A large‐aperture sodium fluorescence lidar with very high resolution for mesopause dynamics and adaptive optics studies
A large‐aperture sodium fluorescence lidar with very high resolution for mesopause dynamics and adaptive optics studies
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DOI：
10.1029/2009gl038802
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发表时间：
2009-08
影响因子：
5.2
通讯作者：
T. Pfrommer;P. Hickson;C. She
中科院分区：
文献类型：
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作者：
T. Pfrommer;P. Hickson;C. She
使用大孔径激光雷达系统对地球中层和低热层中钠原子密度结构进行高分辨率观测，更详细地揭示了这一动态区域的特征。钠是高度结构化的，显示出密度和高度在从几分钟到几小时的时间尺度上变化的多层。大规模的不稳定性和Kelvin-Helmholtz波涛被观察到沿着与层的整体向下传播。相干的短周期重力波振荡有时会出现在整个钠区。单个流星的烧蚀尾迹会产生短暂的密度峰值，最多持续几秒钟。平均钠高度被发现有一个时间功率谱成比例的-1.9功率的频率，接近预期的柯尔莫哥洛夫湍流。
High‐resolution observations of the density structure of atomic sodium in the Earth's mesosphere and lower thermosphere, using a large‐aperture lidar system, reveal features of this dynamic region in greater detail. The sodium is highly structured, showing multiple layers that vary in density and altitude on timescales ranging from minutes to hours. Large‐scale instabilities and Kelvin‐Helmholtz billows are observed along with an overall downward propagation of the layers. Coherent short‐period gravity wave oscillations are sometimes seen extending over the entire sodium region. Individual meteor ablation trails produce transient density spikes that last at most a few seconds. The mean sodium altitude is found to have a temporal power spectrum proportional to the –1.9 power of the frequency, close to that expected for Kolmogorov turbulence.