Comparative assessment of heat mitigation strategies across hotspot local climate zones in a hot arid city

Urban heat stress in cities has intensified due to rapid urbanization (land use/land cover changes), which led to higher urban temperatures, substantially worsened outdoor thermal comfort (OTC), and increased building energy demand. Although investigations of urban heat mitigation strategies are extensive, they are not systematic or comprehensive, limiting the comparability between findings. Therefore, this study presents an integrated, transferable framework that links high-resolution local climate zone (LCZ) classification, long-term thermal hotspot identification, microclimate simulation, and building energy assessment to evaluate urban heat mitigation strategies. Using Doha as a case study, the city was classified into built (LCZs 1-6) and land cover (LCZs A-F) classes through a high-resolution LiDAR-GIS approach (overall accuracy: 95.7%), revealing substantial discrepancies relative to the global 100 m LCZ product. Analysis of Landsat imagery showed that compact urban forms are thermal hotspots, with mean summer land surface temperature reaching 43 degrees C in compact midrise areas (LCZ 2) and 42 degrees C in compact low-rise areas (LCZ 3). Two representative hotspot study areas (Mansoura-LCZ 2 and Salwa-LCZ 3) were selected, and their microclimates were simulated using the ENVI-met model for typical midsummer days. The model performance was evaluated against on-site measurements. Baseline simulations show severe urban thermal stress (T-a > 40 degrees C, MRT > 70 degrees C, PET > 54 degrees C for much of daytime). Eight mitigation scenarios based on green infrastructure and cool materials are comparatively evaluated. Green infrastructure scenarios provided consistent OTC benefits, with tree canopies producing the greatest localized cooling (T-a reductions of 3-5 degrees C, MRT reductions >15 degrees C). Building energy simulations for July show the largest cooling demand reductions for building envelope interventions (15-25%), while tree cover scenarios produced limited savings (<3%). Overall, the study implements a cross-scale methodology for evaluating heat mitigation strategies while revealing key trade-offs in their impacts on T-a, OTC, and building energy performance.