Ketterer Christine, Gangwisch Marcel, Fröhlich Dominik, Matzarakis Andreas
iMA Richter & Röckle, Eisenbahnstrasse 43, 79098, Freiburg, Germany.
Chair of Environmental Meteorology, Albert-Ludwigs- University of Freiburg, Werthmannstraße 10, 79085, Freiburg, Germany.
Int J Biometeorol. 2017 Jan;61(1):189-198. doi: 10.1007/s00484-016-1203-2. Epub 2016 Jul 1.
Wind speed is reduced above urban areas due to their high aerodynamic roughness. This not only holds for above the urban canopy. The local vertical wind profile is modified. Aerodynamic roughness (both roughness length and displacement height) therefore is relevant for many fields within human biometeorology, e.g. for the identification of ventilation paths, the concentration and dispersion of air pollutants at street level or to simulate wind speed and direction in urban environments and everything depending on them. Roughness, thus, also shows strong influence on human thermal comfort. Currently, roughness parameters are mostly estimated using classifications. However, such classifications only provide limited assessment of roughness in urban areas. In order to calculate spatially resolved roughness on the micro-scale, three different approaches were implemented in the SkyHelios model. For all of them, the urban area is divided into reference areas for each of the obstacles using a voronoi diagram. The three approaches are based on building and [+one of them also on] vegetation (trees and forests) data. They were compared for the city of Stuttgart, Germany. Results show that the approach after Bottema and Mestayer (J Wind Eng Ind Aerodyn 74-76:163-173 1998) on the spatial basis of a voronoi diagram provides the most plausible results.
由于城市地区具有较高的空气动力学粗糙度，风速在城市上空会降低。这不仅适用于城市冠层上方。当地的垂直风廓线会发生改变。因此，空气动力学粗糙度（粗糙度长度和位移高度）在人类生物气象学的许多领域都具有相关性，例如用于确定通风路径、街道层面空气污染物的浓度和扩散，或模拟城市环境中的风速和风向以及所有依赖于它们的因素。粗糙度因此也对人体热舒适度有很大影响。目前，粗糙度参数大多通过分类来估算。然而，这种分类对城市地区粗糙度的评估有限。为了在微观尺度上计算空间分辨的粗糙度，在SkyHelios模型中实施了三种不同的方法。对于所有这些方法，使用voronoi图将城市区域划分为每个障碍物的参考区域。这三种方法基于建筑物数据，其中一种还基于植被（树木和森林）数据。它们在德国斯图加特市进行了比较。结果表明，基于voronoi图空间基础的Bottema和Mestayer方法（《风工程与工业空气动力学杂志》74 - 76:163 - 173，1998年）提供了最合理的结果。
