The vertical structure of the observed stable boundary layer often deviates substantially from textbook profiles. Even over flat homogeneous surfaces, the turbulence may not be completely related to the surface conditions and instead generated by elevated sources of turbulence such as low-level jets and transient modes. In stable conditions, even modest surface heterogeneity can alter the vertical structure of the stable boundary layer. With clear skies and low wind speeds, cold-air drainage is sometimes generated by very weak slopes and induces a variety of different vertical structures. Our study examines the vertical structure of the boundary layer at three contrasting tower sites. We emphasize low wind speeds with strong stratification. At a given site, the vertical structure may be sensitive to the surface wind direction. Classification of vertical structures is posed primarily in terms of the profile of the heat flux. The nocturnal boundary layer assumes a variety of vertical structures, which can often be roughly viewed as layering of the heat-flux divergence (convergence). The correlation coefficient between the temperature and vertical velocity fluctuations provides valuable additional information for classification of the vertical structure.

观察到的稳定边界层的垂直结构通常与教科书的轮廓有很大的不同。即使在平坦的均质表面上，湍流也可能与表面条件不完全相关，而是由高位湍流源（例如低空射流和瞬态模式）产生。在稳定条件下，即使是适度的表面异质性也会改变稳定边界层的垂直结构。在晴朗的天空和低风速的情况下，有时非常薄弱的​​斜坡会产生冷空气排水，并引发各种不同的垂直结构。我们的研究检查了三个对比塔位的边界层的垂直结构。我们强调具有强烈分层的低风速。在给定地点，垂直结构可能对地面风向敏感。垂直结构的分类主要根据热通量的分布。夜间边界层呈现出多种垂直结构，通常可以粗略地看成是热通量发散（会聚）的分层。温度和垂直速度波动之间的相关系数为垂直结构的分类提供了有价值的附加信息。