A case study of HF radar spectral width in the post midnight magnetic local time sector and its relationship to the polar cap boundary
A case study of HF radar spectral width in the post midnight magnetic local time sector and its relationship to the polar cap boundary
复制标题
午夜后磁当地时间扇区高频雷达谱宽的案例研究及其与极冠边界的关系
DOI：
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发表时间：
2002
期刊：
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通讯作者：
M. Lester
中科院分区：
文献类型：
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作者：
E. Woodfield;J. Davies;P. Eglitis;M. Lester
摘要。本文的目的是提高对相干高频雷达观测到的谱宽参数的现有认识。特别地，我们讨论了经常观测到的低（200米/秒）光谱宽度与磁层边界之间的梯度的关系。以前的工作已经将这种光谱宽度的梯度，在磁地方时的夜间部分，与极帽边界（PCB），以及中央等离子体片（CPS）和等离子体片边界层（PSBL）之间的边界联系起来。本案例通过与630.0 nm光发射的对比研究了前者。没有合适的数据来检验第二个假设。结果表明，在这段时间内，光谱宽度梯度在630.0 nm光发射范围内。对相干和非相干散射雷达数据进行了比较，结果表明，高谱宽的值通常与较高的f区电子温度同时存在。我们得出结论，研究区间内的高谱宽区域与颗粒降水有关，并且谱宽梯度不是定位PCB的可靠方法。关键字。电离层（极光电离层；电离层不规则）
Abstract. The aim of this paper is to advance the current understanding of the spectral width parameter observed by coherent high frequency (HF) radars. In particular, we address the relationship of a frequently observed gradient, between low ( 200 m/s) spectral width, to magnetospheric boundaries. Previous work has linked this gradient in the spectral width, in the nightside sector of magnetic local time, to the Polar Cap Boundary (PCB), and also to the boundary between the Central Plasma Sheet (CPS) and the Plasma Sheet Boundary Layer (PSBL). The present case study investigates the former by comparison with the 630.0 nm optical emission. No suitable data were available to test the second of the two hypotheses. It is found that during the interval in question the spectral width gradient is within the region of the 630.0 nm optical emission. A comparison of coherent and incoherent scatter radar data is also conducted, which indicates that values of high spectral width are typically collocated with elevated F-region electron temperatures. We conclude that the high spectral width region in the interval under study is associated with particle precipitation and also that the spectral width gradient is not a reliable method for locating the PCB. Key words. Ionosphere (auroral ionosphere; ionospheric irregularities)