Kent Christoph W, Grimmond Sue, Barlow Janet, Gatey David, Kotthaus Simone, Lindberg Fredrik, Halios Christos H
1Department of Meteorology, Reading University, RG6 6UR Reading, UK.
2Risk Management Solutions, EC3R 8NB London, UK.
Boundary Layer Meteorol. 2017;164(2):183-213. doi: 10.1007/s10546-017-0248-z. Epub 2017 Apr 28.
Nine methods to determine local-scale aerodynamic roughness length and zero-plane displacement are compared at three sites (within 60 m of each other) in London, UK. Methods include three anemometric (single-level high frequency observations), six morphometric (surface geometry) and one reference-based approach (look-up tables). A footprint model is used with the morphometric methods in an iterative procedure. The results are insensitive to the initial and estimates. Across the three sites, varies between 5 and 45 m depending upon the method used. Morphometric methods that incorporate roughness-element height variability agree better with anemometric methods, indicating is consistently greater than the local mean building height. Depending upon method and wind direction, varies between 0.1 and 5 m with morphometric consistently being 2-3 m larger than the anemometric . No morphometric method consistently resembles the anemometric methods. Wind-speed profiles observed with Doppler lidar provide additional data with which to assess the methods. Locally determined roughness parameters are used to extrapolate wind-speed profiles to a height roughly 200 m above the canopy. Wind-speed profiles extrapolated based on morphometric methods that account for roughness-element height variability are most similar to observations. The extent of the modelled source area for measurements varies by up to a factor of three, depending upon the morphometric method used to determine and .
在英国伦敦相距不超过60米的三个地点，对确定局地尺度空气动力学粗糙度长度和零平面位移的九种方法进行了比较。这些方法包括三种风速测量法（单高度高频观测）、六种形态测量法（地表几何形状）和一种基于参考的方法（查找表）。形态测量法在迭代过程中使用了足迹模型。结果对初始的z0和d0估计不敏感。在这三个地点，根据所使用的方法，z0在5至45米之间变化。纳入粗糙度元素高度变异性的形态测量法与风速测量法的一致性更好，这表明z0始终大于当地建筑物的平均高度。根据方法和风向，d0在0.1至5米之间变化，形态测量法得出的d0始终比风速测量法得出的d0大2至3米。没有一种形态测量法能始终如一地与风速测量法相似。多普勒激光雷达观测到的风速剖面提供了用于评估这些方法的额外数据。局地确定的粗糙度参数用于将风速剖面外推到冠层上方约200米的高度。基于考虑了粗糙度元素高度变异性的形态测量法外推得到的风速剖面与观测结果最为相似。测量的模拟源区范围变化高达三倍，这取决于用于确定z0和d0的形态测量法。
