Anthropogenic heat emission is an important factor for street air warming. In this study, the transient street air warming process caused by anthropogenic heat is investigated by both the analytical model and Large-Eddy Simulation (LES). A new analytical model is developed based on the empirical exchange velocity modelling and heat exchange rate estimation. In the model, the buoyancy effect is included by introducing a buoyancy coefficient. With the new analytical model, both transient time and steady-state street air temperature increment (${\mathrm{\Theta }}_c$) can be easily estimated in urban areas. This new model is calibrated and validated by cross-comparing with LES results. A good agreement is found between the results after including the buoyancy coefficient into the analytical model. Modelling results indicate that ${\mathrm{\Theta }}_c$could be limited because the buoyancy effect increases the exchange velocity between the urban canopy layer and overlying atmosphere. Furthermore, the buoyancy is also important to the transient air exchange process. A transformation of the urban canopy layer flow structure is found in the transient period, suggesting a large scale turbulence structure induced by anthropogenic heat. Lastly, the air temperature increment in the residential areas of Singapore is estimated with GIS (Geography Information System) tool to show the application of the analytical model in practice.

人为热量散发是导致街道空气变暖的重要因素。在这项研究中，通过分析模型和大涡模拟（LES）研究了由人为热引起的短暂街道空气变暖过程。基于经验交换速度模型和热交换速率估计，开发了一种新的分析模型。在模型中，通过引入浮力系数来包括浮力效应。使用新的分析模型，瞬态时间和稳态街道空气温度增量（${\mathrm{\Theta }}_C$）可以在市区轻松估算。通过与LES结果进行交叉比较来校准和验证此新模型。将浮力系数纳入分析模型后，在结果之间找到了很好的一致性。建模结果表明${\mathrm{\Theta }}_C$由于浮力作用增加了城市冠层和上覆大气之间的交换速度，因此可能受到限制。此外，浮力对于瞬态空气交换过程也很重要。在过渡时期发现了城市冠层流动结构的转变，表明人为热量引起的大规模湍流结构。最后，使用GIS（地理信息系统）工具估算了新加坡居民区的气温升高，以表明分析模型在实践中的应用。