Enhancing Urban Sustainability through Green Roofs: A Thermal Performance Evaluation in Dubai

The Dubai Municipality has launched the ‘Green Roofs Awareness Initiative’ to achieve a green area per capita of 23.4 m² in the city. Given the numerous symptoms caused by the unprecedented urban expansion, green roofs and facades can provide various benefits to the city. This study intends to develop an evaluation method for the performance of green roofs (artificial ground reforestation) by quantifying the thermal environment functionality of a low-maintenance lightweight green roof. As a methodology, this study analyzed the change in the thermal environment of the surface, including sensible heat and latent heat, using four types of plants, namely Polytrichum Commune (PC), Thuidium Kanedae (TK), Anomobryum Filiforme (AF), and Kentucky Bluegrass (KB). The results showed that PC reduced the ground surface temperature by 2.58°C to 3.81°C while planting PC increased relative humidity (RH) from 48.0% to 93.3%. KB had the highest effect on humidity control, resulting in a 49.31% increase in RH. Regarding the temperature change by ground surface type, the surface temperature was 0.4 ~ 0.9°C lower for PC, AF, and TK at 18 ~ 24°C, while KB showed a 0.5 ± 0.2°C lower than the set temperature. KB did not show any significant change in temperature up to 24°C, but as the set temperature increased from 30 to 36°C, the surface temperature decreased remarkably. This research provides primary data that will serve to raise awareness, reduce installation costs, and systemize government support for green roofs in Dubai.