A very high spatial resolution (∼25 m pixel at 90 km altitude) OH airglow imager was installed at the Andes Lidar Observatory on Cerro Pachón, Chile, in February 2016. This instrument was collocated with a Na wind‐temperature lidar. On 1 March 2016, the lidar data showed that the atmosphere was dynamically unstable before 0100 UT and thus conducive to the formation of Kelvin‐Helmholtz instabilities (KHIs). The imager revealed the presence of a KHI and an apparent atmospheric gravity wave (AGW) propagating approximately perpendicular to the plane of primary KHI motions. The AGW appears to have induced modulations of the shear layer leading to misalignments of the emerging KHI billows. These enabled strong KHI billow interactions, as they achieved large amplitudes and a rapid transition to turbulence thereafter. The interactions manifested themselves as vortex tube and knot features that were earlier identified in laboratory studies, as discussed in Thorpe (1987, https://doi.org/10.1029/JC092iC05p05231; 2002, https://doi.org/10.1002/qj.200212858307) and inferred to be widespread in the atmosphere based on features seen in tropospheric clouds but which have never been identified in previous upper atmospheric observations. This study presents the first high‐resolution airglow imaging observation of these KHI interaction dynamics that drive rapid transitions to turbulence and suggest the potential importance of these dynamics in the mesosphere and at other altitudes. A companion paper (Fritts et al., 2020, https://doi.org/10.1029/2020JD033412) modeling these dynamics confirms that the vortex tubes and knots yield more rapid and significantly enhanced turbulence relative to the internal instabilities of individual KHI billows.

中文翻译：

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安第斯激光雷达天文台的中层开尔文-亥姆霍兹巨浪相互作用和不稳定性：1.观测

很高的空间分辨率（〜2016年2月，在90 km高度的25 m像素处）安装了OH辉光成像仪，该成像仪安装在智利CerroPachón的安第斯激光雷达天文台上。该仪器与Na风温激光雷达搭配使用。2016年3月1日，激光雷达数据显示，大气在0100 UT之前是动态不稳定的，因此有助于形成Kelvin-Helmholtz不稳定性（KHIs）。成像仪显示出存在KHI和大约垂直于主要KHI运动平面传播的视在大气重力波（AGW）。AGW似乎引起了剪切层的调制，从而导致出现的KHI滚滚未对准。由于它们实现了较大的振幅并此后迅速过渡到湍流，因此实现了强大的KHI涛涛相互作用。如Thorpe（1987，https://doi.org/10.1029/JC092iC05p05231; 2002，https://doi.org/10.1002/qj）中所讨论的，相互作用的表现为实验室研究中较早发现的涡管和结特征。 （200212858307），并根据对流层云中所见的特征推断其在大气中的分布广泛，但以前的高层大气观测从未发现过这些特征。这项研究首次对这些KHI相互作用动力学进行了高分辨率的气辉成像观测，这些动力学推动了湍流快速过渡，并暗示了这些动力学在中层和其他高度的潜在重要性。随行论文（Fritts等人，2020，https://doi.org/10。