[P-EM10] Space Weather and Space Climate

[PEM10-22] Improving Predictions of Geomagnetic Storms

*Nariaki Nitta¹, Meng Jin¹, Kazumasa Iwai² (1.Lockheed Martin Advanced Technology Center, 2.Institute for Space-Earth Environmental Research, Nagoya University)

Keywords:Space Weather, Solar Wind, Coronal Mass Ejections, Geomagnetic Storms, Numerical Simulations, Solar Magnetic Field

Agencies around the world engaged in space weather forecast routinely issue alerts on the arrival of solar disturbances, such as interplanetary coronal mass ejections (ICMEs) and stream interaction regions (SIRs), when some notable events are seen in remote-sensing solar data (e.g., CMEs and their likely low-coronal manifestations, extended coronal holes, etc.). The alerts may even contain predictions of the magnitude of the expected geomagnetic storm. It is now customary to employ advanced numerical models in space weather forecast. However, the performance of predicting geomagnetic storms has not yet risen to an actionable level. One obvious question to ask is if the numerical models are good enough. It may not be easy to answer this question since the models are highly dependent on the input magnetic maps as inner boundary conditions and the solar magnetic field measurement has been made only from the Sun-Earth line, leaving almost 2/3 of the solar surface unfilled with good data. Here we present the results of Sun-to-Earth simulations for two CMEs that produced major geomagnetic storms, one associated with an X-class flare in solar maximum, and another that was stealthy in solar minimum. In the two events, we compare two sets of simulations, SUSANOO and AWSoM, using common magnetic maps. We discuss the importance of modeling the ambient solar wind and its interaction with the CME flux rope at various distances from the Sun, and the value of incorporating information complementary to near-Sun remote-sensing and 1 AU in situ data, such as that coming from IPS observations.