A dedicated robust instrument for water vapor generation at low humidity for use with a laser water isotope analyzer in cold and dry polar regions
Obtaining precise continuous measurements of water vapor isotopic composition in dry places (polar or high-altitude regions) is an important challenge. The current limitation is the strong influence of humidity on the measured water isotopic composition by laser spectroscopy instruments for low humi...
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Published in | Atmospheric measurement techniques Vol. 14; no. 4; pp. 2907 - 2918 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Katlenburg-Lindau
Copernicus GmbH
15.04.2021
European Geosciences Union Copernicus Publications |
Subjects | |
Online Access | Get full text |
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Summary: | Obtaining precise continuous measurements of water vapor isotopic
composition in dry places (polar or high-altitude regions) is an important
challenge. The current limitation is the strong influence of humidity on the
measured water isotopic composition by laser spectroscopy instruments for
low humidity levels (below 3000 ppmv). This problem is addressed by
determining the relationships between humidity and measured
δ18O and δD of known water standards. Here, we present the
development of a robust field instrument able to generate water vapor, down
to 70 ppmv, at very stable humidity levels (average 1σ lower than 10 ppmv). This instrument, operated by a Raspberry interface, can be coupled to
a commercial laser spectroscopy instrument. We checked the stability of the
system as well as its accuracy when expressing the measured isotopic
composition of water vapor on the VSMOW–SLAP (Vienna Standard Mean Ocean Water – Standard Light Antarctic Precipitation) scale. It proved to be highly
stable during autonomous operation over more than 1 year at the East
Antarctic Concordia and Dumont d'Urville stations. |
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ISSN: | 1867-8548 1867-1381 1867-8548 |
DOI: | 10.5194/amt-14-2907-2021 |