VALIDATION OF AN ESTIMATION MODEL FOR URBAN SURFACE ALBEDO

Abstract

The albedo measurements of Aida (1982), made over simulated urban surfaces constructed from arrangements of concrete blocks into canyon and grid configurations, are used to evaluate the performance of the urban canyon radiation model of Arnfield (1976a, 1982). The model is shown to be capable of producing acceptable estimates of surface albedo for city land-use zones consisting predominantly of canyons with lengths considerably greater than their width, especially for high sun (high irradiance) conditions. For the data best suited to model validation, about half the albedos were estimated to within ±5% and all were within ±10%. For grid canyon configurations, the method yields less satisfactory results but it is argued that errors will be less significant for surface geometries more realistic than those employed by Aida which possessed very short block lengths in relation to street widths. [Key words: urban climate, energy-budget climatology, albedo, radiation model.]