Sky View Factor Analysis of Street Canyons And Its Implication For Urban Heat Island Intensity

Abstract

The sky view factor (SVF) Iws been shown to be an important factor in determining the micro climate in urban canyons . However the results analyzing the relationships between urban heat island intensity (UHf) and SVF found in the literature are empirical and location dependent, and "'ometimes, contradictory, while the studies are mostly based on individual field measurement (e .g .fisheye plwto) . Continuous SVF values for a whole terrain are important to derive the thermal pattern of tlwt area . However, a rapid method for calculating continuous SVF values with enough accuracy for large areas (f(X)O /un2 scale. e.g.) , is yet to be devel,')ped. This paper presents a GIS-based approach where a computer program is developed for calculating continuous SVF values in an entire urban environment. A /IUlp of SVF values is generated. The result is evallUlted against oota obt,rJined in field measurements from seaside to downtown area. Various parameters such as areal mean are studied. The study aims to investigate the relationship between SVF and UHI in Hong Kong and to derive an overall pattern of Iww Hong Kong's unique building bulk chnracteristics and UHI are related. The expected significance of this research work is that the relationship derived can be used as a prognostic approach for categorizing Hong Kong's urban area for planning concerns for high dense sub-tropical cities.