摘要:对城市地形组合类型及其地形对风场影响的研究，有助于城市风场机理的认识与生态环境的优化。以高层建筑密集的广州市主城区为例，在确定城市宏观地形类型的基础上，基于最小成本路径（LCP）辨识了风道，并对风环境质量进行评价。主要结论有：（1）将城市地形简要概括划分为4个一级地形、11个二级地形类型。（2）以LCP路径与盛行风交角不超过22.5°的标准，筛选确定通风路径作为风道。根据LCP格网的密度与频次，结合不同风向下风速与风频，评价分析了风环境类型与空间分布。（3）根据自然与城市地形的配置，北风风环境质量远高于西北风和东风；东风由于风频与风速最低，因此通风条件较差。（4）珠江航道在三种风向下都是尺度最宽贯穿城市最好的风道；区域性的风道与风环境较好的地段集中在与主风向平行的主干道上，但以近似南北走向的居多；由于广州城市地形高度以珠江新城峰林为中心向外递减，以低地地形为主的主城区外围通风优于中心区域，特别是珠江新城峰林与网络状台地为主的老城区，通风环境较差。基于LCP的评价结果需要同其他方法相互验证，才能使其不断完善优化。



Abstract:Research on the types of urban terrain combination and the influence of terrain on wind field is helpful to understand the mechanism of urban wind field and optimize its ecological environment. Taking the main urban area of Guangzhou with dense high-rise buildings as an example, on the basis of determining the urban macro-terrain type, the air duct is identified based on the low cost path (LCP), and the wind environment quality is evaluated. The results show that (1) the urban terrain is briefly divided into 4 first-grade terrains and 11 second-grade terrains. (2) According to the standard that the intersection angle between LCP path and prevailing wind does not exceed 22.5°, the ventilation path is screened and determined as the wind duct. Base on the density and frequency of LCP grid, combined with wind speed and wind frequency under different wind directions, the wind environment type and spatial distribution were evaluated and analyzed. (3) According to the configuration of natural and urban topography, the environmental quality of north wind is much higher than that of northwest wind and east wind. The east wind has the lowest wind frequency and wind speed, so its ventilation condition is poor. (4) The results show that the Pearl River waterway is the widest and the best wind passage in the city under three wind directions. The regional wind tunnel and the section with better wind environment are concentrated on the main road parallel to the prevailing wind direction, but the most of them are similar to the north-south direction. Because the height of Guangzhou urban terrain decreases outward with the Peak Clusters of Pearl River New Town as the center, the ventilation of the periphery of the main urban area dominated by low-lying terrain is better than that of the central area. In particular, the old urban area with Peak Clusters and network platform in New Pearl River City has poor ventilation environment. Based on the LCP evaluation results, this paper requires mutual verification of different technical routes in order to improve and optimize them continuously.





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