Urban Canyon Analysis

Urban canyon analysis characterises a street flanked by buildings as a 'canyon' and studies how its geometry — chiefly the ratio of building height to street width — governs airflow, radiation, temperature, and pollutant dispersion within it. The single most important descriptor is the aspect ratio H/W, which determines whether wind skims over the top, recirculates inside, or interacts between adjacent canyons. The framework was set out by Timothy Oke's 1988 paper on street design and the urban canopy layer, which tied canyon geometry to the microclimate of the air below roof level.