TY - JOUR
T1 - Field testing of cavity ring-down spectroscopy analyzers measuring carbon dioxide and water vapor
AU - Richardson, Scott J.
AU - Miles, Natasha L.
AU - Davis, Kenneth J.
AU - Crosson, Eric R.
AU - Rella, Chris W.
AU - Andrews, Arlyn E.
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/3
Y1 - 2012/3
N2 - Prevalent methods for making high-accuracy tower-based measurements of the CO 2 mixing ratio, notably nondispersive infrared spectroscopy (NDIR), require frequent system calibration and sample drying. Wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) is an emerging laser-based technique with the advantages of improved stability and concurrent water vapor measurements. Results are presented from 30 months of field measurements from WS-CRDS systems at five sites in the upper Midwest of the United States. These systems were deployed in support of the North American Carbon Program's Mid-Continent Intensive (MCI) from May 2007 to November 2009. Excluding one site, 2σ of quasi-daily magnitudes of the drifts, before applying field calibrations, are less than 0.38 ppm over the entire 30-month field deployment. After applying field calibrations using known tanks sampled every 20 h, residuals from known values are, depending on site, from 0.02 ± 0.14 to 0.17 ± 0.07 ppm. Eight months of WS-CRDS measurements collocated with a National Oceanographic and Atmospheric Administrations (NOAA)/Earth System Research Laboratory (ESRL) NDIR system at West Branch, Iowa, show median daytime-only differences of -0.13 ± 0.63 ppm on a daily time scale.
AB - Prevalent methods for making high-accuracy tower-based measurements of the CO 2 mixing ratio, notably nondispersive infrared spectroscopy (NDIR), require frequent system calibration and sample drying. Wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) is an emerging laser-based technique with the advantages of improved stability and concurrent water vapor measurements. Results are presented from 30 months of field measurements from WS-CRDS systems at five sites in the upper Midwest of the United States. These systems were deployed in support of the North American Carbon Program's Mid-Continent Intensive (MCI) from May 2007 to November 2009. Excluding one site, 2σ of quasi-daily magnitudes of the drifts, before applying field calibrations, are less than 0.38 ppm over the entire 30-month field deployment. After applying field calibrations using known tanks sampled every 20 h, residuals from known values are, depending on site, from 0.02 ± 0.14 to 0.17 ± 0.07 ppm. Eight months of WS-CRDS measurements collocated with a National Oceanographic and Atmospheric Administrations (NOAA)/Earth System Research Laboratory (ESRL) NDIR system at West Branch, Iowa, show median daytime-only differences of -0.13 ± 0.63 ppm on a daily time scale.
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U2 - 10.1175/JTECH-D-11-00063.1
DO - 10.1175/JTECH-D-11-00063.1
M3 - Article
AN - SCOPUS:84857468468
SN - 0739-0572
VL - 29
SP - 397
EP - 406
JO - Journal of Atmospheric and Oceanic Technology
JF - Journal of Atmospheric and Oceanic Technology
IS - 3
ER -