Water-vapor measurement via cavity ring down spectroscopy in the visible

1998 ◽  
Author(s):  
Fuge Sun ◽  
Dongxu Dai ◽  
Lu Kang ◽  
Guohea Sha ◽  
JinChun Xie ◽  
...  
Keyword(s):  
Water Vapor ◽  
Cavity Ring Down Spectroscopy ◽  
Cavity Ring Down

scholarly journals Field Testing of Cavity Ring-Down Spectroscopy Analyzers Measuring Carbon Dioxide and Water Vapor

2012 ◽  
Vol 29 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Scott J. Richardson ◽  
Natasha L. Miles ◽  
Kenneth J. Davis ◽  
Eric R. Crosson ◽  
Chris W. Rella ◽  
...  
Keyword(s):  
Water Vapor ◽  
Field Measurements ◽  
Field Testing ◽  
The United States ◽  
Upper Midwest ◽  
Cavity Ring Down Spectroscopy ◽  
The North ◽  
Improved Stability ◽  
Field Deployment ◽  
Cavity Ring Down

Abstract Prevalent methods for making high-accuracy tower-based measurements of the CO2 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.

scholarly journals High-accuracy continuous airborne measurements of greenhouse gases (CO<sub>2</sub> and CH<sub>4</sub>) using the cavity ring-down spectroscopy (CRDS) technique

2010 ◽  
Vol 3 (2) ◽  
pp. 375-386 ◽  
Author(s):  
H. Chen ◽  
J. Winderlich ◽  
C. Gerbig ◽  
A. Hoefer ◽  
C. W. Rella ◽  
...  
Keyword(s):  
Water Vapor ◽  
Greenhouse Gases ◽  
Ambient Air ◽  
High Accuracy ◽  
Mean Difference ◽  
Pressure Broadening ◽  
Cavity Ring Down Spectroscopy ◽  
Airborne Measurements ◽  
The Mean ◽  
Cavity Ring Down

Abstract. High-accuracy continuous measurements of greenhouse gases (CO2 and CH4) during the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) phase B campaign in Brazil in May 2009 were accomplished using a newly available analyzer based on the cavity ring-down spectroscopy (CRDS) technique. This analyzer was flown without a drying system or any in-flight calibration gases. Water vapor corrections associated with dilution and pressure-broadening effects for CO2 and CH4 were derived from laboratory experiments employing measurements of water vapor by the CRDS analyzer. Before the campaign, the stability of the analyzer was assessed by laboratory tests under simulated flight conditions. During the campaign, a comparison of CO2 measurements between the CRDS analyzer and a nondispersive infrared (NDIR) analyzer on board the same aircraft showed a mean difference of 0.22±0.09 ppm for all flights over the Amazon rain forest. At the end of the campaign, CO2 concentrations of the synthetic calibration gases used by the NDIR analyzer were determined by the CRDS analyzer. After correcting for the isotope and the pressure-broadening effects that resulted from changes of the composition of synthetic vs. ambient air, and applying those concentrations as calibrated values of the calibration gases to reprocess the CO2 measurements made by the NDIR, the mean difference between the CRDS and the NDIR during BARCA was reduced to 0.05±0.09 ppm, with the mean standard deviation of 0.23±0.05 ppm. The results clearly show that the CRDS is sufficiently stable to be used in flight without drying the air or calibrating in flight and the water corrections are fully adequate for high-accuracy continuous airborne measurements of CO2 and CH4.

Cavity ring-down spectroscopy of 17O-enriched water vapor between 12,055 and 12,260 cm−1

2019 ◽  
Vol 239 ◽  
pp. 106651 ◽  
Author(s):  
A.-W. Liu ◽  
G.-L. Liu ◽  
X.-Q. Zhao ◽  
J. Wang ◽  
Y. Tan ◽  
...  
Keyword(s):  
Water Vapor ◽  
Cavity Ring Down Spectroscopy ◽  
Cavity Ring Down

Dual-laser frequency-stabilized cavity ring-down spectroscopy for water vapor density measurements

