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Abundance and sources of atmospheric halocarbons in the Eastern Mediterranean

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Schoenenberger Fabian, Henne Stephan, Hill Matthias, Vollmer Martin K., Kouvarakis Giorgos, Mihalopoulos Nikolaos, O&,apos,Doherty Simon, Maione Michela, Emmenegger Lukas, Peter Thomas, Reimann Stefan,
Project Measurement-based verification of regional emissions of halogenated greenhouse gases
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Original article (peer-reviewed)

Journal Atmospheric Chemistry and Physics
Volume (Issue) 18(6)
Page(s) 4069 - 4092
Title of proceedings Atmospheric Chemistry and Physics
DOI 10.5194/acp-18-4069-2018

Open Access

URL http://doi.org/10.5194/acp-18-4069-2018
Type of Open Access Publisher (Gold Open Access)

Abstract

Abstract. A wide range of anthropogenic halocarbons is released to the atmosphere, contributing to stratospheric ozone depletion and global warming. Using measurements of atmospheric abundances for the estimation of halocarbon emissions on the global and regional scale has become an important top-down tool for emission validation in the recent past, but many populated and developing areas of the world are only poorly covered by the existing atmospheric halocarbon measurement network. Here we present 6 months of continuous halocarbon observations from Finokalia on the island of Crete in the Eastern Mediterranean. The gases measured are the hydrofluorocarbons (HFCs), HFC-134a (CH 2 FCF 3 ), HFC-125 (CHF 2 CF 3 ), HFC-152a (CH 3 CHF 2 ) and HFC-143a (CH 3 CF 3 ) and the hydrochlorofluorocarbons (HCFCs), HCFC-22 (CHClF 2 ) and HCFC-142b (CH 3 CClF 2 ). The Eastern Mediterranean is home to 250 million inhabitants, consisting of a number of developed and developing countries, for which different emission regulations exist under the Kyoto and Montreal protocols. Regional emissions of halocarbons were estimated with Lagrangian atmospheric transport simulations and a Bayesian inverse modeling system, using measurements at Finokalia in conjunction with those from Advanced Global Atmospheric Gases Experiment (AGAGE) sites at Mace Head (Ireland), Jungfraujoch (Switzerland) and Monte Cimone (Italy). Measured peak mole fractions at Finokalia showed generally smaller amplitudes for HFCs than at the European AGAGE sites except for periodic peaks of HFC-152a, indicating strong upwind sources. Higher peak mole fractions were observed for HCFCs, suggesting continued emissions from nearby developing regions such as Egypt and the Middle East. For 2013, the Eastern Mediterranean inverse emission estimates for the four analyzed HFCs and the two HCFCs were 13.9 (11.3–19.3) and 9.5 (6.8–15.1) Tg CO 2 eq yr −1 , respectively. These emissions contributed 16.8 % (13.6–23.3 %) and 53.2 % (38.1–84.2 %) to the total inversion domain, which covers the Eastern Mediterranean as well as central and western Europe. Greek bottom-up HFC emissions reported to the UNFCCC were higher than our top-down estimates, whereas for Turkey our estimates agreed with UNFCCC-reported values for HFC-125 and HFC-143a, but were much and slightly smaller for HFC-134a and HFC-152a, respectively. Sensitivity estimates suggest an improvement of the a posteriori emission estimates, i.e., a reduction of the uncertainties by 40–80 % in the entire inversion domain, compared to an inversion using only the existing central European AGAGE observations.
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