The representation of subgrid-scale surface heterogeneities in numerical weather and climate models has been a challenging problem for more than a decade. The Evaporation at Grid and Pixel Scale (EVA-GRIPS) project adds to the numerous studies on vegetation-atmosphere interaction processes through a comprehensive field campaign and through simulation studies with land surface schemes and mesoscale models. The mixture of surface types in the test area in eastern Germany is typical for larger parts of northern Central Europe. The spatial scale considered corresponds to the grid scale of a regional atmospheric weather prediction or climate model and to the pixel scale of satellite images. Area-averaged fluxes derived from point measurements, scintillometer measurements, and a helicopter-borne turbulence probe were widely consistent with respect to the sensible heat flux. The latent heat flux from the scintillometer measurements is systematically higher than the eddy covariance data. Fluxes derived from numerical simulations proved the so-called mosaic approach to be an appropriate parameterization for subgrid heterogeneity.

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GKSS Research Center, Geesthacht, Germany

Meteorological Observatory–Lindenberg, German Meteorological Service (DWD), Tauche, Germany

Meteorological Institute, University of Bonn, Bonn, Germany

Institute for Geophysics and Meteorology, University of Cologne, Cologne, Germany

Institute for Aerospace Systems, Technical University Braunschweig, Braunschweig, Germany

Department of Micrometeorology, University Bayreuth, Bayreuth, Germany

Max-Planck-lnstitute for Meteorology, Hamburg, Germany

Institute of Hydrology and Meteorology, Dresden University of Technology, Tharandt, Germany

Institute for Meteorology and Climatology, University Hannover, Hannover, Germany

KNMI, De Bilt, Netherlands

Wageningen University, Wageningen, Netherlands