A New Prediction Method for the Arrival Time of Interplanetary Shocks

Abstract

Abstract. Solar transient activities such as solar flares, disappearing filaments, and coronal mass ejections (CMEs) are solar manifestations of interplanetary (IP) disturbances. Forecasting the arrival time at the near Earth space of the associated interplanetary shocks following these solar disturbances is an important aspect in space weather forecasting because the shock arrival usually marks the geomagnetic storm sudden commencement (SSC) when the IMF Bz component is appropriately southward and/or the solar wind dynamic pressure behind the shock is sufficiently large. Combining the analytical study for the propagation of the blast wave from a point source in a moving, steady-state, medium with variable density (Wei, 1982;Wei and Dryer, 1991) with the energy estimation method in the ISPM model Dryer, 1990, 1995), we present a new shock propagation model (called SPM below) for predicting the arrival time of interplanetary shocks at Earth. The duration of the X-ray flare, the initial shock speed and the total energy of the transient event are used for predicting the arrival of the associated shocks in our model. Especially, the background speed, i.e., the convection effect of the solar wind is considered in this model. Applying this model to 165 solar events during the periods of January 1979 to October 1989 and February 1997 to August 2002, we found that our model could be practically equivalent to the prevalent models of STOA, ISPM and HAFv.2 in forecasting the shock arrival time. The absolute error in the transit time in our model is not larger than those of the other three models for the same sample events. Also, the prediction test shows that the relative error of our model is ≤10% for 27.88% of all events, ≤30% for 71.52%, and ≤50% for 85.46%, which is comparable to the relative errors of the other models. These results might demonstrate a potential capability of our model in terms of real-time forecasting.

The Physical Processes of CME/ICME Evolution

“…Finally, it should be noted that there are also various forms of empirical forecasting methods that rely on relationships between CME-driven shocks and CMEs, CME-associated flares, or type II radio bursts. Analytical models also exit as well as hybrid approaches that combine components of empirical and analytical models (e.g., Feng and Zhao 2006;Zhao and Dryer 2014;Zhao and Feng 2015;Zhao et al 2016, and references therein).…”

Models of Solar Wind Structures and Their Interaction with the Earth’s Space Environment

“…Using better estimates of the shock velocity than those which had been used earlier they demonstrated a shock prediction accuracy of a few hours with both the HAFv2 and the HHMS models. They also note that the interactions which occur en route to 1 AU cannot be modeled by other models such as the STOA-2 and the Shock Prediction Model (SPM-not to confuse with the ISPM) developed by Feng and Zhao (2006). SPM is an analytical model which was tested by Feng and Zhao (2006) on 165 solar events and shown to perform equally well as the semi-empirical models chosen for reference.…”

“…The results reproduce properly the normalized components of the magnetic field but not the magnetic field strength. Feng et al (2006) proposed a new method of identifying the configuration and boundaries of MCs based on a force-free flux rope configuration. This technique may also be used in other magnetic field configurations.…”

Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

“…As for the prediction of the arrival time of ICMEs at 1 au, various methods have been proposed (Dryer & Smart 1984;Smith & Dryer 1990;Cargill et al 1996;Gopalswamy et al 2000Gopalswamy et al , 2005Feng & Zhao 2006). One of the most typical models is the empirical CME arrival (ECA) model proposed by Gopalswamy et al (2000).…”