedstad Naval Research Laborary Stennis Space Center, MS 39529 rhodes@nrlssc.navy.mil

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NRL's coupled ice-ocean forecast system: Current capabilities and future plans

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  1. NRL's coupled ice-ocean forecast system: Current capabilities and future plans Robert C. Rhodes, Ruth H. Preller, Pamela G. Posey, Alan J. Wallcraft, E. Joseph Metzger and Lucy F. Smedstad Naval Research Laborary Stennis Space Center, MS 39529 rhodes@nrlssc.navy.mil 2005 Layered Ocean Model Workshop Jan 26- 28, 2005 University of Miami/RSMAS

  2. 6.2 ONR CICE Validation for PIPS upgrade 6.2 NOPP HYCOM GODAE CICE/HYCOM Coupling 6.4 SPAWAR CICE/NCOM/HYCOM Coupling PIPS 2.0 Upgrades PIPS 3.0 in NCOM PIPS 3.0 in HYCOM Operational Systems at NAVO

  3. Polar Ice Prediction System – 2.0 PIPS 2.0 • Currently run at NAVO on the SV1 clusters • Using 4 CPU’s, 40 MW memory and takes • ~ 9 minutes per day. • Grid resolution (~27 km, 15 vertical levels) • Hibler Ice Model / Bryan-Cox Ocean Model • Daily 5 day forecast • Daily products sent to National Ice Center: • Ice Thickness • Ice Concentration • Ice Displacement • PIPS2.0 uses 3 hourly NOGAPS 0.50 forcing

  4. Ice Thickness (m) Ice Concentration (%) PIPS2.0 Operational Products for June 2, 2004 Ice Displacement (km/day)

  5. Polar Ice Prediction System 3.0 Global NCOM Model CICE Model Polar Ice Prediction System 2.0 Forecast Restart (ice-ocean) or Ocean Analysis/ SSMI Ice Concentration Atmospheric Forcing NOGAPS Cox Ocean Model Hibler Ice Model Model Output Ice Drift Ice Thickness Ice Concentration Ice conv/div Ocean Currents Ocean Temps Ocean Salinity 24-hour Forecast for Ice-Ocean Restart

  6. CICE – LANL Sea Ice Model • EVP (efficient, improved response to forcing) • Energy conserving Bitz and Lipscomb (1999) thermodynamics • Multi-category, linearly remapped ice thickness • Energy-based ice ridging • Other improvements to physics parameterizations • Improves the capability to predict areas of lead opening/closing for the warfighter, ice edge location, ice thickness and ice drift. • Mainly tested on O3K (ERDC)

  7. PIPS 3.0 Grid ~ 9 km resolution

  8. March CICE has 5 ice thickness categories (meters): Category 1 0.000 – 0.644 Category 2 0.645 – 1.391 Category 3 1.392 – 2.470 Category 4 2.471 – 4.567 Category 5 4.568 – 9.333 March

  9. Global Modeling, Balancing Resources and Capabilities NRL Layered Ocean Model (NLOM) 1/16°, 6 vertical layers, restricted to depths >200m Operational Linked Global Navy Coastal Ocean Model (NCOM) 1/8°, 40 vertical layers Transition Global NRL Layered Ocean Model (NLOM) 1/32°, 6 vertical layers, restricted to depths >200m Transition Global Hybrid Coordinate Ocean Model (HYCOM) 1/12°, 40 vertical coordinates Operational FY08

  10. 1/8° Global Navy Coastal Ocean Model (NCOM) • 41 sigma-z levels in the vertical • 20 sigma/1m deep-water upper level thickness • Depth of sigma-Z interface is 139 m • assimilation of SST, SSS, 3-d T&S from MODAS using 1/16° NLOM SSH • NOGAPS wind stress, radiation, heat flux  generic grid extraction capability

  11. The global NCOM grid produces a global overlap by transforming the northern hemisphere around poles over land in Canada and Russia. The 1/8° grid resolution refers to an average midlatitude spacing of the 2048x1280 grid. The figures at left indicate the sigma-z vertical coordinate in NCOM: - sigma levels over z levels

  12. Global NCOM coupling with CICE • NCOM Arctic resolution ~10 km however bi-polar grid causes aspect ratios over arctic to be not optimal to run CICE on NCOM grid • CICE will run on PIPS grid which will ease transition to PIPS 3.0 for operations • Coupling will be done as separate runs with coupling at the file level possibly with PIPS 3.0 running during the 12Z watch • Sensitivity runs currently underway for validation • Scheduled for transition to NAVOCEANO in early FY06

  13. Arctic Grid Resolution for PIPS 3.0 Grid Grid Resolution (DX) Grid Resolution (DY) Grid Aspect Ratio DX/DY

  14. Arctic Grid Resolution for Global NCOM Grid Grid Resolution (DX) Grid Resolution (DY) Grid Aspect Ratio DX/DY

  15. Global HYCOM coupling with CICE • CICE will run on HYCOM grid which will ease coupling between ocean and ice models • Sensitivity runs are currently underway for validation at coarser resolution (~35 km) • Coupling will be done in fully-coupled mode using ESMF (coordinated with BEI institute) • HYCOM Arctic grid resolution ~3.5 km (for 1/12 degree global HYCOM planned for FY07 transition to NAVOCEANO)

  16. Arctic Grid Resolution for Global HYCOM 0.720 Grid Grid Resolution (DY) Grid Resolution (DX) Grid Aspect Ratio DX/DY

  17. Arctic Grid Resolution for Global HYCOM .080 Grid Grid Resolution (DX) Grid Resolution (DY) Grid Aspect Ratio DX/DY

  18. Ice Concentration – Mean Error0.72° Arctic Cap HYCOM vs. NOAA OI SST v2Energy-loan ice model 1999 2000 2001 HYCOM with 1999-2003 6 hourly FNMOC NOGAPS wind and thermal forcing

  19. CICE/HYCOM grid ~35 km CICE/PIPS3 grid ~9 km Jan 1999 Ice concentration (%) Jan 1999 Ice thickness (m)

  20. Ice Assimilation • PIPS 2.0 currently assimilates SSMI ice concentration using non-optimal scheme • Navy also performs daily ice OI analysis for both poles using NCODA system (assimilates SSMI ice concentration) • Plan for PIPS 3.0 (CICE/NCOM) will initially emulate PIPS 2.0 assimilation • Upgrades will include cycling PIPS 3.0 / NCODA system for HYCOM (will include both poles) • Navy currently planning for NPOESS which will include additional ice parameters (ice age, sea ice temperature) for assimilation

  21. The End

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