[摘　要]城市地表通风潜力是城市通风评估和通风廊道规划的前提条件，目前尚缺乏科学合理的指标来表征。文章面向城市区域尺度，基于城市形态学模型构建了通风潜力系数(VPC)指标，对城市通风潜力的强弱进行评估。随后，分别以北京和广州中心城为例，应用1∶2　000基础地理信息和Landsat8卫星资料，开展了2015年VPC估算及通风潜力评估分析。研究结果表明，VPC可有效反映城市地表通风潜力大小，其与天空开阔度呈负相关关系，线性回归模型R2为0.459　1，与建筑高度、容积率、迎风截面积密度和粗糙度长度呈明显正相关关系，线性回归模型R2分别为0.717　9、0.784　2、0.796　2和0. 842　4；北京和广州中心城地表通风潜力最差的区域分别为三环—二环区域和越秀区，广州中心城的总体地表通风潜力明显好于北京中心城，这是由于广州具有更大面积的利于通风的林地、绿地和水体等冷源区域。

[关键字]通风潜力系数；建筑形态；天空开阔度；迎风截面积密度；粗糙度长度

[文章编号]1006-0022(2019)10-0032-09　[中图分类号]TU984.199　[文献标识码]B

[引文格式]刘勇洪，徐永明，张方敏，等．城市地表通风潜力研究技术方法与应用—以北京和广州中心城为例[J]．规划师，2019(10)：32-40．

Research and Application of Urban Surface Ventilation Potential: Cases of Beijing and Guangzhou/Liu Yonghong, Xu Yongming, Zhang Fangmin, Cheng Chen

[Abstract] The urban surface ventilation potential is a prerequisite for urban ventilation assessment and ventilation corridor planning. Currently it lacks scientific quantitative indicators to characterize. A quantitative index, the ventilation potential coefficient (VPC), is developed to describe the ventilation potential on the urban regional scale. Using the above methods, taking Beijing and Guangzhou as examples, with the geographic information of 1:2  000 and Landsat8 satellite data, the VPC spatial distribution map was made and the comparative analysis of the ventilation potential of the two cities was carried out. The research results show that the VPC can effectively reflect the urban surface ventilation potential, and the VPC was negatively correlated with the sky view factor and the R2 is 0.459  1; the VPC was significantly positively correlated with the building height, floor area ratio, frontal area density and roughness length, and the R2 is 0.717  9, 0.784  2, 0.796  2 and 0.842  4 respectively. The areas with the worst ventilation potential are between the third ring and the second ring in Beijing and in Yuexiu District of Guangzhou. The overall surface ventilation potential of central Guangzhou is significantly better than that of central Beijing. This is most likely due to the fact that central Guangzhou has a larger area of natural cold source areas such as forest land, green space and water bodies that are conducive to ventilation than the central Beijing.

[Keywords] Ventilation potential coefficient, Architectural form, Sky view factor, Frontal area density, Roughness length

0引言

近30年来，随着城镇化的快速发展，大量密集的新建楼宇和新区出现，使得城市下垫面粗糙度增加，城区风速普遍呈现逐年下降趋势，而在城市快速膨胀中不尽合理的规划和布局使城市内部地区的通风环境恶化，加剧了城市热岛效应和空气污染[1]。由此，城市通风成为城市建设和规划中的重要内容，以及城市可持续发展的目标之一[2]。城市通风是指利用江河、湖泊及山谷等自然通风道，人工建立的绿地、水体，以及城市主干道来引导城市空气流动、改善城市空气品质的技术手段，在缓解城市热岛效应、减轻城市空气污染、降低建筑物能耗及提高城市居民宜居性方面起着不可忽视的作用[3-6]。

目前常用的城市通风研究方法主要有风玫瑰图、数值模拟、风洞试验、地理信息系统(GIS)和遥感技术(RS)[7]。风玫瑰图是在城市建设、规划和工业布局通风中常用的一种气象方法[8]。在现有的国内城市规划中，一般以风玫瑰图和污染系数玫瑰图为主要依据来规划城市布局。通过这两个玫瑰图可以指导风向频率与风速频率，但是因为采用的具备长时间序列风观测资料的观测台站一般远离城市中心，代表性较差，且城市结构和地理地貌特点也不尽相同，所以单一依靠这两个玫瑰图，使得风环境信息在规划实践中有很大的局限性，甚至存在一定的负面影响。数值模拟以中尺度气象模拟[9]和街区尺度的计算流体力学(CFD)模拟[10]为主。中尺度气象模拟结果的空间分辨率一般为1～3km，无法在城市总体规