Atmospheric Measurement Techniques
Atmospheric Measurement Techniques
AMT
Articles | Volume 9, issue 3
Articles | Volume 9, issue 3
https://doi.org/10.5194/amt-9-1361-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/amt-9-1361-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Articles | Volume 9, issue 3
Research article
 | 
31 Mar 2016
Research article |  | 31 Mar 2016

Dimensioning IRGA gas sampling systems: laboratory and field experiments

Marc Aubinet, Lilian Joly, Denis Loustau, Anne De Ligne, Henri Chopin, Julien Cousin, Nicolas Chauvin, Thomas Decarpenterie, and Patrick Gross

Abstract. Both laboratory and field experiments were carried out in order to define suitable configuration ranges for the gas sampling systems (GSSs) of infrared gas analyzers (IRGAs) used in eddy covariance measurements.

In the laboratory, an original dynamic calibration bench was developed in order to test the frequency attenuation and pressure drop generated by filters. In the field, three IRGAs of the same type equipped with different filters or different rain caps were installed and run and the real frequency response of the complete setup was tested.

The main results are as follows.

– Filters may have a strong impact on the pressure drop in the GSS and this impact increases with flow rate.

– Conversely, no impact of the tested filters on cut-off frequency was found, GSSs with and without filters presenting similar cut-off frequencies.

– The main limiting factor of cut-off frequency in the field was found to be the rain cap design. In addition, the impact of this design on pressure drop was also found to be noteworthy.

How to cite. Aubinet, M., Joly, L., Loustau, D., De Ligne, A., Chopin, H., Cousin, J., Chauvin, N., Decarpenterie, T., and Gross, P.: Dimensioning IRGA gas sampling systems: laboratory and field experiments, Atmos. Meas. Tech., 9, 1361–1367, https://doi.org/10.5194/amt-9-1361-2016, 2016.
Received: 06 Sep 2015 – Discussion started: 20 Oct 2015 – Revised: 23 Dec 2015 – Accepted: 27 Feb 2016 – Published: 31 Mar 2016
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Short summary
Laboratory and field experiments were carried out in order to define suitable configuration ranges for the gas sampling systems of infrared gas analyzers used in eddy covariance measurements. They show that filters may have a strong impact on the pressure drop in the GSS but no significant impact on cut-off frequency. Conversely, the rain cup design was found to be the main limiting factor of cut-off frequency in the field. Its impact on pressure drop was also found to be noteworthy.
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