Integrated modelling of microclimate adaptation: Evaluating heat mitigation strategies for Doha, Qatar

Cities in the Middle East face intensified heat stress and thermal discomfort due to rapid urbanization and global warming. Many Gulf cities, characterized by a hot arid climate (Köppen-Geiger: BWh), experience prolonged and extremely hot, dry summers exacerbated by the urban heat island effect. This poses challenges of extremely high cooling energy demand, increased outdoor thermal discomfort, and adverse impacts on well-being, energy use, economic growth, and the environment. Therefore, this research involves developing a microscale model for a dense mid-rise urban area in Doha, Qatar, characterized by limited vegetation and natural surfaces. The study begins by assessing the current outdoor thermal environment and thermal comfort for a typical mid-summer day (5^th July). It then simulates future climate scenarios using projections from IPCC high (A2) emission scenarios for 2041–2069 and 2070–2099. The microclimate simulation software ENVI-met computes the outdoor thermal conditions, while its outputs are integrated into EnergyPlus to calculate localized building energy consumption. Subsequently, the research designs, models, and evaluates various heat mitigation scenarios based on four main strategies: (1) green infrastructure, including extensive and intensive green roofs and walls, increased tree canopy cover, and the introduction of a small urban park; (2) cool materials for roofs (α=0.8) and pavements (α=0.5); (3) urban morphology modifications, varying building heights (15, 25, 35 m) and form; and (4) shading structures installation in pedestrian areas. Later, combinations of the best-performing heat mitigation strategies are simulated to maximize the cooling effects. These strategies' cooling benefits are analyzed under current and future climate scenarios to identify optimal solutions for mitigating urban heat stress, reducing buildings’ energy consumption, and enhancing thermal comfort in hot arid urban environments.

Acknowledgments:

Research reported in this work was supported by the Qatar Research Development and Innovation Council (Grant: ARG01-0503-230061).