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| Titel |
A statistical study of the performance of the Hakamada-Akasofu-Fry version 2 numerical model in predicting solar shock arrival times at Earth during different phases of solar cycle 23 |
| VerfasserIn |
S. M. P. McKenna-Lawlor, C. D. Fry, M. Dryer, D. Heynderickx, K. Kecskemety, K. Kudela, J. Balaz |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 30, no. 2 ; Nr. 30, no. 2 (2012-02-27), S.405-419 |
| Datensatznummer |
250017188
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| Publikation (Nr.) |
 copernicus.org/angeo-30-405-2012.pdf |
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| Zusammenfassung |
| The performance of the Hakamada
Akasofu-Fry, version 2 (HAFv.2) numerical model, which provides predictions
of solar shock arrival times at Earth, was subjected to a statistical study
to investigate those solar/interplanetary circumstances under which the
model performed well/poorly during key phases (rise/maximum/decay) of solar
cycle 23. In addition to analyzing elements of the overall data set (584
selected events) associated with particular cycle phases, subsets were
formed such that those events making up a particular sub-set showed common
characteristics. The statistical significance of the results obtained using the
various sets/subsets was generally very low and these results were not significant
as compared with the hit by chance rate (50%). This implies a low level
of confidence in the predictions of the model with no compelling
result encouraging its use. However, the data
suggested that the success rates of HAFv.2 were higher when the background
solar wind speed at the time of shock initiation was relatively fast. Thus,
in scenarios where the background solar wind speed is elevated and the
calculated success rate significantly exceeds the rate by chance, the
forecasts could provide potential value to the customer.
With the composite statistics available for solar cycle 23,
the calculated success rate at high solar wind speed, although clearly above
50%, was indicative rather than conclusive. The RMS error
estimated for shock arrival times for every cycle phase and for the
composite sample was in each case significantly better than would be
expected for a random data set. Also, the parameter "Probability of
Detection, yes" (PODy) which presents the Proportion of Yes observations
that were correctly forecast (i.e. the ratio between the shocks correctly
predicted and all the shocks observed), yielded values for the
rise/maximum/decay phases of the cycle and using the composite sample of
0.85, 0.64, 0.79 and 0.77, respectively. The statistical results obtained
through detailed analysis of the available data provided insights into how
changing circumstances on the Sun and in interplanetary space can affect the
performance of the model. Since shock arrival predictions are widely
utilized in making commercially significant decisions re. protecting space
assets, the present detailed archival studies can be useful in future
operational decision making during solar cycle 24. It would be of added
value in this context to use Briggs-Rupert methodology to estimate the cost
to an operator of acting on an incorrect forecast. |
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