2. Formation of pancake ice in a wave field Hayley Shen, Stephen Ackley Clarkson University and Mark Hopkins USACRREL NSF/McMurdo Ground Station Science Workshop, Columbus OH, March 9-11, 2004 NSF OPP-9814968

3. Pancake size Rafting thickness Early ice cover development Heat transfer between air/ice

4. Result #1 Pancake Size

6. How to determine limit size? Bending failure mode: Tensile failure mode: Shen, Ackley, Hopkins 2001

7. 95% confidence interval

8. CRREL-2001winter, summer, 2003 summer

10. 95% confidence interval Example: 100m wave of 5m amplitude yields 0.9m diameter pancakes.

12. HSVA-2002winter Pancake ice formation However….

14. Result #2 Equilibrium Ice Thickness from Wave Rafting

16. Non-dimensional result Dai, Shen, Ackley 2004

17. Wave Tank Experiment Results

19. Computer Simulation

20. Computer Simulation (no friction)

21. Computer Simulation (friction)

22. Result #3 Early Ice Cover Establishment due to Wave Rafting

23. Some old models results Hibler and Ackley 1983

24. Geiger 1997

25. Effects of h0 on Ice Cover Development (Earlier Appearance) Dai, Shen, Ackley 2004, in preparation

26. Effects of Initial Ice Thickness on Ice Cover Development

27. Result #4 Air/Ice Heat Transfer in a Wave Field

28. Problem Definition W H Ice Water Air

29. Experiments

30. Results Calm water cases Wave cases The standard deviation for wave cases is high, suggesting that heat transfer coefficient may depend on wave parameters Enhanced turbulence, increased surface area, and a thin boundary layer above water/ice may be the reasons Dai, Shen, Ackley, 2004, in preparation

31. Pancake ice size can be predicted from waves Rafting thickness can also be predicted Rafting thickness is important in early ice cover development Waves may greatly increase the thermodynamic growth of ice Waves may not always result in pancakes, the critical condition has not been identified We have found:

32. Next Steps Heat transfer between air/ice in a wave field The critical condition for pancake formation Incorporating Wave Effects into short and long term climate models

33. We need….. Accurate weather data Accurate hydrographical data

34. Why?

35. Temperature of Dec. 30, 1993. Left panel is from NCEP real-time data, right from NCEP/NCAR Reanalysis data (Wang, Shen, and Shen, Okhotsk Sea Conference, 2000)

36. Temperature difference between NCEP real-time and reanalysis data for 92-93 winter.

37. Ice concentration. Date: March 5, 1993. Input data: NCEP real-time. Ice concentration. Date: March 5, 1993. Input data: NCEP Reanalysis.

38. Observed buoy trajectories and simulated ice floe trajectories in the winter of 1993-94.

39. A lot of work to be done! Collaborations!