Assessing urban heat islands and thermal comfort in Noida City using geospatial technology

Abstract Incessant conurbation in Noida has exacerbated its microclimate, causing rise in the thermal anomalies within the city. Between 2011 and 2019, there is an immoderate increase in the hotspots and overall decrease in the thermal comfort of the city, evaluated using the Urban Thermal Field Variance Index (UTFVI). The study further explores the association between land surface temperature (LST) and spectral indices - Normalized Difference Vegetation Index (NDVI) and Index-based built-up Index (IBI) for both the years. The results highlight that there is an increase of 6.42 °C in eight years. The NDVI values have increased from 0.06 to 0.14 during these years, suggesting increase in the total urban greenness in the city. The observed increase in IBI values explains the rising LST of the city. LST exhibits negative correlation with NDVI ascertaining the cooling impact of green spaces and positive correlation with IBI highlighting the heating effect of built-up on urban microclimate. Measuring and monitoring the intensity of these UHI in space and time is important to analyse the thermal environment at the city scale. Identification of such anomalies in the urban thermal environment can provide the best input for equipping urban areas to be more resilient and sustainable.