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| Titel |
Inter-comparison of two high-accuracy fast-response spectroscopic sensors of carbon dioxide: a case study |
| VerfasserIn |
B. A. Flowers, H. H. Powers, M. K. Dubey, N. G. McDowell |
| 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 ; 5, no. 5 ; Nr. 5, no. 5 (2012-05-08), S.991-997 |
| Datensatznummer |
250002860
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| Publikation (Nr.) |
 copernicus.org/amt-5-991-2012.pdf |
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| Zusammenfassung |
| Tunable diode laser absorption (TDL) and cavity ring-down spectroscopic
(CRDS) sensors for atmospheric carbon dioxide were co-deployed during summer
and fall of 2010 in field and laboratory conditions at Los Alamos National
Laboratory. Both sensors were characterized for accuracy and precision for
ambient carbon dioxide measurements at ground level and compared using both
laboratory and ambient field data. After post-processing that included water
vapor correction and calibration to WMO reference standards, overall mean
[12C16O2] = 392.05 ± 8.92 ppm and
[12C16O2] = 392.22 ± 9.05 ppm were observed between 29 July and 16 August 2010.
The mean difference between the CRDS and TDL data for 12CO2 was
0.04 ± 1.80 ppm (±1σ in 60 s) for ambient field
data, demonstrating the sensors meet the WMO/IAEA compatibility standard.
The observations show over the 19-day period the [CO2]CRDS'/[CO2]TDL ratio exhibits a Gaussian
distribution centered at x0 = 1.003 ± 3.38 × 10−5 (±1σ),
indicating the ratio is dominated by random
noise as opposed to a bias in the output of either sensor. The CRDS sensor
is capable of measuring [12C16O2] to a precision of 23 ppb in
1 min and decreases to 6.5 ppb in 58 min. At one and 58-min,
the TDL exhibits precisions of 29 ppb and 53 ppb. The CRDS is compact, fast,
and stable; the TDL is larger and requires frequent calibrations to maintain
its precision. The sensors also exhibit consistent hourly averaged diurnal
values underscoring the interplay of biological, anthropogenic, and
transport processes regulating CO2 at the site. |
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