Abstract

The openness of the sky is an important element in the balance of urban microclimate, being essential in the thermal exchange and in the dispersion of long waves emitted by urban surfaces. The intense urban development and high rates of densification in cities usually reduces this opening in a large extend, limiting the visibility of the sky from an urban observation point. To quantify this openness, an index named sky view factor (SVF) is often applied. This paper analyses this index to investigate the influence of urban vegetation as an element of obstruction of the sky opening. For this purpose, thermal measurements with data loggers were carried out, collecting thermal samples of points of a university campus, which lie under two vegetation conditions: heterogeneous area (predominantly with adult trees and several species) and homogeneous areas (predominantly with adult trees and only one species). Digital images were taken with a camera equipped with a fisheye lens, being subsequently subjected to RayMan software for the calculation of the SVF values. By an analysis of several thermal parameters, the contribution of the vegetation integrated to the SVF was verified. The results allowed the determination of some correlations of these indexes with the surrounding microclimate.