A micro-climatic study on cooling effect of an urban park in a hot and humid climate

The cooling effect of a 4.5 ha urban forest park located in a dense city center area in a hot and humid climate was investigated with the three-dimensional microclimate simulation tool ENVI-met v3.1. Dynamic predictions are firstly performed with different wind directions (northerly, southerly, easterly and westerly) for a typical summer day. Then the meteorological data were averaged to eliminate the effect of wind direction, considering equal probability for each wind direction. Overall, when wind speed is 1.5m/s, park cool island (PCI) intensity is about 2 °C and the PCI center is offset from the park center if a preponderant prevailing wind direction exists. After eliminating the influence of wind direction by considering equal probability for each wind direction, PCI intensity is about 0.8 °C and the PCI center is near to the park center. A higher wind speed would lead to a lower PCI intensity and a smaller area of influence. Compared to air temperature, the spatial distributions of mean radiant temperature and relative humidity are not significantly affected by a preponderant prevailing wind direction. And mean radiant temperature was found to be about 30 °C lower in shaded areas of the park.