1. Using atmospheric CO2 data More than 100 CO2 records Use LMDz model as an “offline” transport tool based on “retro-plumes” (pre-calculated response function) Compare monthly model vs Obs CO2 conc. (period covered: 1980 – 2010)  Script easy to use with no « LMDz expertise » !

2. Using atmospheric CO2 data Work for CO2 or non reactive species Need to prepare YOUR surface CO2 fluxes Fluxes: 3D array (lon, lat, time) Time variable : from monthly to daily fluxes Run the script (few hours for several sites) OUTPUTS: Netcdf file: time series of atm conc. Graphs: Your model Conc against Observed CO2 (possibly adding Fossil fuel & ocean fluxes)

3. CO2 : atmospheric concentration

5. S3: CO 2 concentrations (obs. In grey) Year Monthly CO 2 (ppm)