Radiocarbon observations in atmospheric CO2: determining fossil fuel CO2 over Europe using Jungfraujoch observations as background.

Monthly mean 14CO2 observations at two regional stations in Germany (Schauinsland observatory, Black Forest, and Heidelberg, upper Rhine valley) are compared with free tropospheric background measurements at the High Alpine Research Station Jungfraujoch (Swiss Alps) to estimate the regional fossil fuel CO2 surplus at the regional stations. The long-term mean fossil fuel CO2 surplus at Schauinsland is 1.31+/-0.