We assess the impact of advanced heat-mitigation technologies in a coastal temperate city under heatwave conditions. For the first time urban-heating mitigation scenarios that refer to ‘cool/reflective’ roofs and roads, ‘green/living’ roofs and shading by replacing low urban vegetation with deciduous broadleaf trees are considered at the highly dense-populated city of Athens (Greece). Numerical simulations are performed for a typical see-breeze and a heatwave day with the Weather Research and Forecasting (WRF) model coupled to an urban-canopy model. Highresolution data on vegetation and urban land use, derived from satellite image analysis, are considered. All scenarios show a cooling effect, with the maximum mean daytime temperature reduction in the case of ‘cool/reflective’ roofs and roads. During daytime, the mean ambient-temperature reduction reaches up to 1 °C while for the surface-temperature up to 9.5 °C and 11.5 °C, on the see-breeze and heatwave day respectively. In the case of ‘green/living’ roofs, the mean daytime latent-heat flux is increased (e.g. up to 140 W/m² on the heatwave day) due to increased evapotranspiration while the surface temperature is more affected during nighttime. Both scenarios result in a sea-breeze attenuation of 0.5–1 m/s. The presence of deciduous broadleaf street trees has a minor impact on mean ambient temperature but an evident reduction in surface temperature. The mean urban-heating reduction ranges from 0.1 °C to 0.8 °C and from 0.3 °C to 1.7 °C during the sea breeze and heatwave day respectively, with the maximum reduction shown in ‘cool/reflective’ roofs and roads and the minimum in ‘shading trees’ scenarios.

我们评估了先进的散热技术在热浪条件下对沿海温带城市的影响。在雅典人口稠密的城市中，首次考虑了采用``凉爽/反射性''屋顶和道路的城市取暖缓解方案，``绿色/生活''屋顶和通过用落叶阔叶树代替低矮的城市植被的阴影（希腊）。将天气研究和预报（WRF）模型与城市雨棚模型结合使用，对典型的微风和热浪天气进行了数值模拟。考虑了通过卫星图像分析得出的有关植被和城市土地利用的高分辨率数据。所有情况均显示出降温效果，在“凉/反光”屋顶和道路的情况下，日平均温度最大降低。在白天，在凉风习习日和热浪日，平均环境温度分别降低了1°C和9.5°C和11.5°C的表面温度。在“绿色/活动”屋顶的情况下，平均日潜热通量增加了（例如，高达140 W / m²在热浪日），这是由于蒸散量增加，而夜间的地表温度受到的影响更大。两种情况都导致海风衰减为0.5–1 m / s。落叶阔叶行道树的存在对平均环境温度影响较小，但表面温度明显降低。在海风和热浪日，城市平均供暖减少幅度分别为0.1°C至0.8°C和0.3°C至1.7°C，最大减少量显示在“凉/反射”屋顶和道路上，而最小减少量为在“阴影树”场景中。