CBD greening and air temperature variation in Melbourne

Melbourne, the second most populous city in Australia, is growing rapidly. To accommodate this growth, CBD area is undergoing dense urban development and consequently the microclimate of the city is affected. Understanding how greenery can influence the air temperature is very important in urban planning. This study presents a simulation approach to examine the impact of CBD greening on the air temperature variation, during a summer day in Melbourne. The numerical simulation system, ENVI-met was used to examine the impact of vegetation on the air temperature in CBD area, under various scenarios. Three scenarios were applied; without any vegetation, with the existing trees (2%), and enhanced number of the trees (6%). The simulation results showed significant lower air temperatures in both greening scenarios compared to the base case scenario without any vegetation. Increasing 4% tree coverage in the study area, led to 0.2 C° reduction in the air temperature. The study also found that the maximum cooling effect, occurs at mid afternoon. The outcomes of this study could be used to assist urban planners in developing policy suggestions for improving Melbourne's microclimate and offsetting the likely temperature impacts from increasing urban densities.