Monitoring the global evolution of the storm ring current and storm indices from confined ground geomagnetic observatories
Monitoring the global evolution of the storm ring current and storm indices from confined ground geomagnetic observatories
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DOI：
10.1016/j.jastp.2019.05.013
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发表时间：
2019-06
影响因子：
1.9
通讯作者：
G. Zeng;C. Shen;Z. Rong;X. Li;T. Chen;Z.Q. Chen;Y. Ma
中科院分区：
文献类型：
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作者：
G. Zeng;C. Shen;Z. Rong;X. Li;T. Chen;Z.Q. Chen;Y. Ma
首次从有限经度范围内的地面观测站的磁场测量中推导出地球周围地磁扰动场的全球结构以及磁暴指数。地磁扰动场H分量的空间梯度仅由东半球的地面地磁台获得，只要地磁扰动场在空间上近似线性变化。在此基础上，导出了风暴对称指数和非对称指数，研究了风暴环流的空间分布和时间演变。结果表明，东半球各台站的暴雨指数与官方公布的京都标准指数一致，后者是由全球分布的6个台站的暴雨指数计算得到的。我们还利用HER、KAK和SJG三个观测站的资料计算了1941-1956年的风暴指数。三个观测站的对称指数与全球六个观测站的对称指数的相关系数为0.98，两种非对称指数的相关系数为0.79。这些结果表明，我们的方法是合理的，并在全球地面观测站不容易获得显着。
For the first time, the global structure of the geomagnetic disturbance field around the Earth as well as the magnetic storm indices have been deduced from magnetic field measurements by ground observatories in a confined range of longitude. The spatial gradient of theHcomponent of the geomagnetic disturbance field was obtained from ground geomagnetic observatories only in the Eastern Hemisphere, provided the geomagnetic disturbance field varies approximately linearly in space. Furthermore, the storm symmetric and asymmetric indices were derived and the spatial distribution and temporal evolution of the storm ring current was investigated. It was found that the storm indices derived from observatories in the Eastern Hemisphere are consistent with the officially published Kyoto standard indices which are derived from six globally distributed observatories. We also calculated the storm indices for 1941–1956 by using data from three observatories (HER, KAK and SJG). The correlation coefficient between the symmetric index deduced from three observatories and the one from the global six observatories is 0.98, and the correlation coefficient between the two kind of asymmetric indices is 0.79. Those results suggest that our approach is reasonable and significant when global ground observatories are not readily available.