A low-volume cavity ring-down spectrometer for sample-limited applications

Stowasser, C.; Farinas, Alejandro D.; Ware, John A.; Wistisen, D. W.; Rella, Chris W.; Wahl, E.; Crosson, E.; Blunier, Thomas

doi:10.1007/s00340-013-5528-9

Cited by 17 publications

(17 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The analyzer used in this study (Picarro cavity ring-down spectrometer (CRDS); G2310) pulls the sample at 110 sccm and measuring at 0.5 Hz makes one measurement every 3.7 scc (standard cubic centimeters). The analyzer cell has a standard volume of approximately 6 scc, since it is 35 cc in volume, but is maintained at 187 hPa (140 torr) and 45 • C. The volume of the cell needs to be flushed about three times for the air to be completely renewed (Stowasser et al, 2014).…”

Section: Impact Of Diffusion and Dispersion On The Vertical Resolutionmentioning

confidence: 99%

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH4 and CO2

et al. 2017

View full text Add to dashboard Cite

Abstract. An original and innovative sampling system called AirCore was presented by NOAA in 2010 (Karion et al., 2010). It consists of a long ( > 100 m) and narrow (< 1 cm) stainless steel tube that can retain a profile of atmospheric air. The captured air sample has then to be analyzed with a gas analyzer for trace mole fraction. In this study, we introduce a new AirCore aiming to improve resolution along the vertical with the objectives to (i) better capture the vertical distribution of CO 2 and CH 4 , (ii) provide a tool to compare AirCores and validate the estimated vertical resolution achieved by AirCores. This (high-resolution) AirCore-HR consists of a 300 m tube, combining 200 m of 0.125 in. (3.175 mm) tube and a 100 m of 0.25 in. (6.35 mm) tube. This new configuration allows us to achieve a vertical resolution of 300 m up to 15 km and better than 500 m up to 22 km (if analysis of the retained sample is performed within 3 h). The AirCore-HR was flown for the first time during the annual StratoScience campaign from CNES in August 2014 from Timmins (Ontario, Canada). High-resolution vertical profiles of CO 2 and CH 4 up to 25 km were successfully retrieved. These profiles revealed well-defined transport structures in the troposphere (also seen in CAMS-ECMWF high-resolution forecasts of CO 2 and CH 4 profiles) and captured the decrease of CO 2 and CH 4 in the stratosphere. The multi-instrument gondola also carried two other low-resolution AirCore-GUF that al-

show abstract

Section: Impact Of Diffusion and Dispersion On The Vertical Resolutionmentioning

confidence: 99%

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH4 and CO2

et al. 2017

View full text Add to dashboard Cite

show abstract

“…As several combinations of reference gases were used to determine the response time of the analyzer, data were first normalized to the difference in concentration or isotope composition between the two measured gases. How fast the analyzer reaches a new steady state after a stepwise change in inlet composition is quantified using the 5-95 % response time [21], i.e., the time needed for the measurement to go from 5 to 95 % of the difference between the initial and final values. After a change in the sample gas concentrations and delta values at the inlet of the multi-inlet unit, the analyzer response remains stable and equal to the initial values for some time, while the inlet gas has already been changed.…”

Section: Performance Of the Analyzermentioning

confidence: 99%

Monitoring CO2 concentration and δ13C in an underground cavity using a commercial isotope ratio infrared spectrometer

2015

View full text Add to dashboard Cite

International audienceCO2 stable carbon isotopes are very attractive in environmental research to investigate both natural and anthropogenic carbon sources. Laser-based isotope ratio infrared spectrometers (IRIS) allow in situ continuous monitoring of CO2 isotopes, and therefore they have a potential for unprecedented understanding of carbon sources and dynamics with a high temporal resolution. Here we present the performance assessment of a commercial IRIS analyzer, including the measurement setup and the data processing scheme that we used. Even if the analyzer performs 1-Hz measurements, an integration time of the order of 1 h is commonly needed to obtain acceptable precision for δ13C. The main sources of uncertainty on δ13C come from the concentration dependence and from the temporal instability of the analyzer. The method is applied to the in situ monitoring of the CO2 carbon isotopes in an underground cavity (Roselend Natural Laboratory, France) during several months. On a weekly timescale, the temporal variability of CO2 is dominated by transient contamination by human breath. Discarding these anthropogenic contaminations, CO2 and δ13C backgrounds do not show diurnal or seasonal fluctuations. A CO2 flux released into the tunnel by the surrounding rocks is measured. The carbon isotope composition of this CO2, identified with a Keeling plot, is consistent with a main production by microbial respiration and a minor production from weathering of carbonate minerals. The presented instrument and application study are relevant to cave monitoring, whether to understand CO2 dynamics in visited and/or painted caves for preservation purposes or to understand paleoclimate recording in speleothems

show abstract

“…3b). These smoothed transitions are the combined result of (i) the rate of gas replenishment in the optical cavity (Stowasser et al, 2014), (ii) partial mixing (turbulence and diffusion) of gas compositions downstream of the sample inlet (Gkinis et al, 2011), and (iii) molecular sorption and desorption on internal surfaces of the cavity and inlet tubes (Friedrichs et al, 2010). Although reported response times of CRDS instruments typically range from 1 to 3 min (Picarro, 2011;Sumner et al, 2011), the actual time required for an optical cavity to completely transition to a new gas composition can be substantially longer.…”

