SH21B-2401
Low-Frequency Type II Radio Detections and Coronagraph Data to Describe and Forecast the Propagation of 71 CMEs/Shocks
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Hebe Cremades1, O C St Cyr2, Francisco Andres Iglesias3, Hong Xie4, Michael L. Kaiser2 and Nat Gopalswamy5, (1)UTN-FRM and CONICET, Mendoza, Argentina, (2)NASA Goddard Space Flight Center, Code 670, Greenbelt, MD, United States, (3)Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, (4)Catholic University of America, Washington, DC, United States, (5)NASA Goddard SFC, Greenbelt, MD, United States
Abstract:
Motivated by improving predictions of arrival times at Earth of shocks driven by coronal mass ejections (CMEs), we have analyzed 71 Earth-directed events in different stages of their propagation. The study is primarily based on approximated locations of interplanetary (IP) shocks derived from Type-II radio emissions detected by the Wind/WAVES experiment during 1997-2007. Distance-time diagrams resulting from the combination of white-light corona, IP Type-II radio, and in situ data lead to the formulation of descriptive profiles of each CME's journey toward Earth. Furthermore, two different methods to track and predict the location of CME-driven IP shocks are presented. The linear method, solely based on Wind/WAVES data, arises after key modifications to a pre-existing technique that linearly projects the drifting low-frequency Type-II emissions to 1 AU. This upgraded method improves forecasts of shock arrival time by almost 50%. The second predictive method is proposed on the basis of information derived from the descriptive profiles, and relies on a single CME height-time point and on low-frequency Type-II radio emissions to obtain an approximate value of the shock arrival time at Earth. In addition, we discuss results on CME-radio emission associations, characteristics of IP propagation, and the relative success of the forecasting methods.
