Spatio-temporal relation of urban density and surface urban heat island index

Abstract

Over the decades, an unprecedent growth in urban areas has impacted cities population and its local climate. The
urban built-up densification has increased local temperature of cities in comparison to its surrounding areas covered
majorly with open land and vegetation. It gives rise to urban heat island effect, but it does not affect the entire city in
homogenous manner and depends upon its urban density. For incorporating spatial non-homogeneity, a non-linear
mathematical function is required to understand the spatio-temporal change in urban density and urban heat island
effect in cities. An inverse s-shape function is used in this study explaining city expansion around the central
business district and its relation to the surface urban heat island index. The temporal change in inverse s-shape
function signifies urban expansion and is validated via urban sprawl matrices. Also, urban density and surface urban
heat island index exhibits high degree of fitness between the value 0.95-0.98. This study helps in understanding
spatial -change in urban heat island effect and urban density and can be use in future for vulnerability assessment
studies of cities against extreme events.