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| Titel |
Trend evolution and seasonal variation of tropospheric and stratospheric carbonyl sulfide (OCS) above Jungfraujoch. |
| VerfasserIn |
Bernard Lejeune, Emmanuel Mahieu, Parvadha Suntharalingam, Pierre Duchatelet, Christian Servais, Philippe Demoulin |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048595
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| Zusammenfassung |
| Carbonyl sulfide (OCS) is the most abundant sulfur-containing trace gas in the atmosphere
and accounts for a substantial portion of the sulfur in the stratospheric aerosol layer which
influences the Earth’s radiation budget and stratospheric ozone chemistry. The major
identified OCS sources are oceans and anthropogenic emissions, while atmospheric loss and
uptake by vegetation and soils constitute the main OCS sinks. The uptake by vegetation
strongly influences the distribution and seasonality of OCS throughout most of
the Northern Hemisphere, just like for CO2. Montzka et al. (2007) pointed that
atmospheric OCS measurements have the potential to constrain the biomass Gross Primary
Production (GPP). Unfortunately, there remain large uncertainties on some components
strengths of the atmospheric OCS budget. A recent work by Suntharalingam et al.
(2008) showed that uptake by plants has been strongly underestimated in actual
balanced budgets, suggesting that additional significant OCS sources have still to be
identified.
In order to improve our understanding of the different processes governing seasonal and
inter-annual OCS variability, a new approach has been developed and optimized, using the
SFIT-2 algorithm, to retrieve atmospheric abundance of OCS from high-resolution
ground-based infrared solar spectra. Our observations are recorded on a regular basis with
Fourier Transform Infrared spectrometers (FTIRs), under clear-sky conditions, at the
NDACC site (Network for the Detection of Atmospheric Composition Change,
http://www.ndacc.org) of the International Scientific Station of the Jungfraujoch (Swiss
Alps, 46.5Ë N, 8.0Ë E, 3580m asl). Information content analysis of the retrieved
OCS products shows us that we are able to distinguish between tropospheric and
stratospheric partial column contributions for this species. Thanks to our unique
observational database, we have produced an updated OCS long-term trend from
1995 to 2010, representative for both the troposphere and stratosphere at northern
mid-latitudes.
In this contribution, we will present and critically discuss the recent OCS trend evolution,
in particular the end of the slow decline of its abundance observed in 2002 and the maximum
reached in 2008. In addition to the OCS inter-annual variations, we will analyze the OCS
seasonal cycle during the 15 last years. We will also compare our results with simulations of
seasonal OCS variations issued from a 3D global atmospheric chemical transport model
(CTM), in order to try to quantify the individual contribution of the various processes
playing a role in the Jungfraujoch OCS variability and influencing its atmospheric
abundance.
Acknowledgments
The University of Liège involvement has primarily been supported by the PRODEX
program (SECPEA and A3C projects) funded by the Belgian Federal Science Policy Office,
Brussels and by the Swiss GAW-CH program. The FRS-FNRS and the Communauté
française de Belgique are further acknowledged. We thank the International Foundation High
Altitude Research Stations Jungfraujoch and Gornergrat (HFSJG, Bern) for supporting the
facilities needed to perform the observations.
References
Kettle A.J., U. Kuhn, M. von Hobe, J. Kesselmeier, and M.O Andreae, Global budget of
atmospheric carbonyl sulfide: Temporal and spatial variations of the dominant sources and
sinks, Journal of Geophysical Research, vol. 107, D22, 4658, 2002.
Montzka S.A., P. Calvert, B.D. Hall, J.W. Elkins, T.J. Conway, P.P. Tans and C. Sweeney,
On the global distribution, seasonality, and budget of atmospheric carbonyl sulfide (COS) and
some similarities to CO2, Journal of Geophysical Research, vol. 112, D09302,
2007.
Rothman, L.S., I.E. Gordon, A. Barbe and al., The HITRAN 2008 molecular
spectroscopic database, Journal of Quantitative Spectroscopy & Radiative Transfer, 110,
533-572, 2008.
Suntharalingam, P., A.J. Kettle, S.M. Montzka and D.J. Jacob, Global 3-D model
analysis of the seasonal cycle of atmospheric carbonyl sulfide: Implications for
terrestrial vegetation uptake, Geophysical Research Letters, vol. 35, L19801, 2008. |
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