This paper studies heat fluxes from contributors and mitigators of urban heat islands using thermal images and weather data. Thermal images were collected from an observatory operating on the rooftop of a building between November 2021 and April 2022. Over the same period, an automatic weather station network was used to measure weather conditions at several locations on a university campus in Singapore. From data collected by the observatory and the automatic weather station network, a method was developed to estimate the heat emitted by building facades, vegetation, and traffic. Before performing the analysis of urban heat fluxes, it was observed that the surface temperature collected from the observatory is sensitive to some variables. After the sensitivity analysis, thermal images were calibrated against measurements of the surface temperature in an outdoor environment. Finally, several contributors and mitigators of urban heat islands were analyzed from heat fluxes assessed with thermal images and weather data. According to thermal images collected by the rooftop observatory, concrete walls are an important contributor to urban heat islands due to the longwave radiation they emit at night. Vegetation, on the other hand, seems to be an effective mitigator because of latent heat fluxes generated by evapotranspiration. Traffic looks to be a negligible source of heat if considered over a small portion of a road. In the future, more efforts can be made to estimate the magnitude of the heat released by an air-conditioning system from thermal images.
翻译:本文用热图像和天气数据对城市热岛的供热者和缓解器的热通量进行研究,从2021年11月至2022年4月的一座建筑屋顶上的一个观测站收集热图像,在同一期间,利用自动气象站网络测量新加坡大学校园若干地点的天气状况,从观测站和自动气象站网络收集的数据,开发出一种方法来估计建筑外墙、植被和交通造成的热量。在分析城市热通量之前,观察到从观测站收集的表面温度对一些变量敏感。在敏感度分析后,根据室外环境中地温的测量结果对热图像进行了校准。最后,利用热图象和天气数据对城市热岛的若干供热和缓解器进行了分析。根据天台观测站和自动气象站网络收集的数据,开发出一种方法来估计城市热岛因夜间发生长波辐射而释放的热量。另一方面,从观测站收集到的表面温度温度似乎是一种有效的减轻温度的有效因素,因为通过蒸发波通量生成的低温通量而产生潜在的热通量。