Fig. 4

Statistical analysis on the FS3 anomalies in combination with sunspot numbers. a Relationship between solar cycle variations and the number of the FS3 anomalies. The two dash lines denote solar minimum and solar maximum. The blue asterisks denote the yearly averages of daily sunspot numbers for individual years. The red squares indicate the numbers of the FS3 anomalies for individual years. b Relationship between the occurrence rate of the FS3 anomalies and sunspot numbers. The green histogram illustrates the days in terms of sunspot numbers during the mission period of FS3. The red squares represent the occurrence rates of the FS3 anomalies in terms of sunspot numbers