Urban Growth Dynamics Over Selected Indian Cities, Future Prediction, And Association with The Local Microclimate

Abstract

Urbanization in Indian megacities is quite prominent and it has been growing at an irreversible rate. This phenomenon is customarily driven by population migration and thereby, exerts considerable stress on the local environment. The current study analyzes the growth dynamics, forecasts future urban growth of selected Indian cities (viz., Mumbai, Chennai, Kolkata, Bhubaneswar-Cuttack, Vishakhapatnam, Kochi, and Guwahati), and highlights the association with the local microclimate. Land Use Land Cover (LULC) thematic datasets are classified using Landsat imageries processed through the Random Forest algorithm for the years 1990 to 2023. These thematic datasets are used to explore the capabilities of deep learning models like CNN and ConvLSTM for accurately projecting the future urban growth in the considered cities. The variability of the urban LULC indicated the expansion that mostly took place at the expense of barren lands in the form of dispersive outward growth, with a significant amount of compaction near the city core in recent years. The results derived through Shannon’s Entropy, and various Spatial Metrics also indicated a similar outcome. The urbanization is found to be considerably higher in both Guwahati and Bhubaneswar-Cuttack (from 1990 to 2023), while the projected rate is higher in the case of Mumbai (from 2024 to 2035). The rainfall climatological trends indicate no significant trends for the considered cities, with Mumbai being the exception that shows a rising trend. The future trend (realized through the ConvLSTM model) is projected to be unaltered except for Vishakhapatnam, where it is expected to increase in the coming years. The average temperature across all cities depicts an increasing trend. For Mumbai and Vishakhapatnam, however, the "increasing trend" is anticipated to change to "no significant trend" by 2035. Besides, the other factors that are impacted due to urbanization include surface urban heat islands, PM2.5 concentration, aerosol optical depth, etc.