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Titel |
Substorm classification with the WINDMI model |
VerfasserIn |
W. Horton, R. S. Weigel, D. Vassiliadis, I. Doxas |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1023-5809
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Digitales Dokument |
URL |
Erschienen |
In: Nonlinear Processes in Geophysics ; 10, no. 4/5 ; Nr. 10, no. 4/5, S.363-371 |
Datensatznummer |
250007837
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Publikation (Nr.) |
copernicus.org/npg-10-363-2003.pdf |
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Zusammenfassung |
The results of a
genetic algorithm optimization of the WINDMI model using the Blanchard-McPherron
substorm data set is presented. A key result from the large-scale
computations used to search for convergence in the predictions over the
database is the finding that there are three distinct types of vx Bs
-AL waveforms characterizing substorms. Type I and III substorms are
given by the internally-triggered WINDMI model. The analysis reveals an
additional type of event, called a type II substorm, that requires an
external trigger as in the northward turning of the IMF model of Lyons
(1995). We show that incorporating an external trigger, initiated by a
fast northward turning of the IMF, into WINDMI, a low-dimensional model of
substorms, yields improved predictions of substorm evolution in terms of
the AL index. Intrinsic database uncertainties in the timing
between the ground-based AL electrojet signal and the arrival time
at the magnetopause of the IMF data measured by spacecraft in the solar
wind prevent a sharp division between type I and II events. However,
within these timing limitations we find that the fraction of events is
roughly 40% type I, 40% type II, and 20% type III. |
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