Comparison of the GOSAT TANSO-FTS TIR CH volume mixing ratio vertical profiles with those measured by ACE-FTS, ESA MIPAS, IMK-IAA MIPAS, and 16 NDACC stations

• Published in: Atmospheric Measurement Techniques
• Main Authors: K. S. Olsen, K. Strong, K. A. Walker, C. D. Boone, P. Raspollini, J. Plieninger, W. Bader, S. Conway, M. Grutter, J. W. Hannigan, F. Hase, N. Jones, M. de Mazière, J. Notholt, M. Schneider, D. Smale, R. Sussmann, N. Saitoh
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2017
• Subjects: Environmental engineering; TA170-171; Earthwork. Foundations; TA715-787; Arctic; Canada; Eureka
• Online Access: https://doi.org/10.5194/amt-10-3697-2017; https://doaj.org/article/006538a713404372bc91cea86bf28b56

The primary instrument on the Greenhouse gases Observing SATellite (GOSAT) is the Thermal And Near infrared Sensor for carbon Observations (TANSO) Fourier transform spectrometer (FTS). TANSO-FTS uses three short-wave infrared (SWIR) bands to retrieve total columns of CO 2 and CH 4 along its optical line of sight and one thermal infrared (TIR) channel to retrieve vertical profiles of CO 2 and CH 4 volume mixing ratios (VMRs) in the troposphere. We examine version 1 of the TANSO-FTS TIR CH 4 product by comparing co-located CH 4 VMR vertical profiles from two other remote-sensing FTS systems: the Canadian Space Agency's Atmospheric Chemistry Experiment FTS (ACE-FTS) on SCISAT (version 3.5) and the European Space Agency's Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat (ESA ML2PP version 6 and IMK-IAA reduced-resolution version V5R_CH4_224/225), as well as 16 ground stations with the Network for the Detection of Atmospheric Composition Change (NDACC). This work follows an initial inter-comparison study over the Arctic, which incorporated a ground-based FTS at the Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka, Canada, and focuses on tropospheric and lower-stratospheric measurements made at middle and tropical latitudes between 2009 and 2013 (mid-2012 for MIPAS). For comparison, vertical profiles from all instruments are interpolated onto a common pressure grid, and smoothing is applied to ACE-FTS, MIPAS, and NDACC vertical profiles. Smoothing is needed to account for differences between the vertical resolution of each instrument and differences in the dependence on a priori profiles. The smoothing operators use the TANSO-FTS a priori and averaging kernels in all cases. We present zonally averaged mean CH 4 differences between each instrument and TANSO-FTS with and without smoothing, and we examine their information content, their sensitive altitude range, their correlation, their a priori dependence, and the variability within each data set. Partial columns are ...