Lee Hyunjung, Park Sookuk, Mayer Helmut
Department of Environmental Engineering, College of Ocean Science, Jeju National University, Jeju, Republic of Korea.
Laboratory of Landscape Architecture, Department of Horticultural Science, College of Applied Life Science, Jeju National University, Jeju, Republic of Korea.
Int J Biometeorol. 2025 Mar;69(3):567-580. doi: 10.1007/s00484-024-02835-x. Epub 2024 Dec 3.
The applicability of the Universal Thermal Climate Index (UTCI) at the urban pedestrian level is analysed in relation to the approach for the vertical wind speed profile (VWSP) used in the UTCI basics. As the UTCI refers to the human-biometeorological reference height (z) of 1.1 m above ground level (agl), all meteorological input variables for UTCI calculations should also be originated from z. Since the development of the UTCI considered meteorological conventions for stations routinely operated by national weather services, the wind speed (v) as one of four meteorological input variables is initially required at 10 m agl (v). In order to calculate v at z from v, the logarithmic law for the VWSP is implemented in the UTCI basics, but only for neutral atmospheric stability and a roughness length (z) for short-cut grassland (z = 0.01 m). This methodological approach cannot be changed in the UTCI basics so far. The UTCI developers also recommend the application of the same logarithmic law, if v values at lower heights have to be extrapolated to 10 m agl. However, the use of this VWSP approach disregards basic air flow findings and principles in the urban canopy layer (UCL). If the UTCI is nevertheless applied at the urban pedestrian level, inaccuracies in the UTCI values will occur. With reference to z = 0.80 m, which is more typical for the UCL, they can be up to 7 K, as shown in the example of three different climate zones.
结合通用热气候指数（UTCI）基础中使用的垂直风速剖面（VWSP）方法，分析了UTCI在城市行人层面的适用性。由于UTCI所指的人体生物气象参考高度（z）为地面以上1.1米，UTCI计算的所有气象输入变量也应源自该高度z。由于UTCI的制定考虑了国家气象服务机构常规运行站点的气象惯例，作为四个气象输入变量之一的风速（v）最初要求在10米高度（v）。为了根据v计算高度z处的v，UTCI基础中采用了VWSP的对数定律，但仅适用于中性大气稳定度和短草草原的粗糙度长度（z）（z = 0.01米）。到目前为止，这种方法在UTCI基础中无法改变。UTCI开发者还建议，如果必须将较低高度处的v值外推到10米高度，则应用相同的对数定律。然而，这种VWSP方法的使用忽略了城市冠层（UCL）中的基本气流发现和原理。如果仍在城市行人层面应用UTCI，UTCI值将出现不准确情况。以UCL更典型的z = 0.80米为例，如三个不同气候区的示例所示，误差可达7开尔文。
