Solar and

geomagnetic activity at 19-24 cycles

Sumaruk Yu., Sumaruk P.

Institute of Geophysics National Academy of

Science of Ukraine, Kiev, Ukraine


According to

instrumental observations at the magnetic observatories of INTERMAGNET

and the data of the international centers on solar–terrestrial

physics, geomagnetic and solar activities reached their maximums late

in the 1950s (Wmax = 190 in 1957). Subsequently, activities

spasmodically decreased.

Geomagnetic and solar activities were lower in cycle 20 (Wmax = 106 in

1964–1976) and were minimal during the growth phase of cycle 24

(Wmax = 62 in 2009–2013).

The GSMF value decreases at solar activity minimums.

Geomagnetic activity sharply decreases and lags behind solar activity

represented by Wolf numbers. The delay time decreases in the course of

time; in cycles 22 and 23, solar and geomagnetic activities developed

in phase.

The abrupt decrease in geomagnetic activity in cycle 24 can be

explained as follows:

(a) the GSMF value decreases;

(b) the 200-year cycle minimum approaches (the minimum is anticipated

in 2050–2060 between cycles 25 and 27;

(c) activity develops at negative GSMF.