Publication Details

Warneke, T., Meirink, J. F., Bergamaschi, P., Grooss, J. -U., Notholt, J., Toon, G. C., Velazco, V., Goede, A. & Schrems, O. (2006). Seasonal and latitudinal variation of atmospheric methane: A ground-based and ship-borne solar IR spectroscopic study. Geophysical Research Letters, 33 (14), L14812-1-L14812-5. Copyright 2006 the American Geophysical Union.


Column-averaged volume mixing ratios of CH4 were retrieved with a precision of better than 0.5% from infrared solar absorption spectra obtained at Ny-Alesund (Spitsbergen, 79°N) between 1997 and 2004 and during two ship cruises (54°N–34°S) on the Atlantic in 2003. The retrieval has been performed in a spectral region available to all operational FTIR (Fourier Transform InfraRed) spectrometers performing solar absorption measurements. The seasonality and the long-term increase of the tropospheric volume-mixing ratio, derived from the infrared measurements agree well with data from surface sampling at this site. The latitudinal variation of ship-borne measurements between 54°N and 34°S is in agreement with inverse model simulations which are optimized vs. the global NOAA/ESRL measurements.



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