author = "Balan, N. and Ebihara, Y. and Skoug, R. and Shiokawa, K. and 
                         Batista, Inez Staciarini and Ram, S. Tulasi and Omura, Y. and 
                         Nakamura, T. and Fok, M. C.",
          affiliation = "{Kyoto University} and {Kyoto University} and {Los Alamos National 
                         Laboratory} and {Nagoya University} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Indian Institute of Geomagnetism} 
                         and {Kyoto University} and {National Institute of Polar Research} 
                         and {NASA Goddard Space Flight Center}",
                title = "A scheme for forecasting severe space weather",
              journal = "Journal of Geophysical Research: Space Physics",
                 year = "2017",
               volume = "122",
               number = "3",
                pages = "2824--2835",
                month = "Mar.",
             keywords = "severe space weather, CME front, CME shock, B-z southward, 
                         impulsive action.",
             abstract = "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 
                         (DstMin <=-100 nT) in 1998-2016. The coincidence of high coronal 
                         mass ejection (CME) front (or CME shock) velocity Delta V (sudden 
                         increase in V over the background by over 275km/s) and 
                         sufficiently large B-z southward at the time of the Delta V 
                         increase is associated with SvSW; and their product (Delta VxB(z)) 
                         is found to exhibit a large negative spike at the speed increase. 
                         Such a product (Delta VxB(z)) exceeding a threshold seems suitable 
                         for forecasting SvSW. However, the coincidence of high V (not 
                         containing Delta 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 Delta 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. Plain Language Summary Severe space weather has been 
                         known to affect the society by damaging satellite systems and 
                         electric power grids. For example, a space weather of the type 
                         that occurred in September 1859, if occurs at present times, can 
                         cause very serious damages costing up to 1 to 2 trillion U.S. 
                         dollars. It is therefore important to study space weather and 
                         understand what determines the severity of space weather and 
                         whether it can be forecasted and predicted. In this paper we show 
                         that the coincidence of the speed of solar storms and southward 
                         orientation of the north-south component of the interplanetary 
                         magnetic field is responsible for severe space weather at the 
                         Earth, and it can be forecasted by 35 min using the data from a 
                         satellite that stays at 220 x radius of Earth away from the 
                  doi = "10.1002/2016JA023853",
                  url = "http://dx.doi.org/10.1002/2016JA023853",
                 issn = "2169-9402",
             language = "en",
           targetfile = "balan_scheme.pdf",
        urlaccessdate = "27 nov. 2020"