Mapping electrodynamic features of the high-latitude ionosphere from localized observations: Combined incoherent-scatter radar and magnetometer measurements for January 18-19, 1984
Mapping electrodynamic features of the high-latitude ionosphere from localized observations: Combined incoherent-scatter radar and magnetometer measurements for January 18-19, 1984
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根据局部观测绘制高纬度电离层的电动力学特征：1984 年 1 月 18 日至 19 日的非相干散射雷达和磁力计组合测量
DOI：
10.1029/ja093ia06p05760
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发表时间：
1988
影响因子：
--
通讯作者：
A. Zaitzev
中科院分区：
文献类型：
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作者：
A. Richmond;Y. Kamide;B. Ahn;S. Akasofu;D. Alcaydé;M. Blanc;O. Beaujardiere;D. Evans;J. Foster;E. Christensen;T. Rowell;J. Holt;D. Knipp;H. Kroehl;R. Lepping;R. Pellinen;C. Senior;A. Zaitzev
本文利用里士满和Kamide的技术，根据非相干散射雷达和地面磁力计的联合观测，估计了1984年1月18-19日期间北方高纬度地区描述电离层对流的大尺度电位图象（本期）。图案通常具有占主导地位的两个细胞的特性，虽然细胞的强度，取向和形状随时间发生相当大的变化。在亚暴扩张阶段，低电位的“舌”在夜间沿着高电位单体的低纬度边缘向东延伸。最大和最小电势的时间序列图表明，它们可以迅速响应行星际磁场Bz分量的变化。这2天期间的总估计电位降范围约为15 kV至108 kV。分析了不同类型的数据对所得的估计电势模式的影响。在可用的情况下，雷达的直接电场观测主要控制估计的潜在模式的特征，而磁力计数据在直接电场测量不可用的区域具有最大的影响。我们还采用了Foster et al.（1986）的统计电势模型来帮助填充非线性分析区域中的模式。对于目前的研究，数据覆盖面往往是足够好的统计模型在确定估计的对流模式只发挥次要作用。Sondrestrom和EISCAT雷达的电离层电导观测非常重要，有助于修正Fuller-Rowell和Evans（1987）的统计电导模型，以产生适合于电场、电流和磁扰动相互关联的修正电导分布。在估计的大规模电场模式的统计不确定性分析表明，不确定性超过50%，在极冠和亚极光区，只有在附近的雷达电场观测小于20%。
The large-scale electric potential patterns, describing ionospheric convection, are estimated for northern high latitudes during January 18-19, 1984, from combined incoherent-scatter radar and ground magnetometer observations, using the technique of Richmond and Kamide (this issue). The patterns usually have a dominant two-cell characteristic, although the intensities, orientations and shapes of the cells undergo considerable changes with time. Often evident during substorm expansive phases is a “tongue” of low electric potential extending toward the east along the low-latitude edge of the high potential cell at night. Time-series plots of the maximum and minimum electric potentials show that they can respond rapidly to changes in the interplanetary magnetic field Bz component. Total estimated potential drops for this 2-day period range from about 15 kV up to 108 kV. The influence of the different types of data on the resultant estimated electric potential patterns is analyzed. Where available, the direct electric field observations by the radars primarily control the characteristics of the estimated potential patterns, while the magnetometer data have their greatest influence in regions where direct electric field measurements are unavailable. We also employ the statistical electric potential model of Foster et al. (1986) to help fill in the patterns in datasparse regions. For the present study, data coverage is often good enough that the statistical model plays only a secondary role in determining the estimated convection patterns. The ionospheric electrical conductance observations from the Sondrestrom and EISCAT radars are very important in helping modify the statistical conductance model of Fuller-Rowell and Evans (1987) to yield modified conductance distributions suitable for interrelating the electric fields, currents, and magnetic perturbations. Analysis of the statistical uncertainty in the estimated large-scale electric field patterns shows the uncertainty to exceed 50% in the polar cap and sub auroral regions and to be less than 20% only in the vicinity of the radar electric field observations.