by Prof. F. Vahrenholt and F. Bosse, May 7, 2019 in NoTricksZone

If we speak of an average of the last 23 cycles in the months of the minimum, our only significant energy source at the center of the solar system was below average active last month as well.

The sunspot number (SSN) was 9.1, which was thus only 42% of the average of the cycles for month no. 125. Some cycles (No. 21, 18, 16, 15, 8 ) were already completed in month no. 125.

Fig. 1: The monthly sunspot activity of the current solar cycle (SC 24) since December 2008 (red) compared to the mean value of all previously systematically observed cycles since the beginning of SC 1 in March 1755 (blue) and the very similar SC 5 (black).

Figure 1 clearly shows that the latest cycle was quite below-normal, especially at the beginning and after the second peak which had an SSN of over 140 towards the end. Since February 2014 (the maximum of the entire cycle 24 with SSN = 146 in cycle month 63), it only reached 2/3 of the average activity.

What are the effects? The total radiation (TSI for total solar irradiance) is only moderately influenced:

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