Urbanization and its thermal footprint: A spatiotemporal analysis of land-use/land-cover changes and land surface temperature in Ha Noi city, Viet Nam

Urbanization significantly alters environmental systems, leading to notable changes in land-use/land-cover (LULC) and associated increases in land surface temperature (LST), intensifying urban heat island (UHI) effects. This study investigates spatiotemporal variations in LULC and LST dynamics in Ha Noi, Viet Nam, from 1998 to 2022, using Landsat satellite imagery, remote sensing, and GIS techniques. LULC was classified into built-up areas, agriculture, forests, barren land, and open water, with results indicating significant urban expansion at the expense of agricultural land. Built-up areas grew substantially from 7.45% in 1998 to 16.99% in 2022, resulting in a marked rise in average LST, reaching 25.28°C by 2022. Urbanization intensified the urban heat island (UHI) effect, evidenced by higher LST in built-up and barren areas compared to vegetated regions and water bodies. The correlation analysis revealed strong positive associations between LST and urban indices (NDBI, BI), while vegetation and water indices (NDVI, NDWI) correlated negatively with LST. Additionally, the Contribution Index (CI) analysis demonstrated that built-up and barren land substantially increased surface temperatures, whereas forested areas and water bodies mitigated this effect. The results underscore the critical role of urban green and blue infrastructure in mitigating thermal stress and emphasize the urgency of sustainable urban planning and environmental management. Findings from this study provide valuable insights for urban planners and policymakers to enhance urban climate resilience, balance environmental sustainability, and accommodate ongoing urban growth in rapidly urbanizing cities like Ha Noi.