The midlatitude ionosphere during the total solar eclipse of March 9, 1997
The midlatitude ionosphere during the total solar eclipse of March 9, 1997
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DOI：
10.1029/1999ja900228
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发表时间：
1999-12
影响因子：
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通讯作者：
O. N. Boitman;A. D. Kalikhman;A. V. Tashchilin
中科院分区：
文献类型：
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作者：
O. N. Boitman;A. D. Kalikhman;A. V. Tashchilin
1997年3月9日的日全食，在世界时0时45分至0时130分在中国、蒙古和东西伯利亚的一些地区可以看到。这次日食与一个相对较长的地磁平静期相吻合。在日全食期间，观测包括斜入射电离图记录；还沿着指定方向测量了可见光全球定位系统卫星的总电子含量，并对所审议区域的各种高频射线路径进行了多普勒探测。本文介绍了在数值模拟的基础上研究中纬度电离层对这次日食响应的空间格局的结果。利用电离层-等离子体层耦合模型进行了计算。模型结果与所有测量数据的比较显示了良好的定性和定量一致性。结果表明，总的来说，在日食期间电离层的行为表现为一个短暂的（约1小时）重排到夜间，离子流从等离子层向下引导，F2层的最大值上升了约20公里，并且在日食全食阶段的最大值高度，电子密度增加了两倍。电子温度下降200 - 400k，而离子温度仅略有下降。结果表明，在日食期间，电子密度沿高频射线路径的空间分布发生了变化，引起了多普勒频移的变化，其幅度约为1 Hz，持续时间约为120 min。本文报道的研究结果并不能证实日食产生大气重力波和相关的电离层扰动的假设。
The total solar eclipse of March 9, 1997, was visible from some regions of China, Mongolia, and East Siberia during 0045–0130 UT. The eclipse coincided with a relatively long geomagnetically quiet period. During the total solar eclipse, the observations included oblique-incidence ionograms recording; also measurement the total electron content along specified directions to the visible Global Positioning System satellites and the Doppler sounding on various HF ray paths over the region under consideration were carried out. This paper presents results derived from studying the spatial pattern of midlatitude ionospheric response to this eclipse on the basis of a numerical simulations. Calculations have been executed using a model for ionosphere-plasmasphere coupling. Comparison of model results with data of all measurements showed a good qualitative and quantitative agreement. It is shown that by and large the behavior of the ionosphere during the eclipse manifests itself as a short-lasting (∼l-hour) rearrangement to nighttime conditions with the ion flow directed downward from the plasmasphere, as a rise of the F2 layer maximum by about 20 km, and as a twofold increase in electron density at the height of the maximum during the eclipse's totality phase. The electron temperature decreases by 200–400 K, while the ion temperature drops only slightly. It is found that changes in the spatial distribution of electron density along the HF ray paths during the eclipse give rise to variations of Doppler frequency shift with amplitudes of about 1 Hz and a duration of about 120 min. The findings reported in this paper do not validate the hypothesis that solar eclipses generate atmospheric gravity waves and associated traveling ionospheric disturbances.