Summary:

The files contained in this dataset contain values of fluxes and errors in fluxes, that were submitted by five groups involved in the project "National Scale CH4 Inversion Intercomparison for Europe", described in the paper Ioannidis, E. et al.: An inter-comparison of inverse models for estimating European CH4 emissions. Earth System Science Data Copernicus (in review), https://doi.org/10.5194/essd-2025-235. The set mainly contains a division of the fluxes into separate constituents, either “natural” and “anthropogenic”, or a further subdivision. Because of the small number of submissions of this kind of data, they were not used in the intercomparison, but were preserved and are being shared because they can possibly be of use for a future project. 

General description

-The files are netcdf-files, one for each model for which data were submitted that were in the end not used for the intercomparison.
-General project-information, authors names etc., can be found in the metadata of the files.
-The variables are index-variables, and fluxes and/or errors in fluxes. 
-The domain is again: latitude from 33 to 73 degrees (except NIM: 35 to 70), longitude from -15 to 35 degrees. Resolution ¼ degree.
-The encompassed years are again dependent on the model (see descriptions of separate files), and always part of the range 2005-2018.
-The index-variables are of course the same as for the intercomparison-files (latitude, longitude, time). In particular, times indicate months; the months are labelled with the number of days between 2000- 01-01 (day 1), and a day in the middle of them month.
-Like for the intercomparison-files, fluxes are averaged over a grid cell and a month, have a prior and posterior value, and pertain to a core-experiment or (for some submissions) to an “exp1”-experiment. See the paper for further explanation.
-The flux-values pertain to constituents (“natural”,  “anthropogenic”,  or further sub-classes). Total fluxes are not repeated here, since they are included in the data that were used for the intercomparison.
-The errors can pertain to constituents, but also to total fluxes.

EMPA-data (file: “ch4_inversions_additional_fluxes_EMPA.nc”):
Years: 2008, 2013, 2018.
Experiments: both core and exp1.
Errors in total flux are included.
Fluxes from separate categories (“natural” and “anthropogenic”) are included, see comments in file for the classification details.
Errors in these separate categories are also given.

FMI-data (file: “ch4_inversions_additional_fluxes_FMI.nc”):
Years: 2005 – 2018.
Experiments: only core.
Errors in total flux are given.
Fluxes from 11 separate categories are given (see the variable names in the file).
No errors in the separate fluxes are given.

Lund-data (file: “ch4_inversions_additional_fluxes_Lund.nc”):
Years: 2006 – 2018.
Experiments: both core end exp1.
Errors in total flux are given.
Fluxes from separate categories (natural and anthropogenic) are given (see comments in file for classification details).
No errors in the separate categories are given.

NIM-data (file: “ch4_inversions_additional_fluxes_NIM.nc”):
Years: 2008, 2013, 2018.
Experiments: both core and exp1.
Errors in total flux are given.

VUA-data (file: “ch4_inversions_additional_fluxes_VUA.nc”):
Years: 2008, 2013, 2018.
Experiments: only core.
Errors in total flux are given.
Fluxes from separate categories (natural and anthropogenic) are given (see comments in file for classification details).
No errors in the separate fluxes are given.

Creation date: 2025-06-06
