INVESTIGATION OF MID-RANGE PERIODICITY DURING SOLAR CYCLE 22 AND 23 USING EMPIRICAL MODE DECOMPOSITION

SOUMYA ROY, JADAVPUR UNIVERSITY

Aim: The data of Mg II core to wing ratio during solar cycle 22 and 23 is undergone for mid-range periodicity analysis. Method: Periodicity analysis has been performed using Empirical Mode Decomposition and Raleigh Power Spectrum Algorithm. Result: Various significant intermediate periodicities are observed in daily Mg II core to wing ratio data. The most significant periods are as follows: (i) the period of 7 days due to the presence of short-lived regions inside the Sun and 27 days due to the existence of rotational modulation; (ii) various mid-range periodicity including 54 days (due to emerging magnetic field inside the Sun), 160 days (due to concentration of a strong magnetic field), annual variation oscillation (328 days), quasi triennial periodicity (3.7 years); (iii) the 10.5 years period associated with the 11-year cycle of the sunspot which implies polarity interchange of the magnetic field of the Sun. The result indicates that that the Mg II core to wing ratio together with the other solar activities are originated from the same location and the Mg II core to wing ratio has a unique signature on the forecasting of space weather.