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.