Temperature Reduction Effects of Rooftop Garden Arrangements: A Case Study of Seoul National University

Increasing urbanization has highlighted the need for more green spaces in built-up areas, with considerable attention of vertical installations such as green walls and rooftop gardens. This study hypothesizes that the rooftop-garden-induced temperature reduction effects vary depending on the type of arrangements. Therefore, the objective of this study is to find the most efficient arrangement of the roof gardens for temperature reduction. This paper presents the results of a quantitative analysis of the temperature reduction effect of rooftop gardens installed on structures and sites on the campus of Seoul National University. An ENVI-Met simulation is utilized to analyze the effects of roads, buildings, green areas, and vacant land on temperature and humidity. The effects of the following five rooftop garden configurations were compared: extreme, linear (longitudinal), linear (transverse), checkerboard, and unrealized rooftop gardens. The extreme and linear (longitudinal) gardens achieved the maximum temperature reduction, -0.3 degrees C, while the lowest maximum reduction of -0.2 degrees C was achieved by the checkerboard pattern. Over larger areas, the greatest impact has been recorded in the mornings rather than in the afternoons. The results of this study will be useful for those planning and installing rooftop gardens at the district and city levels.