Predicting the Time of Arrival of Coronal Mass Ejections at Earth From Heliospheric Imaging Observations. Issue 9 (14th September 2020)

• Record Type: Journal Article
• Authors: Braga, Carlos Roberto; Vourlidas, Angelos; Stenborg, Guillermo; Dal Lago, Alisson; Mendonça, Rafael Rodrigues Souza de; Echer, Ezequiel
• Is Part Of: Journal of geophysical research. Volume 125:Issue 9(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-09-14
• Subjects: Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2020JA027885
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: The time of arrival (ToA) of coronal mass ejections (CMEs) at Earth is a key parameter due to the space weather phenomena associated with the CME arrival, such as intense geomagnetic storms. Despite the incremental use of new instrumentation and the development of novel methodologies, ToA estimated errors remain above 10 h on average. Here, we investigate the prediction of the ToA of CMEs using observations from heliospheric imagers, i.e., from heliocentric distances higher than those covered by the existent coronagraphs. In order to perform this work, we analyze 14 CMEs observed by the heliospheric imagers HI‐1 onboard the twin STEREO spacecraft to determine their front location and speed. The kinematic parameters are derived with a new technique based on the Elliptical Conversion (ElCon) method, which uses simultaneous observations from the two viewpoints from STEREO. Outside the field of view of the instruments, we assume that the dynamics of the CME evolution is controlled by aerodynamic drag, i.e., a force resulting from the interaction with particles from the background solar wind. To model the drag force, we use a physical model that allows us to derive its parameters without the need to rely on drag coefficients derived empirically. We found a CME ToA mean error of 1.6 ± 8.0 h ToA and a mean absolute error of 6.9 ± 3.9 h for a set of 14 events. The results suggest that observations from HI‐1 lead to estimates with similar errors to observations from coronagraphs. Key Points: We study CME propagation relying on simultaneous observations of Earth‐directed CMEs from the inner Heliospheric Imagers onboard STEREO We adopt an elliptical front‐fitting approach to the two HI‐1 viewpoints and use a drag model to simulate the CME propagation We derive a CME time of arrival and speed on arrival mean absolute errors of 6.9 ± 3.9 h and 117 ± 102 km/s for a set of 14 events