Open Access

Andreas Ostler

• Methane is the second most important anthropogenic greenhouse gas and there is renewed strong increase of atmospheric methane since 2007. Although the overall global budget of methane emissions is well constrained, the quantitative attribution to the underlying sources remains an up-to-date open scientific question. The column-averaged dry-air mixing ratio of methane, denoted as XCH4, is a special atmospheric measure attainable only via ground-based and satellite-derived observations. The resulting data enable a global spatiotemporal overview of the atmospheric methane concentrations and, thus, are very suitable for the quantification of methane emission sources by means of inverse modeling. However, even the strongest surface emission fluxes only produce a slight change in the XCH4 signal in relation to the co-resident background level in XCH4. For this reason, an accurate quantification of methane emissions from XCH4 data only is possible, if observations and simulations of XCH4Methane is the second most important anthropogenic greenhouse gas and there is renewed strong increase of atmospheric methane since 2007. Although the overall global budget of methane emissions is well constrained, the quantitative attribution to the underlying sources remains an up-to-date open scientific question. The column-averaged dry-air mixing ratio of methane, denoted as XCH4, is a special atmospheric measure attainable only via ground-based and satellite-derived observations. The resulting data enable a global spatiotemporal overview of the atmospheric methane concentrations and, thus, are very suitable for the quantification of methane emission sources by means of inverse modeling. However, even the strongest surface emission fluxes only produce a slight change in the XCH4 signal in relation to the co-resident background level in XCH4. For this reason, an accurate quantification of methane emissions from XCH4 data only is possible, if observations and simulations of XCH4 achieve high accuracy (<0.3 %). Meeting this standard requires that XCH4 as a vertically integrating measure correctly accounts for the existing methane concentrations of various height layers. Therefore, this work examines the effects of atmosphere dynamical processes in the upper troposphere and the stratosphere on the accuracy of XCH4 observations, and simulations, respectively.…