engleski

Drag-based Forecast for CME Arrival

Forecasting the arrival of CMEs is a challenging issue due to ever- changing properties of the interplanetary plasmas through which the CMEs propagate. In this work, we investigate the performance of the recent DBEM model for CME arrival (Dumbović et al., 2018 ; Žic et al., 2015, Vršnak et al., 2013). Our data sample consists of twelve geoeffective Earth-directed fast halo CMEs. We use as input the observed CMEs’ shock speed and the velocity of the respective preceding solar wind. Overall, the model produced a wide distribution of arrival times. The predictions were rather good, being confined in the range of ± 10 h. When matching also the predicted to the observed arrival speeds, the best average result corresponding to +4.5 h CME arrival time was achieved with higher drag than the recommended one. This suggest that the exerted to the CME solar wind drag was higher than anticipated. To investigate further, we looked at details in the outlier events with greatly under- and over- estimated arrival times. Preliminary results showed that the outliers are complex events associated with multiple eruptions at the source regions, implying the importance of the preconditioning of the interplanetary space through which the CMEs are propagating.

coronal mass ejections, space weather

nije evidentirano