Connections Between West Antarctic Ice Core Sulfate and
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, 109 th Air National Guard, Ice Core Drilling Services, Raytheon Polar Services.
RESEARCH QUESTIONS ● Has sulfate deposition remained stable across West Antarctica for 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?
ICE CORE LOCATIONS Map created using the RAMP DEM (Liu and others, 2001).
MAJOR ION SOURCE CHEMISTRY (Separated into xs and ss SO 4) (Na + K + Mg + Ca) + (Cl + NO 3 + SO 4) = 95% of Dissolved Ions (Also test for MS – Biological Signal) ? sea salt ICE SHEET
RESEARCH QUESTIONS ● Has sulfate deposition remained stable across West Antarctica for the last 200 years?
RAW xs. SO 4 (RED) AND ss. SO 4 (GREEN) CONCENTRATIONS FROM 1800 -2002 AD
RAW xs. SO 4 (RED) AND ss. SO 4 (GREEN) CONCENTRATIONS FROM 1800 -2002 AD
ROBUST SPLINE SMOOTHED ANNUAL xs. SO 4 CONCENTRATIONS (in ppb)
ICE CORE LOCATIONS Map created using the RAMP DEM (Liu and others, 2001).
RESEARCH QUESTIONS ● Have anthropogenic emissions affected West Antarctic sulfate concentrations in recent decades?
NORTHERN HEMISPHERE (GISP 2) SULFATE RECORD (Data for this figure provided by Dr. Paul A. Mayewski)
ROBUST SPLINE SMOOTHED ANNUAL xs. SO 4 CONCENTRATIONS (in ppb)
RESEARCH QUESTIONS ● Do sea ice extent fluctuations affect sulfate concentrations across West Antarctica?
SDM-94 xs. SO 4 and Sea Ice Extent Sea Ice Data From SIMMONDS AND JACKA (1995)
SDM-94 xs. SO 4 and Sea Ice Extent
LINEAR CORRELATIONS BETWEEN ANNUALLY AVERAGED SEA ICE EXTENT AND xs. SO 4 CONCENTRATIONS - - All Values Above 95% Significant (r ≥ 0. 414) - Latitudinal position of labels has no significance + + + High xs. SO 4 Concentrations Associated with Decreased Sea Ice Extent.
LINEAR CORRELATIONS BETWEEN ANNUALLY AVERAGED SEA ICE EXTENT AND ss. SO 4 CONCENTRATIONS + All Values Above 95% Significant (r ≥ 0. 405) Latitudinal position of labels has no significance + - - High ss. SO 4 Concentrations Associated with Increased Sea Ice Extent. - - -
CONCLUSIONS ● A climate transition affects Central West Antarctic sulfate concentrations around 1940. ● There is no compelling evidence for anthropogenic impact on Antarctic SO 4 concentrations. ● When sea ice extent is increased (decreased), ss. SO 4 (xs. SO 4) concentrations are higher.
Thank You For Listening…
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