Toward park design optimization to mitigate the urban heat Island: Assessment of the cooling effect in five U.S. cities

Urban parks can cool the urban environment and mitigate the urban heat island effect. Quantifying the park cooling effect and its relationships with park characteristics is important to guide park design in practical urban planning. Therefore, we proposed a modified Gaussian model to estimate three park cooling indexes from the spatial perspective. Focusing on a total of 384 parks in five U.S. cities, the results show that most parks were ‘cold spots’, but their cooling effect varied markedly among different cities. Correlation analysis showed that the parks’ land surface temperature cooling intensity, distance, and efficiency were primarily influenced by park area. The surface evapotranspiration, to a great extent, affected the park cooling potential in Austin and Los Angeles. Further detailed analysis using a random forest model demonstrated non-linear sensitivities of park cooling effects to differences in the park area and evapotranspiration, which can inform the optimal path to maximize the park cooling benefits in the five study cities. This study provides an improved method to measure the park cooling effect and an understanding of the major influential factors, which can inform better urban park planning and management in the future.