1. Representation of Atlantic Water in the Eastern Arctic in the Finite Element Sea-ice Ocean Model
Xuezhu Wang, Qiang Wang, Sergey Danilov, Thomas Jung,
Dmitry Sidorenko, Jens Schroeter
Alfred Wegener Institute, Germany
16th AOMIP and 1st FAMOS Meetings
23-26 October, 2012, Woods Hole, USA

2. Motivations
Implement the unstructured ocean –sea ice coupled model FESOM to the Arctic Ocean
Evaluate the general model performance in the Arctic simulation using available observation data
Study the sensitivities to local mesh refinement with different resolutions in the Arctic Ocean
Apply FESOM with flexible resolutions to resolve multi-scale dynamical processes with focus on the Atlantic Water (AW) inflow
The motivation of my project on the Arctic is as following, We plan to implement FESOM to this region with flexible resolutions. Our final goal is using this model to study the dynamical processes of AW inflow into the Arctic Ocean. Before it, we also need to evaluate the model performance and study the sensitivity of local mesh refinement.

3. Current Model Setup
Two different refinements in the Arctic region (~24km and ~9km) in a global configuration.
The model is forced by COREv.2 interannual atmospheric forcing and initialized with salinity and temperature fields from PHC3.
Integrated time period:
Two passive tracers of Atlantic water are added since 1993 for Fram Strait Branch (FSB) and Barents Sea Branch (BSB)
Currently, I have conducted several simulations. First is 24km in the whole Arctic and second is 9km in the whole Arctic and the third is 9km only in the all gates of the Arctic. The model is forced by CORE2 dataset and integrated from I have planed to study the sensitivity to the different refinement, but the results in all simulations have same problems and the AW inflow can’t be simulated correctly. I’ll show the details and want to discuss with all of you.

4. Resolutions of experiments
24km
9km
Today I just show the results with these two meshes. The left one has 24km in the Arctic and the right one has 9km.

5. Gateways of the Arctic Ocean
Bering Strait
Landcaster Sound
Nares Strait
Fram Strait
Davis Strait
Barents Sea Opening

6. (2003-2006, neglects 0-35m which probably adds ~0.25Sv)
Results
Net Volume Fluxes Through the Critical Gateways
Gateway
Barents Sea
Opening (Sv)
Fram Strait
(Sv)
Bering Strait
Nares Strait
Lancaster Sound (Sv)
Davis Strait
Observation
2.0 1,2
( )
-2.7±2.7 3
0.8±0.2 4,5,6
( )
-0.47±0.05 7
( , neglects 0-35m which probably adds ~0.25Sv)
-0.7 8
( )
-2.3±0.7 9
( )
Modeled
24km
1.91
-2.46
1.37
-0.15
-0.44
-0.75
9km
2.11
-1.52
1.43
-0.89
-0.72
-1.49
The table shows the calculated net volume transports from the observation and model simulations.
1Smedsrud et al. (2010); 2Skagseth et al. (2008); 3Schauer et al. (2008); 4Roach et al. (1995); 5Woodgate et al. (2010); 6Woodgate et al. (2006); 7Rabe et al. (2010); 8Prinsenberg et al. (2009); 9Curry et al. (2011)

7. Results 24km 9km Franz Josef Land SevernayaZemlya Novaya Zemlya
Simulated mean potential temperature (averaged for last 10 years) at 300m (left for 24km and right for 9km)

8. Results: Fram Strait Observation Core depth of FSB: 150-200m
Boundary: m
24km
9km
Observed (upper, Beszczynska-Moeller, 2012) and simulated mean potential temperature and meridional velocity in Fram Strait (middle for 24km and lower for 9km, averaged for )

9. Results: Barents Sea Opening
24km
NAW (North)
9km
NAW (South)
Simulated mean potential temperature and zonal velocity in Barents Sea Opening (upper for 24km and lower for 9km, averaged for )

10. Results: Novaya Zemlya—Franz Josef Land
North Zemlya Coastal Current
24km
Western North Zemlya Current
9km
NZCC
WNZC
Simulated mean potential temperature and zonal velocity in the section between Novaya Zemlya and Franz Josef Land (upper for 24km and lower for 9km, averaged for )

11. Results: Franz Josef Land—Severnaya Zemlya
24km
9km
FSB
Simulated mean potential temperature and meridional velocity in the section between Franz Josef Land and Severnaya Zemlya (upper for 24km and lower for 9km, averaged for )

12. Results： Passive tracers
Horizontal distributions of passive tracer 1 for FSB at 300m and passive tracer 2 for BSB at 200m

13. Results： Passive tracers
Vertical distributions of passive tracer 1 for FSB and passive tracer 2 for BSB in the section between Josef Land and Severnaya Zemlya (St. Anna Through)

14. Conlusion and discussion
Simulated temperature and velocity are relatively lower in coarse resolution and higher in fine resolution. Results in high resolution are more realistic compared to observations
High resolution simulation is necessary for reproducing small scale dynamical processes (recirculation, eddies, etc)
Added passive tracers are useful tools for tracking pathways of different Atlantic Water branches and water mass modification

15. Challenges
The pathway of FSB after it meets BSB at the St. Anna Trough!!!
SEITE 15

16. .
Thank you!