Impact of Urban Sprawling on Urban Heat Island: A Microclimate Change Study in Chattogram City

The land surface temperature of Chattogram city in Bangladesh increased more quickly than that of the surrounding areas due to changes in land use, rapid urbanization, and population growth. Consequently, identifying Urban Heat Islands (UHI) or climatic change in the region was the main goal of this study. Changes in the city's day and nighttime temperatures were analyzed, and their link to urban sprawl was investigated. Trends in urban areas and surrounding temperature rise were examined in order to distinguish between temperature rise caused by UHI and global warming. The MODIS Land Surface Temperature (LST) (2000-2021) data were used for this purpose. R programming software was used to download, preprocess, analyze, and visualize data. Modified Mann-Kendal (MMK) test and sen's slope estimator were used to assess the trends of UHI and LST. The urban expansion curve, urban nightlight maps from various years, and the urban spreading map revealed the city's rapid growth over time. The results revealed that urban temperature has increased throughout the year. Based on the study's findings, it can be stated with confidence that urban sprawling seriously impacts UHI and the microclimate of Chattogram city. This finding allows us to compare and see that LST is rising over time due to urbanization and the shrinking amount of naturally vegetated areas. The present study did not offer a forecast for the future due to time restrictions. Further research may be utilized to forecast the Land Surface Temperature, and upcoming UHI trends and identify mitigation strategies. This study could provide information on the effects of urbanization on the microclimate, which could help with urban developmental projects.