Abundance and sources of atmospheric halocarbons in the Eastern Mediterranean
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 too...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/18/4069/2018/acp-18-4069-2018.pdf |
| Summary: | 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<sub>2</sub>FCF<sub>3</sub>), HFC-125 (CHF<sub>2</sub>CF<sub>3</sub>), HFC-152a
(CH<sub>3</sub>CHF<sub>2</sub>) and HFC-143a (CH<sub>3</sub>CF<sub>3</sub>) and the
hydrochlorofluorocarbons (HCFCs), HCFC-22 (CHClF<sub>2</sub>) and HCFC-142b
(CH<sub>3</sub>CClF<sub>2</sub>). 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<sub>2</sub>eq yr<sup>−1</sup>, 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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| ISSN: | 1680-7316 1680-7324 |