English

Abstract

Predicting the arrival time of Coronal Mass Ejections (CMEs) with a lower value of average error of the difference between the predicted and the observed transit time is very crucial in space weather forecast. A modified Empirical Coronal Mass Ejection Arrival (ECA) model was proposed, namely, Ojih-Okeke modified ECA model to predict the transit time of twenty eight fast CMEs from the sun to the earth. This is the first time the Ojih-Okeke modified ECA model is being applied in prediction of transit time of CMEs from the sun to the earth. The proposed modified model was tested using data obtained from coronagraph observations of large angle spectrometric aboard, the Solar and Heliospheric Observatory (SOHO/LASCO) CME catalogue from the period of 1997 to 2015. To ascertain the accuracy of the modified model, the three ECA model of Gopalswamy (G2000, G2001, and VG2002) were applied to our data points. Linear regression analyses were carried out on the data points and scatter plots were generated using excel software package. The average error of the difference between the CMEs transit time and models predicted transit time with their fractional errors were 4.27 h and 0.10 for the Ojih-Okeke modified model; 10.36 h and 0.23 for the VG2002 model; 12.93 h and 0.29 for G2001 model; and 14.42 h and 0.32 for the G2000 model. The proposed modified model has proved very effective in prediction of arrival time of CMEs. It is our recommendation that future work on prediction of the arrival time of CMEs be carried out employing our modified ECA model.   Key words: Coronal mass ejections, arrival time, intense geomagnetic storm, observed transit time, earth and phase.