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A scheme for forecasting severe space weather
Author(s) -
Balan N.,
Ebihara Y.,
Skoug R.,
Shiokawa K.,
Batista I. S.,
Tulasi Ram S.,
Omura Y.,
Nakamura T.,
Fok M.C.
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023853
Subject(s) - space weather , physics , coronal mass ejection , meteorology , event (particle physics) , shock (circulatory) , interplanetary spaceflight , solar wind , geomagnetic storm , interplanetary magnetic field , storm , astrophysics , plasma , nuclear physics , medicine
A scheme is suggested and tested for forecasting severe space weather (SvSW) using solar wind velocity ( V ) and the north‐south component ( B z ) of the interplanetary magnetic field (IMF) measured using the ACE (Advanced Composition Explorer) satellite from 1998 to 2016. SvSW has caused all known electric power outages and telegraph system failures. Earlier SvSW events such as the Carrington event of 1859, Quebec event of 1989 and an event in 1958 are included with information from the literature. Dst storms are used as references to identify 89 major space weather events ( Dst Min ≤ −100 nT) in 1998–2016. The coincidence of high coronal mass ejection (CME) front (or CME shock) velocity Δ V (sudden increase in V over the background by over 275 km/s) and sufficiently large B z southward at the time of the Δ V increase is associated with SvSW; and their product (Δ V × B z ) is found to exhibit a large negative spike at the speed increase. Such a product (Δ V × B z ) exceeding a threshold seems suitable for forecasting SvSW. However, the coincidence of high V (not containing Δ V ) and large B z southward does not correspond to SvSW, indicating the importance of the impulsive action of large B z southward and high Δ V coming through when they coincide. The need for the coincidence is verified using the CRCM (Comprehensive Ring Current Model), which produces extreme Dst storms (< Dst MP > < −250 nT) characterizing SvSW when there is coincidence.