A critical review of Urban Heat Island phenomenon in the context of Greater Kuala Lumpur, Malaysia

Urban Heat Island (UHI) phenomenon has become a regional issue for Greater Kuala Lumpur (GKL) as a number of studies reported an elevated air temperature in highly dense urban areas compared to the rural peripheries. An initial literature survey of UHI studies in GKL revealed an insufficiency and paucity of field measurements for more than one decade (since 1991) before gaining its momentum again after 2004. Despite a very limited number of studies in GKL, many studies used a vague set of site classification, operational definitions of Urban Heat Island Intensity (UHII) derived from such vague classification, uncontrolled and old set of data, limited coverage of weather station network and limited number of weather parameters in data collection. Therefore, this paper attempts to provide an overview of UHI studies in GKL by highlighting the major methodological shortcomings that hamper the reliability of previous measurements and by providing vital suggestions for an improved UHI quantification in future. The findings of most of the studies disclose an increasing trend in the UHII which is associated to the reduction in vegetation cover and land use changes. Eventually, this open up new opportunities for the upcoming studies to investigate the sensitivity of UHI to other unexplored factors in the local context. Besides focusing on the role of vegetation on urban temperature reduction, future studies need to focus more on examining the feasibility of other remediation technologies. This paper also suggests that rigorous attention should be given to a systematic site characterization, controlled and synchronous measurements, broader weather station network as well as incorporation of real-time data to elucidate the current UHII status. In addition, local studies could significantly benefit from the utilization of advanced modelling and simulation technologies as a basis for a more informed decision-making in line with the aspiration of GKL to achieve a world class sustainable metropolis by 2020 (GKL Initiative under the National Key Economic Area). Lastly, the incorporation of UHI phenomena in local policies is also essential to mitigate its deleterious impacts via more urban climate-friendly practices by various stakeholders.