Urban Microclimate and Outdoor Thermal Comfort of Public Spaces in Warm-Humid Cities: A Comparative Bibliometric Mapping of the Literature

Abstract

Intensified human population encourages urbanization changing the morphology and metabolism of urban environments, thus altering the local climate and outdoor thermal comfort (OTC) in public spaces. OTC is an increasingly urgent area of research for tropical climates. This study explores the literature from the Scopus database on urban microclimate and OTC in public spaces and contrasts the studies in warm-humid cities through a bibliometric mapping of literature. The adapted methodology includes; Bibliometric Search, Scientometric Analysis, and Content analysis using VOSviewer software to identify the evolution paths, gaps, and the most recent movement of OTC assessments in urban public spaces. Results reveal five evolution paths related to all climatic regions; 1) materials and cooling strategies, 2) simulation modeling and urban planning, 3) design parameters affecting thermal perception, 4) cooling effects of green infrastructure, and 5) thermal adaptation in urban design. Although urban morphology and vegetation have been received the highest attention respectively, only a few for blue infrastructure related to warm-humid cities. This review identified five research gaps; the impact of blue infrastructure on OTC, strategies to overcome the effect of reflective materials, vegetation configurations in street canyons with wind flow, OTC improvements in asymmetrical street canyons, and how local climate zone (LCZ) classification approach could be used for OTC assessments. Past empirical studies have revealed that urban vegetation, surface materials, and morphological parameters are of paramount importance. Yet, the urban blue infrastructure has not received adequate research. Recently, the attention of researchers has been drawn to strategies in improving OTC using micro-meteorological simulation modelling to examine the impact of urban design interventions. Finally, comprehensive content analysis, bibliographic coupling based on documents, co-occurrence of all-keywords, are suggested for future bibliometric reviews. Finally, further research on recommended areas would assist decision-makers in planning and design to enhance livability by improving microclimate and OTC in urban spaces.