Is urban albedo or urban green covering more effective for urban microclimate improvement?: A simulation for Osaka

Urban planning, building design and landscaping can all provide strategies for urban heat island mitigation, urban microclimate improvement and directly affect people's living environment and thermal comfort. This study aims to contribute to urban design for a new residential area of 10,000 m2 area and urban aspect ratio (UAR) of 1.8, which is planned to be built in Osaka, Japan. In order to explore an appropriate design for the planned new residential area via rational building envelope and landscaping designs to better improve the urban microclimate, the effect of urban albedo (UA) and urban green covering (UGC) on the urban microclimate of the planned new residential area in terms of affecting outdoor air temperature and mean radiant temperature was analyzed using the environmental analysis model, ENVI-met. A total of six scenarios with UA of 0.3 and 0.7, UGC of 0%, 20% and 40%, were simulated. It showed that the scenario simulated with low UA of 0.3 and UGC of 20% has the greatest potential in improving urban microclimate of the planned new residential area in Osaka among the six simulated scenarios.