PRIMARY APPLICATION OF THE MEMBERSHIP FUNCTIONS IN THE GEOMAGNETIC DISTURBANCE PREDICTIONS
Wei Feng-si Cai Hong-chang(Center for Space Science and Applied Research, Academa Sinica, Beijing)
Prediction test for 40 geomagnetic disturbance events caused by the flare-associated interplanetary shock waves, which can be identified by interplanetary scintillation (IPS) observations during 1984-1985, are made based on the membership functions established by using observational data on the solar flares, the interplanetary shock waves and the geomagnetic disturbances during the period of 1966-1982. Main results are: (1) Prediction of the magnetic disturbance onset time-for 50% of all events, the relative error, δT/T≤10%; and for 70%,δT/r≤20%; (2) Prediction of the geomagnetic disturbance amplitudes-for 80% of allevents, the relative error, δ∑Kp/∑Kp≤30% ; and only for 15%, δ∑Kp/∑Kp≥60%. These results show that the method adoption in this paper has some potential prospects for investigating the flare-associated interplanetary shock waves and the geomagnetic disturbance predictions.