Three sites with different surface roughness were selected to explore the turbulent/synoptic separation and self-similar wall-attached coherent structures in the atmospheric surface layer. At each site, the facility permits synchronous multi-point measurements of three-dimensional wind velocity and temperature at different heights, as well as synchronous measurements via the global positioning system among the three sites. A filter based on the linear coherent spectrum between two sites (separated by 500 m) is adopted to separate turbulent and synoptic signals. After the separation, the two-point correlations of the filtered turbulent streamwise velocity component reveal that increasing surface roughness leads to less coherence in both the wall-normal and streamwise directions. The present results with unstable stratification and different surface roughness also demonstrate good agreement with the self-similar range of the wall-attached turbulence reported in Baars et al. (J Fluid Mech 823:R2, 2017). The aspect ratio of coherent structures (defined as the ratio of streamwise wavelength to the wall-normal offset) for the streamwise and spanwise velocity components and temperature increases with increasing surface roughness.

选择了三个不同表面粗糙度的站点来探索大气表面层中的湍流/天气分离和自相似壁附着相干结构。在每个站点，该设施允许对不同高度的三维风速和温度进行多点同步测量，以及通过全球定位系统在三个站点之间进行同步测量。采用基于两个站点（相隔 500 m）之间线性相干谱的滤波器来分离湍流和天气信号。分离后，过滤后的湍流流向速度分量的两点相关性表明，表面粗糙度的增加导致壁法向和流向方向的相干性降低。目前具有不稳定分层和不同表面粗糙度的结果也表明与 Baars 等人 报道的壁附着湍流的自相似范围非常吻合。(J Fluid Mech 823:R2, 2017)。流向和展向速度分量和温度的相干结构的纵横比（定义为流向波长与壁法向偏移的比率）随着表面粗糙度的增加而增加。