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© 2019. This work is published under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Tunable laser direct absorption spectroscopy is a widely used technique for the in situ sensing of atmospheric composition. Aircraft deployment poses a challenging operating environment for instruments measuring climatologically relevant gases in the Earth's atmosphere. Here, we demonstrate the successful adaption of a commercially available continuous wave quantum cascade laser (QCL) and interband cascade laser (ICL) based spectrometer for airborne in situ trace gas measurements with a local to regional focus. The instrument measures methane, ethane, carbon dioxide, carbon monoxide, nitrous oxide and water vapor simultaneously, with high 1 s1σ precision (740 ppt, 205 ppt, 460 ppb, 2.2 ppb, 137 ppt and 16 ppm, respectively) and high frequency (2 Hz). We estimate a total 1 s1σ uncertainty of 1.85 ppb, 1.6 ppb, 1.0 ppm, 7.0 ppb and 0.8 ppb in CH4, C2H6, CO2, CO and N2O, respectively. The instrument enables simultaneous and continuous observations for all targeted species. Frequent calibration allows for a measurement duty cycle90 %. Custom retrieval software has been implemented and instrument performance is reported for a first field deployment during NASA's Atmospheric Carbon and Transport – America (ACT-America) campaign in fall 2017 over the eastern and central USA. This includes an inter-instrumental comparison with a calibrated cavity ring-down greenhouse gas analyzer (operated by NASA Langley Research Center, Hampton, USA) and periodic flask samples analyzed at the National Oceanic and Atmospheric Administration (NOAA). We demonstrate good agreement of the QCL- and ICL-based instrument to these concurrent observations within the combined measurement uncertainty after correcting for a constant bias. We find that precise knowledge of theδ13C of the working standards and the sampled air is needed to enhance CO2 compatibility when operating on the 2227.604 cm-1 13C16O2 absorption line.

Details

Title
Adaptation and performance assessment of a quantum and interband cascade laser spectrometer for simultaneous airborne in situ observation of CH4, C2H6, CO2, CO and N2O
Author
Kostinek, Julian 1 ; Roiger, Anke 1 ; Davis, Kenneth J 2   VIAFID ORCID Logo  ; Sweeney, Colm 3 ; DiGangi, Joshua P 4   VIAFID ORCID Logo  ; Choi, Yonghoon 5   VIAFID ORCID Logo  ; Baier, Bianca 6 ; Hase, Frank 7 ; Groß, Jochen 7 ; Eckl, Maximilian 1 ; Klausner, Theresa 1   VIAFID ORCID Logo  ; Butz, André 8   VIAFID ORCID Logo 

 Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany 
 Department of Meteorology and Atmospheric Science, The Pennsylvania State University, University Park, PA 16802, USA 
 NOAA ESRL Global Monitoring Division, Boulder, CO 80305-3328, USA 
 NASA Langley Research Center, Hampton, VA 23681-2199, USA 
 NASA Langley Research Center, Hampton, VA 23681-2199, USA; Science Systems and Applications, Inc., Hampton, VA 23681, USA 
 NOAA ESRL Global Monitoring Division, Boulder, CO 80305-3328, USA; Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO 80305, USA 
 Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany 
 Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany 
Pages
1767-1783
Publication year
2019
Publication date
2019
Publisher
Copernicus GmbH
ISSN
18671381
e-ISSN
18678548
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2193514968
Copyright
© 2019. This work is published under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.