Characteristics of the urban heat island in a tropical city of Phnom Penh, Cambodia

Abstract

The rapid urbanization drives Phnom Penh, Cambodia experiences the increased urban heat island (UHI) effects. However, no studies on the UHI effect in Phnom Penh have been conducted to date. Air temperature and ventilation data during 2021-2023 were used to investigate daily, seasonal, yearly variations of the UHI intensity and evaluate the impact of ventilation on the UHI intensity in Phnom Penh. Findings indicated the UHI intensity is stronger during the daytime (0.55 C) than at night (0.25 C) in dry season, primarily due to the increase in impervious surfaces that trap more thermal energy throughout the day. Furthermore, the UHI intensity is greater in the dry season with 0.40 C than in the wet season with 0.15 C, mainly due to the less moisture and the cold island effects occurred during the cooler and drier months. The study emphasizes the importance of implementing approaches to mitigate the UHI intensity in Phnom Penh.