广州城市近地风场特征研究

利用实测广州市近地风速、风向数据资料,分析广州市近地风场特征。结果表明：（1）城市近地风速微弱,风速范围在0.1~0.71 m.s-1,平均风速约0.25 m.s-1,处于静风状况。城市对盛行风风速的削减达90%左右;（2）在盛行风被极度削弱的同时,珠江江风促成了城区一些区域风速的增强。同时,白云山等北部山林的山风以及大型绿地对周围测点的风场均有影响,这些局地的热力效应促进了大气的流动,增强近地风速,改善近地风速微弱甚至无风的状况。广州大道北联白云山,南通珠江,道路开敞,受到白云山山风和珠江江风的影响,广州大道监测点风速相对较大。有些地方则成为＂风影区＂,监测点基本处于无风状态。随着城市的扩展,城市近地风速微弱,通风不良,风向变化复杂,这对于汽车日益增多,尾气污染激增的城市是极为不利的。因此,城市的河流、山林以及大型绿地对城市近地风场的影响值得关注,值得进一步研究如何利用其布局改善城市的无风状况。

Study on the near-surface flow field in urban areas of Guangzhou

We analyze the characteristics of the near-surface flow field in urban areas of Guangzhou by using observational data of 15 measurement sites.The results show that：（1） the range of wind speed is 0.1~0.71 m？s-1,and the average value is 0.25 m？s-1.The prevailing winds speed decrease 90% or so because that urban building plays role the windshield.（2） When the prevailing winds were extremely weakened impact of urbanization,the local thermal circulation from Pearl River contributed to some area of the city wind speed increase.At the same time,the Bai-yun Mountain etc.northern mountain forest and large green space surrounding the measuring point of the wind speed impact is remarkable.These local thermal circulations promoted the flow and enhanced wind speed,improve urban faint wind condition.Such as the wind speed of the measuring point of Guangzhou Avenue that alliance Bai-yun Mountain and the Pearl River is enhanced because of the local thermal circulation from Pearl River and Bai-yun Mountain.Some places would become ＂the wind shadow area＂,basically in a state without wind.With urbanization,the surface layer wind speed is faint and urban in static condition,poor ventilation,change the direction of the wind,which is a very unfavorable to the urban that growing car exhaust pollution.Therefore,it is worth to pay close attention to that the rivers,mountain forest,and large green space impact to urban wind field near the ground surface,further,it is worth to research how to improve wind conditions by the layout of the urban in the future.