Simulating microclimate adaptation: Evaluating heat mitigation strategies for Doha, Qatar, under current and future climate conditions

Cities have become epicenters of heat stress and thermal discomfort due to rapid urbanization and the escalating impacts of global warming. Cities in hot arid climates endure prolonged, extremely hot, dry summers exacerbated by the urban heat island effect. Therefore, this research work designs, models, and evaluates thirteen heat mitigation scenarios for a compact midrise area in the hot arid city of Doha, Qatar, using ENVI-met and OpenStudio simulations. The scenarios are based on four heat mitigation strategies: (1) Green infrastructure, including extensive and intensive green roofs and facades, increased tree canopy cover, and introduction of an urban park, (2) cool and super cool materials for roofs, facades, and pavements, (3) urban morphology modifications, increasing building heights, and (4) shading structures. Given the limitations of the individual strategies, a combined heat mitigation strategy was developed, integrating the best-performing scenarios: Urban Morphology 35 m, Intensive Green Roofs and Facades, Trees Addition, and Urban Park. This strategy resulted in consistent and substantial cooling benefits, lowering maximum T_a, MRT, and PET by up to 4.4 °C, 26.9 °C, and 8.7 °C, respectively, and shortening the extreme heat stress period by two hours (from 7 am–5 pm (10 h) to 8 am–4 pm (8 h)) for the simulated midsummer day. Moreover, the combined strategy proved effective under high-emissions climate change scenario (A2) for 2041–2069 (2050) and 2070–2099 (2080), improving the outdoor thermal environment and mitigating the intensified heat stress levels. Furthermore, it considerably reduced building's cooling energy consumption, lowering demand by over 24 %.