Sensitivity of Model Estimates of CME Propagation and Arrival Time to Inner Boundary Conditions

Abstract Accurately forecasting the arrival of coronal mass ejections (CMEs) at Earth is important to enabling mitigation associated space weather risks society. This only possible with accurate modeling event. To do so, we must understand propagation a CME through heliosphere and quantify performance models comparison spacecraft observations. For 12 December 2008 Earth‐directed event, compute ensembles using HUXt solar wind model analyze distortion structured explore hindcast time error (ATE). By highlighting impact shape has on Root‐Mean‐Square‐Error (RMSE) values, show that time‐elongation profiles fronts captured by Heliospheric Imager (HI) instruments onboard NASA's STEREO mission match those modeled nose flank can therefore be used infer details longitudinal extent CME. We then accounting for enable estimates Earth. achieved either observations multiple features in HI data evolution or mapping back lower inner boundary allow CMEs distorted close Sun. event studied these approaches resulted reduced RMSEs 0.73° 0.64° an ATE 1 hour 3 hours respectively.