1. Monitoring polar climate change from space Thorsten Markus Cryospheric Sciences Branch NASA Goddard Space Flight Center Greenbelt, MD

2. IPY sea ice project in the Antarctic sea ice

3. The big news last year: The record minimum in Arctic sea ice Data from satellite passive microwave data

4. 2007 Previous minimum 2005

5. From Rothrock et al.

6. From Holland and Bitz, 2006

7. February 1996 September 1996

9. Importance of sea ice (1): Global energy balance; Ice/snow albedo feedback Ocean Forest Snow/ice

10. Importance of sea ice (2): Ocean circulation What makes the ocean move? 1) Wind-driven surface currents 2) Thermohaline circulation

13. Change in temperature 30 years after collapse of the thermohaline circulation Michael Vellinga, Hadley Centre

14. Importance of sea ice (3): Ecology, e.g. polar bears

15. February 1996 September 1996

16. ?

17. From Gordon and Comiso, 1988 Moisture flux Albedo Ice drift Precipitation Processes:

18. Warmer temperatures More moisture More precipitation More freshwater input into ocean More stable Southern Ocean Less entrainment of WDW Antarctic sea ice increase with global warming? More sea ice production

19. Warmer temperatures More moisture More precipitation More freshwater input into ocean More stable Southern Ocean Less entrainment of WDW Antarctic sea ice increase with global warming? More sea ice production Thicker snow on sea ice More snow- to-ice conversion More thermal insulation Less basal freezing

20. Change in sea ice volume as a function of precipitation (Balance between thermal insulation and snow-to-ice conversion)

21. IPY sea ice campaign in the Antarctic sea ice Part of the project was dedicated to validate ICESat measurements

22. What is ICESat?

23. hs hi hf ii ss ww ICESat (laser altimeter) Cryosat2 (radar altimeter, 2009) hs = snow depth hi = ice thickness hf = freeboard What is missing? The 3rd dimension!

39. Preliminary ICESat freeboard measurements (for cloud-free areas only) on top of AMSR-E sea ice concentrations.

40. ICESat-derived freeboard (the height over the sea ice above water)

41. It is a long process to carefully validate satellite measurements of the polar regions and international collaboration is essential. The polar regions are experiencing drastic changes and we still don’t fully understand all the processes but we cannot effort to turn our heads away.