Simulation of the energy budget of an urban canyon—II. Comparison of model results with measurements

Abstract

A simple numerical model that attempts to simulate the energy budget of an urban canyon is assessed by comparing its predictions against measurements made at an urban field site. A street is chosen that satisfieds many of the model's requirements and a measurement scheme is devised to measure variables which are also simulated. The model is run using input information collected from the field and the data produced are compared with the measured data. The results indicate that the model is capable of simulating many of the climate attributes (such as surface temperatures and net radiation at the canyon top) accurately, but does not simulate the dominant mechanism of sensible heat exchange between the canyon and its environment. Nevertheless, the model predicts a small and largely invariant exchange, similar to that measured. The results of the field study, when compared with other published work, indicates that as street canyons become narrower they become increasingly isolated in terms of heat exchange from the overlying atmosphere. The results of the computer runs appear to follow this pattern.