1. Integrated SAR and lidar observations of the sea ice cover: Resolving the contributions of thermodynamics and dynamics to the ice thickness distribution Ron Kwok, Jet Propulsion Laboratory California Institute of Technology IGARSS-2010 Honolulu, HI July 25-30

2. Arctic Ocean ice cover Ice thickness distribution Expression of dynamics (ice motion) and thermodynamics (growth and melt) Present observational capabilities Motion and thickness Observational requirements Coupled observation of motion and thickness at appropriate time scales Outlook - DESDynI Topics

3. Arctic Ocean sea ice cover

4. Ice thickness distribution:Interplay of Dynamics and Thermodynamics

5. Model Development/Improvements/Validation Process Studies Ice Mechanics/Ice-ocean interactions Deformation-induced ice production Ocean interactions Sea ice area/volume balance Ice growth and melt Ice export Fram Strait, Nares Strait, Canadian Arctic Archipelago Narrow passages Arctic Ecology Ice motion and thickness observations

6. Present Observational Capability ofIce motion and thickness

7. Ice Drift (Large scale forcing -> small-scale response) 2000 km 100 km L (Kwok, 2002) Gradients in large-scale surface wind stress is often concentrated along quasi-linear fractures hundreds of kilometers long.

8. Small-scale kinematics and ice production One Grid Cell Grid Cell Area 10 km 10 km Uncertainty in displacement requirement: 300 m

9. Small-scale (~km) deformation alongfracture zones

10. Animation of small-scale sea ice kinematics

11. Freeboard, snow depth and ice thickness air air snow Freeboard (ice / snow) sea surface sea ice thickness draft sea water sea water

12. ICESat (profiling lidar) and RADARSAT (image) ICESat track on RADARSAT image Δt = 1 day freeboard draft meters *Reference thickness estimated using ice age from RGPS

13. Winter sea Ice thickness from ICESat 04 05 06 07 08 Greenland Greenland Greenland Greenland Greenland Thickness (m) (Kwok et al., 2009) MY = all ice with MY fraction>50%

14. Trend in winter sea ice thickness:2004-2009 MY fraction Thickness (m) 0.8 m Between 04-09 Trend = -0.20 m/yr

15. Limitations of current capabilities High resolution ice motion Synthetic Aperture Radars RADARSAT not longer available, Envisat covers only part of the Arctic Need routine and reliable coverage of entire Arctic Ocean Sea ice thickness Freeboard from lidars ICESat provided only glimpses of the ice cover (twice a year); mission ended last year CryoSat-2 is now operational No coordinated acquisitions of ice motion and thickness

16. Sea ice observations with DESDynI DESDynI Mission Synthetic Aperture Radar High-res imagery Coverage of Arctic Ocean every 3-4 days Multi-beam Lidar 25 m spots Near simultaneous coverage of the sea ice cover below 82 N Monthly coverage of Arctic Ocean Allows coupled observation of ice motion and thickness

17. DESDynI SAR and lidar allow Coordinated observations/mapping of motion and thickness at length and time scales important for resolving the thermodynamic and dynamic processes Data products for Monitoring of the changes in the relative proportions of these processes associated with changing climate Model validation/assessments/improvements Assimilation into global and regional models Improved projection of global climate Conclusions

19. Simulations with Elastic-Decohesion Approach

20. Joint project of the Alaska Satellite Facility and the Jet Propulsion Laboratory Continuation of REASoN project Project Objectives To produce fine-scale sea ice motion ESDRs for the years 2004 through 2008. These products will add to the 7-year record of RADARSAT-1 data. To produce 3-day ice motion ESDRs of the northern Bering Sea from 1997-2008. To produce a record of high-resolution (100 m) image mosaics of the Arctic Ocean from 1991-2008 using available ERS-1, ERS-2, and RADARSAT-1 SAR imagery. To distribute, archive, and provide user services to promote and support the wide-spread use of these ESDRs. Project Overview 6-day deformation fields of the Arctic Ocean ice cover

21. Persistence in fracture patterns