Multi-year mole fraction and isotopic records for 5 UK sites

CH4 mole fraction and δ13C data that have been measured by Royal Holloway, University of London (RHUL) from five locations around the UK. The samples were collected at Barra/Vatersay (BAR) in the Outer Hebrides, RHUL in Egham (EGH), Weybourne Atmospheric Observatory (WAO) - University of East Anglia, and the Western Channel Observatory (WCO) at two locations (E1 and L4) in the English Channel - Plymouth Marine Lab (PML). The Met Office's Numerical Atmospheric-dispersion Modelling Environment (NAME) was used to calculate the sensitivity of measurements, taken at EGH and WAO, to the surrounding emissions field. The raw NAME output files contain information about the locations of the modelled air particles at each time step. This information is processed to create hourly footprints in units of (mol/mol)(mol/m$^2$/s) for each latitude/longitude grid cell.