Solar Cycle 24’s Sunspot number bounced up a little as did the F10.7cm radio flux. However, Cycle 24 is still on track to be the least active Cycle since the first part of the last century. The Sun’s North pole appears to have firmly switched its polarity but the South Pole may be months away from switching its polarity. A cycle’s “maximum” is usually called when both poles have done the swap.
The August Sunspot and the F10.7cm radio flux are shown below (Click on Charts to enhance view):
The Sunspot butterfly diagram for the current cycle and past cycles is shown below:
If you are not familiar with this chart, it is a plot of the Sunspots locations on the Sun’s face as time goes by for Cycles back to 1880 beginning with Solar Cycle 12 continuing on to the partially completed Cycle 24. As the Solar Cycle ages, its Sunspots move toward the Sun’s equator. After a relatively short time of little sunspot activity, a new Solar Cycle’s Sunspots begin at about 30°North and 30°South.
There will be many more Sunspots to be plotted for Cycle 24 before it comes to an end. We do not know how its butterfly diagram will ultimately look, but it is likely to look more like the less robust Cycles 12, 13 and 14 than the more active Cycles 19,20, 21, 22, and 23.
The next posting will include a chart showing the Sun’s polar polarity. The chart will be part of a posting to discuss one of the several methods used to forecast Solar Cycles.