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Reliability of CME speed from single-point observations: Analysis utilizing the Time-of-Arrival on Earth

Evangelos Paouris - National Observatory of Athens, Greece; Angelos Vourlidas - Johns Hopkins University Applied Physics Laboratory, United States; Athanasios Papaioannou - National Observatory of Athens, Greece; Anastasios Anastasiadis - National Observatory of Athens, Greece

Session: Interplanetary CMEs and Solar Particle Events


Two of the most important uncertainties to Space Weather forecasts, since all estimates of the CME Time-of-Arrival (ToA) at a certain point within the heliosphere, utilize as input parameters, are the angular width and the linear speed of Coronal Mass Ejections (CMEs). We present a new twofold approach by applying a limitation to the projected angular width between a lower and an upper width values and a new correction of the CME speed. This method is based on the utilization of the direct height-time measurements for each CME correcting the linear speed from projection effects, resulting in physically reasonable speeds. The assessment of the ToA problem is being studied using the empirical data-driven Effective Acceleration Model (EAM) calculating statistical metrics such as the mean absolute error (MAE) for a sample of 214 CMEs/ICMEs. The MAE shows a clear dependence on the plane-of-sky CME speed. The lower MAE value of 11.6 hours occurs for CMEs with speeds between 691-878 km/s. For the first time, to the best of our knowledge, a further analysis concerning 2nd order speeds at distances from 15 up to 30 solar radii and the impact on ToA problem is presented.

Approaching deadlines:

Registration opens:

16 July 2020

Abstract submission opens:

16 July 2020

European Space Weather Medals:

6 September 2020

Registration deadline:

25 September 2020

Registration deadline: [extended]

10 October 2020

Abstract submission deadline:

4 September 2020