Urban Heat Island: State of the Art

The urban heat island (UHI) phenomenon refers to temperature differences between cities and their surrounding rural regions, with higher temperatures in densely built cities and lower temperatures in surrounding rural regions, and it is considered as one of the main parameters influencing directly the urban microclimate. The UHI is considered as one of the largest environmental issue associated with the urbanization and human activities since the increased temperatures associated with the UHI tend to exacerbate human health threats. Furthermore, the UHI has a tendency to raise the heatwave intensities which in turn adversely contribute to increasing risks leading to excess mortality rate. The UHI has been a central theme among climatologists, and it is well documented and analyzed in many megalopolis areas around the world. This paper presents the state of the art of the UHI phenomenon and gives a general overview of the different research focused on the study of UHI events since 1818, the types and the dynamic process of UHI as well as its drivers and impact.