Analysis of the 1.3-1.7 yr Oscillation Relationship between Solar and Geomagnetic Activities
Abstract
The 1.3-1.7 yr periodic study of solar and geomagnetic activities is very important for understanding the possible physical processes in the solar-terrestrial coupling system. The sunspot is the most prominent magnetic field structure in the solar photosphere, and the Ap index is an important indicator of global geomagnetic activity. The 1.3-1.7 yr period of the sunspot number and the geomagnetic Ap index is obtained by the synchro-squeezing wavelet transform, and the phase relationship between them is studied by cross-correlation analysis. The main results are as following: (1) The 1.3-1.7 yr periods of the geomagnetic Ap index and sunspot number exhibit intermittent evolutionary characteristics, and change with time; (2) the geomagnetic Ap index has a higher periodic component in odd solar cycles than the neighboring even solar cycles, which is characterized by fluctuations; (3) the phase relationship between geomagnetic Ap index and sunspot number is not always consistent, in most cases the geomagnetic Ap index lags behind the sunspot number, except in the 18th and 22th solar cycles.
- Publication:
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Acta Astronomica Sinica
- Pub Date:
- January 2019
- Bibcode:
- 2019AcASn..60....3Q
- Keywords:
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- Sun: activity;
- sunspots;
- methods: data analysis