Authors: M L Mays A Taktakishvili A Pulkkinen P J MacNeice L Rastätter D Odstrcil L K Jian I G Richardson J A LaSota Y Zheng M M Kuznetsova
Publish Date: 2015/05/13
Volume: 290, Issue: 6, Pages: 1775-1814
Abstract
Ensemble modeling of coronal mass ejections CMEs provides a probabilistic forecast of CME arrival time that includes an estimation of arrivaltime uncertainty from the spread and distribution of predictions and forecast confidence in the likelihood of CME arrival The realtime ensemble modeling of CME propagation uses the Wang–Sheeley–Arge WSA–ENLIL+Cone model installed at the Community Coordinated Modeling Center CCMC and executed in realtime at the CCMC/Space Weather Research Center The current implementation of this ensemblemodeling method evaluates the sensitivity of WSA–ENLIL+Cone model simulations of CME propagation to initial CME parameters We discuss the results of realtime ensemble simulations for a total of 35 CME events that occurred between January 2013 – July 2014 For the 17 events where the CME was predicted to arrive at Earth the mean absolute arrivaltime prediction error was 123 hours which is comparable to the errors reported in other studies For predictions of CME arrival at Earth the correctrejection rate is 62 the falsealarm rate is 38 the correctalarm ratio is 77 and the falsealarm ratio is 23 The arrival time was within the range of the ensemble arrival predictions for 8 out of 17 events The Brier Score for CME arrivalpredictions is 015 where a score of 0 on a range of 0 to 1 is a perfect forecast which indicates that on average the predicted probability or likelihood of CME arrival is fairly accurate The reliability of ensemble CMEarrival predictions is heavily dependent on the initial distribution of CME input parameters eg speed direction and width particularly the median and spread Preliminary analysis of the probabilistic forecasts suggests undervariability indicating that these ensembles do not sample a wideenough spread in CME input parameters Prediction errors can also arise from ambientmodel parameters the accuracy of the solarwind background derived from coronal maps or other model limitations Finally predictions of the K P geomagnetic index differ from observed values by less than one for 11 out of 17 of the ensembles and K P prediction errors computed from the mean predicted K P show a mean absolute error of 13The work was carried out as a part of NASA’s Game Changing Development Program Advanced Radiation Protection Integrated Solar Energetic Proton ISEP project LK Jian acknowledges the support of NSF grants AGS 1242798 and 1321493 ML Mays thanks T NievesChinchilla and BJ Thompson for useful discussions We gratefully acknowledge the participants of the CME Arrival Time Scoreboard kauaiccmcgsfcnasagov/CMEscoreboard The ACE and Wind solarwind plasma and magneticfield data were obtained at NASA’s CDAWeb cdawebgsfcnasagov OMNI data were obtained from NASA’s COHOWeb omniwebgsfcnasagov/coho The Dst geomagnetic index was obtained from the World Data Center for Geomagnetism in Kyoto Japan Estimated realtime planetary K P indices are from NOAA and the NGDC and final definitive K P indices are from the Helmholtz Center Potsdam GFZ German Research Centre for Geosciences The SOHO/LASCO CME catalog is generated and maintained at the CDAW Data Center by NASA and the Catholic University of America in cooperation with the Naval Research Laboratory SOHO is a mission of international cooperation between the European Space Agency and NASA The STEREO/SECCHI data are produced by an international consortium of the NRL LMSAL and NASA GSFC USA RAL and University of Birmingham UK MPS Germany CSL Belgium IOTA and IAS France Some figure colors are based on ColorBrewerorg
Keywords: