FLEXPART for methane
Atmospheric inverse modelling has the potential to provide observation-based estimates of greenhouse gas emissions at the country scale, thereby allowing for an independent validation of national emission inventories. A leading example of a regional-scale inverse modelling study to quantify the emissions of methane (CH4) comes from Switzerland (Henne et al., 2016), making use of the newly established CarboCount-CH measurement network and a high-resolution Lagrangian transport model (FLEXPART).
Source sensitivities giving the direct influence of a mass emission from a source location onto the mole fraction at a receptor site were calculated with two different versions of the Lagrangian particle dispersion model (LPDM) FLEXPART (Stohl et al., 2005). The first represents the standard FLEXPART model (version 9.02) driven by analysis fields of the operational runs of the Integrated Forecast System (IFS) of the European Centre for Medium Range Weather Forecast (ECMWF). The second FLEXPART version is the one adapted to the use output from the COSMO regional numerical weather prediction (NWP) model (Baldauf et al., 2011).

Henne et al., 2016, https://doi.org/10.5194/acp-16-3683-2016