The influence of the atmosphere on radar meteor rates
The influence of the atmosphere on radar meteor rates
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大气对雷达流星率的影响
DOI：
10.1017/s007418090006650x
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
W. Elford
中科院分区：
文献类型：
--
作者：
W. Elford
大多数流星射电研究都是在高于 17MHz 的频率下进行的，大多数速率观测是在高于 30MHz 的频率下进行的。在这些频率下，流星会发生严格的高度选择。图 1（a）显示了阿德莱德在 27MHz 和 2MHz 频率上观测到的零星流星的标准化高度分布（Brown，1976）。后者分布在 87 公里以下的急剧截止是有帮助的。高度分布的差异是由于流星尾迹的有限直径对其雷达可探测性的影响。如果尾迹直径为<A，来自近边缘和远边缘的信号会增强，但随着尾迹因扩散而扩展且直径变为~A/4，干扰会减小幅度。由速度为 30 km·s"1 的粒子产生的流星尾迹，在 80 km 处的初始直径为 0.4 m，在 104 km 处为 2.0 m，在 116 km 处为 4.0 m。
The majority of radio studies of meteors have been carried out at frequencies higher than 17MHz and most of the rate observation at frequencies above 30MHz. At these frequencies a severe height selection of meteors occurs. In Figure 1(a) are shown the normalized height distributions of sporadic meteors observed at Adelaide on frequencies of 27MHz and 2MHz (Brown, 1976). The sharp cutoff of the latter distribution below 87 km is instrumental. The difference in the height distributions is due to the effect of the finite diameter of a meteor trail on its radar detectability. If the trail diameter is « A signals from the near and far edges reinforce but as the trail expands due to diffusion and the diameter becomes ~ A/4 , interference reduces the amplitude. A meteor trail, produced by a particle with a velocity of 30 km s"1 , has an initial diameter of 0.4m at 80 km, 2.0m at 104 km and 4.0m at 116 km.