Intra-urban relationship between surface geometry and urban heat island: review and new approach

This paper provides a comprehensive review of the intra-urban sky view factor (SVF)-temperature relationship. A new approach to reveal the real connection between SVF and air temperature in an entire city is presented. The results found in the literature are rather contradictory, possibly due the fact that previous investigations were limited to the central or specific parts (e.g. inner city, urban canyons) of cities and used few sites and measurements. Comparisons were often based on element pairs measured at selected sites. In some cases areal means were also discussed, but always in connection with one of the variables examined. For comparison, the present study in Szeged, SE Hungary, utilizes a large number of areal means of SVF and air temperature. The values are related to almost a whole city and based on numerous measurements. The results show a strong relationship in the intra-urban variations of these variables, i.e. urban surface geometry is a significant determining factor of the air temperature distribution inside a city if the selected scale is appropriate. Therefore, investigation of a sufficient number of appropriate-sized areas covering the largest part of a city or the entire city is needed to draw well-established conclusions.