Author(s): Zhang Wei and Liu Fang

Abstract: The increasing intensity of the Urban Heat Island (UHI) effect poses a critical environmental challenge for rapidly urbanizing regions worldwide. This study investigates the role of urban green roof systems in mitigating urban thermal stress through a comprehensive case study approach that integrates field experimentation with microclimatic modeling. Two comparable mid-rise commercial buildings one equipped with an extensive green roof and another with a conventional concrete roof were monitored over a six-month summer period to assess variations in surface and ambient air temperatures, substrate conditions, and energy flux parameters. Empirical data revealed that the green roof significantly reduced mean surface temperature by approximately 3.1 °C and ambient air temperature by 0.6 °C compared to the control roof, confirming its measurable contribution to UHI mitigation. Statistical analyses, including paired t-tests and linear regressions, validated the observed temperature differentials (p<0.001) and identified substrate depth and soil moisture as major determinants of cooling performance. The results from ENVI-met simulations further demonstrated that cooling effects extended beyond the rooftop, reducing near-surface urban canopy temperatures within a 200 m radius. These findings align with global evidence supporting vegetated roofs as a sustainable, low-energy, and climate-adaptive strategy for urban environments. The study concludes that optimized green roof design emphasizing appropriate substrate depth, moisture retention, and vegetation selection—can serve as a highly effective tool for urban climate resilience. Practical recommendations include integrating green roof systems into urban development policies, promoting incentive-based adoption, and ensuring periodic maintenance to sustain long-term performance. Overall, this research highlights the multifaceted value of green roofs in promoting thermal comfort, improving air quality, conserving energy, and fostering ecological sustainability within modern cities.

Pages: 25-30 | Views: 6 | Downloads: 4

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