In the stable boundary layer, thermal submesofronts (TSFs) are detected during the Shallow Cold Pool experiment in the Colorado plains, Colorado, USA in 2012. The topography induces TSFs by forming two different air layers converging on the valley-side wall while being stacked vertically above the valley bottom. The warm-air layer is mechanically generated by lee turbulence that consistently elevates near-surface temperatures, while the cold-air layer is thermodynamically driven by radiative cooling and the corresponding cold-air drainage decreases near-surface temperatures. The semi-stationary TSFs can only be detected, tracked, and investigated in detail when using fibre-optic distributed sensing (FODS), as point observations miss TSFs most of the time. Neither the occurrence of TSFs nor the characteristics of each air layer are connected to a specific wind or thermal regime. However, each air layer is characterized by a specific relationship between the wind speed and the friction velocity. Accordingly, a single threshold separating different flow regimes within the boundary layer is an oversimplification, especially during the occurrence of TSFs. No local forcings or their combination could predict the occurrence of TSFs except that they are less likely to occur during stronger near-surface or synoptic-scale flow. While classical conceptualizations and techniques of the boundary layer fail in describing the formation of TSFs, the use of spatially continuous data obtained from FODS provide new insights. Future studies need to incorporate spatially continuous data in the horizontal and vertical planes, in addition to classic sensor networks of sonic anemometry and thermohygrometers to fully characterize and describe boundary-layer phenomena.

在稳定的边界层中，2012年在美国科罗拉多州的科罗拉多平原进行的浅冷池实验期间，检测到了热亚中界（TSF）。地形是通过形成两个不同的空气层而汇聚在一起，同时堆叠在山谷侧壁上的，从而诱发了TSF。垂直于山谷底部。热风层是由Lee湍流机械产生的，该湍流持续升高近地表温度，而冷空气层是由辐射冷却以热力学方式驱动的，相应的冷空气排放会降低近地表温度。半固定式TSF只能在使用光纤分布式传感（FODS）时进行详细的检测，跟踪和研究，因为点观测通常会错过TSF。TSF的出现或每个空气层的特征都与特定的风或热状态无关。然而，每个空气层的特征在于风速和摩擦速度之间的特定关系。因此，在边界层内分隔不同流态的单个阈值过于简单化，尤其是在TSF发生期间。没有局部强迫作用或其组合可以预测TSF的发生，除了它们在较强的近地表或天气尺度流中发生的可能性较小之外。尽管边界层的经典概念和技术未能描述TSF的形成，但从FODS获得的空间连续数据的使用提供了新的见解。