Solar Cycle 24: June 2015 Update

How Cycle 24 June Sunspot plot will look when the new Sunspot numbering system is used is not yet clear. Using the “old Wolf system” that is the sun-womanInternational Smoothed Sunspot number basis, it would be expressed as 57.2 thirty day average versus last months number of 58.8.   The number for June 2015 is estimated to be 46.9 when the smoothing process is employed. What ever the measuring system, Cycle 24 is still heading downward to a minimum.

In the last posting about the Sunspot number, it was mentioned that the Solar Flux 10.7cm could be used as it has a very good correspondence with Sunspot activity without the need to interpret how many clusters, etc.. To illustrate this correlation, the Solen Chart — Solar Terrestrial Activity Report (below) –shows daily readings of Wolf and NOAA sunspot numbers and F10.7cm solar flux.


The green is the Wolf Sunspot number the red is the NOAA number and the daily F10.7 in black (maybe brown?).   The sunspot and solar flux correlate quite well. The purple line showing the running 90 average shows that solar flux has been declining since January.

Below is the NOAA chart for F10.7cm solar flux from January 2000 to May of 2015. The smoothed curve compares closely to the Sunspot charts.   Could be a good substitute for Sunspots.



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