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| Titel |
Real time, ambient air laser monitor for rare CO2 isotopic tracers: Δ13 C18 O16 O and Δ17 O |
| VerfasserIn |
David Nelson, Joanne Shorter, Barry McManus, Dylan Jervis, Mark Zahniser, Shuhei Ono |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250145639
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| Publikation (Nr.) |
 EGU/EGU2017-9601.pdf |
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| Zusammenfassung |
| Greenhouse gas (GHG) emissions are the primary drivers of global climate change and hence
there is a crucial need to quantify their sources and sinks. A powerful technique to help
constrain source and sink strengths in GHG exchange processes is the analysis of the relative
proportions of isotopic variants of GHGs. We present a new laser isotope monitor
based on Tunable Infrared Laser Direct Absorption Spectroscopy (TILDAS) to
measure the primary clumped isotopologue of CO2 (Δ13 C18 O16 O) and to
simultaneously measure the mass independent 17 O-CO2 content (Δ17 O). The instrument
directly measures dried atmospheric samples without cryogenic preconcentration of
CO2 .
The instrument has several novel features. The instrument’s sensitivity is enhanced by
employing a 400 meter optical absorption cell. Measurement drift is suppressed by
using a rapid sample switching method with frequent comparison to a working
reference. A new dual-pressure measurement scheme is demonstrated. This scheme
solves the dynamic range challenge that arises in simultaneously measuring the main
isotopologues of CO2 together with much less abundant clumped isotopologue
species.
Our initial results address measurement precision, measurement drift and calibration. We
show the potential to reach 0.03 per mil repeatability with time resolution of 3 minutes and
with minimal drift over an 18 hour measurement period. The instrument is sufficiently
compact to be field deployed thus providing the possibility of continuous measurements of
Δ13 C18 O16 O and Δ17 O rather than occasional flask samples. |
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