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Fifteen Years of HFC-134a Satellite Observations: Comparisons With SLIMCAT Calculations

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journal contribution
posted on 14.09.2021, 09:34 by Jeremy J Harrison, Martyn P Chipperfield, Christopher D Boone, Sandip S Dhomse, Peter F Bernath
The phase out of anthropogenic ozone-depleting substances such as chlorofluorocarbons under the terms of the Montreal Protocol led to the development and worldwide use of hydrofluorocarbons (HFCs) in refrigeration, air conditioning, and as blowing agents and propellants. Consequently, over recent years, the atmospheric abundances of HFCs have dramatically increased. HFCs are powerful greenhouse gases and are now controlled under the terms of the 2016 Kigali Amendment to the Montreal Protocol. HFC-134a is currently the most abundant HFC in the atmosphere, breaking the 100 ppt barrier in 2018, and can be measured in the Earth's atmosphere by the satellite remote-sensing instrument ACE-FTS (Atmospheric Chemistry Experiment-Fourier Transform Spectrometer), which has been measuring since 2004. This work uses the ACE-FTS v4.0 data product to investigate global distributions and trends of HFC-134a. These measurements are compared with a simulation of SLIMCAT, a state-of-the-art three-dimensional chemical transport model, which is constrained by global surface HFC-134a measurements. The agreement between observation and model is good, although in the tropical troposphere ACE-FTS measurements are biased low by up to 10–15 ppt. The overall ACE-FTS global trend of HFC-134a for the altitude range 5.5–24.5 km and 2004–2018 time period is approximately linear with a value of 4.49 ± 0.02 ppt/year, slightly lower than the corresponding SLIMCAT trend of 4.66 ppt/year. Using a simple box model, we also estimate the annual global emissions and burdens of HFC-134a from the model data, indicating that emissions of HFC-134a have increased almost linearly, reaching 236 Gg by 2018.

Funding

UKRI | Natural Environment Research Council (NERC). Grant Number: PR140015

UK Research and Innovation

National Centre for Earth Observation

Canadian Space Agency

Royal Society

History

Citation

Journal of Geophysical Research: Atmospheres, Volume 126, Issue 8, 27 April 2021, e2020JD033208

Author affiliation

Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Journal of Geophysical Research: Atmospheres

Volume

126

Issue

8

Publisher

Wiley for American Geophysical Union (AGU)

issn

2169-897X

eissn

2169-8996

Acceptance date

17/02/2021

Copyright date

2021

Available date

14/09/2021

Language

English