Assessing Two Decades o f Temperature Dynamics Across Local Climate Zones i n Hanoi, Vietnam

This study examines the diurnal temperature variation in relation to Local Climate Zones (LCZs) in Hanoi, Vietnam, using a 20 - year time series (2004 – 2024) of MODIS Land Surface Temperature (LST) data. The use of MODIS imagery provides a consistent and reli able dataset for analyzing long - term urban thermal dynamics. LCZ classifications were derived from globally available datasets integrated within the Google Earth Engine (GEE) platform. Results reveal a significant warming trend during the daytime across al l LCZs. Notably, LCZs 1 to 8 , repr esenting highly urbanized areas, exhibit the most pronounced temperature increases, ranging from 2.3°C to 3.0°C over the study period. In contrast, nighttime temperatures show only a modest increase of approximately 0.18°C across all LCZ types, with limited variability between them. These findings underscore a growing daytime urban heat island (UHI) effect, particularly in densely built environments such as compact mid - rise zones. Areas with dense vegetation exhibit the lea st temperature rise, highlighting the moderating influence of green cover. Overall, the study emphasizes the critical role of urban form and land cover in shaping spatial patterns of surface temperature variation, offering important insights for climate - re sponsive urban planning in rapidly developing cities like Hanoi.