Study On The Relationship Between Urban Plaza Conformation Within Blocks And Sky View Factor

The urban heat island effect is defined as the phenomenon that there is a temperature difference between the urban areas and the surrounding natural areas, whose causes are diverse and work comprehensively, among them urban form plays an important role in the impact of the urban heat island effect. In the field of the relationship between urban form and urban heat island effect, the sky view factor is widely used as an associated parameter. Numerous scholars have proved that there exists a strong negative correlation between the sky view factor and the urban heat island effect through measured and statistical analysis, which means that the greater the average sky view factor is, the less likely the urban hear island effect will be. On the other hand, it is difficult to study the relationship between the sky view factor and urban form from the perspective of the urban fabric, especially in contemporary Chinese cities where building height and mass are quite different. Therefore, this study concerns the spatial conformation of urban plaza as the direct research object and focuses on the influence the morphological changes of the urban space interface have on the sky view factor. The significance of this study is to bring driving force for the emergence of new urban form through the intervention of the sky view factor as well as to provide guidance and basis for urban micro climate based urban planning and design.Firstly, on the one hand, this study sorts out the classification of urban plaza form, selects Leon Krier’s inductive and deductive principles on traditional urban plaza and determines the principle of spatial conformational changes of urban plaza. On the other hand, this study establishes an experimental platform to digitally describe the urban plaza conformation based on Rhino-Grasshopper through the review of the methods of digitally describing urban form such as Martin Center’s basic urban prototype induction and shape grammar’s advantage in the representation of formal evolution.In the second place, based on this platform, this paper discusses the impact the plaza planar form, plaza interface concession, road connection type, plot height variation and the tower set would have on the sky view factor through the formal parameter adjustment. Through the comparison of the tower set, the overall height increase of plots and the plaza interface concession, this paper obtains a "sky view factor contour interface", which can control the plaza spatial interface to remain the same sky view factor value.Finally, on the basis of the conclusions of a number of thematic studies, from the perspective of planning control and design guidance, this paper summarizes the recommendations based on reasonable sky view factor of the effective control of urban plaza form and provides three generally applicable deductive methods to maintain the same sky view factor.Through the operation of this method, we can find that it has potential to increase the plot ratio of the block in the case of remaining the same sky view factor.In summary, this study has established a reasonable and viable method to digitally describe urban plaza spatial conformation, explored the relationship between the morphological changes of urban plaza and the sky view factor, and obtained the operational solutions to optimize the sky view factor through formal adjustment, which would provide the basis of urban planning and design and possibilities for the emergence of new urban form.