Urban heat island (UHI) variations within a city boundary: A systematic literature review

Urban heat islands (UHI) in a city tend to vary with changes in time and space. To effectively cope with the accelerating intensity of UHI due to global warming and the resulting damage, it is essential to accurately analyze and understand the spatial and temporal variations of UHI. This study conducted a systematic literature review (SLR) to better understand how existing studies have classified and analyzed UHI variations. Research trends and limitations related to UHI variation were reviewed focusing on 55 studies extracted through a five-stage protocol to identify critical studies. The selected studies were analyzed and synthesized in detail. The results showed that studies use different research ranges, data collection methods, analysis, and prediction models depending on the type of UHI variation. These results also indicate that studies have not used universal and specific protocols that apply to UHI variations. To address the limitations of these studies, it is necessary to develop more specific UHI research design methods and an analytical model that reflects the three-dimensional elements of the collected data. In addition, researchers should develop indexes to explain the spatial and temporal variations of UHIs. Further studies can help establish policies and planning codes to counter the spatiotemporal variability of UHIs. •Review of spatial and temporal variations of UHIs using an SLR framework.•Lack of general protocols to set the research scope and determine data collection methods to efficiently study UHI variations.•Need to develop a model and indexes to explain the intensity and magnitude of UHI variations.