Verdunstungsprozesse in lokalen bis regionalen Skalen Endbericht

Abstract

Regional evaporation was investigated using aircraft measurements in heterogeneous areas corresponding to the grid size of limited area and global circulation models. The main focus was on scale aggregation methods and the validation of parameterization schemes. Data from the first and second field phase of NOPEX (NOrthern hemisphere climate Processes landsurface EXperiment) were used to study the aggregation of energy and moisture fluxes over an inhomogeneous area of 80 km by 100 km covered to a large extent by forest. Observations on a smaller scale were performed in a lake area in North-East Germany using the DLR motorglider turbulence measurement system. The main conclusion from both analyses suggests that advective processes and mesoscale flux contributions are significant and can modulate and enhance the vertical energy and moisture exchange. From the boundary layer budgets it follows that area-weighted average surface fluxes agree with the effective fluxes obtained form aircraft measurements. A case study of mesoscale moisture variability orginating from a synoptic-scale disturbance shows evidence of large vertical flux divergence in the surface layer. Parameterizations based on similarity relationships cannot be used in this case. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(65,38) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman