Impacts of Spatio-temporal land use land cover changes on the Development of Urban Heat Islands in a Diverse Topographic Region of District Nowshera, Pakistan

This study analyses the impact of Land Use Land Cover (LULC) dynamics on the development of Urban Heat Islands (UHI) in a diverse topographic region of Nowshera district, Pakistan. The rapid increase in the study region is causing a rise in land surface temperatures, and subsequently bring alterations in the local climate. The growth of cities and changes in LULC have modified the surface of land and near-surface atmospheric temperature and changed the thermal properties of the gray infrastructure (built-up areas), causing warming compared to the area of non-urbanized surroundings, contributing to the formation of the Urban Heat Island effect. For this study, Landsat 5 (1990), Landsat 7 (2005), and Landsat 8 (2020) were used. LST, LULC, Normalized Difference Vegetation Index (NDVI), Normalized Difference Built-up Index (NDBI), Normalized Difference Bareness Index (NDBaI), and Urban Index (UI) were derived to assess the influence of LULC changes on UHI. The analysis revealed a 12.44% increase in built-up areas between 1990 and 2020, driven by population growth and urbanization, which led to a 2°C rise in mean LST, with maximum temperatures increasing from 46°C to 48°C. In contrast, vegetation cover, water bodies, and barren land declined by 6.1%, 1.3%, and 5%, respectively, reflecting trade-offs between urban expansion and natural resources. Higher LST values were concentrated around main urban centers and gray infrastructure, while green infrastructure and water bodies experienced lower LST. A negative correlation was observed between NDVI and LST, whereas LST showed positive correlations with NDBI, NDBaI, and UI. The urban and rural temperature range widened with LULC change during the study period. These changes in LST were mainly associated with changes in LULC. This study will be helpful in highlighting the importance of vegetation areas, especially in urban areas, in minimizing the increasing impacts of UHI.