Detecting the changing impact of urbanisation on urban heat islands in a tropical megacity using local climate zones

Sharmin, Tania ORCID: https://orcid.org/0000-0001-6229-2035 and Chappell, Adrian ORCID: https://orcid.org/0000-0002-0694-7348 2025. Detecting the changing impact of urbanisation on urban heat islands in a tropical megacity using local climate zones. Energy and Built Environment 10.1016/j.enbenv.2025.02.002

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Abstract

This study integrates urban morphology-based heat island estimates with Local Climate Zone (LCZ) classifications, a methodology that is relatively underexplored in the context of tropical megacities. We use Land Surface Temperature (LST), and Normalised Difference Vegetation Index (NDVI) measured from satellite data to establish the differences across the LCZ classes and to identify suitable climate-sensitive built-environments for the megacities. High-density built-up areas had higher LSTs and Surface Urban Heat Island (SUHI) estimates than areas with more vegetation. When comparing average summer LSTs in built-up areas, areas with higher building density and minimal vegetation cover were 1.2°C warmer than the more open built environments. Natural areas, on the other hand, showed an average LST that was 2.4°C cooler than the compact built environment and 1.3°C cooler than the open built environment. For tropical megacity Dhaka, open low-rise, mid-rise and high-rise morphology emerges as more favourable built environment benefiting both people and the local biodiversity. Conversely, areas comprising compact mid-rise, large low-rise and heavy industry buildings that are becoming increasingly densely populated, are the least suitable options. Given the increasing need for high-density living, our results indicate that the most suitable approach to planning would be to substitute compact low-rise housing, typically prevalent in developing country megacities as slums, with a combination of open high-rise and open mid-rise housing. This study demonstrates that increasing SUHI and LSTs can be mitigated in densely populated tropical megacities by appropriate planning using urban morphology as demonstrated by LCZ classification.

Item Type:	Article
Date Type:	Published Online
Status:	In Press
Schools:	Schools > Earth and Environmental Sciences Schools > Architecture
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0/, Start Date: 2025-02-06
Publisher:	Elsevier
ISSN:	2666-1233
Date of First Compliant Deposit:	17 February 2025
Date of Acceptance:	5 February 2025
Last Modified:	17 Feb 2025 15:30
URI:	https://orca.cardiff.ac.uk/id/eprint/176253

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