Does Spatial Configuration of Green Spaces Matter in Ameliorating Extreme Urban Heat?

Extreme heat has emerged as a significant challenge to the quality of urban life, posing substantial challenges to cities in terms of sustainability and liveability. Introducing urban greenspaces has proven an effective nature-based solution for ameliorating extreme heat. However, in practice, uncertainties remain regarding whether and how spatial configuration affects effectiveness. We tackle this question by comparing effectiveness of urban parks with the same green ratio in different spatial configurations for microclimatic amelioration potential based on simulations conducted in three highly developed urban settings in Melbourne during one of the worst heatwave events. Microscale climate simulations are conducted using ENVI-met. Linear mixed models are used for diurnal data from all outdoor grids for nine heat-related indices, including meteorological, thermal comfort and energy balance components, to determine the effect of spatial configuration on improving outdoor thermal conditions. We find that spatial configuration matters in microclimate amelioration. However, the effects are highly context-specific, and there is no universally effective design across locations, even for those within proximity in the same city. This suggests the importance of considering factors such as surface cover characteristics and building configurations, and conducting site-specific simulations for the most effective ways of introducing green infrastructure for heat mitigation.