Wednesday, 15 July 2015

A More Optimistic Cycle 25


With all of the doom and gloom forecasts for the upcoming solar cycles, I was reminded of the various prognostications that were made for our present Cycle 24. I recall one in particular, made in the winter of 2006 ...

Solar cycle 24, due to peak in 2010 or 2011 "looks like its going to be one of the most intense cycles since record-keeping began almost 400 years ago," says solar physicist David Hathaway of the Marshall Space Flight Center. He and colleague Robert Wilson presented this conclusion last week at the American Geophysical Union meeting in San Francisco.

So much for that prediction!

It seems that at least one group, led by Leif Svalgaard, got it right, as W4ZV recently reminded us on the Topband reflector ...

I had to do a memory refresh but finally recalled that Leif Svalgaard,
accurately predicted Cycle 24 in October 2004. He did not use conveyor
belt theory but polar field measurements:

"Using direct polar field measurements, now available for four solar
cycles, we predict that the approaching solar cycle 24 ( 2011 maximum) will
have a peak smoothed monthly sunspot number of 75 ± 8, making it
potentially the smallest cycle in the last 100 years."

The actual smoothed sunspot peak for Cycle 24 was around 82 in early 2014
(blue line on the graph below). He missed the peak date because it
occurred during the cycle's second peak.

73, Bill W4ZV

But Svalgaard wasn't the only one with an accurate forecast. Searching for a less-gloomy outlook for upcoming Cycle 25, I happened upon a paper by Hamid Helal and A.A. Galal of the National Research Institute of Astronomy and Geophysics, in Cairo. In "An early prediction of the maximum amplitude of the solar cycle 25", the authors cite a methodology that was bang-on for the last three cycles and gives a very optimistic outlook for Cycle 25.

Table 2 gives our prediction for cycle 25 in comparison with the published predictions of other authors in chronologic alphabetic order. It is obvious that our results agree with some contributions and disagree with others. In fact the differences of the predicted strengths by different authors may be attributed to the variety of the used techniques and methodology. Although some authors think that cycle 25 could be one of the weakest in centuries, in contrast, we think that the next cycle will be relatively stronger than cycle 24 and it will have nearly the same strength of cycle 23, i.e. the sunspot maximum may rebound in the near future.


If Cycle 25 is comparable to Cycle 23 it will be happy days again ... it was a very robust cycle and provided several winters of high F2 MUFs, leading to day after day of amazing 50MHz propagation!

I'm somewhat vexed about which scenario I'd prefer, being both an LF'er (quiet, weak cycle) and a diehard 6m guy (chaotic, strong cycle). In any event, Cycle 25 will likely be the last one of any interest to me. I was born at the peak of Cycle 18 ... you do the math!

Obviously it will be a few years yet before we see who is right, but I'm kind of pulling for Helal and Galal's big numbers for one last 6m hoorah!


Gareth Howell said...

Hi Steve
I sympathise and understand your desire for a better cycle 25 etc. Unfortunately, the scientists seem not to have the same view :-)

Take a look at
It covers a new model of the solar cycle, and appears to predict that we are heading for another "Maunder Minimum".

Time to improve those LF antennas.

73, Gareth - M5KVK

Steve McDonald said...

Gareth - apparently you didn't read the previous blog:

It seems that every cycle rollover spawns some new theories (usually to explain why the old one didn't work so well!). At this point in time I'm prepared to give the optimistic outlook as much weight as the double-dynamo theory as both seemed to have accurately predicted the past few cycles...or more likely, the model has been tweaked to jive with the past three cycle's numbers. It will be interesting to see what transpires but I'd sure like to see a better cycle than Cycle 24 as it was just awful. The down-time between 23 and 24 was much more interesting as it produced some truly amazing LF propagation for two winters.

Bren + Lucy said...

Here's hoping what Steve suggests works for us - very frustrated to say the least.