Testing the Empirical Shock Arrival Model using Quadrature Observations

摘要

The empirical shock arrival (ESA) model was developed based on quadraturedata from Helios (in-situ) and P-78 (remote-sensing) to predict the Sun-Earthtravel time of coronal mass ejections (CMEs) [Gopalswamy et al. 2005a]. The ESAmodel requires earthward CME speed as input, which is not directly measurablefrom coronagraphs along the Sun-Earth line. The Solar Terrestrial RelationsObservatory (STEREO) and the Solar and Heliospheric Observatory (SOHO) were inquadrature during 2010 - 2012, so the speeds of Earth-directed CMEs wereobserved with minimal projection effects. We identified a set of 20 full haloCMEs in the field of view of SOHO that were also observed in quadrature bySTEREO. We used the earthward speed from STEREO measurements as input to theESA model and compared the resulting travel times with the observed ones fromL1 monitors. We find that the model predicts the CME travel time within about7.3 hours, which is similar to the predictions by the ENLIL model. We also findthat CME-CME and CME-coronal hole interaction can lead to large deviations frommodel predictions.