1. Connections Between West Antarctic Ice Core Sulfate and Climate Over the Last 200 Years Daniel A. Dixon, Paul A. Mayewski, Susan Kaspari, Karl Kreutz, Gordon Hamilton, Kirk Maasch, Sharon B. Sneed and Michael J. Handley Climate Change Institute, Department of Earth Sciences, University of Maine, USA ACKNOWLEDGEMENTS: Office of Polar Programs, National Science Foundation, 109th Air National Guard, Ice Core Drilling Services, Raytheon Polar Services.

2. RESEARCH QUESTIONS ● Has sulfate deposition remained stable across West Antarcticafor the last 200 years? ● Have anthropogenic emissions affected West Antarctic sulfate concentrations in recent decades? ● Do sea ice extent fluctuations affect sulfate concentrations across West Antarctica?

3. ICE CORE LOCATIONS Map created using the RAMP DEM (Liu and others, 2001).

4. ICE SHEET (Na + K + Mg + Ca) + (Cl + NO3 + SO4) = 95% of Dissolved Ions (Also test for MS – Biological Signal) (Separated into xs and ss SO4) MAJOR ION SOURCE CHEMISTRY sea salt ?

5. RESEARCH QUESTIONS ● Has sulfate deposition remained stable across West Antarcticafor the last 200 years?

6. RAW xsSO4 (RED) AND ssSO4 (GREEN) CONCENTRATIONS FROM 1800-2002 AD

7. RAW xsSO4 (RED) AND ssSO4 (GREEN) CONCENTRATIONS FROM 1800-2002 AD

8. ROBUST SPLINE SMOOTHED ANNUAL xsSO4 CONCENTRATIONS (in ppb)

9. ICE CORE LOCATIONS Map created using the RAMP DEM (Liu and others, 2001).

10. RESEARCH QUESTIONS ● Have anthropogenic emissions affected West Antarctic sulfate concentrations in recent decades?

11. NORTHERN HEMISPHERE (GISP2) SULFATE RECORD (Data for this figure provided by Dr. Paul A. Mayewski)

12. ROBUST SPLINE SMOOTHED ANNUAL xsSO4 CONCENTRATIONS (in ppb)

13. RESEARCH QUESTIONS ● Do sea ice extent fluctuations affect sulfate concentrations across West Antarctica?

14. SDM-94 xsSO4 and Sea Ice Extent Sea Ice Data From SIMMONDS AND JACKA (1995)

15. SDM-94 xsSO4 and Sea Ice Extent

16. LINEAR CORRELATIONS BETWEEN ANNUALLY AVERAGED SEA ICE EXTENT AND xsSO4 CONCENTRATIONS High xsSO4 Concentrations Associated with Decreased Sea Ice Extent. + + - - - + + + + All Values Above 95% Significant (r ≥ 0.414) Latitudinal position of labels has no significance

17. + - - - - + - - - High ssSO4 Concentrations Associated with Increased Sea Ice Extent. All Values Above 95% Significant (r ≥ 0.405) LINEAR CORRELATIONS BETWEEN ANNUALLY AVERAGED SEA ICE EXTENT AND ssSO4 CONCENTRATIONS Latitudinal position of labels has no significance

18. CONCLUSIONS ● A climate transition affects Central West Antarctic sulfate concentrations around 1940. ● There is no compelling evidence for anthropogenic impact on Antarctic SO4 concentrations. ● When sea ice extent is increased (decreased), ssSO4 (xsSO4) concentrations are higher.

19. Thank You For Listening…