We present a joint analysis of data obtained by Fourier transform infrared measurements of CH4 and EMAC model calculations for Petergof station (St. Petersburg State University) in 2009–2012. The systematic differences between observed and calculated data are 1.3% and 0.3% for the values of total column and atmospheric column-averaged mole fraction of methane, respectively. The high correlation for experimental and model data of the total column (r = 0.8) indicates that EMAC reproduces the total variability of the methane total column in the atmosphere due to meteorological processes. Using model data, we have analyzed the effect of meteorological conditions typical for Fourier transform IR observations on the resulting estimates of the mean values of total column and column-averaged mole fraction of CH4. We have shown that there can be systematic shifts (up to ~0.4%) in the experimental estimates for the mean value relative to the “true” value. This fact should be taken into account in comparing the climatological or model data with the results of Fourier transform IR measurements, especially for stations with a relatively small number of observation days.
Analysis of Methane Total Column Variations in the Atmosphere near St. Petersburg using Ground Based Measurements and Simulation
Makarova, M.V., Kirner, O., Timofeev, Yu.M., Poberovskii, A.V., Imkhasin, Kh.Kh., Osipov, S.I., Makarov, B.K
Izvestiya, Atmospheric and Oceanic Physics, 51, 2, 201-209, doi: 10.1134/S0001433815010089