Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 6 6 2009 10.5194/bg-6-1015-2009 http://www.biogeosciences.net/6/1015/2009/ http://www.biogeosciences.net/6/1015/2009/bg-6-1015-2009.html http://www.biogeosciences.net/6/1015/2009/bg-6-1015-2009.pdf 1015 1026 2009-06-17 Detecting regional variability in sources and sinks of carbon dioxide: a synthesis A. J. Dolman han.dolman@geo.falw.vu.nl C. Gerbig J. Noilhan C. Sarrat F. Miglietta VU University Amsterdam, Department of Earth Sciences, Boelelaan 1085, 1081 HV Amsterdam, The Netherlands Max Planck Istitute for Biogeochemistry, Hans-Knoell-Str. 10, 07745 Jena, Germany Météo France, CNRM_GMME 42, avenue G. Coriolis, 31057 Toulouse, France Institute of Biometeorology, National Research Council (IBIMET-CNR), Via Caproni, 8-50145 Firenze, Italy The current paper reviews the experimental setup of the CarboEurope Experimental Strategy (CERES) campaigns with the aim of providing an overview of the instrumentation used, the data-set and associated modelling. It then assesses progress in the field of regional observation and modelling of carbon fluxes, bringing the papers of this special issue into a somewhat broader context of analysis. <br><br> Instrumental progress has been obtained in the field of remotely monitoring from tall towers and the experimental planning. Flux measurements from aircraft are now capable, within some constraints, to provide regular regional observations of fluxes of CO₂, latent and sensible heat. <br><br> Considerable effort still needs to be put into calibrating the surface schemes of models, as they have direct impact on the input of energy, moisture and carbon fluxes in the boundary layer. Overall, the mesoscale models appear to be capable of simulating the large scale dynamics of the region, but in the fine detail, like the precise horizontal and vertical CO₂ field differences between the models still exist. These errors translate directly into transport uncertainty, when the forward simulations are used in inverse mode. Quantification of this uncertainty, including that of inadequate boundary layer height modelling, still remains a major challenge for state of the art mesoscale models. 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