Design and Deployment of a Quantum Cascade Laser Absorption Spectrometer in an Open-Path Sensor System For Trace Gas Analysis

2009 ◽  
Author(s):  
Anna P. M. Michel ◽  
Peter Q. Liu ◽  
June K. Yeung ◽  
Paul Corrigan ◽  
Mary Lynn Baeck ◽  
...  
Keyword(s):  
Quantum Cascade Laser ◽  
Gas Analysis ◽  
Sensor System ◽  
Trace Gas ◽  
Quantum Cascade ◽  
Laser Absorption ◽  
Trace Gas Analysis ◽  
Open Path ◽  
Absorption Spectrometer

Application of quantum cascade lasers to trace gas analysis

2007 ◽  
Vol 90 (2) ◽  
pp. 165-176 ◽  
Author(s):  
A. Kosterev ◽  
G. Wysocki ◽  
Y. Bakhirkin ◽  
S. So ◽  
R. Lewicki ◽  
...  
Keyword(s):  
Quantum Cascade Lasers ◽  
Gas Analysis ◽  
Trace Gas ◽  
Quantum Cascade ◽  
Trace Gas Analysis ◽  
Cascade Lasers

scholarly journals The development and evaluation of airborne in situ N<sub>2</sub>O and CH<sub>4</sub> sampling using a Quantum Cascade Laser Absorption Spectrometer (QCLAS)

2015 ◽  
Vol 8 (8) ◽  
pp. 8859-8902 ◽  
Author(s):  
J. R. Pitt ◽  
M. Le Breton ◽  
G. Allen ◽  
C. J. Percival ◽  
M. W. Gallagher ◽  
...  
Keyword(s):  
Quantum Cascade Laser ◽  
Ambient Pressure ◽  
Calibration Procedure ◽  
Atmospheric Measurements ◽  
Quantum Cascade ◽  
Laser Absorption ◽  
Influence Of Water ◽  
Research Aircraft ◽  
Potential Case ◽  
Absorption Spectrometer

Abstract. Spectroscopic measurements of atmospheric N2O and CH4 mole fractions were made on board the FAAM (Facility for Airborne Atmospheric Measurements) large Atmospheric Research Aircraft. We present details of the mid-IR Aerodyne Research Inc. Quantum Cascade Laser Absorption Spectrometer (QCLAS) employed, including its configuration for airborne sampling, and evaluate its performance over 17 flights conducted during summer 2014. Two different methods of correcting for the influence of water vapour on the spectroscopic retrievals are compared and evaluated. A new in-flight calibration procedure to account for the observed sensitivity of the instrument to ambient pressure changes is described, and its impact on instrument performance is assessed. Test flight data linking this sensitivity to changes in cabin pressure is presented. Total 1σ uncertainties of 1.81 ppb for CH4 and 0.35 ppb for N2O are derived. We report a mean difference in 1 Hz CH4 mole fraction of 2.05 ppb (1σ = 5.85 ppb) between in-flight measurements made using the QCLAS and simultaneous measurements using a previously characterised Los Gatos Research Fast Greenhouse Gas Analyser (FGGA). Finally, a potential case study for the estimation of a regional N2O flux using a mass balance technique is identified, and the method for calculating such an estimate is outlined.

scholarly journals The development and evaluation of airborne in situ N<sub>2</sub>O and CH<sub>4</sub> sampling using a quantum cascade laser absorption spectrometer (QCLAS)

2016 ◽  
Vol 9 (1) ◽  
pp. 63-77 ◽  
Author(s):  
J. R. Pitt ◽  
M. Le Breton ◽  
G. Allen ◽  
C. J. Percival ◽  
M. W. Gallagher ◽  
...  
Keyword(s):  
Quantum Cascade Laser ◽  
Ambient Pressure ◽  
Calibration Procedure ◽  
Atmospheric Measurements ◽  
Quantum Cascade ◽  
Laser Absorption ◽  
Influence Of Water ◽  
Research Aircraft ◽  
Potential Case ◽  
Absorption Spectrometer

Abstract. Spectroscopic measurements of atmospheric N2O and CH4 mole fractions were made on board the FAAM (Facility for Airborne Atmospheric Measurements) large atmospheric research aircraft. We present details of the mid-infrared quantum cascade laser absorption spectrometer (QCLAS, Aerodyne Research Inc., USA) employed, including its configuration for airborne sampling, and evaluate its performance over 17 flights conducted during summer 2014. Two different methods of correcting for the influence of water vapour on the spectroscopic retrievals are compared and evaluated. A new in-flight calibration procedure to account for the observed sensitivity of the instrument to ambient pressure changes is described, and its impact on instrument performance is assessed. Test flight data linking this sensitivity to changes in cabin pressure are presented. Total 1σ uncertainties of 2.47 ppb for CH4 and 0.54 ppb for N2O are derived. We report a mean difference in 1 Hz CH4 mole fraction of 2.05 ppb (1σ =  5.85 ppb) between in-flight measurements made using the QCLAS and simultaneous measurements using a previously characterised Fast Greenhouse Gas Analyser (FGGA, Los Gatos Research, USA). Finally, a potential case study for the estimation of a regional N2O flux using a mass balance technique is identified, and the method for calculating such an estimate is outlined.

scholarly journals Eddy covariance carbonyl sulfide flux measurements with a quantum cascade laser absorption spectrometer

2017 ◽  
Vol 10 (9) ◽  
pp. 3525-3537 ◽  
Author(s):  
Katharina Gerdel ◽  
Felix Maximilian Spielmann ◽  
Albin Hammerle ◽  
Georg Wohlfahrt
Keyword(s):  
Eddy Covariance ◽  
Quantum Cascade Laser ◽  
Gross Primary Production ◽  
Carbonyl Sulfide ◽  
Linear Interpolation ◽  
Trace Gas ◽  
Quantum Cascade ◽  
Laser Absorption ◽  
Flux Measurements ◽  
High Pass

Abstract. The trace gas carbonyl sulfide (COS) has lately received growing interest from the eddy covariance (EC) community due to its potential to serve as an independent approach for constraining gross primary production and canopy stomatal conductance. Thanks to recent developments of fast-response high-precision trace gas analysers (e.g. quantum cascade laser absorption spectrometers, QCLAS), a handful of EC COS flux measurements have been published since 2013. To date, however, a thorough methodological characterisation of QCLAS with regard to the requirements of the EC technique and the necessary processing steps has not been conducted. The objective of this study is to present a detailed characterisation of the COS measurement with the Aerodyne QCLAS in the context of the EC technique and to recommend best EC processing practices for those measurements. Data were collected from May to October 2015 at a temperate mountain grassland in Tyrol, Austria. Analysis of the Allan variance of high-frequency concentration measurements revealed the occurrence of sensor drift under field conditions after an averaging time of around 50 s. We thus explored the use of two high-pass filtering approaches (linear detrending and recursive filtering) as opposed to block averaging and linear interpolation of regular background measurements for covariance computation. Experimental low-pass filtering correction factors were derived from a detailed cospectral analysis. The CO2 and H2O flux measurements obtained with the QCLAS were compared with those obtained with a closed-path infrared gas analyser. Overall, our results suggest small, but systematic differences between the various high-pass filtering scenarios with regard to the fraction of data retained in the quality control and flux magnitudes. When COS and CO2 fluxes are combined in the ecosystem relative uptake rate, systematic differences between the high-pass filtering scenarios largely cancel out, suggesting that this relative metric represents a robust key parameter comparable between studies relying on different post-processing schemes.

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