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

6.2 ONR CICE Validation for PIPS upgrade

PIPS 2.0 Upgrades

Operational Systems at NAVO

PIPS 3.0 in NCOM

PIPS 3.0 in HYCOM

6.4 SPAWAR CICE/NCOM/HYCOM Coupling

6.2 NOPP HYCOM GODAE CICE/HYCOM Coupling

Polar Ice Prediction System – 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:1. Ice Thickness 2. Ice Concentration3. Ice Displacement

PIPS2.0 uses 3 hourly NOGAPS 0.50 forcing

PIPS 2.0

PIPS2.0 Operational Products for June 2, 2004

Ice Thickness (m)Ice Concentration (%)

Ice Displacement (km/day)

Hibler Ice Model

Cox Ocean Model

Atmospheric ForcingNOGAPS

Polar Ice Prediction System 2.0

Model Output Ice Drift Ice Thickness Ice Concentration Ice conv/div Ocean Currents Ocean Temps Ocean Salinity

Forecast Restart(ice-ocean)

orOcean Analysis/

SSMI Ice Concentration

24-hour Forecastfor Ice-Ocean

Restart

Global NCOMModel

CICE Model

Polar Ice Prediction System 3.0

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)

PIPS 3.0 Grid

~ 9 km resolution

CICE has 5 ice thickness categories (meters):

Category 1 0.000 – 0.644Category 2 0.645 – 1.391Category 3 1.392 – 2.470Category 4 2.471 – 4.567Category 5 4.568 – 9.333

March

March

Global Modeling, Balancing Resources and Capabilities

NRL Layered Ocean Model (NLOM)1/16°, 6 vertical layers, restricted to depths >200m

Global Navy Coastal Ocean Model (NCOM)1/8°, 40 vertical layers

Global NRL Layered Ocean Model (NLOM)1/32°, 6 vertical layers, restricted to depths >200m

Global Hybrid Coordinate Ocean Model (HYCOM) 1/12°, 40 vertical coordinates

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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

1/8° Global Navy Coastal Ocean Model (NCOM)

The figures at left indicate the sigma-z vertical coordinate in NCOM: - sigma levels over z levels

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.

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

Arctic Grid Resolution for PIPS 3.0 Grid

Grid Resolution (DX) Grid Resolution (DY)

Grid Aspect Ratio DX/DY

Arctic Grid Resolution for Global NCOM Grid

Grid Resolution (DX) Grid Resolution (DY)

Grid Aspect Ratio DX/DY

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)

Arctic Grid Resolution for Global HYCOM 0.720 Grid

Grid Resolution (DX) Grid Resolution (DY)

Grid Aspect Ratio DX/DY

Grid Resolution (DX) Grid Resolution (DY)

Grid Aspect Ratio DX/DY

Arctic Grid Resolution for Global HYCOM .080 Grid

Ice Concentration – Mean Error0.72° Arctic Cap HYCOM vs. NOAA OI SST v2

Energy-loan ice model1999 20012000

HYCOM with 1999-2003 6 hourly FNMOC NOGAPS wind and thermal forcing

CICE/HYCOM grid ~35 km CICE/PIPS3 grid ~9 km

Ice concentration (%)

Ice thickness (m)

Jan 1999

Jan 1999

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

The End