Mauder, M*; Foken, T: Impact of post-field data processing on CO2-flux estimates from eddy covariance measurements
Vortrag, 40th CMOS Congress, Toronto: 29.05.2006 - 01.06.2006

Eddy covariance measurements are widely used to determine the net ecosystem exchange of carbon dioxide. This study evaluates the impact of post-field data processing methods on eddy covariance flux estimates. To that end, a dataset from the LITFASS-2003 field campaign in the vicinity of the Meteorological Observatory Lindenberg of the German Weather Service was analysed using an experimental software package. Widely discussed issues in data processing, like an adequate flux averaging time, coordinate transformations, and alternative approaches for the correction of density effects are examined. The impact of all the single processing steps on CO2-flux estimates is demonstrated. The mean value of the CO2-flux can be halved or doubled through the correction for density effects. The approach after Liu (2005) leads to an increased net assimilation estimate by 26% compared to the classic WPL correction. Large flux contributions from wavelengths longer than 30 minutes were found for the CO2-flux at the test site. Very longwave turbulent structures can be explained through the strong heterogeneity of the surrounding landscape. This thesis is also supported through an LES analysis.

Letzte Änderung 26.05.2006