Rieger-type periodicities on the Sun and the Earth during solar cycles 21 and 22
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Rieger-type periods of the magnetic sunspot area time series have been found in two atmospheric time-series variables: neutron monitor count rate and atmospheric electric potential gradient. The data considered comprises two solar cycles (21, 22) and spans from 1978 to 1990. The study reveals the existence of similar and correlated features in sunspot area as well as neutron counts and atmospheric electric potential gradient, favoring the possibility that the Sun’s activity affects the Earth’s atmosphere and weather at a time scale between 150–300 days. Moreover, five different Rieger-type periods in the sunspot area time series are found, four of which are detected in the neutron monitor count rate, and three in the atmospheric electric potential gradient. These values are consistent with the periods predicted for stationary solar Rossby waves existing inside the Sun. The possibility is discussed that instabilities on the solar magnetic field caused by solar Rossby waves in the Sun’s interior might indirectly be affecting the activity of the heliosphere and the Earth’s atmosphere.
KeywordsSolar physics Space–Earth weather Surface Earth’s atmosphere Atmospheric electricity
Gratitude is expressed to Cláudia Serrano and Samuel Bárias for digitalizing the PG data recorded by Doctor Mário Figueira (former Portuguese Service of Meteorology). The authors are thankful to the Climax Neutron Counter Facility for access to the NC time series and to NOAA for making available the SSA data. Gratitude is also expressed for ELECTRONET (CA15211) COST-Action.
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