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| Titel |
Development of a High Precision Oxygen, Carbon Dioxide, and Water Monitor for Fast Plume and Eddy Flux Measurements |
| VerfasserIn |
Mark Zahniser, David Nelson, Rob Roscioli, Scott Herndon, Dylan Jervis, Barry McManus, Tara Yacovitch |
| 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 |
250146304
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| Publikation (Nr.) |
 EGU/EGU2017-10324.pdf |
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| Zusammenfassung |
| A central concept of the carbon cycle is the inverted relationship between CO2 and O2 ,
which provides detailed information about CO2 sources and sinks. For example, Keeling was
able to use very precise O2 and CO2 measurements to understand oceanic vs terrestrial
carbon sinks. It has been a long-standing challenge to measure both species with
enough precision and response time to understand the CO2 /O2 exchange on a
local scale. Such a capability would allow for detailed measurements of ecosystem
exchange, fossil fuel burning processes, and emissions from carbon sequestration
sites.
Here we report on recent advances using near-infrared direct absorption spectroscopy to
measure CO2 , O2 , and H2 O on timescales of 0.1 to 1 second and at high precision, for
eddy flux quantification of ecosystem exchange. O2 is quantified using the A-band
electronic absorption at 763 nm, yielding a 1 s precision of 6 ppm and 100 s precision of 1
ppm (30 and 5 per meg fractional precision, respectively). CO2 and H2 O are quantified
using overtone transitions at 2 micron, providing 1 s precisions of <0.02 ppm and <0.2 ppm,
respectively. The monitor uses a compact multipass cell with a time response is <0.3 s at 3
SLPM flow rate. We present long-term O2 and CO2 rooftop measurements,
revealing multiple combustion sources contributing to the local CO2 enhancement. |
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