Abstract

Coronal mass ejections (CMEs) cause various disturbances of the space environment; therefore, forecasting their arrival time is very important. However, forecasting accuracy is hindered by limited CME observations in interplanetary space. This study investigates the accuracy of CME arrival times at the Earth forecasted by three-dimensional (3D) magnetohydrodynamic (MHD) simulations based on interplanetary scintillation (IPS) observations. In this system, CMEs are approximated as spheromaks with various initial speeds. Ten MHD simulations with different CME initial speed are tested, and the density distributions derived from each simulation run are compared with IPS data observed by the Institute for Space-Earth Environmental Research (ISEE), Nagoya University. The CME arrival time of the simulation run that most closely agrees with the IPS data is selected as the forecasted time. We then validated the accuracy of this forecast using 12 halo CME events. The average absolute arrival-time error of the IPS-based MHD forecast is approximately 5.0 h, which is one of the most accurate predictions that ever been validated, whereas that of MHD simulations without IPS data, in which the initial CME speed is derived from white-light coronagraph images, is approximately 6.7 h. This suggests that the assimilation of IPS data into MHD simulations can improve the accuracy of CME arrival-time forecasts. The average predicted arrival times are earlier than the actual arrival times. These early predictions may be due to overestimation of the magnetic field included in the spheromak and/or underestimation of the drag force from the background solar wind, the latter of which could be related to underestimation of CME size or background solar wind density.

Details

Title
Validation of coronal mass ejection arrival-time forecasts by magnetohydrodynamic simulations based on interplanetary scintillation observations
Author
Iwai Kazumasa 1   VIAFID ORCID Logo  ; Shiota Daikou 2 ; Tokumaru Munetoshi 1 ; Fujiki Ken’ichi 1 ; Den Mitsue 3 ; Kubo Yûki 3 

 Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan (GRID:grid.27476.30) (ISNI:0000 0001 0943 978X) 
 Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan (GRID:grid.27476.30) (ISNI:0000 0001 0943 978X); National Institute of Information and Communications Technology, Tokyo, Japan (GRID:grid.28312.3a) (ISNI:0000 0001 0590 0962) 
 National Institute of Information and Communications Technology, Tokyo, Japan (GRID:grid.28312.3a) (ISNI:0000 0001 0590 0962) 
Publication year
2021
Publication date
Jan 2021
Publisher
Springer Nature B.V.
e-ISSN
18805981
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2475611426
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.