Quantification of strong emissions of methane in the Arctic using spectral measurements from TANSO-FTS and IASI
Résumé
Methane is the second most important greenhouse gas after the carbon dioxide but it is 25 times more effective in
contributing to the radiative forcing than the carbon dioxide.
Since the pre-industrial times global methane concentration have more than doubled in the atmosphere. This
increase is generally caused by anthropogenic activities like the massif use and extraction of fossil fuel, rice paddy
agriculture, emissions from landfills...
In recent years, several studies show that climate warming and thawing of permafrost act on the mobiliza-
tion of old stored carbon in Arctic causing a sustained release of methane to the atmosphere(2),(3),(4).
The methane emissions from thawing permafrost and methane hydrates in the northern circumpolar region will
become potentially important in the end of the 21st centry because they could increase dramatically due to the
rapid climate warming of the Artic and the large carbon pools stored there.
The objective of this study is to evaluate and quantify methane strong emissions in this region of the globe
using spectral measurements from the Thermal And Near Infrared Sensor for carbon Observations-Fourier
Transform Spectrometer (TANSO-FTS) and the Infrared Atmospheric Sounding Interferometer (IASI). We use
also the LMDZ-PYVAR model to simulate methane fluxes and to estimate how they could be observed by Infrared
Sounders from space.
To select spectra with high values of methane we developed a statistical approach based on the singular
value decomposition. Using this approach we can identify spectra over the important emission sources of methane
and we can by this way reduce the number of spectra to retrieve by an line-by-line radiative transfer model in
order to focus on those which contain high amount of methane.
In order to estimate the capacity of TANSO-FTS and IASI to detect peaks of methane emission with short
duration at quasi-real time, we used data from MACC (Monitoring Atmospheric Composition and Climate)
simulations to compute spectra which we are compared to those from TANSO-FTS and IASI.
Origine | Fichiers produits par l'(les) auteur(s) |
---|
Loading...