Increased Magnetic Storm Activity from 1868 to 1995
Abstract
The aa index provides the longest continuous data set which can be used in the analysis of magnetospheric and ionospheric phenomenology. All phases of the solar cycle show increases in activity since cycle 14. The activity increase does not appear to be primarily associated with any instrumental, ionospheric or magnetospheric effects. However, some effects have been identified in the long-term change in magnetic latitude of the observatory sites, the positions of high-latitude ionospheric features such as the cusp, and ionospheric Pedersen and Hall conductivities due to changing magnetic field orientation and strength. One of the hardest effects to quantify is the influence of the Earth's decreasing dipole moment. Preliminary results of a study of the characteristics of substorms over the last 130 years are presented with a view to illuminating this question.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2001
- Bibcode:
- 2001AGUSM..SH51A03C
- Keywords:
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- 1600 GLOBAL CHANGE (New category);
- 2400 IONOSPHERE;
- 2700 MAGNETOSPHERIC PHYSICS