Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 5 2005 10.5194/acpd-5-8979-2005 http://www.atmos-chem-phys-discuss.net/5/8979/2005/ http://www.atmos-chem-phys-discuss.net/5/8979/2005/acpd-5-8979-2005.html http://www.atmos-chem-phys-discuss.net/5/8979/2005/acpd-5-8979-2005.pdf 8979 9001 2005-09-20 The effect of systematic measurement errors on atmospheric CO₂ inversions: a quantitative assessment C. Rödenbeck T. J. Conway R. Langenfelds Max Planck Institute for Biogeochemistry, Jena, Germany NOAA Climate Monitoring and Diagnostics Laboratory, Boulder CO, USA Commonwealth Scientific and Industrial Research Organisation, Australia Surface-atmosphere exchange fluxes of CO₂, estimated by an interannual atmospheric transport inversion from atmospheric mixing ratio measurements, are affected by several sources of errors, one of which is experimental errors. Quantitative information about such measurement errors can be obtained from regular co-located measurements done by different laboratories or using different experimental techniques. The present quantitative assessment is based on intercomparison information from the CMDL and CSIRO atmospheric measurement programs. We show that the effects of systematic measurement errors on inversion results are very small compared to other errors in the flux estimation (as well as compared to signal variability). As a practical consequence, this assessment justifies the merging of data sets from different laboratories or different experimental techniques (flask and in-situ), if systematic differences (and their changes) are comparable to those considered here. This work also highlights the importance of regular intercomparison programs.