The parametrization of boundary layer processes in general circulation models

An assessment and comparison are made of two separate methods of parametrizing the boundary-layer processes in a general circulation model. The first method is based on the use of eddy diffusivities. By using the framework of asymptotic similarity theory to describe the boundary layer as observed: and as predicted by single-column models, an objective assessment is made of formulations of the eddy diffusivities. Idealised neutral. conditions and diabatic conditions are examined separately. A formulation based on the specification of the mixing-length is recommended.