Assessing Urban Heat Dynamics Using Satellite-Derived Land Surface Temperature: A Case Study of Chennai, India

Abstract

Coastal cities are increasingly facing thermal stress due to rapid urban growth, land-use change, and climate variability. Chennai, a major coastal city in southern India, exemplifies this challenge, where extensive urban development coexists with ecologically sensitive peri-wetlands and a dynamic land–sea boundary. This study examines the spatial and temporal variation of land surface temperature (LST) across distinct land-use categories in Chennai using satellite-derived data. LST was obtained from the MODIS MOD11A2 Version 6.1 product (8-day composite, 1 km spatial resolution) through the AppEEARS platform for four representative locations — urban, coastal, peri-wetland, and industrial — over an 11-year period (2015–2025). Coastal observations were affected by persistent mixed land–water pixel contamination (0% valid retrievals) and were therefore excluded from the quantitative analysis; this limitation and possible mitigation strategies are discussed explicitly. Statistical, diurnal, and seasonal analyses of the remaining three classes reveal a consistent Surface Urban Heat Island (SUHI) effect, with urban areas exhibiting the highest daytime and night-time temperatures and the lowest diurnal temperature range (DTR). Relative to earlier Chennai UHI studies, this work extends the observational record to 2025, explicitly incorporates a peri-wetland comparison class, and combines diurnal and seasonal decomposition within a single reproducible, low-code AppEEARS-based workflow. The findings can inform sustainable urban planning, climate adaptation, and ecosystem conservation in coastal urban settings.