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Title: The urban physical environment: temperature and urban heat islands. Chapter 2
Author: Heisler, Gordon M.; Brazel, Anthony J.
Publication: In: Aitkenhead-Peterson, Jacqueline; Volder, Astrid, eds. Urban Ecosystem Ecology. Agronomy Monograph 55. Madison, WI: American Society of Agronomy, Crop Science Society of America, Soil Science Society of America: 29-56.
Abstract: The term urban heat island (UHI) describes the phenomenon in which cities are generally warmer than adjacent rural areas. The UHI effect is strongest with skies free of clouds and with low wind speeds. In moist temperate climates, the UHI effect causes cities to be slightly warmer in midday than rural areas, whereas in dry climates, irrigation of vegetation in cites may cause slight midday cooling compared to rural areas. In most climates, maximum UHIs occur a few hours after sunset; maximum intensities increase with city size and may commonly reach 10°C, depending on the nature of the rural reference. Since the recognition of London's UHI by Luke Howard in the early 1800s, UHIs of cities around the world have been studied to quantify the intensity of UHIs, to understand the physical processes that cause UHIs, to estimate the impacts of UHIs, to moderate UHI effects, and to separate UHI effects from general warming of Earth caused by accumulation of greenhouse gases in the upper atmosphere. This chapter reviews a portion of the literature on UHIs and their effects, literature that has expanded greatly in the last two decades spurred on by a series of successful international conferences.
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