The microclimatic interaction of a small urban park in central Melbourne with its surrounding urban environment during heat events

Abstract

Urban parks are important within cities and towns for mitigating high air temperatures and improving human thermal comfort, especially during hot summer conditions. We demonstrate this benefit through an analysis of the climatic interactions between a relatively small (1.5 Ha), inner-city park and its surrounding urban environment in Melbourne, Australia, during the hot Austral summer of 2013−14. On average, the park was cooler than its surrounding built-up area at all times and in all weather conditions. The park’s mean maximum cooling reached 1.0 °C during peak daytime heating (15:00), with the magnitude of difference between the park and its surroundings varying from 0.5−3 °C. During the day, the magnitude of park cooling was greater in sunny conditions and under higher wind speeds in the park (relative to the surrounding streets). However at night, park cooling was less variable and dominantly influenced by the characteristics of the site such as Sky View Factor (SVF), vegetation distribution and irrigation. The results showed a downwind propagation of the cooling effect of the park that extended up to one half a park width away from the park. Tree shading and evapotranspiration in the park could reduce the level of heat stress from strong in the nearby streets, to comfortable within the park.