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| Titel |
New Isotopic Water Analyzer for Hydrological Measurements of Both Liquid Water and Water Vapor |
| VerfasserIn |
T. Owano, M. Gupta, E. Berman, D. Baer |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250070766
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| Zusammenfassung |
| Measurements of the stable isotope ratios of liquid water allow determination of water
flowpaths, residence times in catchments, and groundwater migration. Previously,
discrete water samples have been collected and transported to an IRMS lab for isotope
characterization. Due to the expense and labor associated with such sampling, isotope studies
have thus been generally limited in scope and in temporal resolution.
We report on the recent development of the first Isotopic Water Analyzer that
simultaneously quantifies δ2H, δ17O and δ18O in liquid water or in water vapor
from different natural water sources (e.g., rain, snow, streams and groundwater). In
High-Throughput mode, the IWA can report measurements at the unprecedented rate of over
800 injections per day, which yields more than 140 total unknown and reference samples per
day (still with 6 injections per measurement). This fast time response provides isotope
hydrologists with the capability to study dynamic changes in δ values quickly (minutes) and
over long time scales (weeks, months), thus enabling studies of mixing dynamics in
snowmelt, canopy throughfall, stream mixing, and allows for individual precipitation events
to be independently studied.
In addition, the same IWA can also record fast measurements of isotopic water vapor
(δ2H, δ17O, δ18O) in real time (2 Hz data rate or faster) over a range of mole fractions greater
than 60000 ppm H2O in air. Changing between operational modes requires a software
command, to enable the user to switch from measuring liquid water to measuring water
vapor, or vice versa. The new IWA, which uses LGR’s patented Off-axis ICOS technology,
incorporates proprietary internal thermal control for stable measurements with essentially
zero drift despite changes in ambient temperature (over the entire range from 0-45
degrees C). Measurements from recent field studies using the IWA will be presented. |
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