|Fig. 2. Long-term variations of the sunspot-related (full circles, solid line) and non-sunspot-related (open circles, dashed line) geomagnetic activity, moving averages over 30 years with a step of 10 years (climatic normals).|
Solar influences on atmospheric circulation
- a Space and Solar-Terrestrial Research Institute, Bulgarian Academy of Sciences
- b Institute of Atmospheric Physics, Czech Academy of Sciences
Various atmospheric parameters are in some periods positively and in others negatively correlated with solar activity. Solar activity is a result of the action of solar dynamo transforming solar poloidal field into toroidal field and back. The poloidal and toroidal fields are the two faces of solar magnetism, so they are not independent, but we demonstrate that their long-term variations are not identical, and the periods in which solar activity agents affecting the Earth are predominantly related to solar toroidal or poloidal fields are the periods in which the North Atlantic Oscillation is negatively or positively correlated with solar activity, respectively. We find further that solar poloidal field-related activity increases the NAM index, while solar toroidal field-related activity decreases it. This is a possible explanation of the changing correlation between the North Atlantic Oscillation and solar activity.
► Solar poloidal and toroidal fields have different long-term variations. ► The correlation NAO/solar activity changes with the ratio poloidal/toroidal field. ► Solar poloidal field-related activity increases the NAM index. ► Solar toroidal field-related activity decreases the NAM index
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