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Estimation of the Occurrence Probability of Extreme Geomagnetic Storms by Applying Extreme Value Theory to Aa Index
Author(s) -
Chen Si,
Chai Lihui,
Xu Kaihua,
Wei Yong,
Rong Zhaojin,
Wan Weixing
Publication year - 2019
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2019ja026947
Subject(s) - extreme value theory , earth's magnetic field , geomagnetic storm , maxima , storm , space weather , index (typography) , climatology , environmental science , meteorology , mathematics , atmospheric sciences , statistics , geology , geography , physics , history , computer science , magnetic field , performance art , art history , quantum mechanics , world wide web
In this work, the occurrence probability of extreme geomagnetic storms is estimated by applying extreme value theory to the geomagnetic activity Aa index. The Aa index has 172 years observation time span, which is much longer than other geomagnetic indices, and thus is more suitable for analysis for rarely occurred extreme geomagnetic storms. We use two newly developed extreme value theory methods, block maxima method and peak over threshold, and find that the extreme geomagnetic storm that happened in March 1989 may happen once per century. This result implies that we should pay more attention to such extreme geomagnetic storms that can cause space weather hazards.