Airborne measurements and mesoscale modelling to constrain the CO₂ budget on regional scales

Quantification of greenhouse gas exchange between surface and atmosphere on regional scales is crucial for process understanding, but also for verification of greenhouse gas budgets in the context of emission trading. The combination of regional modelling and airborne measurements allows a rigorous assessment of the methods used in the quantification of trace gas fluxes, both with respect to the measurement strategy (measurement network design), but also with respect to the modelling approach (atmospheric transport modelling, biospheric modelling). The long term goal is the optimal integration of measurements within the modelling systems, taking unavoidable representation errors into account quantitatively. This presents a precondition for estimating the uncertainties associated with trace gas budgets.