城市高温热浪调控机制模拟研究

在全球气候变暖和城市化加速发展的共同影响下,高温热浪事件频繁发生、日趋严重。为了分析屋顶亮化、城市绿化和地表增湿在调节城市热力环境、缓解城市高温灾害中的作用,本文选择了2013年8月的高温天气过程,利用耦合了城市冠层模式的WRF模拟系统,采用屋顶亮化、屋顶绿化和地表增湿3种不同的调控方案模拟分析其对城市热环境、湿度和近地面热量通量的影响,及其不同的降温效果和影响时段。研究发现:(1)3种调控方案通过改变城市地区的辐射过程或者能量平衡过程,降低白天尤其是正午时分的近地面气温,可有效的减缓夏季城市地区的高温热浪。(2)采用地表增湿方案,当城市街道表面含水层厚度从0mm增加到3mm时,潜热通量迅速增加,感热通量迅速减少,降温迅速。这说明在白天用较少水量多次对城市街道增湿,是一种显著降温的有效方法。

Simulation of summer high temperature regulation mechanism in urban areas

Under the influence of global warming and accelerating urbanization,high-temperature events have become more frequent and have become more severe.White roofs,green roofs and humidification are the main methods for regulating the urban thermal environment.We selected a rare high-temperature weather process in August 2013.The WRF simulation system coupled with the urban canopy model was used to simulate the effects of three different control schemes and control modes on the urban thermal environment,humidity,sensible and latent heat exchange between the surface and the atmosphere,and discuss the alleviation of summer high temperature events.It shows that:(1)Three kinds of control schemes can effectively reduce the high-temperature events in urban areas by changing the radiation process or energy balance process in urban areas and reducing the near-surface air temperature during the day,especially at noon.(2)At the increased humidity schemes,while the thickness of water layer on the streets and buildings increases from 0mm to 3mm,the latent heat flux increases rapidly,the sensible heat flux decreases rapidly,and the temperature decreases rapidly.This shows that by using less water to humidify city streets and buildings during the day,significant cooling effects can be achieved.