Investigation on the distribution patterns and predictive model of solar radiation in urban street canyons with panorama images

Abstract

Solar radiation is the main driving force responsible for adjusting the urban climate and heat balance in street canyons. In this study, the model for predicting urban solar radiation used in RayMan is improved with respect to the reflected radiation and its accuracy is verified in field experiments. In total, 35763 sample sites in Xi'an are generated and categorized using basic urban morphology parameters (building density, average building height, and floor area ratio). The verified model is used to calculate the solar radiation intensities based on Baidu panorama images. The solar radiation distributions in Xi'an are mapped. The patterns of urban morphology affecting solar radiation are investigated. The results shows that solar radiation is affected by street canyons and the morphology of urban plots, as follows. (1) The effect of the width of street canyons on the solar radiation intensity is stronger in the transition and cold season (September to May) than the hot season (June to August), where the influence is stronger when the season is colder. (2) In east–west street canyons, the effects on solar radiation of urban morphology parameters in southern plots are stronger. (3) The relationship between the floor area ratio and solar radiation is strongest and negative.