CME引起的地磁暴穿越时间

日冕物质抛射(CME)从发生至引起地磁暴最大值的时间间隔称为穿越时间.本文选取1997-2015年89个CME-Dst事件,分析CME速度、能量、耀斑类型等对穿越时间的影响;采用非线性拟合以及支持向量机(SVM)非线性回归技术,建立基于1997-2009年62个CME-Dst事件的CF模型和SVM模型,并利用其余27个CME-Dst事件对模型预报效果分别进行检验.结果表明,CF模型和SVM模型的预报准确率均达到85.2%,其中CF模型的平均绝对值误差为13.77 h,而SVM模型为13.88 h.与ECA模型结果(准确率为77.8%,平均绝对值误差为14.55 h)进行对比发现,CF模型和SVM模型的准确率更高而误差更小.CF模型和SVM模型能够提前1~5天较好地预报地磁暴爆发时间.

Transport Time for the Geomagnetic Storm Caused by CME

The transport time is defined as the interval time between the occurrence of CME and the maximum value of the geomagnetic storm. In view of the 89 CME-Dst events collected from 1997 to 2015, the impact of CME speed, energy, and flare type on the transport time is analyzed. Using the non-linear fitting and the nonlinear regression of the Support Vector Machine (SVM), the Curve Fitting (CF) model and the Support Vector Machine (SVM) model for the CME transport time are built. In these models, 62 CME-Dst events during 1997-2006 are used as model input, and the remaining 27 CME-Dst events are used to test the model prediction. The results show that the prediction accuracies both of CF model and SVM model reach at about 85.2%, and the average absolute error of CF model is 13.77h while the SVM model is 13.88h. Comparing with the ECA model (its prediction accuracy is 77.8%, and the average absolute error is 14.55h), the accuracy of these two models is higher and the error is smaller than that of the ECA model. Therefore, CF model and SVM model can predict accurately the geomagnetic storm explosion with 1~5 days in advance.