Abstract
Abstract
More frequent and intense heat waves, especially in urban centers, represent a growing challenge for urban designers and building planners. In the last five years, extensive research has been undertaken on the relation between urban form, including density, and urban heat phenomena. Dense urban configurations are often considered central drivers of hot microclimates. However, less dense cities easily cause other ecological (e.g. land consumption), functional (public mobility), and socioeconomic (social diversity) problems. Consequently, the current panoply of recommended heat mitigation and sustainability measures constitutes an unclear basis for strategic planning decisions. Thus, this study examines the literature on urban morphology in relation to urban heat events. Around 800 scientific articles and studies are categorized regarding the applied methodology, the studied geographic location, the observed urban form parameters, and the examined thermal parameter. Most identified literature uses traditional field measurement, remote sensing, numerical simulation, or a combination. Air temperature and land surface temperature are the most observed thermal parameters, while the growing number of studies that focus on human outdoor thermal comfort is highly relevant for effective heat mitigation and adaptation. This study suggests that from a scientific point of view, urban morphology measures do not principally carry a paramount role in heat mitigation compared to other aspects, such as vegetation or materialization. Current planning approaches for climate-resilient cities are highly case-specific, where no generally applicable rules or effective recipes regarding urban built form are available.