Evaluation of land use land cover dynamics and urban heat island effects over Mumbai metropolitan Region, India

The rapid urbanization in the Mumbai Metropolitan Region (MMR) has intensified and altered the Land Use and Land Cover (LULC) patterns, which can change the microclimate and thermal comfort of the residents. This study investigates the relationship between LULC changes and the spatiotemporal patterns of Urban Heat Island (UHI) which helps to identify thermal discomfort zones in the MMR. It identifies these zones in the city’s core and the rapidly developing suburban areas poised to become metropolitan. Analysis of the thermal environment over these suburban zones, often overlooked in previous research, is critical for future urban planning. The satellite imagery for 1993–2023 during the summer season was employed to extract temporal trends in LULC, geospatial indices, and Land Surface Temperature (LST). The results in the past three decades indicate a continual expansion of urban areas by 77.82%, whereas vegetation, water, coastal, and barren land declined by 37.17%, 24.90%, 5.50%, and 7.40%, respectively. There is a decadal average increase in LST from 1.5 °C to 2.5 °C, and exponential growth is observed in the area affected by the UHI effect. It is noted that NDBI shows a positive correlation (r ≥ 0.56), which elucidates that a 1% increase in NDBI leads to a notable rise in LST by 0.3 °C to 0.4 °C. This is one pioneer study to examine spatiotemporal variation in thermal discomfort within the hot, humid (Aw) tropical climate, using satellite-based NDMI and LST data. This approach addresses the limitations of weather station data, which often lacks spatial coverage and fails to capture local microclimatic variations. The findings reveal that 26% to 30% of the total area is under the discomfort zone, 4% to 6% is under the extreme discomfort zone, and 10.32% moved into the thermal discomfort zone in the past three decades. The outcomes of this research underscore the critical need for implementing climate-resilient strategies to ensure the sustainability of MMR.