The cooling effect of green infrastructure in mitigating nocturnal urban heat islands: a case study of Yoyogi Park and Meiji Jingu Shrine in Tokyo

This study assesses the implementation of green infrastructure plans to mitigate the effects of nocturnal urban heat islands in Yoyogi Park and Meiji Jingu Shrine in the surrounding Shibuya urban area, Tokyo. The study revealed there to be a strong correlation between green spaces and air temperature (Ta) during the early morning, where a Ta inversion occurred tens of metres from the ground due to radiant cooling. Air (park breeze) flowed through valleys and gaps between mid-high-rise buildings. Based on wind simulation results, three green infrastructure plans were created to connect the Yoyogi Park green space and the airflow area with the green network. Computational fluid dynamics (CFD) modelling and thermal simulations clarified a cooling effect of the green infrastructure plans on the surrounding Shibuya urban area. This will be useful for consensus building among the Shibuya population and decision making regarding the City Master Plan, and other urban areas.