Super Dual Auroral Radar Network observations of fluctuations in the spectral distribution of near range meteor echoes in the upper mesosphere and lower thermosphere
Super Dual Auroral Radar Network observations of fluctuations in the spectral distribution of near range meteor echoes in the upper mesosphere and lower thermosphere
复制标题
超级双极光雷达网对中层上层和热层下层近程流星回波光谱分布波动的观测
DOI：
10.5194/angeo-19-425-2001
复制
发表时间：
2001
影响因子：
1.9
通讯作者：
P. Chapman
中科院分区：
文献类型：
--
作者：
Neil Arnold;T. Robinson;M. Lester;P. Byrne;P. Chapman
SuperDARN高频雷达网测得的流星回波多普勒频移已被用于若干研究，以观测上层中间层和下层热层区域的中性风。在缺乏个别流星的准确高度资料的情况下，有必要假定一个统计平均流星层，在这个层中，高度的变化与水平风的变化无关。雷达对谱宽分布变化的观测可以独立地确定高度的系统误差。我们已经研究了这种分布对许多因素的依赖性，包括雷达几何，日和季节周期，太阳紫外辐照度和地磁活动的变化。在不同的雷达距离上观测到的平均流星层高度的变化，使我们对流星被烧蚀的上层中间层和下层热层的结构有了一些了解。在1997年4月一次风暴突发事件的前后几天，对芬兰CUT-LASS雷达测得的谱宽进行了一次检验，说明了观测区域的谱特性是如何受到影响的。宽度的变化与模型计算的温度分布在此期间的变化是一致的。在确定的光谱宽度的进一步改进概述了未来的实验。
The Doppler shifts of meteor echoes measured by the SuperDARN HF radar network have been used in several studies to observe neutral winds in the upper mesosphere and lower thermosphere region. In the absence of accurate height information for individual meteors, it has been necessary to assume a statistical mean meteor layer where the variations in altitude were not correlated to changes in the horizontal winds. Observations of spectral width distribution variations made by the radars allow an independent determination of the systematic error in the height. We have investigated the de- pendence of this distribution on a number of factors including the radar geometry, diurnal and seasonal cycles, variations in solar UV irradiance and geomagnetic activity. Changes in the altitude of the mean meteor layer observed at different radar ranges provide us with some insight into the structure of the upper mesosphere and the lower thermo- sphere within which the meteors are being ablated. An ex- amination of the spectral widths, as measured by the CUT- LASS Finland radar, in the days preceding and following a Storm Sudden Commencement in April 1997, illustrates how the spectral properties of the observed region can be affected. The variations in the widths were consistent with model calculations of the changes to the temperature profile over this interval. Further refinements in the determination of the spectral width are outlined for future experiments.