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| Titel |
Development and field testing of a rapid and ultra-stable atmospheric carbon dioxide spectrometer |
| VerfasserIn |
B. Xiang, D. D. Nelson, J. B. McManus, M. S. Zahniser, R. A. Wehr, S. C. Wofsy |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 12 ; Nr. 7, no. 12 (2014-12-15), S.4445-4453 |
| Datensatznummer |
250115995
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| Publikation (Nr.) |
 copernicus.org/amt-7-4445-2014.pdf |
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| Zusammenfassung |
| We present field test results for a new spectroscopic instrument to measure
atmospheric carbon dioxide (CO2) with high precision
(0.02 μmol mol−1, or ppm at 1 Hz) and demonstrate high
stability (within 0.1 ppm over more than 8 months), without the need for
hourly, daily, or even monthly calibration against high-pressure gas
cylinders. The technical novelty of this instrument (ABsolute Carbon dioxide,
ABC) is the spectral null method using an internal quartz reference cell with
known CO2 column density. Compared to a previously described prototype,
the field instrument has better stability and benefits from more precise
thermal control of the optics and more accurate pressure measurements in the
sample cell (at the mTorr level). The instrument has been deployed at a
long-term ecological research site (the Harvard Forest, USA), where it has
measured for 8 months without on-site calibration and with minimal
maintenance, showing drift bounds of less than 0.1 ppm. Field measurements
agree well with those of a commercially available cavity ring-down CO2
instrument (Picarro G2301) run with a standard calibration protocol. This
field test demonstrates that ABC is capable of performing high-accuracy,
unattended, continuous field measurements with minimal use of reference gas
cylinders. |
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