The impact of glacial-interglacial climate variability on the oxidizing capacity of the atmosphere
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We are currently simulating the glacial-interglacial variability in atmospheric oxidant concentrations using the ICECAP (ICE age Chemistry And Proxies) model. The model results are constrained by observations of Δ17O(SO42-) and Δ17O(NO3-) from the Antarctic ice core record. Stay tuned for results as they develop! |
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ICECAP model framework. Meteorology archived from the GISS GCM is used to drive GEOS-Chem and BIOME4. Vegetation type and leaf area extent calculated by BIOME4 are applied to GEOS-Chem. Coupling Linoz to GEOS-Chem allows us to capture the effect of a changing stratospheric O3 column on tropospheric photolysis rates. Oxidant fields archived from the full chemistry version of GEOS-Chem are applied to the aerosol isotope version of this model. Calculated oxygen isotopes of sulfate and nitrate aerosol are then compared to the ice core record. | |
Observations of Δ17O(SO42-) (black symbols) and δD (red line, indicative of temperature) over the last 130,000 years from the Vostok, Antarctic ice core. The observations of Δ17O(SO42-) show that gas-phase oxidation by OH conctributed 40% more to sulfate production in the glacial period relative to the interglacials that came before and after. From Alexander et al. (2002). |
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People: |
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Eric Sofen and Becky Alexander,
University of Washington Lee Murray and Loretta J. Mickley, Harvard University Gavin Schmidt ,NASA GISS Jed O. Kaplan, École Polytechnique Fédérale de Lausanne Joël Savarino, Laboratoire de Glaciologie et Géophysique de l'Environnement | ||
| References: | ||
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Murray, L. T., Mickley, L. J., Kaplan, J.
O., Sofen, E. D., Leibensperger, E. M., Alexander, B., Jones, D. B. A.,
and Jacob, D. J.: Evolution of the oxidative capacity of the troposphere
since the Last Glacial Maximum, EOS Trans AGU, Abstract A53E-03, 2009. Alexander, B., Savarino, J., Thiemens, M.H., and Delmas, R., “Climate driven changes of the oxidation pathways of atmospheric sulfur,” Geophys. Res. Lett., 29(14), 30 (2002). (.pdf) |
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| Funding: | ||
| NSF-AGS 0704169 | ||
