On the Association of Substorm Identification Methods

Lao, C.J.; Forsyth, C.; Freeman, Mervyn ORCID: https://orcid.org/0000-0002-8653-8279; Smith, A.W.; Mooney, M.K.. 2024 On the Association of Substorm Identification Methods. JGR Space Physics, 129 (9), e2024JA032762. 16, pp. https://doi.org/10.1029/2024JA032762

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Abstract/Summary

Substorms are a rapid release of energy that is redistributed throughout the magnetosphere‐ionosphere system, resulting in many observable signals, such as enhancements in the aurora, energetic particle injections, and ground magnetic field perturbations. Numerous substorm identification techniques and onset lists based on each of these signals have been provided in the literature, but often with no cross‐calibration. Since the signals produced are not necessarily unique to substorms and may not be sufficiently similar to be identified for each and every substorm, individual event lists may miss or misidentify substorms, hindering our understanding and the development and validation of substorm models. To gauge the scale of this problem, we use metrics derived from contingency tables to quantify the association between lists of substorms derived from Super MAG SML/SMU indices, midlatitude magnetometer data, particle injections, and auroral enhancements. Overall, although some degree of pairwise association is found between the lists, even lists generated by applying conceptually similar gradient‐based identification to ground magnetometer data achieve an association with less than 50% event coincidence. We discuss possible explanations of the levels of association seen from our results, as well as their implications for substorm analyses.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1029/2024JA032762
ISSN:	2169-9402
Additional Keywords:	substorm, magnetosphere, system science, aurora particle injections, substorm identification
Date made live:	17 Sep 2024 13:29 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/538033

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1029/2024JA032762

ISSN:

2169-9402

Additional Keywords:

substorm, magnetosphere, system science, aurora particle injections, substorm identification

Date made live:

17 Sep 2024 13:29 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/538033