Hydrological Implications of Urban Vegetation and Energy Dynamics in Heat and Climate Adaptation

ABSTRACT This research paper investigates the interplay between urban vegetation, surface energy fluxes, and hydrological processes in mitigating heat and adapting to global warming. Through climate model simulation, this study explored how vegetation coverage (measured by leaf area index, LAI) and the impervious surface fraction ( f imp ) influence hydrological dynamics, urban heat island (UHI), and energy fluxes across various climate zones within Asian cities for the period of 2000 to 2014. Kuala Lumpur and Singapore (tropical rainforest) showed significant increasing UHI trends of 0.319°C and 0.271°C/month, respectively. Bangkok and Ho Chi Minh (tropical savanna) showed a negative correlation between LAI and temperature (UHI) of −0.31 (−0.57), indicating the cooling effects of vegetation through evapotranspiration. In tropical rainforest climates, a strong positive correlation between LAI and latent heat flux highlights the critical role of water availability in modulating hydrological cycles and vegetation dynamics. Humid continental/subtropical climates showed a positive correlation between LAI and sensible heat flux, highlighting the influence of sensible heat exchange on vegetation growth. A positive correlation was demonstrated between energy fluxes and f imp across all climate zones, indicating that urbanisation intensifies hydrological disruptions, exacerbating the UHI effect. This study emphasises the importance of integrating hydrological insights into urban vegetation strategies for effective heat mitigation and climate adaptation.