Land surface temperature evolution in rapidly urbanizing areas of Southeast Asia: studies from Vietnam and Cambodia

Land surface temperature (LST) is one of the crucial variables in urban microclimate studies. Satellite-based thermal data and vegetation indices, like the normalized difference vegetation index (NDVI), offer valuable insights into changes in LST and the development of urban heat islands (UHI). We analyzed the variations in LST and vegetation coverage in two rapidly urbanizing provinces, each in Southern Vietnam and Cambodia, respectively, during the 10 years between 2013 and 2024. In addition, complementary ERA5 Interim air temperature data were also used. Spatiotemporal changes in NDVI showed rapid urbanization in the eastern region of Battambang city and throughout the southern areas of Binh Duong Province. Time-series analysis indicated a consistent increase in LST in both study sites. There has been a notable increase in minimum LST since 2017 in the entire city of Battambang, whereas the central area of Battambang has become consistently warmer after 2020. The LST in southern Binh Duong gradually increased between 2014 and 2025 due to rapid urbanization and vegetation loss. The outcome of this study holds considerable importance, as the phenomenon of UHI formation has been documented in rapidly expanding cities globally, especially in Southeast Asia.