Comparison of regional and ecosystem CO2 fluxes

A budget method to derive the regional surface flux of CO 2 from the evolution of the boundary layer is presented and applied. The necessary input for the method can be deduced from a combination of vertical profile measurements of CO 2 concentrations by i.e. an airplane, successive radio-soundings and standard measurements of the CO 2 concentration near the ground. The method was used to derive the regional flux of CO 2 over an agricultural site at Zealand in Denmark during an experiment on 12-13 June 2006. The regional fluxes of CO 2 represent a combination of agricultural and forest surface conditions. It was found that the regional flux of CO 2 in broad terms follows the behavior of the flux of CO 2 at the agricultural (grassland) and the deciduous forest station. The regional flux is comparable not only in size but also in the diurnal (daytime) cycle of CO 2 fluxes at the two stations.