## 3 Methods and Analysis  
The definition of duration of possible sunshine by the WMO refers to that without any shade; in other words, the sum of time when sunlight irradiates the ground, where the sun passes from the eastern horizon to the western horizon of a certain area [17]. In the northern hemisphere, the duration of possible sunshine in the summer generally increases with the latitude, whereas in the winter, it decreases with the increase in the latitude. The sunshine hours is the sum of time during which direct solar irradiance intensity reaches or  
Figure 4: Urban tissue of (**a**) Minsheng Road and (**b**) Xingning Road. Figure 3: Temperature distributions for Qilou street area. exceeds 120 W/m\({}^{2}\) in a certain area. The actual sunshine hours of solar radiation received on the ground is less than the number of possible sunshine hours, which is due to the occlusion of clouds and mist in the sky, and the various degrees of sun-shading caused by urban morphology and greening. As a consequence, sunshine hours are often used instead of possible sunshine hours in solar radiation models. Furthermore, the sunshine hours is the most commonly used parameter [30]. However, the global solar radiation which reflects the sunshine condition in a block environment can be calculated from sunshine hours [26]. In addition, the sunshine-hours model is the most widely used meteorological parameter model, and has the most accurate calculation results and the most accessible data among global solar radiation models [31]. According to the actual size of the buildings in the Qilou streets, Figure 5 shows the simulation of sunshine on Xingning Road and Minsheng Road by using software Ladybug, which is green building analysis software based on a parameterized design frame. The simulation time is at 8:00-16:00 on 22 June, the Summer Solstice, and the grid size is set to 1. The street scale parameters refer to street orientation, width, length, building height and depth, all of which affect sunshine hours directly. Therefore, it is necessary to explore prediction methods and optimization strategies pertaining to the height-to-width ratio of commercial Qilou streets being affected by sunshine hours. The effects of street scale parameters on sunshine hours for Qilou streets, namely Xingning Road and Minsheng Road, which elevation is 77 m, will be investigated:  
1. The street orientation angle: Minsheng Road spans from 43\({}^{\circ}\) Northeast to 29\({}^{\circ}\) Northeast, whereas Xingning Road spans from 119\({}^{\circ}\) Northeast to 73\({}^{\circ}\) Southeast. In this study, the initial direction of the street is the East-West direction which was set to 0\({}^{\circ}\). 2. Street width: the street width of the pedestrian street or mall ranged from 9 to 13 m.
3. Street length: the pedestrian streets were partitioned by some branches of roads. The continuous building was 90-130 m long. 4. Building level height: the level height of the building along the sides of the pedestrian street was 2.7-4 m. Hence, the level height was set to 3.3 m in the sunshine model. 5. Number of building levels: Figure 6 shows that the distribution of building storeys along the sides of the pedestrian street ranges from 1 to 9. Both the level heights and number of levels determine the heights of the buildings. The effects of building height and street orientation on street sunshine hours are shown in Figures 7 and 8, respectively. The heights increased or decreased in proportion to the average height of actual architectural complexes. Figure 5: Distribution of sunshine hours on Xingning Road and Minsheng Road. Creating a comfortable environment in street design requires not only the consideration of a single parameter, but also the comprehensive consideration of the scale parameters and psychological perception of the street. For building height \(H\) and street width \(W\), [PERSON] [32] believed that when \(H/W<1\), people feel more detached as the ratio decreases.