1Spectroscopie de l'Atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (U.L.B.), 50 Av. F. D. Roosevelt, 1050, Brussels, Belgium
2Laboratoire de l'Atmosphère et des Cyclones (LACy), Université de la Réunion, UMR CNRS-Météo-France 8105, Saint-Denis de la Réunion, France
3School of Chemistry, University of Wollongong, Wollongong, New South Wales, Australia
4UPMC Université Paris 06, Université Versailles-St. Quentin, CNRS/INSU, LATMOS-IPSL, Paris, France
5Belgian Institute for Space Aeronomy (BIRA-IASB), 3, Av. Circulaire, 1180, Brussels, Belgium
6UMS3365 de l'OSU-Réunion, CNRS – Université de la Réunion, Saint Denis de la Réunion, France
7Institut d'Astrophysique et de Géophysique, Université de Liège, 17, Allée du 6 Août, B-4000, Liège, Belgium
8Institute for Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology, Karlsruhe, Germany
Received: 13 Apr 2015 – Discussion started: 21 May 2015
Abstract. We present global distributions of C2H2 and hydrogen cyanide (HCN) total columns derived from the Infrared Atmospheric Sounding Interferometer (IASI) for the years 2008–2010. These distributions are obtained with a fast method allowing to retrieve C2H2 abundance globally with a 5 % precision and HCN abundance in the tropical (subtropical) belt with a 10 % (25 %) precision. IASI data are compared for validation purposes with ground-based Fourier transform infrared (FTIR) spectrometer measurements at four selected stations. We show that there is an overall agreement between the ground-based and space measurements with correlation coefficients for daily mean measurements ranging from 0.28 to 0.81, depending on the site. Global C2H2 and subtropical HCN abundances retrieved from IASI spectra show the expected seasonality linked to variations in the anthropogenic emissions and seasonal biomass burning activity, as well as exceptional events, and are in good agreement with previous spaceborne studies. Total columns simulated by the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) are compared to the ground-based FTIR measurements at the four selected stations. The model is able to capture the seasonality in the two species in most of the cases, with correlation coefficients for daily mean measurements ranging from 0.50 to 0.86, depending on the site. IASI measurements are also compared to the distributions from MOZART-4. Seasonal cycles observed from satellite data are reasonably well reproduced by the model with correlation coefficients ranging from −0.31 to 0.93 for C2H2 daily means, and from 0.09 to 0.86 for HCN daily means, depending on the considered region. However, the anthropogenic (biomass burning) emissions used in the model seem to be overestimated (underestimated), and a negative global mean bias of 1 % (16 %) of the model relative to the satellite observations was found for C2H2 (HCN).
Revised: 23 Aug 2015 – Accepted: 04 Sep 2015 – Published: 24 Sep 2015
Duflot, V., Wespes, C., Clarisse, L., Hurtmans, D., Ngadi, Y., Jones, N., Paton-Walsh, C., Hadji-Lazaro, J., Vigouroux, C., De Mazière, M., Metzger, J.-M., Mahieu, E., Servais, C., Hase, F., Schneider, M., Clerbaux, C., and Coheur, P.-F.: Acetylene (C2H2) and hydrogen cyanide (HCN) from IASI satellite observations: global distributions, validation, and comparison with model, Atmos. Chem. Phys., 15, 10509-10527, doi:10.5194/acp-15-10509-2015, 2015.