Stereoscopic view on CMEs; differences in predicted CME arrivals based on STEREO-A/STEREO-B HI data
Abstract
Over the last decades numerous models to predict the arrival times and speeds of CMEs (coronal mass ejections) have been developed. They range from computationally very fast drag-based models to expensive MHD models. However, uncertainties in the forecasts are large for all the models available so far. In this study, we use ELEvoHI (ELlipse Evolution model based on Heliospheric Imager observations) ensemble modeling for CME post-event arrival prediction. The model assumes an elliptical shape of the CME front within the ecliptic plane and makes use of time-elongation profiles provided by HI (Heliospheric Imager) onboard the STEREO (Solar TErrestrial RElations Observatory) twin spacecraft. In addition, ELEvoHI utilizes an ambient solar wind provided by the Wang-Sheeley-Arge model to account for the drag force that is exerted on the CME during the propagation in the heliosphere. For this study, we carefully select 12 CMEs between February 2010 and July 2012. The CMEs have to fulfill the following three criteria: 1) clear signatures in STEREO-A and STEREO-B HI images, 2) corresponding in-situ signature, and 3) propagation close to the ecliptic plane. Based on typical input data we analyze the arrival times and speeds of each CME using STEREO-A and STEREO-B time-elongation profiles and compare them with each other. The results show differences up to 10 hours and 200 km/s. We give possible reasons for the discrepancies in relation to the input data and dependencies on the two vantage points.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E1039H