Monitoring the effects of vegetation cover losses on land surface temperature dynamics using geospatial approach in Rajshahi City, Bangladesh

Abstract

Urban green space is one of the most essential components in contributing to ecological balance and environmental sustainability. Due to rapid urbanization in the last few decades, massive reduction of urban vegetation cover (VC) has increased the land surface temperature (LST) and hampered the environmental sustainability. This study aims to identify the VC cover loss on LST increase in Rajshahi City Corporation (RCC) area using geospatial techniques. The study established the relationship between VC loss and LST increase using transformation analysis and micro-level directional mapping in ArcGIS 10.6 software. Multi-temporal Landsat TM/OLI satellite images were used for the years 1990, 2000, 2010 and 2020, to classify land use/land cover (LULC) classes, the transition between VC and urban area (UA), directional distribution of UA and VC, and variation of ward wise LST distribution due to VC loss in the study area. The maximum likelihood supervised classification algorithm was used to classify the LULC maps. All the classified LULC maps demonstrated an overall accuracy of more than 85%. The spectral radiance model was used to extract LST information from satellite images. The analysis of LULC estimation suggests a significant net increase in UAs (+18%) and a reduction in VC (-17%) from 1990 to 2020. The maximum temperature of the city was increased to 37.75 °C in 2020 from 23.46 °C in 1990. The assessed LST showed that the lower recorded temperature zones in 1990 were converted into a higher temperature zone in 2020. The mean LST distribution showed a growing trends in UA, and reduction in VC, which converted the study region from a moderate temperature zone to a high-temperature zone. The study demonstrates that a rise in the non-evaporated surfaces, i.e., UA and a reduction in the green cover, were the most significant influential factors to increase the LST effect. Remote sensing techniques have been proved a very useful tool for urban planners and policymakers in taking appropriate measures to ensure sustainable development, conservation of the city's natural resources and minimize the influence of urbanization on LST.