1. Integration and Synthesis WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM Preface

2. Component-level data and understanding WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM Component / sub-system Sea-ice extent summer minimum Sea-ice export and melt Sea ice preconditioning (low concentration, less MY vs. FY, ice thickness) Lower troposphere – temp. and precip. Atmospheric circulation Clouds and aerosols (radiation) Arctic Ocean – SST and heat content Marine ecosystem (lower and higher-level) Terrestrial ecosystem / vegetation / land-cover Terrestrial hydrology (rivers and lakes) Greenland ice-sheet Other terrestrial Human response and other HD Spatial Temporal Quant.

3. Steele, M., W. Ermold, and J. Zhang (2008), Arctic Ocean surface warming trends over the past 100 years, Geophys. Res. Lett. Schweiger, A., J. Zhang, R. Lindsay, and M. Steele (2008), Did unusually sunny skies help drive the record sea ice minimum of 2007?, submitted to Geophys. Res. Lett. Lindsay, R., J. Zhang, A. Schweiger, M. Steele, and H. Stern (2008), Arctic ice retreat in 2007 follows thinning trend, submitted to J. Climate. Ogi, M., I. Rigor, M. McPhee, and J.M. Wallace (2008), Record low Arctic sea ice extent in September 2007: Role of summer winds, in revision. Zhang, J., R. Lindsay, M. Steele, and A. Schweiger (2008), What drove the dramatic retreat of Arctic sea ice during summer 2007?, submitted to Geophys. Res. Lett. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM Summer 2007 analyses published or submitted University of Washington

4. Integration and Synthesis WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM Goal 2. Improve integration: cross-disciplinary and national / international Goal 3. Produce an integrated overview of the summer 2007 sea-ice minimum

5. Integration and Synthesis 1. Integration 2. Synthesis and outcomes 3. Synthesis approach WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM

6.  Integration of expertise and efforts – develop “collaboration” and “synergy”  across disciplinary, institutional and national boundaries 1. Integration

7. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM  Integration of data and understanding at the component-level to improve understanding of linkages and system behavior – “synthesis” 1. Integration  across disciplinary boundaries  Observing and understanding change

8. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM  Integration of data and understanding at the component-level to improve understanding of linkages and system behavior 2. Synthesis  Synthesis does NOT involve new collection of data  Synthesis better exploits existing data, knowledge and methods through a focused (and consistent and quantitative) integrative framework.

9. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM  Integration of data and understanding at the component-level to improve understanding of linkages and system behavior  Synthesis involves putting together disparate data and strands of knowledge  Synthesis papers are NOT (necessarily) reviews or overviews. There is however a 'gray zone' between data synthesis and review papers 2. Synthesis

10. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM EXAMPLES of data synthesis papers Dickson et al. (2000): "synthesize“ Dickson et al. (2002): "analysis of long records“ Mann et al. (1998 and others): "calibration of widely distributed multi-proxy data“ Polyakov et al. (2004): "investigate using a wide range of datasets". 2. Synthesis

11. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM EXAMPLES of data synthesis papers Nordic Seas AGU monograph: several papers Drange et al. (2005): an "overview“ to provide a "synthesis” of "review papers"! 2. Synthesis

12. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM 2. Synthesis EXAMPLES of data synthesis papers

13. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM EXAMPLES of data synthesis papers 2. Synthesis

14. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM Specific OUTCOMES of synthesis, beyond 'improved knowledge and understanding'? 2. Synthesis New compilation and consistent comparison, plot and/or map of diverse records Fig. 2. Dickson et al. (2002)

15. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM Specific OUTCOMES of synthesis, beyond 'improved knowledge and understanding'? 2. Synthesis New conceptual models, feedback loop or schematic diagram, ideally with numbers Chapin et al. (2005)

16. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM Specific OUTCOMES of synthesis, beyond 'improved knowledge and understanding'? 2. Synthesis New up-to-date estimates, evaluations of budgets, parameterizations, etc. Chapin et al. (2005)

17. WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM Approach  Synthesis can be observational data analysis  Synthesis can be based on modelling analysis  Combination of observational and modelling 2. Synthesis process:

18. Understanding: Faster-than-forecast recent summer sea-ice decline Anthropogenic:  Models under-represent sea-ice sensitivity to GHGs [Stroeve et al., 2007] Natural variability:  Increases in lower troposphere temperature due to atmos. circulation  Changes in spring cloud cover [Francis and Hunter, 2006]  Changes in sea-ice circulation and ice age associated with atmos.-circulation variability [Rigor et al., 2002; Rigor and Wallace, 2004; Maslanik et al., 2007a]  Increases in ocean heat transport to the Arctic Ocean [Polyakov et al., 2005; Shimada et al., 2006] WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM

19. Understanding: Drastic summer 2007 sea-ice decline Preconditioning  Sea-ice circulation and ice age  Increases in ocean heat transport to the Arctic Ocean  Increases in lower troposphere temperature Conditioning – anomalous summer 2007  Atmospheric pressure (wind and cloud-cover)  Sea-ice circulation Feedbacks – positive, enhancement WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM

20. Understanding: Drastic summer 2007 sea-ice decline 2007: “A Perfect Storm” conjunction of factors, an anomalous one-off weather event or a foreshadow of rapid near-term transformation of the arctic system? Synthesis, integrated analysis for system-level understanding, including impacts and predictability Prediction for 2008 and beyond: Accelerating mechanisms? Decelerating mechanisms? WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM

21. Understanding: Recent, summer 2007 and future sea-ice System behavior: Drivers, linkages and feedbacks Synthesis, integrated analysis for system-level understanding predictability impacts Can we learn from similar anomalies in sea ice and/or related components in the long instrumental and historical record? Paleo record? WORKSHOP : LESSONS FROM THE 2007 ICE MINIMUM