山谷地带城市冷热岛及其影响初探

本文利用华北某城市现场实测资料,对实测到的谷地上空“冷岛"的形成机制进行了研究,借助于二维数值模拟,分析了城市冷热岛对山谷地带坡风环流和污染物浓度分布的影响。结果表明:城市热岛在晚间出现则可以加速坡风环流,加之逆温层存在,不利于污染物输送;白天冷岛的出现,加强坡风环流,有利于污染物的扩散和输送。 

Preliminary Study of the Urban COLD-HEAT Island and ITS Effects in the Valley Region

The formative mechanism of the cold island has been studied by treatment and analysis of the data obtained from field observation. On the basis of a two-dimensional numerical study of the slope wind circulation over a basin terrain, it has been analysed that the urban cold-heat island has an effect on the slope wind circulation and the distribution of pollutant concentrations in the valley region. The results show that at night the slope wind circulation will increase when there exists heat island, and there is a disadvantageous effect on the transport of the pollutants due to the increased slope wind circulation: and there is a beneficial effect on the diffusion and transport of the pollutants when there exists cold island at daytime.