Surface flux parameterization schemes : developments and experiences at KNMI

In this paper a summary is given of observations and modelling efforts on surface fluxes, which have taken place at KNMI. Emphasis is put on those aspects that are important for numerical weather and climate models e.g. surface roughness lengths for momentum and heat, surface stomatal resistance for evaporation and related quantities. Comparisons of flux estimates with observations from the Cabauw facilities and from the MESOGERS data are given. We present a discussion of exchange coefficients for momentum and heat in stable and very stable conditions and compare current approaches. New formulae for the exchange coefficients are proposed, which are consistent with observations from the Cabauw facilities.