Publication Date:
2015-11-11
Description:
Geomagnetic indices provide a comprehensive dataset with which to quantify space climate, that is, how the statistical likelihood of activity varies with the solar cycle. We characterize space climate by the AE index burst distribution. Burst sizes are constructed by thresholding the AE timeseries; a burst is the sum of the excess in the timeseries for each time interval over which the threshold is exceeded. The distribution of burst sizes is two-component with a cross-over in behaviour at thresholds ≈1000nT. Above this threshold, we find a range over which the mean burst size varies weakly with threshold for both solar maxima and minima. The burst size distribution of the largest events is exponential. The relative likelihood of these large events varies from one solar maximum and minimum to the next. Given the relative overall activity of a solar maximum/minimum, these results constrain the likelihood of extreme events of a given size.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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