1. Collaborative Research: A Heat Budget Analysis of the Arctic Climate System Mark C. Serreze, Andrew Barrett, Andrew Slater CIRES/NSIDC, University of Colorado, Boulder, CO Michael Steele Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle WA

2. Objective: Examine the Arctic climate system from the integrating, yet simplifying viewpoint of its large- scale heat budget Draw From ERA-40 and NCEP Reanalyses Oceanographic Observations Terrestrial Observations Satellite Data Land Surface Models Coupled Ice-Ocean Models

3. What are the interplays between heat transports from lower latitudes, extreme seasonality in radiative forcing and heat exchanges between atmospheric and subsurface reservoirs that shape the observed state of the Arctic’s coupled atmosphere-land-ice-ocean system? How are recent changes and projected future states of the Arctic system reflected in components of the heat budget, and can we separate forcing from response? What are the major uncertainties that hamper our ability to achieve a system-level understanding? Science Questions

4. Heat Budget Equations: Atmospheric Column Δ E/ Δ t = Fwall+Frad+Fsfc Ice/Ocean Land Column Δ E*/ Δ t = Fo+Fi-Fsfc

5. Moist Static Energy FluxLatent Heat Flux Atmospheric Heat Fluxes Across 70 deg. N

6. Annual Cycle of Atmospheric Terms from ERA-40 Annual Cycle of Surface Terms from ERA-40 Important Point: There are large seasonal variations in the net surface flux. Acts as a negative feedback.

7. Jan 3.65633 Feb 2.95006 Mar 3.01168 Apr 2.92278 May 3.49785 Jun 4.90397 Jul 6.20166 Aug 7.25292 Sep 7.33829 Oct 7.01069 Nov 6.52471 Dec 3.66975 MJ * 10 15 Months Arctic Ocean Sensible Heat Content 1000 MJ/m 2 Annual mean 70-90 degN J M M M JSN F A J A OD Courtesy M. Steele

8. Seasonality in the Sea Ice Cover

9. ERA-40 Net Surface Heat Flux (1979-2001)

10. Courtesy NSIDC

11. Energy Fluxes Across 70 deg. N

12. ERA-40 Residual Heat Flux (1979-2001)

13. Net Surface Heat Flux for the Arctic Ocean from ERA-40 Need to examine data from MERRA, CERES, coupled ice-ocean models and AOGCMs

14. Annual Mean Temperature Anomalies By Height and Latitude: 2000 to 2005 (Referenced to 1979 to 1999)

15. Annual Mean Temperature Anomalies by Height and Latitude for 2005 (Referenced to 1979-2004)

17. Questions?

18. End of slideshow