Metrologia ◽  
2018 ◽  
Vol 55 (5) ◽  
pp. 662-669 ◽  
Author(s):  
Eugenio Fasci ◽  
Hemanth Dinesan ◽  
Luigi Moretti ◽  
Andrea Merlone ◽  
Antonio Castrillo ◽  
...  
Keyword(s):  
Water Vapor ◽  
Laser Frequency ◽  
Vapor Density ◽  
Cavity Ring Down Spectroscopy ◽  
Density Measurements ◽  
Dual Laser ◽  
Cavity Ring Down

scholarly journals Calibrated high-precision <sup>17</sup>O<sub>excess</sub> measurements using laser-current tuned cavity ring-down spectroscopy

2013 ◽  
Vol 6 (6) ◽  
pp. 10191-10229 ◽  
Author(s):  
E. J. Steig ◽  
V. Gkinis ◽  
A. J. Schauer ◽  
S. W. Schoenemann ◽  
K. Samek ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Precision ◽  
Isotope Ratio ◽  
Isotope Ratio Mass Spectrometry ◽  
Specific Interest ◽  
Cavity Ring Down Spectroscopy ◽  
New Instrument ◽  
Current Tuning ◽  
Better Than ◽  
Cavity Ring Down

Abstract. High precision analysis of the 17O/16O isotope ratio in water and water vapor is of interest in hydrological, paleoclimate, and atmospheric science applications. Of specific interest is the parameter 17Oexcess, a measure of the deviation from a linear relationship between 17O/16O and 18O/16O ratios. Conventional analyses of 17Oexcess are obtained by fluorination of H2O to O2 that is analyzed by dual-inlet isotope ratio mass spectrometry (IRMS). We describe a new laser spectroscopy instrument for high-precision 17Oexcess measurements. The new instrument uses cavity ring-down spectroscopy (CRDS) with laser-current tuning to achieve reduced measurement drift compared with previous-generation instruments. Liquid water and water vapor samples can be analyzed with better than 8 per meg precision for 17Oexcess using integration times of less than 30 min. Calibration with respect to accepted water standards demonstrates that both the precision and the accuracy are competitive with conventional IRMS methods. The new instrument also achieves simultaneous measurements of δ18O, 17Oand δD with precision < 0.03‰, < 0.02‰ and < 0.2‰, respectively.

scholarly journals Accurate measurements of carbon monoxide in humid air using the cavity ring-down spectroscopy (CRDS) technique

2012 ◽  
Vol 5 (5) ◽  
pp. 6493-6517 ◽  
Author(s):  
H. Chen ◽  
A. Karion ◽  
C. W. Rella ◽  
J. Winderlich ◽  
C. Gerbig ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Water Vapor ◽  
Near Infrared ◽  
Infrared Region ◽  
Humid Air ◽  
Cavity Ring Down Spectroscopy ◽  
Carbon Dioxide Co2 ◽  
Air Streams ◽  
Line Interference ◽  
Cavity Ring Down

Abstract. Accurate measurements of carbon monoxide (CO) in humid air have been made using the cavity ring-down spectroscopy (CRDS) technique. The measurements of CO mole fractions are determined from the strength of its spectral absorption in the near infrared region (∼1.57 μm) after removing interferences from adjacent carbon dioxide (CO2) and water vapor (H2O) absorption lines. Water correction functions that account for the dilution and pressure-broadening effects as well as absorption line interferences from adjacent CO2 and H2O lines have been derived for CO2 mole fractions between 360–390 ppm. The line interference corrections are independent of CO mole fractions. The dependence of the line interference correction on CO2 abundance is estimated to be approximately −0.3 ppb/100 ppm CO2 for dry mole fractions of CO. Comparisons of water correction functions from different analyzers of the same type show significant differences, making it necessary to perform instrument-specific water tests for each individual analyzer. The CRDS analyzer was flown on an aircraft in Alaska from April to November in 2011, and the accuracy of the CO measurements by the CRDS analyzer has been validated against discrete NOAA/ESRL flask sample measurements made on board the same aircraft, with a mean difference between integrated in situ and flask measurements of −0.6 ppb and a standard deviation of 2.8 ppb. Preliminary testing of CRDS instrumentation that employs new spectroscopic analysis (available since the beginning of 2012) indicates a smaller water vapor dependence than the models discussed here, but more work is necessary to fully validate the performance. The CRDS technique provides an accurate and low-maintenance method of monitoring the atmospheric dry mole fractions of CO in humid air streams.

Sign in / Sign up

Export Citation Format

Share Document