The optimal ratio in the street canyons: Comparison of two methods of satellite images and simulation

Abstract

Different street-canyon ratios can have significant effects on urban microclimates. These changes affect the intensity of urban heat islands. To formulate urban standards, we need to know the optimal ratios of street-canyons, whose efficiency has been proven in the actual conditions of the city. The values provided by the previous studies regarding the investigation of thermal conditions and microclimates in street-canyons are the result of numerical and software simulations. Since several factors affecting the test conditions may be ignored in the simulation, therefore, these software findings may provide different results from the actual city context conditions. Therefore, this research compares the results of numerical simulations and the analysis of thermal satellite images to achieve optimal values and better understand the temperature conditions in actual street-canyons with different ratios of height to width of the canyon (H/W). The results show that ratios close to 1–1.5 have the lowest and most balanced temperature in different physical conditions. Although the results in other ratios have differences from the outcomes of software simulations, since these studies have also introduced the ratio H/W = 1 as an optimal value, this ratio can be used with more confidence in Future planning and research.