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| Titel |
Recent increase of ethane detected in the remote atmosphere of the Northern Hemisphere |
| VerfasserIn |
Bruno Franco, Whitney Bader, Benoît Bovy, Emmanuel Mahieu, Emily V. Fischer, Kimberly Strong, Stephanie Conway, James W. Hannigan, Eric Nussbaumer, Peter F. Bernath, Chris D. Boone, Kaley A. Walker |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105212
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| Publikation (Nr.) |
 EGU/EGU2015-4675.pdf |
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| Zusammenfassung |
| Ethane (C2H6) has a large impact on tropospheric composition and air quality because
of its involvement in the global VOC (volatile organic compound) – HOx – NOx
chemistry responsible for generating and destroying tropospheric ozone. By acting
as a major sink for tropospheric OH radicals, the abundance of C2H6 influences
the atmospheric content of carbon monoxide and impacts the lifetime of methane.
Moreover, it is an important source of PAN, a thermally unstable reservoir for NOx
radicals.
On a global scale, the main sources of C2H6 are leakage from the production, transport of
natural gas loss, biofuel consumption and biomass burning, mainly located in the Northern
Hemisphere. Due to its relatively long lifetime of approximately two months, C2H6 is a
sensitive indicator of tropospheric pollution and transport.
Using an optimized retrieval strategy (see Franco et al., 2014), we present here a 20-year
long-term time series of C2H6 column abundance retrieved from ground-based Fourier
Transform InfraRed (FTIR) solar spectra recorded from 1994 onwards at the high-altitude
station of Jungfraujoch (Swiss Alps, 46.5° N, 3580 m a.s.l.), part of the Network for the
Detection of Atmospheric Composition Change (NDACC, see http://www.ndacc.org). After a
regular 1994 – 2008 decrease of the C2H6 amounts, which is very consistent with prior major
studies (e.g., Aydin et al., 2011; Simpson et al., 2012) and our understanding of global C2H6
emissions, trend analysis using a bootstrap resampling tool reveals a C2H6 upturn and a
statistically-significant sharp burden increase from 2009 onwards (Franco et al.,
2014).
We hypothesize that this observed recent increase in C2H6 could affect the whole Northern
Hemisphere and may be related to the recent massive growth in the exploitation of shale gas
and tight oil reservoirs. This hypothesis is supported by measurements derived from
solar occultation observations performed since 2004 by the Atmospheric Chemistry
Experiment – Fourier Transform Spectrometer (ACE-FTS) instrument and at other
NDACC sites, namely Toronto (44° N) and Thule (77° N). Indeed, the recent rates of
changes characterizing these data sets are consistent in magnitude and sign with the
one derived from the FTIR measurements at Jungfraujoch. In contrast, the C2H6
time series from Lauder (45° S) shows a monotonic decrease over the last two
decades.
Investigating both the cause and impact on air quality of the C2H6 upturn should be a high
priority for the atmospheric chemistry community.
Acknowledgments:
The University of Liège contribution has mainly been supported by the AGACC-II project of
the SSD program of the Belgian Science Policy Office (BELSPO, Brussels). Additional
support was provided by MeteoSwiss (GAW-CH), the Fédération Wallonie-Bruxelles and the
F.R.S. – FNRS. We thank the International Foundation High Altitude Research Stations
Jungfraujoch and Gornergrat (HFSJG, Bern). E. Mahieu is Research Associate with F.R.S. –
FNRS. We are grateful to the many colleagues who have contributed to the FTIR data
acquisition at the Jungfraujoch station. The Atmospheric Chemistry Experiment (ACE), also
known as SCISAT, is a Canadian-led mission mainly supported by the Canadian Space
Agency and the Natural Sciences and Engineering Research Council of Canada. We thank D.
Smale from NIWA Lauder for producing and making public the ethane time series at Lauder
in the framework of NDACC.
References:
- Aydin M, Verhulst KR, Saltzman ES, Battle MO, Montzka SA, Blake DR, Tang Q, Prather
MJ. Recent decreases in fossil-fuel emissions of ethane and methane derived from firn air.
Nature 2011;476:198-201. doi:10.1038/nature10352.
- Franco B, Bader W, Toon GC, Bray C, Perrin A, Fischer EV, Sudo K, Boone CD, Bovy B,
Lejeune B, Servais C, Mahieu E. Retrieval of ethane from ground-based FTIR solar spectra
using improved spectroscopy: recent burden increase above Jungfraujoch. JQSRT, 2014,
under review.
- Simpson IJ, Sulbaek Andersen MP, Meinardi S, Bruhwiler L, Blake NJ, Helmig D, Rowland
FS, Blake DR. Long-term decline of global atmospheric ethane concentrations and
implications for methane. Nature 2012;488:4904. doi:10.1038/nature11342. |
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