The determination of a regional atmospheric background mixing ratio for anthropogenic greenhouse gases: a comparison of two independent methods

Halocarbons are powerful greenhouse gases capable of significantly influencing the radiative forcing of the Earth’s atmosphere. Halocarbons are monitored in several stations which are globally distributed in order to assess long term atmospheric trends and to identify source regions. However, to achieve these aims the definition of background mixing ratios, i.e. the mixing ratio in a given air mass when the recent contribution of local sources is absent, is necessary. This task can be accomplished using different methods. This paper presents a statistical methodology that has been devised specifically for a mountain site located in Continental Europe (Monte Cimone, Italy), characterised by the vicinity of strong sources. The method involves the decomposition of the observed data distribution into a Gaussian distribution, representative of background values, and a Gamma distribution, ascribable to contribution from stronger sources. The method has been applied to a time series from a European marine remote station (Mace Head, Ireland) as well as to time series from Monte Cimone. A comparison of the methodology described in this paper with a well-established meteorological filtering procedure at Mace Head has shown an excellent agreement. A comparison of the baselines at Mace Head, Mt. Cimone and the Swiss alpine station of the Jungfraujoch highlighted the occurrence of a specific background concentration. Although this paper presents the application of the method to three hydrofluorocarbons, the proposed methodology can be extended to any long lived atmospheric component for which a long term time series is available and at any location even if affected by strong source regions.

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Michela Maione (The University of Urbino "Carlo Bo" - Chemical Science Institute) - Francesco Furlani (The University of Urbino "Carlo Bo"-Department of Basic Sciences and Fundamentals (DiSBeF)) - Umberto Giostra (The University of Urbino "Carlo Bo" -Science campus Sogesta) - Stefan Reimann (Swiss Federal Laboratories for Materials Science and Research (EMPA)) - Jgor Arduini (The University of Urbino "Carlo Bo" - Chemical Science Institute) - Simon O'Doherty (School of Chemistry, University of Bristol,) - Alistair Manning (Met Office,Exeter) - Daniela Cava (Institute of Atmospheric Sciences and Climate (ISAC) - CNR) (2008) . The determination of a regional atmospheric background mixing ratio for anthropogenic greenhouse gases: a comparison of two independent methods. Elsevier Science Publishing Company https://geoportal.mountaingenius.org/geonetwork/srv/api/records/7f08ed13-d2dd-4b0b-adc0-1615be14b88a

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File identifier: 7f08ed13-d2dd-4b0b-adc0-1615be14b88a XML

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Metadata language: eng

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Climatology, meteorology, atmosphere
Environment

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Time series , Anthropogenic factor , Application method , Organic compounds , Background concentration , Gaussian distribution , Mountain , Air mass , Trend analysis , Long term , Surveillance , Halogen Organic compounds , Greenhouse gas

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