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标题：Statistical analysis of extreme auroral electrojet indices
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作者：Masao Nakamura ; Asato Yoneda ; Mitsunobu Oda 等
期刊名称：Earth, Planets and Space
电子版ISSN：1880-5981
出版年度：2015
卷号：67
期号：1
页码：1-8
DOI：10.1186/s40623-015-0321-0
出版社：Springer Verlag
摘要：Extreme auroral electrojet activities can damage electrical power grids due to large induced currents in the Earth, degrade radio communications and navigation systems due to the ionospheric disturbances and cause polar-orbiting satellite anomalies due to the enhanced auroral electron precipitation. Statistical estimation of extreme auroral electrojet activities is an important factor in space weather research. For this estimation, we utilize extreme value theory (EVT), which focuses on the statistical behavior in the tail of a distribution. As a measure of auroral electrojet activities, auroral electrojet indices AL, AU, and AE, are used, which describe the maximum current strength of the westward and eastward auroral electrojets and the sum of the two oppositely directed in the auroral latitude ionosphere, respectively. We provide statistical evidence for finite upper limits to AL and AU and estimate the annual expected number and probable intensity of their extreme events. We detect two different types of extreme AE events; therefore, application of the appropriate EVT analysis to AE is difficult.
关键词：Auroral electrojet activity ;AE AU AL index ;Extreme value theory ;Space weather