Solar Activity Indices in 21, 22 and 23 Cycles

TL;DR

This study analyzes various solar activity indices over 23 solar cycles, examining their correlations and cyclic variations to better understand solar activity patterns.

Contribution

It provides a comprehensive analysis of multiple solar activity indices and their interrelations across three solar cycles, highlighting cyclic correlation variations.

Findings

Correlation coefficients vary cyclically with a period close to half of the 11-year cycle.

Minimum correlation coefficients occurred in 2001.

Indices W and F10,7 show cyclic correlation variations over multiple cycles.

Abstract

The monthly average values of the main solar activity indices such as Wolf numbers (W), 10,7 cm radio flux (F10,7), 0,1-0,8 nm background, total solar irradiance and Mg II UV-index (280 nm core to wing ratio) were studied for 23 activity cycle. The correlation coefficients of linear regression for main solar activity indices versus F10,7 were analyzed for every year of 23 activity cycle. All the correlation coefficients for 23 activity cycle have the minimum values in 2001. We also analyzed the connection between monthly average values of the most popular indices W and F10,7 for 21, 22 and 23 solar activity cycles. The values of every year linear regression correlation coefficients for W versus F10,7 show the cyclic variations with period closed to half path of so-called 11-year period of solar activity.