Abstract Noctilucent clouds (NLC) are mesospheric ice clouds occurring in the summer hemisphere at high latitudes and an altitude of about 83km. This region is the coldest of the earth’s atmosphere and is characterized by the presence of wave interaction and dissipation. The processes involved here lead to a variety of structures and instabilities that become visible in noctilucent clouds and are observed by different instruments. In this work high-resolution lidar measurements are used to give a wide overview of the structures at small scales below the Brunt–Vaisala period of ∼ 5min. For the first time a large amount of NLC profiles from lidar with a temporal resolution of 1s is analyzed in detail, covering about 1400h during the summer from 2011 to 2018. A new categorization focusing on small-scale structures is introduced, and occurrence statistics for these categories in the season of 2014 are performed. Both wave structures with periods below 10min and thin layers of 100m thickness are commonly found. When taking simultaneous wind measurements into account, we find that structures often are advected by the wind.

中文翻译：

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激光雷达观测到的夜光云中的小尺度结构

摘要 夜光云（NLC）是出现在夏半球高纬度、海拔约83km的中间层冰云。该区域是地球大气中最冷的区域，其特点是存在波相互作用和消散。这里涉及的过程会导致在夜光云中可见并被不同仪器观察到的各种结构和不稳定性。在这项工作中，高分辨率激光雷达测量用于在大约 5 分钟的布伦特-维萨拉周期以下的小尺度上对结构进行广泛的概述。首次对时间分辨率为1s的激光雷达的大量NLC剖面进行了详细分析，覆盖了2011年至2018年夏季约1400小时。 引入了一种针对小尺度结构的新分类，并对这些类别在 2014 年的季节进行了发生统计。周期小于 10min 的波浪结构和 100m 厚的薄层都是常见的。当考虑到同步风测量时，我们发现结构经常被风平流。