Abstract
Recently, models of regional heat and moisture fluxes in terrain with bluff roughness elements have been developed, based on observations which indicate that small areas of large roughness or obstacles dominate the regional momentum flux, whereas the regional heat and moisture fluxes are determined by the dominant surface cover. One model (Claussen and Klaassen, Beitr. Phys. Atmos., 65, 243-248, 1992) deduces the regional heat and moisture fluxes from local surface parameters, whereas the other (Beljaars and Holtslag, J. Appl. Meteorol., 30, 327-341, 1991) uses effective parameters. Here, the two models are compared; it is shown that they are equivalent when applied to homogeneous terrain with bluff roughness elements. Moreover, they yield the same results when used in numerical simulations. Both models are tested against an earlier proposal by Brutsaert (Water Resour. Res., 11, 543-550, 1975).
