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| Titel |
Evaluating the sensitivity of nitrate and sulfate Δ¹⁷O to changes in atmospheric oxidant concentrations on the preindustrial-industrial timescale |
| VerfasserIn |
E. D. Sofen, S. A. Kunasek, B. Alexander, E. J. Steig, D. J. Gleason, T. L. Jackson, M. H. Thiemens, M. G. Hastings |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250029676
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| Zusammenfassung |
| Atmospheric oxidants are the primary sink for reduced trace gases such as methane.
Knowledge of past oxidant abundances is critical for closing paleoatmospheric
reduced trace gas budgets. Ice core measurements of Î17O of nitrate and sulfate
(Î17O = δ17O – 0.52à (δ18O)) provide a tracer of paleoatmospheric changes in the
oxidation chemistry of nitrate and sulfate production that may be quantitatively
interpreted using atmospheric photochemical modeling. We use an atmospheric
global chemical transport model of Î17O of nitrate and sulfate (GEOS-Chem,
www-as.harvard.edu/chemistry/ trop/geos/) with both preindustrial and industrial simulations
to investigate the sensitivity of sulfate and nitrate Î17O to oxidant concentration changes on
this timescale. Model results are compared with existing ice core records from Site
A, Greenland, as well as a new record from the West Antarctic Ice Sheet (WAIS
Divide).
Our global model results show a 40-50% preindustrial-industrial increase in global mean
ozone concentrations in the troposphere, while preindustrial-industrial changes in global
mean OH concentrations are much smaller (decrease of |
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