Mapping Surface Urban Heat Islands and the influence of urbanization and heatwaves on urban climate through Local Climate Zones in Tallinn – 2014 and 2022

Abstract

This study analyses urbanization and Surface Urban Heat Island (SUHI) Intensity in Tallinn in 2014 and 2022, focusing on changes during heatwave and non-heatwave conditions. Urbanization was assessed through Local Climate Zone (LCZ) mapping based on supervised classification using building, land cover data, and Landsat 8 imagery. Satellite-derived Land Surface Temperature (LST) was used to evaluate thermal patterns and SUHI intensity. The results indicate urban densification in and around Kesklinn, with no clear evidence of urban sprawl within municipal boundaries. SUHI intensity was consistently higher during heatwaves, particularly in compact, impervious zones, while vegetated and pervious areas mitigated excess heat. Despite built-up densification, no overall increase in SUHI extent or intensity from 2014 to 2022 was observed. The findings underscore the role of land cover in thermal vulnerability and highlight the importance of green infrastructure in climate adaptation. Future studies should refine the methodology in the selection of the reference climate zone for SUHI/non-SUHI delineation and extend the temporal range to enhance the accuracy of SUHI intensity assessments.