Polar mesospheric cloud (PMC) imaging and lidar profiling performed aboard the 5.9‐day PMC Turbo balloon flight from Sweden to northern Canada in July 2018 revealed a wide variety of gravity wave (GW) and instability events occurring nearly continuously at approximately 82 km. We describe one event exhibiting GW breaking and associated vortex rings driven by apparent convective instability. Using PMC Turbo imaging with spatial and temporal resolution of 20 m and 2 s, respectively, we quantify the GW horizontal wavelength, propagation direction, and apparent phase speed. We identify vortex rings with diameters of 2–5 km and horizontal spacing comparable to their size. Lidar data show GW vertical displacements of ±0.3 km. From the data, we find a GW intrinsic frequency and vertical wavelength of 0.009 ± 0.003 rad s⁻¹ and 9 ± 4 km, respectively. We show that these values are consistent with the predictions of numerical simulations of idealized GW breaking. We estimate the momentum deposition rate per unit mass during this event to be 0.04 ± 0.02 m s⁻² and show that this value is consistent with the observed GW. Comparison to simulation gives a mean energy dissipation rate for this event of 0.05–0.4 W kg⁻¹, which is consistent with other reported in situ measurements at the Arctic summer mesopause.

中文翻译：

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PMC Turbo观测到的重力波破碎和涡旋环形成

在2018年7月从瑞典飞往加拿大北部的5.9天PMC Turbo气球飞行中，进行了极地中层云（PMC）成像和激光雷达轮廓分析，发现大约82 km处几乎连续发生各种各样的重力波（GW）和不稳定事件。我们描述了一个表现为GW破裂和由明显的对流不稳定性驱动的相关涡旋环的事件。使用分别具有20 m和2 s的空间和时间分辨率的PMC Turbo成像，我们可以量化GW水平波长，传播方向和视在相速度。我们确定了直径为2–5 km的涡流环，其水平间距与它们的大小相当。激光雷达数据显示GW的垂直位移为±0.3 km。从数据中，我们发现GW的固有频率和垂直波长为0.009±0.003 rad s ^-1和9±4  km。我们表明，这些值与理想化GW断裂的数值模拟的预测一致。我们估计在此事件期间每单位质量的动量沉积速率为0.04±0.02  m s ^-2，并且表明该值与观察到的GW一致。与模拟的比较得出该事件的平均能量耗散率为0.05–0.4 W kg ^-1，这与北极夏季中段的其他现场测量结果一致。