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| Vr: A new index to represent the variation rate of geomagnetic activity |
| Dongmei Yang1, Yufei He1, Chuanhua Chen2, Jiadong Qian3 |
1 Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
2 Tai’an Magnetic Observatory, Earthquake Administration of Shandong Province, Tai’an 271000, China
3 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China |
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Abstract By calculating the hourly standard deviation of the first-order differences of the horizontal geomagnetic component minute data, a new index Vr to represent the variation rate of the geomagnetic field was introduced. Vr-indices show similar trends in the temporal change at different observatories and have simultaneous peak values at the observatories covering a large span geographically, which reveals that the source of geomagnetic disturbances represented by Vr is in the magnetosphere. Based on the comparison among Vr, Kp and ap, it is found that generally Vr changes linearly with Kp and ap, which means that the rapid changes of magnetic field usually exist together with magnetic disturbances. But there are exceptions. As Vr can be easily produced by individual observatory in quasi real time and is more sensitive to the variation rate of geomagnetic field rather than the field itself, it can be expected to serve for monitoring or predicting the geomagnetic-induced event in a quick and intuitive way.
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Received: 08 April 2010
Published: 10 August 2010
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Corresponding Authors:
Dongmei Yang
E-mail: ydmgeomag@263.net
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