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| Titel |
Global modelling of H2 mixing ratios and isotopic compositions with the TM5 model |
| VerfasserIn |
G. Pieterse, M. C. Krol, A. M. Batenburg, L. P. Steele, P. B. Krummel, R. L. Langenfelds, T. Röckmann |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 14 ; Nr. 11, no. 14 (2011-07-20), S.7001-7026 |
| Datensatznummer |
250009929
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| Publikation (Nr.) |
 copernicus.org/acp-11-7001-2011.pdf |
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| Zusammenfassung |
| The isotopic composition of molecular hydrogen (H2) contains
independent information for constraining the global H2
budget. To explore this, we have implemented hydrogen sources and
sinks, including their stable isotopic composition and isotope
fractionation constants, into the global chemistry
transport model TM5. For the first time, a global model now includes
a simplified but explicit isotope reaction scheme for the
photochemical production of H2. We present a comparison of
modelled results for the H2 mixing ratio and isotope
composition with available measurements on seasonal to inter
annual time scales for the years 2001–2007. The base model results
agree well with observations for H2 mixing ratios. For
δD[H2], modelled values are slightly lower than
measurements. A detailed sensitivity study is performed to identify
the most important parameters for modelling the isotopic composition
of H2. The results show that on the global scale, the
discrepancy between model and measurements can be closed by adjusting
the default values of the isotope effects in deposition,
photochemistry and the stratosphere-troposphere exchange within the
known range of uncertainty. However, the available isotope data do not
provide sufficient information to uniquely constrain the global
isotope budget. Therefore, additional studies focussing on the
isotopic composition near the tropopause and on the isotope effects in
the photochemistry and deposition are recommended. |
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