Temporal variability of the telluric sodium layer.
Temporal variability of the telluric sodium layer.
复制标题
大地钠层的时间变化。
作者：
D. Davis;P. Hickson;G. Herriot;C. She
通过分析科罗拉多州立大学激光雷达实验获得的28个夜晚的数据，研究了碲钠层的时间变化。钠层的平均高度功率谱被认为是很好地拟合在所观察到的频率范围内，10微赫兹至4兆赫的幂律。发现最佳拟合幂律为10（beta）nu（alpha），其中alpha=-1.79+/-0.02和beta=1.12+/-0.40。波前传感的应用需要知道钠层在千赫兹频率下的行为。在这些频率上的直接测量是不存在的。从低频行为到高频的外推表明，这种可变性可能是大口径望远镜中激光引导星星自适应光学系统误差的重要来源。
The temporal variability of the telluric sodium layer is investigated by analyzing 28 nights of data obtained with the Colorado State University LIDAR experiment. The mean height power spectrum of the sodium layer was found to be well fitted by a power law over the observed range of frequencies, 10 microHz to 4 mHz. The best-fitting power law was found be be 10(beta)nu(alpha), with alpha=-1.79+/-0.02 and beta=1.12+/-0.40. Applications to wavefront sensing require knowledge of the behavior of the sodium layer at kilohertz frequencies. Direct measurements at these frequencies do not exist. Extrapolation from low-frequency behavior to high frequencies suggests that this variability may be a significant source of error for laser guide star adaptive optics in large-aperture telescopes.