1. Modeling circulation and ice in the Chukchi and Beaufort Seas
Seth Danielson, UAF
Enrique Curchitser, Rutgers
Kate Hedstrom, UAF
Tom Weingartner, UAF
Colors: Sea Surface Temperature
Speckles: Ice

2. Outline Description of model Some model-data comparisons
Ongoing development & future improvements

3. Model setup Pan-arctic domain 50 vertical levels
Seafloor Topography
Pan-arctic domain
50 vertical levels
20-year hindcast ( )
Telescoping grid
3.5-7 km resolution in Chukchi-Beaufort Seas

4. Model setup Pan-arctic domain 50 vertical levels
Grid size (km)
Pan-arctic domain
50 vertical levels
20-year hindcast ( )
Telescoping grid
3.5-7 km resolution in Chukchi-Beaufort Seas

5. Arctic ice-ocean model
Built on the Regional Ocean Modeling System (ROMS)
Oceanic boundary and initial conditions from the Simple Ocean Data Assimilation (SODA) reanalysis
Surface forcing from Common Ocean Reference Experiment (CORE-2)
Air-sea fluxes computed via bulk formulae
Monthly and inter-annually varying river discharge from Dai and Trenberth (2002)
Dynamic-thermodynamic sea ice model following Budgell (2005)

6. Sea ice component
Dynamic-thermodynamic sea ice model implementation of Budgell (2005)
Elastic-Viscous-Plastic (EVP) following Hunke and Dukowicz (1997) and Hunke (2001)
Thermodynamics following Mellor and Kantha (1989) and Hakkinen and Mellor (1992)
Frazil ice production following Steele et al., (1989)
Imposition of landfast ice extent in the Beaufort Sea following monthly climatology of Mahoney et al. (2006;

7. Model-data comparisons
No data assimilation: we can use a wide variety of historical data to independently assess performance.
SSM/I passive microwave ice concentration
ICESat sea ice thickness
Moored temperature, salinity, velocity
CTD hydrography
Satellite-tracked drifters

8. observed:modeled cross-correlation
Sea ice concentration
observed:modeled cross-correlation
1.0
0.8
0.6
0.4
0.2
-0.2
-0.4
-0.6
-0.8
-1.0

9. Averaged over Chukchi-Beaufort region
Sea ice concentration
Averaged over Chukchi-Beaufort region
Modeled
Observed

10. Timing of ice setup in fall
RMSD = 15.5 days
RMSD = 6.5 days

11. Mid-winter ice thickness
Model ice thickness (m)
Model – ICESat Observed (m)
Model ice too thin in NE Chukchi
Model Ice too thick along Siberian coast

12. Northeast Chukchi near Barrow Canyon
(site MK1, 71.1°N, 159.5°W)

13. Northeast Chukchi Offshore (site C2, 71.3°N, 164.5°W)

14. Nearshore Beaufort Sea (McClure site, 70.3°N, 147.5°W)
Landfast Ice
Landfast Ice
Open water

15. Northeast Chukchi near Barrow Canyon
(site MK1, 71.1°N, 159.5°W)

16. Nearshore Beaufort Sea (Dinkum site, 70.4°N, 147.95°W)

17. Next Steps: model improvements underway
Surface forcing from Modern-Era Retrospective Analysis for Research and Applications (MERRA)
Northeast Pacific (NEP6) regional hindcast used for oceanic boundary conditions in Bering Strait
Improved bathymetric Digital Elevation Models
Observed
Run #5
Run #7 (NEP6)

18. Alaska Region Digital Elevation Model (ARDEM)

19. Alaska Region Digital Elevation Model (ARDEM)
Help improve your region of interest! ARDEM update coming in through funding from the North Pacific Research Board. All bathymetric sounding data welcome.

20. Success in many future model advances depends on field observations
Next steps: toward ice/ocean model improvements and operational applications
Algorithm development and testing:
Growth and breakup of landfast ice
Melt pond dynamics… ice algae?
Wind-ice-ocean-oil interactions
Merge ice/ocean components… ice shelf approach?
Surface heat flux algorithms for ice-infested waters
Model validation through community-based ocean monitoring.
Real-time nowcast/forecast ice-ocean models could inform industry, regulators, scientific research programs and emergency response efforts.
Success in many future model advances
depends on field observations

21. Summary Model strengths include: Model weaknesses include:
Capturing seasonal changes in nearshore Beaufort Sea
Wind-driven flows
Reproduction of sea ice concentration anomalies
Model weaknesses include:
Mid-winter ice thickness: too thin in the northeast Chukchi, too thick along the Siberian Coast
Insufficient summer ice melt or too much winter ice growth
The data-model comparisons continue to guide model development efforts by identifying features and sub-grid scale processes that require better parameterizations.