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| Titel |
18O isotope fluxes in water vapor and carbon dioxide: measurements, modeling, and potential application |
| VerfasserIn |
Albin Hammerle, Patrick Sturm, Lydia Gentsch, Matthias Barthel, Alexander Knohl |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250053207
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| Zusammenfassung |
| The stable isotope 18O in water is a powerful tracer to investigate the hydrological cycle,
ecological processes or paleoclimatic archives. Recently, laser spectroscopic techniques
for isotope measurements have been developed which allow for field deployable,
high accuracy and high frequency measurements of isotopic gas-exchange with the
atmosphere.
Here we present a unique dataset of δ 18O in water vapor and δ 18O in carbon dioxide
measured simultaneously by two laser spectrometers (Los Gatos Research and Aerodyne
Research, respectively). The study was conducted on beech trees in a mixed forest in
Switzerland in two campaigns in 2009 and 2010. By using this technique in combination with
steady-state through-flow chambers, leaf water samples, sophisticated data screening
and a modeling approach we (i) were able to provide continuous time series of
leaf water 18O signals for the two campaigns and (ii) determined the ability to
predict 18O of carbon dioxide from these leaf water 18O data. Modeling of leaf water
enrichment in 18O was based on the Peclet-modified Craig-Gordon model and parameter
optimization was done via a Bayesian approach, providing additional information on
parameter and model uncertainty compared to commonly used least squares fitting
approaches. |
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