Sunspot Double-Peak is Underway

May’s sunspot number is out. No double about it. The predicted sunspot double-peak forecast by NASA scientist Dean Pesnell on March 1st has arrived. It arrived early.

According to the Royal Observatory of Belgium, official keeper of sunspot tallies, May’s sunspot count is 78.7, the highest since November 2011.

That is not all. A far more significant earlier forecast predicts the next solar maximum will be the weakest in over 300 years! As it is, the current solar cycle is the weakest in over 100 years.

An average solar sunspot maximum is 119 sunspots. The current smoothed peak for this cycle stands at 66.9 spots.

The new prediction for the next cycle maximum, Solar Cycle 25, is for a frightening high of only 7 spots! The mid-1600s was the last time a solar maximum was that weak. That was the middle of the little ice age.

Climate change effects, if any, this time around are unknown. But sunspots are going away.

Solar Cycle 25 Prediction

Sunspot peak magnetic field strength is decreasing to zero

The next cycle, Solar Cycle 25, will be dramatically different from any cycle since the 1600s.

A peak of only 7 sunspots is predicted in a remarkably accurate paper presented at the International Astronomical Union (IAU) Symposium #273. It is called, “Long-term Evolution of Sunspot Magnetic Fields” by Penn and Livingston of the National Solar Observatory in Tucson, Arizona.

“Long-term” in this case only means this and the next solar cycle.

This paper is the first to predict the amplitude of Cycle 25 based on empirical data and theory.

It is primarily based on an observed linear decline in sunspot magnetic field strength since the early 1990s and these assumptions:

  • Livingston’s 1998-2008 magnetic field observations are a good proxy
  • 1500 gauss is a real physical lower limit to sunspot formation
  • Magnetic field strength will continue decreasing linearly

At a decrease of 65 gauss/year, they predicted that the current cycle would peak at a smoothed value of 66. According to the Royal Observatory of Belgium, the actual observed cycle maximum right now stands at 66.7. Nobody expects it to change, even with the double-peak.

That makes their forecast of only 7 spots for Cycle 25 look pretty strong.


The current sunspot cycle gets compared to multi-peaked Solar Cycle 14 of 1906

The current sunspot cycle is often compared to Cycle 14. That one had 5 or 6 smoothed peaks spread over a four year period from 1905 to 1909. This one probably won’t be like that.

What’s different about Cycle 14 is that it was sandwiched between two weak, but normal solar cycles. The current cycle, on the other hand, comes after a strong Cycle 23 and will be followed by the weakest cycle in centuries.

Obviously, the conditions for sunspot formation during Cycle 14 were much different than they are for future sunspot formation now. Northern hemisphere sunspot activity this cycle peaked in late 2011 with a smoothed  value of 41.

Southern hemisphere sunspots have been exceptionally weak so far. Its highest smoothed monthly count (so far) is 30.1 in March 2012. That will probably be exceeded in the current 2nd peak. Last month’s unsmoothed count just published by Belgium was 38.9, the highest southern hemisphere count of the current cycle.

However, it is hard to imagine that the current cycle could match Cycle 14 in its 2nd half given that literally every condition related to sunspot formation is way down, or in decline.

Sunspot magnetic field strength decline as of May 2013 (Svalgaard)


We are about half way through the current sunspot cycle, at or near its maximum. It has proven to be an exceptionally weak cycle so far. Officially, it was supposed to peak at 90 last month. It didn’t. It is almost 1/3rd below that.

It is not unusual for a cycle to double-peak or have multiple peaks like Cycle 14 did. That is what is underway at this time.

The current cycle now has two distinct peaks. Will it have more?

Given Penn and Livingston’s results and other research, it is logical to concluded that the current 2nd peak will end this cycle’s major activity within the next couple months and sunspot activity will then slowly sputter a bit as it fades towards sunspot minimum.

Declining umbral magnetic field strength will be watched with braided breath.

If sunspots do not return next cycle as forecast, what effect will it have on climate change?

Tune in again next month for July’s exciting episode of ‘Fading Sunspots‘.


About azleader

Learning to see life more clearly... one image at a time!

Posted on Jun 7, 2013, in Business, Climate, climate change, Energy, environment, news, Politics, science, sunspot activity, sunspot report, Thoughts. Bookmark the permalink. 7 Comments.

  1. Thanks… Astronomy was my college major… I wanted to become an astronomer when I grew up.

    Back then knowledge of the sun was miniscule compared to what we know now. We actually thought the “solar constant” was a constant. lol!!!

  2. I think the global warming modellers use the solar constant assumption. If you are right and we are heading for some kind of Minimum, those times were colder on Earth. Maybe our CO2 warming will exactly offset the solar diminishing, and we will have survived by the luckiest of coincidences. Even today man does not have a full understanding or appreciation for the Great Light-bulb in the sky. Keep watching this for us.

    • The absolute magnitude change in solar energy output during the Maunder Minimum 300 years ago is not enough to explain the coldness of the little ice age.

      If the sun caused the little ice age then it wasn’t directly. It must have been through some unknown related forcing mechanism we might rediscover over the next couple decades.

      These are interesting times in the world of solar physics.

  3. will be watched with braided breath. s/b will be watched with bated breath.

  1. Pingback: Sunspot Cycle Double-Peak Underway? | Inform The Pundits!

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