Open AccessStatistical analysis and verification of 3‐hourly geomagnetic activity probability predictions
Author(s) -
Wang Jingjing,
Zhong Qiuzhen,
Liu Siqing,
Miao Juan,
Liu Fanghua,
Li Zhitao,
Tang Weiwei
Publication year - 2015
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1002/2015sw001251
Subject(s) - earth's magnetic field , geomagnetic storm , interplanetary magnetic field , solar wind , meteorology , environmental science , interplanetary spaceflight , space weather , storm , atmospheric sciences , physics , magnetic field , quantum mechanics
The Space Environment Prediction Center (SEPC) has classified geomagnetic activity into four levels: quiet to unsettled ( Kp < 4), active ( Kp = 4), minor to moderate storm ( Kp = 5 or 6), and major to severe storm ( Kp > 6). The 3‐hourly Kp index prediction product provided by the SEPC is updated half hourly. In this study, the statistical conditional forecast models for the 3‐hourly geomagnetic activity level were developed based on 10 years of data and applied to more than 3 years of data, using the previous Kp index, interplanetary magnetic field, and solar wind parameters measured by the Advanced Composition Explorer as conditional parameters. The quality of the forecast models was measured and compared against verifications of accuracy, reliability, discrimination capability, and skill of predicting all geomagnetic activity levels, especially the probability of reaching the storm level given a previous “calm” (nonstorm level) or “storm” (storm level) condition. It was found that the conditional models that used the previous Kp index, the peak value of B t V (the product of the total interplanetary magnetic field and speed), the average value of B z (the southerly component of the interplanetary magnetic field), and B z V (the product of the southerly component of the interplanetary magnetic field and speed) over the last 6 h as conditional parameters provide a relative operating characteristic area of 0.64 and can be an appropriate predictor for the probability forecast of geomagnetic activity level.