Remote Sensing Image-Based Analysis of the Urban Heat Island Effect in Relation to the Normalized Difference Vegetation Index (NDVI): A Case Study of Patna Municipal Corporation

Abstract

Abstract: The consequences of population growth and urbanization on the urban environment, climate, and water supply have caused a wide range of issues. As a result of the rapid urbanization process, vegetation covers are being converted by impervious and dry concrete covers. This has led to the growth of "heat islands," where urban areas experience warmer temperatures than the areas surrounding them. Urban Heat Island (UHI) is a human-caused environmental phenomenon that has a wide range of impacts on city dwellers, including changing the vegetation cover and its usage, which alters the thermal energy flow and raises surface and air temperatures. Such heat islands have far-reaching impacts for cities, the most significant of which is an increase in the expense of maintaining a safe living and working environment. The major objective of this study is to examine multitemporal Land Surface Temperature (LST)/Urban Heat Island (UHI) and Normalized Difference Vegetation Index (NDVI) in the Patna Municipal Corporation (PMC) from 1990 to 2022. The Landsat satellite data sets for the years 1990, 2001, 2011, and 2022 have used to investigate the impact of UHI/LST in relation to NDVI in the study area. The most significant change has been observed in vegetation cover (NDVI), which has declined compared to other types of land use land cover. According to the study, built-up area and barren land have high temperatures, whereas vegetated covers and water bodies have lower temperatures. The LST of some portion of study area is high due to the high population density and high percentage of built-up and concrete cover. The LST over the study area has risen on average by 6.88 °C between 1990 and 2022. The regression line provided a conclusive answer, demonstrating a strong negative relationship between the normalized difference vegetation index (NDVI) and UHI of PMC. According to the findings of this study, a major transition has occurred in PMC in terms of a decline in NDVI due to a rapid growth in urban expansion, and other infrastructure projects. To study urban climate and interactions between people and the environment, land surface temperature (LST) variations within cities are of utmost importance in respect to ascertain the LST/Urban Heat Island (UHI) effect and NDVI variations in PMC. While developing urbanization, the environmental impact must be taken into account.