The value of CME arrival‐time forecasts for space weather mitigation

Owens, M. J. ORCID: https://orcid.org/0000-0003-2061-2453, Lockwood, M. ORCID: https://orcid.org/0000-0002-7397-2172 and Barnard, L. A. ORCID: https://orcid.org/0000-0001-9876-4612 (2020) The value of CME arrival‐time forecasts for space weather mitigation. Space Weather, 18 (9). e2020SW002507. ISSN 1542-7390 doi: 10.1029/2020SW002507

Abstract/Summary

Severe geomagnetic storms are driven by the coronal mass ejections (CMEs). Consequently, there has been a great deal of focus on predicting if and when a CME will arrive in near‐Earth space. However, it is useful to step back and ask, “How value is this information, in isolation, useful for making decisions to mitigate against the adverse effects of space weather?” While all severe geomagnetic storms are triggered by CMEs, not all CMEs trigger severe storms. Thus even perfect knowledge of CME arrival time will provide `actionable' forecast information only in operational situations where false alarms can be tolerated. Of course, any CME transit model used to predict CME arrival time must also produce an estimate of CME speed at Earth. This can help discriminate between geoeffective and non‐geoeffective CMEs, reducing false alarms and expanding the range of operational scenarios under which a forecast provides value. Thus, from an end‐user perspective, CME arrival speed should form part of the standard metric by which CME transit models are evaluated. Looking to the future, even coarse information about the CME magnetic properties would likely provide even greater forecast value. These points are illustrated by a simple analysis of solar wind data.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/91283
Item Type	Article
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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