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| Titel |
On the detection of strong emissions of methane in the Arctic using spectral measurements from IASI and GOSAT |
| VerfasserIn |
Zakia Bourakkadi, Sebastien Payan, Jérôme Bureau |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250092492
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| Publikation (Nr.) |
 EGU/EGU2014-6843.pdf |
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| Zusammenfassung |
| Boreal ecosystems store significant quantities of organic carbon (C) for thousands of years.
Most are presently sequestered in permafrost. In recent years, several studies highlighted that
climate warming and thawing of permafrost in the Arctic acts on the mobilization of old
stored carbon (c) and contribute to a sustained release of methane (CH4) to the atmosphere
[1],[2],[3].
Because methane is an important greenhouse gas, it is necessary to estimate his sources
and sinks in the Arctic. The objective of this study is to evaluate and quantify methane strong
emission in this region of the globe using spectral measurements from two satellite
instruments: IASI-MetOp and TANSO-FTS.
The Infrared Atmospheric Sounding Interferometer (IASI) is a Fourier transform
spectrometer coupled with an integrated imaging system that observes and measures
infrared radiation emitted by the Earth and the atmosphere in the spectral range
645-2760cm-1, which covered the methane ?4 and ?3 absorption band[4]. IASI
provides global Earth’s coverage twice a day and delivers about 1300000 spectra per
day[5].
The second instrument which we will use in this study is the Thermal And Near-infrared
Sensor for Carbon Observation-Fourier Transform Spectrometer (TANSO-FTS), it has a wide
TIR band (5,5-14,3μm)which contain the methane ?4absorption band.TANSO-FTS
completes one revolution in about 100 minutes and it comes back to the same location in 3
days period. Over these 3 days, FTS takes 56000 measurements covering the entire
globe[6].
To have a good estimation of methane emission above the Arctic, we must exploit a vast
amount of spectral information from IASI and TANSO-FTS. But it is well known that
performing line-by-line radiative transfer model is a time-consuming process. So, if we need
to exploit large data we have to look fast method. In this work, we will use a simple approach
based on the Singular Value Decomposition(SVD) to identify spectra over large source of
methane. A more accurate algorithm will be used next to perform an accurate retrieval of
methane vertical column.
References
[1]N. Shakhova, I. Semiletov, A. Salyuk, V. Yusupov, D. Kosmach, O.Gustafsson.:
Extensive Methane venting to the atmosphere from sediments of the East Siberian Arctic
shelf, SCIENCE 5 March 2010, Vol 327.
[2] K. Negandhi, I. Laurion, M. J. Whiticar, P. E. Galand, X. X. Connie Lovejoy.: Small
thaw ponds: An unaccounted source of methane in the canadian high Arctic, PLOS ONE
november 2013/ vol 8/issue 11/e78204.
[3] J. T. Crawford, R. G. Striegl, K. P. Wickland, M . Dornblaser, and E. Stanley.:
Emissions of carbon dioxide and methane from a headwater stream network of interior
Alaska, Journal of Giophysical Recherch : Biogeosciences, VOL, 118, 482-494,
doi:10.1002/jgrg,20034, 2013.
[4] A. Razavi, C. Clerbaux, C. Wespes, L. Clarisse, D. Hurtmans, S. Payan, C.
Camy-Peyret and P.F. Coheur.: Characterization of methane retrievals from the IASI
space-borne sounder , Atmos. Chem. Phys., 9,7889-7899, 2009.
[5] C. Clerbaux, A. Boynard, L. Clarisse, M. George, J. Hadji-Lazaro, H. Herbin, D.
Hurtmans, M. Pommier, A. Razavi, S. Turquety, C. Wespes and P.-F. Coheur.: Monitoring of
atmospheric composition using the thermal infrared IASI/MetOp sounder, Atmos. Chem.
Phys., 9, 6041-6054, 2009.
[6] T . Yokota, Y. Yoshida, N. Eguchi, Y. Ota, T. Tanaka, H. Watanabe and S.
Makasyutov.: Global concentrations of CO2 and CH4 retrieved from GOSAT : First
Preliminary Results, SOLA, 2009, Vol. 5, 160-163, doi:10.2151/sola.2009-041. |
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