Service on Rapid Magnetic Variations
We presented some statistics on actual routine work (number of collaborating
observatories and events reported in the monthly lists) for the period 1995-1996. Then we presented
some statistics on IAGA BULLETIN 32 (1990-1991 period). We noticed that too much events were
reported in the monthly lists. In the process of selection we had to reject 73% of the pretended
SSC events and 68 % of the pretended SFE events.
Then we exposed some problems in the process of identification:
- * Poor coverage of magnetic observatories over the world.
- * Morphology of the events not clear.
- * Definition does not precise limits.
- * Not homogeneous criteria in the observatories.
- * Poor signal/noise ratio.
Some open questions still remains:
- * Meaning of SSC after Mayaud criteria: (Storm - change of rhythm in the agitation).
- * Possible SFE at night (Intrusion of the current system loop in the non-illuminated
hemisphere).
- * SFE only visible in a reduced part of the illuminated hemisphere.
- * SFE without solar confirmation (Hþ, X ray, radio burst).
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