Integrated assessment of urban heat island vulnerability in the Madurai region, India

Bhagavathi Krishnan Ramesh, E. Arivoli, Subbarayan Saravanan, Saksham Joshi, Hari Krishnan

Rapid urbanization in the Madurai region has intensified land surface warming, necessitating a comprehensive understanding of the Urban Heat Island (UHI) phenomenon. Most existing UHI studies over Indian cities rely primarily on satellite-derived land surface temperature (LST), short-term thermal snapshots, or limited spatial coverage, restricting their ability to capture seasonal variability, hydrological influences, and fine-scale intra-urban thermal patterns. This study addresses these limitations by developing a multi-layer UHI vulnerability assessment that integrates land use/land cover (LULC) dynamics, decadal water spread area (WSA) variations, and long-term urban–rural air temperature observations. By combining land transformation, water-body resilience, and thermal response, the study provides a comprehensive representation of the spatial and temporal drivers governing urban heat dynamics. Multi-source geospatial datasets were utilized to assess UHI vulnerability, including long-term reservoir water spread information and high-resolution temperature records. LULC analysis across the taluks of Madurai, Tirumangalam, Melur, Usilampatti, Vadipatti, Aruppukottai, Manamadurai, and Srivilliputhur revealed substantial conversion of agricultural and forest lands into built-up areas and wastelands. Assessment of major water bodies from 2012 to 2025 indicated a progressive decline in water spread area, reducing the hydrological buffering capacity that moderates urban temperatures. Analysis of daily temperature observations from 2015 to 2024 confirmed a persistent urban–rural temperature gradient, with the urban core consistently experiencing higher maximum temperatures than the surrounding rural areas. Experimental analysis further demonstrated that increasing built-up density, declining vegetation cover, and shrinking water spread area are strongly associated with elevated urban temperatures, particularly during the pre-monsoon season. The findings identify critical UHI hotspots in the Madurai region where rapid land transformation and loss of surface water exacerbate thermal stress. The proposed integrated assessment framework offers valuable scientific insights for sustainable urban planning by emphasizing the conservation of water bodies, enhancement of urban green spaces, and regulation of land development to mitigate future heat stress and improve urban climate resilience.