【摘要】 在夜间晴空条件下，近地面大气湍流表现出很强的间歇性，这种间歇现象导致夜间气温短时的急剧下降，随后大幅度增温。近地面大幅度增温表明此时存在着很大的湍流热通量散度，常通量层的概念这时不存在。从各高度层温度和风速变化的曲线上分析，我们发现湍流大多在距离地面较高一点的高度上发生发展，然后向下层传递，尽管上层的湍流可能是由于下层的某一触发机制向上传递而引起的。湍流偶尔也出现自下向上传递的过程，但这一过程较少发生。湍流的这种上下传递说明稳定边界层大气经常处于非平衡状态，在运用相似理论研究稳定边界层大气结构时要特别注意这一情形。更多还原

【Abstract】 During clear nights,the turbulence in the surface layer shows the characteristics of intermittence.The intermittent turbulence results in sharp temperature decreases and subsequent increases. The quick increase of temperature represents that there is large divergence of the turbulent heat flux in the near surface layer and heat flux should not be considered as a constant in this situation. After analysing the variances of temperature and velocity at different levels, it is found that the turbulence is usually stimulated at higher levels and then transported to the atmosphere below even though the trigger factor might come from lower levels. Sometimes it is stimulated at lower levels and then transported to the upper atmosphere. The characteristics presents that the atmosphere is usually not in an equilibrium and care should be taken when we study the nocturnal boundary layer with the similarity theory.更多还原