Flux Parameterization over Land Surfaces for Atmospheric Models

TLDR

The paper summarizes observations and modeling of surface fluxes from Cabauw and MESOGERS‑84 and proposes empirical closure functions for transfer coefficients between the surface and the first model layer. The study focuses on key flux parameters—surface roughness lengths for momentum and heat, stomatal resistance, and subgrid inhomogeneities up to a few kilometres—and compares simple flux parameterizations with observations to develop empirical closure functions. The authors offer a qualitative explanation for the unexpectedly low roughness length values for heat.

Abstract

In this paper a summary is given of observations and modeling efforts on surface fluxes, carried out at Cabauw in The Netherlands and during MESOGERS-84 in the south of France. Emphasis is put on those aspects that are important from a modeling point of view, e.g., surface roughness lengths for momentum and heat, stomatal resistance for evaporation, and related quantities. Special attention is paid to the problem of subgrid surface inhomogeneities up to horizontal scales of a few kilometers. A qualitative explanation is given for the apparent low values of the roughness length for heat. Simple flux parameterizations are compared with observations, and empirical closure functions are proposed to model the transfer coefficients between the surface and the first model layer.