In this project, atmospheric observations of the greenhouse gas methane and inverse modelling will be used to obtain a top-down estimate of emissions from sources in the northern high latitudes. Atmospheric observations of methane from different data sources, e.g., ground-based sites, satellites, or aircraft and ship measurements, provide information with different precision, spatial and temporal resolution. To get a complete picture of both natural and anthropogenic methane emissions in the northern high latitudes, from regional to local scale, a variety of observations and modelling frameworks are needed. In the first part of this project, ground-based observations of methane will be used in a regional modelling framework to investigate methane emissions on the regional scale. This approach is suitable to determine methane emissions from the region as a whole, and how these emissions are changing over time, but since ground-based measuring sites are scarce this approach is not always able to resolve distinct sources. To investigate emission sources on a local scale or from specific sources, detailed observations are needed. In the second part of the project satellite measurements and other sources of data with high spatial resolution, like aircraft or ship measurements, will be used in a high-resolution modelling framework to investigate emission sources on a local scale.