GPS TEC response to the 22 July 2009 total solar eclipse in East Asia
GPS TEC response to the 22 July 2009 total solar eclipse in East Asia
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DOI：
10.1029/2009ja015113
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发表时间：
2010-07
影响因子：
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通讯作者：
F. Ding;W. Wan;B. Ning;Libo Liu;H. Le;Guirong Xu;Min Wang;Guozhu Li;Yiding Chen;Z. Ren;B. Xiong;L. Hu;X. Yue;B. Zhao;Fengqin Li;Min Yang
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文献类型：
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作者：
F. Ding;W. Wan;B. Ning;Libo Liu;H. Le;Guirong Xu;Min Wang;Guozhu Li;Yiding Chen;Z. Ren;B. Xiong;L. Hu;X. Yue;B. Zhao;Fengqin Li;Min Yang
[1]本世纪持续时间最长的日全食发生在2009年7月22日的东亚和南亚。这次月食伴随着一场中等强度的磁暴，其主相发生在月球本影通过后约27分钟。利用60个GPS台站的TEC数据，构建了差分TEC图，研究了26°N-36°N、108°E-118°E范围内（即，磁纬15°N-25°N）。在月全食期间，电离层中的一个“阴影”显示为TEC耗尽区，位于月球本影路径以南约100公里处，最大减少量为5 TECU。TEC的亏损区东移，总日全食区的移动与时间滞后的0.10分钟。增强的TEC由于风暴后，观察到的主相开始。日食引起的TEC相对下降在低纬度地区明显大于高纬度地区，中午前后明显大于上午。通过模拟发现，TEC响应的纬向依赖性可能是由于磁倾角的纬向变化影响了电离层间的扩散。此外，TEC响应的本地时间依赖性与背景大气密度的本地时间变化密切相关，从而影响电离层中的电子损失效率。
[1] The longest total solar eclipse of this century occurred in East and South Asia on 22 July 2009. The eclipse was accompanied with a medium magnetic storm, whose main phase onset occurred ∼27 min after the passage of the Moon's umbral shadow. Using TEC data from 60 GPS stations, we construct differential TEC maps to investigate the ionosphere response to the solar eclipse in central China in the range of 26°N–36°N, 108°E–118°E (i.e., the magnetic latitude 15°N–25°N). During the eclipse's totality, a “shadow” in the ionosphere shown as TEC depletion area was formed ∼100 km south of the Moon's umbral path with a maximum decrease of 5 TECU. The TEC depletion area moved eastward, following the movement of the totality area with a time lag of ∼10 min. Enhancements of TEC due to the storm are observed after the main phase onset. The relative drop of TEC due to the solar eclipse is evidently larger at lower latitudes than that at higher ones and around noontime than that in the morning. By modeling work, we find that the latitudinal dependence of the TEC response may result from latitudinal variation of magnetic inclination, which influences the diffusion of ionization among different layers. Besides, the local time dependence of TEC response is closely related to the local time variation of background atmosphere density, which affects the electron loss efficiency in the ionosphere.