The Sky View Factor (SVF) is a critical parameter in urban climate studies. It represents the proportion of visible sky from a specific location. It ranges from 0 (completely enclosed spaces like narrow alleys or dense tree canopies) to 1 (wide-open areas such as open fields). SVF is a key factor in urban climate studies, influencing temperature, radiation balance, ventilation, and overall thermal comfort.
The sky view factor (SVF) plays a crucial role in shaping the urban climate and air quality, especially in densely built environments.
A common observation is that areas with low SVF — such as narrow streets and enclosed courtyards — tend to trap heat, contributing to the urban heat island (UHI) effect, where cities remain warmer than surrounding rural areas.
These spaces retain heat during the night, slowing down the natural cooling process and exacerbating thermal discomfort for residents. In contrast, higher SVF areas enable better heat dissipation and natural ventilation, allowing temperatures to regulate more effectively.
Urban planners and architects use these insights to design climate-resilient cities, carefully optimizing street layouts, building heights, vegetation placement, and shading strategies to manage urban temperatures.
Beyond temperature regulation, SVF also directly impacts air circulation and air quality.
Areas with low SVF often experience reduced wind flow, accumulating pollutants and consequently poorer air quality. Conversely, environments with a high SVF promote better air exchange, dispersing pollutants more efficiently and improving the overall livability of urban spaces.
By integrating SVF considerations into urban design, cities can create healthier and more sustainable environments that balance thermal comfort, efficient ventilation, and air quality.
Fig 1. Daily development of thermal comfort (Physiological Equivalent Temperature) in a model with high sky view factor
Fig. 2 Daily development of thermal comfort (Physiological Equivalent Temperature) in a model with low sky view factor
The sky view factor (SVF) is a valuable metric in urban climate studies, but it must be considered alongside other environmental factors. By leveraging advanced tools like ENVI-met, urban planners can design cities that balance temperature regulation, ventilation, and overall livability, creating sustainable and climate-resilient urban spaces.