Abstract
Urban growth is the most evident aspect of anthropogenic impact on the earth system, replacing the natural physical characteristics of earth’s surface and thus influencing the thermal environment. The resulting thermal environment impact is especially observed in developing countries like Bangladesh. In this study, we assess, evaluate, and explore the growth of urban areas over Bangladesh for summer and winter seasons of 2003–2013 using Landsat-7 ETM+. We integrate the expected urban growth scenarios with the thermal environment through demographic, environmental, and physical datasets and also predict urban growth. We delineated urban areas over Bangladesh using Impervious Surface Area (ISA) with 90% accuracy and observed a 128% increase in urban areas during the 10 years. We used multivariate technique with satellite-derived land surface temperature, Surface Urban Heat Island Intensity (SUHII), Albedo and artificial heat flux in identifying the urban hotspots in various cities over Bangladesh. The results indicate an increase in urban areas in the first 5 years (2003–2008) by over 100% and in the next 5 years (2008–2013) by 200% mainly due to lack of urban planning policies. Our results indicate an enormous increase of 167% in Urban Heat Island Effect Ratio (UHIER) during the period. We also used advanced statistical analysis to assess the relationship between selected demographic (population), environmental (PM2.5, PM10, relative humidity, and air temperature) and physical parameters (Urbanization Index and Urban Density Cluster) and identified parameters which are most influencing to the thermal environment. Our results suggest the significant increase in UHIER by 2018 over major cities in Bangladesh. To reduce the influence of urban growth on thermal environment, we recommend mitigation measures useful for urban planners and decision makers to ensure safety and public health in Bangladesh.