Predictability of geomagnetic series

Abstract

Abstract. The aim of this paper is to lead a practical, rational and rigorous approach concerning what can be done, based on the knowledge of magnetic series, in the field of prediction of the extreme geomagnetic events. We compare the magnetic vector differential at different locations computed with different resolutions, from an entire day to minutes. We study the classical correlations and the simplest possible prediction scheme to conclude a high level of predictability of the magnetic vector variation. The results obtained are far from a random guessing: the error diagrams are either comparable with earthquake prediction studies or outperform them when the minute sampling is used in accounting for hourly magnetic vector variation. We demonstrate how the magnetic extreme events can be predicted from the hourly value of the magnetic variation with a lead time of several hours. We compute the 2-D empirical distribution of consecutive values of the magnetic vector variation for the estimation of conditional probabilities of different types. The achieved results encourage further development of the approach to prediction of the extreme geomagnetic events.

Predictability of volcano eruption: Lessons from a basaltic effusive volcano

“…A very similar simple prediction scheme applies successfully to geomagnetic data [Bellanger et al, 2003]. The significant predictability we obtain here is still concomitant of a fraction of false alarm larger than 90% (Figure 4).…”

“…[13] The performance of our simple prediction algorithm is comparable to the performance of much more sophisticated ones that use numerous seismic parameters to predict large observed earthquakes [e.g., Kossobokov et al, 1999]. A very similar simple prediction scheme applies successfully to geomagnetic data [Bellanger et al, 2003]. The significant predictability we obtain here is still concomitant of a fraction of false alarm larger than 90% (Figure 4).…”

The irregular variations of the external geomagnetic field from Intermagnet data

“…Nevertheless, the auto-correlation drops fast: only 0.35 for a two-day lag, which tends to indicate that long-term prediction is not possible. In a future study (Bellanger et al, 2003), we will apply methods used in seismology, like the (η, τ ) Molchan (1997) diagram, to the forecasting of magnetic activity, using again Y * (k); more precisely, we will assess rigorously the statistical significance of the forecasting. Let us recall that Y * (k), as demonstrated above, is a representation of R * (k) and is of worldwide significance.…”

Decision theory and the analysis of rare event space weather forecasts

“…As discussed in , this metric is applicable for a different class of user than the one considered in this paper. Bellanger et al [2003] considered the prediction of extreme changes in the ground magnetic field using a threshold algorithm in which the relative percentage of unpredicted events to the ratio of time covered by the alerts was plotted.…”