Surface Roughness Lengths.

摘要

The surface roughness length is the meteorological equivalent of an aerodynamic drag coefficient. The surface morphology and terrain relief contribute to the roughness, have a large effect upon surface drag, and influence the analysis of wind, temperature, and specific humidity profiles in the surface boundary layer, as well as the examination of the surface energy balance. Roughness lengths effectively determine the vertical wind shear just above the surface with atmospheric stability almost a direct function of shear and roughness. Experimentally, roughness lengths over many natural surfaces have been determined. Many summaries of estimated surface roughness have been prepared, with most listing only a few typical values. One comprehensive study tabulated all values according to the year the data were collected. In this current effort, an attempt has been made to list roughness as a function of five categories, that is, natural surfaces, including seasonal variations, agricultural lands, urban roughness, effective roughness, and land-use categories. Satellite winds, Satellite wind errors, Geostrophic wind, Thermal wind.