Regionalization of turbulent fluxes by combining aircraft measurements with footprint analysis

El-Madany T, Geiß H, Schmidt A, Klemm O.

Abstract

This paper presents a method for the regionalization of turbulent fluxes by combiningairborne flux measurements and footprint analysis. Eddy covariance measurementswere performed with a small environmental research aircraft in May 2008 over the"M¨unsterland" 5 region in northwest Germany. This region is dominated by agriculturalpatches that are typically a few hectares in size. An analytic footprint model was testedand 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 weremerged with high resolution land use data (30×30 m), resulting in a quantification of 10 different land use types inside the respective footprints. The fluxes of the sampledarea in the M¨unsterland of 1510 km2 were scaled up to the area of the "Westf ¨ alischeBucht" (6054km2), since the land use composition are comparable to a large extent.The mean fluxes calculated of 99 flight segments and used for the regionalization werefound -0.69mgm-2 s-1 for carbon dioxide and +0.17 gm-2 s-1 for water vapor.

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