Urban heat island modelling of a tropical city: case of Kuala Lumpur

摘要

The steep increase in urban populations results in the spatial extent of cities expanding both horizontally and vertically. The climatic response of urban areas differs greatly to rural areas exposed to the same environmental conditions, with urban temperatures generally being higher, particularly in the late afternoon and evening. Coupled with the upward trend in global temperatures, urban heating can be classified as an atmospheric hazard that affects a high proportion of the population in some countries, which needs to be addressed through local and national government planning strategies. This study presents preliminary findings from a city scale urban climate model developed using the fast climate modelling tool ADMS-Urban for the city of Kuala Lumpur, Malaysia, which is known to suffer from substantial urban heating, and discusses the extent and intensity of the urban heat island in light of existing literature based on field measurements. The model has been configured to use surface characteristic data derived from land-use data as input, and through comparison with temperature variations derived from satellite imagery, the model is seen to clearly capture the spatial variation of temperature over the domain. The urban heat island intensities predicted by the model are comparable to the values reported in literature. This study also demonstrates the strong relationship between temperatures and wind speed, which is generally much lower in tropical Kuala Lumpur compared to mid-latitudes, and the urban heat island intensity and nocturnal cooling. The future modelling studies should account for anthropogenic heating, for instance, from air conditioning units and traffic, which are important sources of heat in tropical areas, and expand more on building materials and morphology for a thorough appraisal of urban heating in Kuala Lumpur.