Urban Heat Island Effect and Urban Density of Savar Municipality

Abstract

This study critically examines the relationship between urbanization and Land Surface Temperature (LST) in the Savar Municipality  area, employing Landsat 8 OLI + TIRS imageries and OpenStreetMap data. The Urban Heat Island (UHI) phenomenon, characterized by  increased temperatures in urban areas compared to surrounding areas, has significant implications for environmental  sustainability. The research objectives encompass a comprehensive analysis of UHI and urban building density using remote sensing and GIS algorithms, as well as an investigation into the correlation between UHI and urban building density within the study area.By  employing advanced remote sensing techniques and GIS algorithms, this research uncovers important insights into the UHI effect and  its association with urban development patterns in Savar Municipality. The analysis entails meticulous processing of satellite imagery, precise extraction of land cover information, rigorous calculation of LST values, and thorough examination of building density  utilizing OpenStreetMap data. These methodologies ensure a robust and accurate assessment of the UHI phenomenon and  its relation to urbanization. Point density calculation with fishnet method was used for analyzing the correlation between Urban Heat  Island and the urban area building density of the study site. The highest temperature on 14th March 2014 was 310 C and the lowest  one was 210 C where the maximum NDBI value was 0.137 and the minimum was -0.357. Again the highest temperature on 9th March   2018 is 290 C and the lowest one is 200 C where the maximum NDBI value is 0.163 and the minimum is -0.347. The highest temperature  on 4th March 2022 was 300 C and the lowest one was 210 C where the maximum NDBI value was 0.156 and the minimum  was - 0.3897. The correlation between LST and NDVI results is negative. In some parts of the study area where the urban density is  higher , the temperature is comparatively lower. It is apparent that the green cover weakens the UHI effect. The correlation analysis  conducted between UHI intensity and urban building density unravels a positive relationship, establishing the significance of urbanization patterns in shaping local temperature patterns. The areas with higher building density consistently exhibit heightened  UHI effects, providing crucial evidence of the role played by urban development in exacerbating heat island phenomena.