Bayesian inversion using observations of a secondary trace gas and a variable emissions ratio, to estimate greenhouse gas emissions. Example data files are provided and can be used with the code to estimate one month of UK fossil fuel methane emissions.
This method is described in the paper:
Ramsden, A.E., Ganesan, A.L., Western, L.M., Rigby, M., Manning, A.J., Foulds, A., France, J.L., Barker, P., Levy, P., Say, D., Wisher, A., Arnold, T., Rennick, C., Stanley, K.M., Young, D., O'Doherty, S.: Quantifying fossil fuel methane emissions using observations ofatmospheric ethane and an uncertain emissions ratio, Atmos. Chem. Phys., link_here, in review, 2021.
**Details of included files:**
*run_multi_gas_model.py*: Extracts variables from a .ini file or the command line and runs the model.
*multi_gas_model.py*: The tracer inversion code, with options for running with one gas or two gases with a fixed or variable emissions ratio.
*mcmc_functions.py*: Functions used by multi_gas_model to carry out the MCMC method.
*data_functions.py*: Functions used to multi_gas_model to process the inputs and outputs.
*model_inputs_example.ini*: Example of all parameters used to run the model with the supplied data files. Can be edited to specify different parameter values.
*config.py*: Used to import parameter values from the .ini file. Written by Rachel Tunnicliffe of the Bristol Atmospheric Chemistry Research Group.
*data_files*: Contains an example month of merged footprints, observations, a priori fluxes etc, and country mask and basis function files, which are required to run the model. C2H6 observations used in Ramsden, A.E. et al. are also in this directory
**To run the code:**
All code is written in Python. A .yml file, containing a list of all required Python packages is included.
The model can be run on the command line, as specified in run_multi_gas_model, but we recommend using a HPC system to run the model when using a large number of iterations.
Outputs are saved into the directory specified in 'model-inputs_example.ini'.
**Additional data:**
C2H6 observations from the UK DECC network, as used in this paper, are included as .netCDF files. For more detail on these observations: Prinn, R.G et al. History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE), Earth Syst. Sci. Data, 2018.
