Influence of rooftop coupled mitigation strategies on the thermal environment and air quality in the Pearl River Delta Region

Abstract

Rooftop Mitigation Strategies (RMSs) are effective methods for urban climate adaptation, yet Rooftop Coupled Mitigation Strategies (RCMSs), which integrate multiple rooftops technologies, remain underexplored, with limited modeling frameworks and systematic evaluations of their impacts on urban climate and air quality. To address these gaps, this study develops parameterization schemes for RCMSs within the Weather Research and Forecasting (WRF) model, incorporating key characterization parameters from observational experiments. The RCMSs examined included Composite Green Roofs (CGRs), Bifacial Photovoltaic Panels (BPVPs) combined with Cool Roofs (CRs) and BPVPs combined with CGRs. Results indicated that RCMSs significantly altered urban boundary layer dynamics in the Pearl River Delta Region (PRD), China, reducing temperatures by up to 0.36 °C, wind speed by 0.6 m/s, and boundary layer height by 200–600 m due to weakened vertical and horizontal turbulence. These meteorological changes affected pollutant dispersion, increasing concentrations of CO (0.4–1.6 mg/m³), PM_2.5 (5–30 μg/m³), and O₃ (5–10 ppb) in the urban core areas, although the over pollutant levels observed at air quality monitoring stations across the PRD did not show significant increase. These findings highlight RCMSs as a promising solution for mitigating urban overheating and enhancing resilience to climate change.