A New Method Based on the STOA Model to Forecast Shock Arrival Times Using Coronal Mass Ejection Observations

Predicting the shock arrival times (SATs) at Earth is crucial in space weather forecasting. Various models have been developed to predict SATs. The shock time of arrival (STOA) model is based on metric type II radio burst data to provide the initial shock speed. However, it cannot make a prediction when metric type II radio burst data are not available. Therefore, in this work, we obtain a new model in the framework of the STOA model, STOAC, by calculating the shock transit time with the initial shock speed using coronal mass ejection (CME) data instead of type II radio burst observations. Our results show that STOAC has similar prediction skills to the traditional STOA model, so that, in the absence of type II radio burst data, the STOAC model provides a viable alternative for SAT prediction if CME data are available. Furthermore, we introduce a hybrid model, STOARC, which combines the STOA model with the STOAC model, and which can be used when both type II radio burst data and CME data are available, providing the initial shock speed. The STOARC model demonstrates a clear improvement in overall forecast skill compared to STOA and STOAC. This work may be used to improve space weather forecasting in the future.