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| Titel |
Measuring the variation of the isotopic composition of H2 in the atmosphere |
| VerfasserIn |
A. M. Batenburg, S. Walter, T. Röckmann |
| 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 |
250025805
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| Zusammenfassung |
| As molecular hydrogen (H2) is expected to become an important energy carrier in the future,
emissions of H2 to the atmosphere are likely to rise as a result of the inevitable leakage
during production, storage and distribution of H2. The associated rise of atmospheric H2
levels may affect methane lifetime and stratospheric ozone depletion. Unfortunately, large
uncertainties still exist in the global H2budget.
Due to the large relative mass difference between deuterated hydrogen (HD) and
‘ordinary’ hydrogen (HH), large isotope effects occur in the H2 cycle. The different sources
and sinks have very distinct isotopic signatures and fractionation coefficients, respectively.
For this reason, measurements of isotopic composition are a promising tool to gain
insight into H2 source and sink processes and to constrain the terms in the global
budget. With the GC-IRMS system at the IMAU (similar to Rhee et al. [2004]), the
concentration and the deuterium content of atmospheric H2 can be determined routinely and
precisely.
Within the ‘EUROH2YDROS’ project a European Network has been initialized for
hydrogen observations. Weekly to monthly air samples from 6 EUROH2YDROS stations are
now measured on a regular basis in the IMAU isotope lab in collaboration with Heidelberg
University, Germany, LSCE, France and MPI Jena, Germany. The longest weekly time series
is the Alert series (Canada), containing approximately weekly samples stretching over 1.5
year. More than two full seasonal cycles (with monthly sampling) are available from
Neumayer (Antarctica). Sampling from more stations is planned; first samples from
Kasprowy Wierch (Poland) and Cabauw (The Netherlands) have already been measured, and
sampling in Korea is in preparation.
These time series show the variation of the isotopic composition of H2 with latitude and
season, and allow investigating the effects of the different sources and sinks. A clear seasonal
cycle is observed in Alert for both the H2 concentration and its deuterium content. The two
quantities vary out-of-phase, which is in accordance with the large role of soil uptake in the
Northern Hemisphere (Rhee et al. [2006]). Average deuterium content is higher in the
Southern Hemisphere than in the Northern Hemisphere, in agreement with Gerst
and Quay [2000]. A selection of these measurements will be presented on this
poster.
References
Rhee, T.S., J. Mak, T. Röckmann, and C.A.M. Brenninkmeijer (2004), Continuous-flow
isotope analysis of the deuterium/hydrogen ratio in atmospheric hydrogen, Rapid Commun.
Mass Spectrom., 18, 299-306
Rhee, T.S., C.A.M. Brenninkmeijer, and T. Röckmann (2006), The overwhelming role of
soils in the global atmospheric hydrogen cycle, Atmos. Chem. Phys, 6, 1611-1625
Gerst, S. and P. Quay, The deuterium content of atmospheric molecular hydrogen:
Method and initial measurements, J. Geophys. Res, 105(D21), 26433-26445
http://www.meteor.uni-frankfurt.de/eurohydros/ |
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