Exploring the Urban Heat Island Effect: A Bibliometric and Topic Modeling Analysis

The urban heat island (UHI) effect, intensified by urbanisation and climate change, leads to increased urban temperatures and poses a serious environmental challenge. Understanding its causes, impacts, and mitigation strategies is essential for sustainable urban planning. The aim of this study is to systematically analyse how the Urban Heat Island (UHI) effect has been addressed in the scientific literature, to identify key research themes and their temporal evolution, and to critically highlight knowledge gaps in order to provide guidance for future research and urban planning policies. Using BERTopic, an advanced natural language processing (NLP) tool, the study extracts dominant themes from a large corpus of academic literature and tracks their evolution over time. A total of 9061 research articles from the Web of Science database were collected, pre-processed, and analysed. BERTopic clustered semantically related topics and revealed their temporal dynamics, offering insights into emerging and declining research areas. The results show that pavement materials and urban vegetation are among the most studied themes, highlighting the importance of surface materials and green infrastructure in mitigating UHI. In line with this aim, the study identifies a rising interest in urban cooling strategies, particularly reflective surfaces and ventilation corridors. Consistent with its aim, the study provides a comprehensive overview of UHI literature, critically identifies existing gaps, and proposes clear directions for future research. It provides supports for urban planners, policymakers, and researchers in developing data-driven strategies to mitigate UHI impacts and strengthen enhance urban climate resilience.