Usability of optical spectrum analyzer in measuring atmospheric CO₂ and CH₄ column densities: inspection with FTS and aircraft profiles in situ

• Main Authors: I. Morino, O. Uchino, T. Tanaka, H. Ohyama, S. Kawakami, D. W. T. Griffith, R. Macatangay, N. B. Jones, H. Yoshioka, M. Kawasaki, T. Ibuki
• Format: Article
• Language: English
• Published: Copernicus Publications 2012-11-01
• Series: Atmospheric Measurement Techniques
• Online Access: http://www.atmos-meas-tech.net/5/2593/2012/amt-5-2593-2012.pdf

The practical usefulness of a desktop optical spectrum analyzer (OSA) for measuring atmospheric CO₂ and CH₄ column densities at surface sites was examined in two separate measurement campaigns. The first comparison involved operating the OSA in parallel with a high resolution Fourier transform spectroscopy (FTS) situated at the University of Wollongong in Australia. Scale factors for the OSA were assigned for the column average volume mixing ratios of <i>x</i>CO₂ and <i>x</i>CH₄ by comparing with the well-studied FTS. The second method is a calibration against aircraft CO₂ profiles in situ over Tsukuba in Japan obtained during a GOSAT validation campaign carried out from 28 January to 7 February 2011. The <i>x</i>CO₂ values in the campaign, deduced by use of a derived OSA scale factor, were in excellent agreement with the integrated aircraft profiles.