Section: Measurement Calibrationmentioning

confidence: 99%

“…the SD of data contained in a 10 min measurement -as with the bottle measurements in Sect. 2.3; also Pang et al, 2016 andStowasser et al, 2014). For our case of 50 mL syringe samples, precision was quantified in both ways: the SD of the 30 s of CRDS data composing each individual sample (intrasample SD; see Sect.…”

Section: Precision and Consistency Testsmentioning

confidence: 99%

“…(4) and (5), thereby forming an extended optimisation problem (n = 216). In a similar vein to the WLS approach used by both Dickinson et al (2017) and Stowasser et al (2014) for calibrating CRDS measurements, residual weights were taken as the reciprocals of the individual summed variances resulting from the SDs of each syringe sample and bottle measurement (see Supplement and Table 1). The WLS solution was determined in R (version 3.2.1, R Core Team, 2015) by general purpose optimisation using the L-BFGS-B algorithm (Zhu et al, 1997) to yield the best-fit correction constants for all available CO 2 mole fraction and 13 C / 12 C isotope ratio data.…”

Section: Measurement Calibrationmentioning

confidence: 99%

See 1 more Smart Citation

System for δ13C–CO2 and xCO2 analysis of discrete gas samples by cavity ring-down spectroscopy

2017

View full text Add to dashboard Cite

Abstract. A method was devised for analysing small discrete gas samples (50 mL syringe) by cavity ring-down spectroscopy (CRDS). Measurements were accomplished by inletting 50 mL syringed samples into an isotopic-CO 2 CRDS analyser (Picarro G2131-i) between baseline readings of a reference air standard, which produced sharp peaks in the CRDS data feed. A custom software script was developed to manage the measurement process and aggregate sample data in real time. The method was successfully tested with CO 2 mole fractions (xCO 2 ) ranging from < 0.1 to > 20 000 ppm and δ 13 C-CO 2 values from −100 up to +30 000 ‰ in comparison to VPDB (Vienna Pee Dee Belemnite). Throughput was typically 10 samples h −1 , with 13 h −1 possible under ideal conditions. The measurement failure rate in routine use was ca. 1 %. Calibration to correct for memory effects was performed with gravimetric gas standards ranging from 0.05 to 2109 ppm xCO 2 and δ 13 C-CO 2 levels varying from −27.3 to +21 740 ‰. Repeatability tests demonstrated that method precision for 50 mL samples was ca. 0.05 % in xCO 2 and 0.15 ‰ in δ 13 C-CO 2 for CO 2 compositions from 300 to 2000 ppm with natural abundance 13 C. Long-term method consistency was tested over a 9-month period, with results showing no systematic measurement drift over time. Standardised analysis of discrete gas samples expands the scope of application for isotopic-CO 2 CRDS and enhances its potential for replacing conventional isotope ratio measurement techniques. Our method involves minimal set-up costs and can be readily implemented in Picarro G2131-i and G2201-i analysers or tailored for use with other CRDS instruments and trace gases.

show abstract

A low-volume cavity ring-down spectrometer for sample-limited applications

Cited by 17 publications

References 17 publications

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH<sub>4</sub> and CO<sub>2</sub>

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH<sub>4</sub> and CO<sub>2</sub>

Monitoring CO2 concentration and δ13C in an underground cavity using a commercial isotope ratio infrared spectrometer

System for <i>δ</i><sup>13</sup>C–CO<sub>2</sub> and <i>x</i>CO<sub>2</sub> analysis of discrete gas samples by cavity ring-down spectroscopy

Contact Info

Product

Resources

About

A low-volume cavity ring-down spectrometer for sample-limited applications

Cited by 17 publications

References 17 publications

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH&lt;sub&gt;4&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt;

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH&lt;sub&gt;4&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt;

Monitoring CO2 concentration and δ13C in an underground cavity using a commercial isotope ratio infrared spectrometer

System for &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;13&lt;/sup&gt;C–CO&lt;sub&gt;2&lt;/sub&gt; and &lt;i&gt;x&lt;/i&gt;CO&lt;sub&gt;2&lt;/sub&gt; analysis of discrete gas samples by cavity ring-down spectroscopy

Contact Info

Product

Resources

About

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH<sub>4</sub> and CO<sub>2</sub>

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH<sub>4</sub> and CO<sub>2</sub>

System for <i>δ</i><sup>13</sup>C–CO<sub>2</sub> and <i>x</i>CO<sub>2</sub> analysis of discrete gas samples by cavity ring-down spectroscopy