Microclimate variations of Urban Heat Island effects in Hong Kong

Abstract

Urbanization is known to cause significant changes in the properties of local climate. Studies have shown that urban areas, compared to rural areas with less artificial lands, registered higher local temperatures as a result of Urban Heat Island (UHI) effects. Hong Kong is one of the most densely populated cities in the world with high portion of population residing in urbanized areas, hot/humid weather and densely built high-rise buildings created severe local thermal discomforts. To fully characterize the spatial and temporal aspects of UHI effects in Hong Kong, my study deployed 25 small, durable and low-cost logging sensors at various sites to take temperature/humidity measurements for 17 consecutive days throughout within a typical urban area of Hong Kong. With the aid of GIS and GPS, the measurements were mapped against the urban structures and land use to enable ratings of environmental settings at various sites. The respective meteorological conditions in duration were correlated with the sensors measurements for further evaluations and validations. This empirical study not only established the feasibility of employing the small and inexpensive logging sensors for widespread deployment but also confirmed the existence and the extent of microclimate variations of UHI in Hong Kong. These empirical data formed the bases of spatio-temporal examination of UHI effects in urbanized areas of Hong Kong. The study and the methodology have also paved a sound foundation and provided essential frameworks for further studies of UHI effects on local human comfort and environmental health of Hong Kong.