SOLAR AND GEOMAGNETIC ACTIVITY IN 19-25 CYCLES

Abstract

The paper presents the results of the analysis of changes solar and geomagnetic activity in 19−25 Wolf cycles. A forecast of the maximum geomagnetic activity cycle 25 is made. Solar activity is presented by sunspot number RZ, geomagnetic activity is expressed by the energetic index calculated from the data of the "Lviv" and "Belsk" geomagnetic observatories. By annual averages RZ values, the 11-year window was used to obtain the solar activity minimum (around 1711, 1810, 1901, and 2009). The minimum of 2009 was one of the smallest in the observed data, and we took it as the beginning of the 24th cycle and the 100-year solar activity cycle. The maximum of the 24th cycle occurred in 2014 for RZ and in 2015 for energetic index. Cycle 25 began in 2019 according to RZ, and in 2020 cording to energetic index. For cycles 19−25 solar activity is 1−2 years ahead of magnetic activity. The identified quasi-biennial variations over the studied period and the lag of geomagnetic activity from solar activity allow us to predict the magnitude of geomagnetic activity and its maximum in cycle 25. According to our calculations, the maximum of geomagnetic activity will occur around 2026 and its magnitude will be 1.5−2 times higher than the maximum of the 24th cycle.