Regionalization of turbulent fluxes by combining aircraft measurements with footprint analysis

Abstract. This paper presents a method for the regionalization of turbulent fluxes by combining airborne flux measurements and footprint analysis. Eddy covariance measurements were performed with a small environmental research aircraft in May 2008 over the "Münsterland" region in northwest Germany. This region is dominated by agricultural patches that are typically a few hectares in size. An analytic footprint model was tested and applied to relate the fluxes, as measured on the aircraft during day time conditions, to different vegetation types on the ground. The geo referenced footprint areas were merged with high resolution land use data (30×30 m), resulting in a quantification of different land use types inside the respective footprints. The fluxes of the sampled area in the Münsterland of 1510 km² were scaled up to the area of the "Westfälische Bucht" (6054 km²), since the land use composition are comparable to a large extent. The mean fluxes calculated of 99 flight segments and used for the regionalization were found −0.69 mg m⁻² s⁻¹ for carbon dioxide and +0.17 g m⁻² s⁻¹ for water vapor.