The Sun Had Its Termination Event

I've been tracking and reporting on Solar Cycle 25 since '18 or when folks first started talking about it.  A couple of the most recent pieces (the one before) have focused on the divergence between the behavior of Cycle 25 and the predictions of other scientists.  Prominent in these discussions have been the predictions of Dr. Scott McIntosh of the National Center for Atmospheric Research (NCAR) and his research partner Bob Leamon of the U. Maryland-Baltimore County for a very simple reason: their predictions have matched reality better than the other predictions.  

McIntosh's predictions are based on an observable thing on the sun which they call the “Termination Event” marking the end of the previous cycle and the new cycle being able to develop with less interference.  Their hypothesized pattern is that the shorter the period between the termination event of the second previous cycle (23 in this case) and the termination event of the previous (24), the stronger the new cycle can be.   The converse is true as well; the longer the period between those two (the longer the previous cycle) the weaker the current cycle will be.  It's important to note that this isn't widely accepted; they're still trying to determine if it's true or not by predicting the developing cycle.  If Solar Cycle 25 unfolds as McIntosh and team predict, the Termination Event will have to be taken seriously.  

Dr. McIntosh has reported (and relayed at SpaceWeather.com) that the termination event happened on December 13th of '21. 

Researchers have long known that solar cycles can overlap. The twist added by McIntosh and Leamon is the realization that overlapping cycles interact. This makes sense. In the early 20th century, George Ellery Hale discovered that the magnetic polarity of sunspot pairs reverses itself from one cycle to the next; indeed, the sun’s entire global magnetic field flips every ~11 years. When adjacent, opposite-polarity solar cycles overlap, they naturally interfere.

The Termination Events, then, mark when opposing polarity magnetic fields stop being present, removing inhibitions on the new cycle.  

Dr. McIntosh notes bright areas seen in Extreme Ultra Violet (called BrightPoints) on the surface of the sun and when they go away. A Twitter thread explains this in greater detail.

What does this all mean?  A precise date for the Termination Event of Cycle 24 allows them to use their algorithms to predict what the peak of this cycle will be.  Cycle 24 hung on far longer than his team expected it to and dramatically affected McIntosh's predictions.  His original prediction was for very high levels of activity, perhaps even being the strongest cycle ever seen.  That has been reduced greatly.

“We have finalized our forecast of SC25’s amplitude,” says McIntosh. “It will be just above the historical average with a monthly smoothed sunspot number of 190 ± 20.”

“Above average” may not sound exciting, but this is in fact a sharp departure from NOAA’s official forecast of a weak solar cycle. It could be just enough to catapult Terminators into the forefront of solar cycle prediction techniques.

 

Predictions for Solar Cycle 25. Blue is the “official” prediction of a weak cycle. Red is a new prediction based on the Termination Event. It's still true that their predictions are matching the current cycle better than the NOAA "consensus panel" forecast (in blue) even after shifting their forecast peak date six months earlier.  McIntosh's predictions appear to be six months earlier than that, and maybe more.  I'd also say that red band looks more like 190 ± 40 or even 50 than ± 20.