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Detailed Reference Information |
Gerst, S. and Quay, P. (2000). The deuterium content of atmospheric molecular hydrogen: Method and initial measurements. Journal of Geophysical Research 105: doi: 10.1029/2000JD900387. issn: 0148-0227. |
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A new technique for determining the ΔD of atmospheric molecular hydrogen (H2) at background mixing ratios is described in detail. An air sample is compressed into a high-pressure cylinder, after which the cylinder is cooled to -196 ¿C to condense the air and generate a headspace greatly enriched in H2. The H2-enriched headspace is collected and admitted into a high-vacuum extraction line, where the H2 is separated from the headspace gases by combustion to water followed by cryogenic collection. The H2-derived water is then reduced back to H2 for measurement of its D/H content via isotope-ratio mass spectrometry. The primary limitation of the method is contamination during compressor collection and subsequent storage of air samples in high-pressure cylinders. The ΔD of atmospheric H2 was measured on air samples collected between 46 ¿N and 72 ¿S during a research cruise in the Pacific Ocean during 1998 and at Cheeka Peak, Washington (48 ¿N), during 1997--1999 and Point Barrow, Alaska (71 ¿N), during 1996--1997. These measurements yield a global average ΔD of atmospheric H2 of +130¿4? and average Northern and Southern Hemispheric ΔD values of +123¿3? and +138¿8?, respectively (versus Vienna standard mean ocean water). ¿ 2000 American Geophysical Union |
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Abstract |
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Keywords
Atmospheric Composition and Structure, Geochemical cycles, Atmospheric Composition and Structure, Troposphere—composition and chemistry, Atmospheric Composition and Structure, Instruments and techniques |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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