Sunspot activity continues to drop


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NOAA yesterday posted its monthly update of the solar cycle, covering sunspot activity for November. Below is my monthly annotated version of that update.

November 2016 Solar Cycle graph

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

In November sunspot activity dropped again, to the second lowest point seen since 2010. Essentially, activity today is about where it was in 2010 when the solar minimum was finally ending. Now, the solar maximum is ending and we are beginning the next solar minimum.

Throughout the entire just completed solar maximum, the Sun continuously under-performed all predictions. Even now, despite following almost precisely the prediction of the 2007 low prediction during 2014 and 2015, in 2016 the ramp down has begun to slip below that prediction. The trend continues to suggest the arrival of solar minimum will be early, possibly as early as sometime late next year.

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2 comments

  • Florencio Fontecilla

    Robert, you say “essentially, activity today is about where it was in 2010 when the solar minimum was finally ending. Now, the solar maximum is ending and we are beginning the next solar minimum”, but I can’t understand this because the cycles are 11 or 12 years, and if in 2010 we were ending a minimun, how can we being starting another solar minimun in 2016/2017?

  • Florencio Fontecilla: You ask an excellent question. Look closely at the graph above. The last solar minimum officially occurred around January 2009. If we reach solar minimum as early as next year, the cycle will have only been 9 years long. While very short, this is not an unprecedented length for a solar cycle. Since scientists have been counting sunspots, cycles have been as short as 9 years and as long as 13, with most lasting 11 years.

    In the past, however, a short cycle meant a very active Sun, while a long cycle signaled a relatively weak maximum. This time we get a short and weak cycle, something that is unprecedented.

    Despite what I wrote, it is not likely that we will hit minimum in 2017. Based on past history, ramp down will probably take its time, and last until 2018, at the earliest, producing a cycle that is about 10 years long. Still short, but not unusually so.

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