Steve Brown: Compilation of Solar Cycle 25 forecasts.

Posted: December 30, 2019 by tallbloke in Forecasting, Natural Variation, Solar physics, solar system dynamics

Contributor Steve Brown has sent me this nice plot he’s made of Solar Cycle 25 forecasts. It’s worth noting that Rick Salvador’s (blue) is the earliest, made back in 2013. The ‘NASA consensus’ forecast (green) is quite similar to Leif Svalgaard’s.

Also of interest is NASA scientist  Irina Kitiashvili’s forecast, made earlier this year. It has similar magnitude to Rick’s, but is billed to start later.

The Sun is a big non-linear beast, and the magnitude of it’s changes in activity are not easy to predict. The next few years will make interesting watching for all solar scientists and researchers.

There are several different prediction methods in play here, and conclusions will be drawn as to which are more useful in the next few years.

UPDATE: Steve has added the monthly percentage of spotless days to the plot.

Easy to use links to the forecasts below.

Monthly mean sunspot number

13 Month moving average sunspot number

Salvador 2013 forecast

Zharkova 2014 forecast

Svalgaard 2018 forecast

Xu 2018 forecast

Kitiashvili 2019 forecast

NASA consensus Dec 2019 forecast

  1. JB says:

    A very nice summary graph to quickly catch some of the prevailing approaches.
    Reminds me of the local TV station weatherman, who offers a prize each year to the person who comes closest to predicting the first day of snow.

  2. tallbloke says:

    Low cycle 24 and onset of minimum is having effects.

  3. oldbrew says:

    ‘Careful to avoid a politically-incorrect narrative contradicting “global warming” mantra, Pálsson simply observed, “It is a fact that it has been colder the last few years. And there was more snowfall in August on the upper part of Langjökull, which is very unusual.” ‘
    – – –
    We hear you 😉

  4. Oldbrew thanks for the Miles Mathis paper- always interesting. Pity about his conspiracy theories, I would rather see the maths. The Fourmilab planetary model is useful -this site has lots of information Go to science-astronomy and space, then solar system live, then click on entire solar system which gives
    Put in 2020-06-31 and get an interesting alignment. In six months time we will know if that means anything.

  5. HM says:

    There a few more planetary gravity theorists than Salvador (above)

    Geoff Sharp, had a prediction seems to be dated 2009
    has cycle 25 shaped to be almost identical to 24 (in the image above this prediction would be most like the green dot prediction)

    Charvatova, you linked to at least once
    maybe did not not predict shape, more of a climate change context

    there is even some a close gas giants gravity + Mercury/Venus/Earth magnetism theory somewhere, way too parametrizable, I imagine

  6. tallbloke says:

    HM: The ‘close gas giants gravity + Mercury/Venus/Earth’ theory is pretty much what Rick Salvador’s model covers. Thanks for the link to Geoff’s prediction, I’ll ask Steve to add it to the plot. Note however, his cycle 24 prediction in his plot was lower than actual by a large margin, so his SC25 prediction will be lower than the NASA consensus.

  7. oldbrew says:

    Reversed Polarity Sunspots Appear on the Sun

    Dec. 24, 2019: Solar Cycle 25 really is coming. Today, for the first time, there are two new-cycle sunspots on the solar disk–one in each hemisphere.
    . . .
    Today’s new-cycle sunspots (along with isolated new-cycle spots earlier this year) suggest that the solar cycle is, in fact, unfolding normally. A new Maunder Minimum does not appear to be in the offing. Forecasters expect Solar Cycle 25 to slowly gain strength in the years ahead and reach a peak in July 2025.
    – – –
    But most of said forecasters struggled with cycle 24.

  8. Hi,

    As well as the Geoff Sharp forecast, I added a forecast from 2006 by NASA. Roger was going to post up the image later.

    Interestingly the Geoff Sharp forecast doesn’t look too bad but for the NASA (Hathaway) forecast they missed cycle 24 by a mile.


  9. tallbloke says:

    Hi Steve and welcome. Plot updated. Worth noting the Sharp series seems to be averaged over a longer period so the baseline at solar minimum isn’t zero. He might weigh in with a comment about where it should be on your plot.

  10. J Martin says:

    Zharkova’s prediction is looking wrong already. Pity, I found her GWPF talk fascinating. Though I notice that she gets the closest to Svalgaard’s peak estimate, both got the peak right last time. I wonder if Miles Mathis has a prediction for solar cycle 25 ?

  11. ren says:

    It seems that activity in both hemispheres will occur at different times. First, spots should appear in the southern hemisphere. Two waves are not in phase.
    “The northern polar field is still gaining strength while the southern polar field reached its peak in November 2015.”

  12. ren says:

    “The northern polar field is still gaining strength while the southern polar field reached its peak in November 2015.”
    “We can conclude with a sufficient degree of confidence that the solar activity in cycles 24–26 will be systematically decreasing because of the increasing phase shift between the two magnetic waves of the poloidal field leading to their full separation into opposite hemispheres in cycles 25 and 26. This separation is expected to result in the lack of their subsequent interaction in any of the hemispheres, possibly leading to a lack of noticeable sunspot activity on the solar surface lasting for a decade or two, similar to those recorded in the medieval period.”;

  13. oldbrew says:

    Wikipedia note:
    The start of solar cycle 25 (as with any other cycle) will be determined restrospectively. Mathematically, this declaration cannot happen less than 7 months after the minimum. Realistically, the declaration must happen some time after this, to discount the possibility of a double trough.

  14. ren says:

    It can be seen that the strength of the solar northern field is constantly increasing, while the southern one is falling.

    Different activity in both solar hemispheres is of great importance, as shown in cycle 24. In cycle 24 there were two separate solar peaks in both hemispheres, which significantly weakened the total solar activity. The more these peaks are not in phase with each other, the weaker the solar cycle will be.

  15. oldbrew says:

    Another nail in the ‘greenhouse gas’ coffin…

    On the Apparent Relationship Between Total Solar Irradiance and the Atmospheric Temperature at 1 Bar on Three Terrestrial-type Bodies
    Earth Sciences
    Volume 8, Issue 6, December 2019

    Robert Ian Holmes, Science & Engineering Faculty, Federation University, Ballarat, Australia


    It has been discovered that there appears to exist a close relationship between relative differences in total solar irradiance and the atmospheric temperature, at a pressure of 1 bar, on all three terrestrial-type bodies which possess thick atmospheres. The apparent relationship is through the quaternary root of total solar irradiance at 1 bar, and applies to the planetary bodies Venus, Earth and Titan. The relationship is so close that the average surface atmospheric temperature of Earth can be easily calculated to within 1 Kelvin (0.5%) of the correct figure by the knowledge of only two numbers, neither of which are related to the Earth’s atmosphere. These are; the atmospheric temperature in the Venusian atmosphere at 1 bar, and the top-of-atmosphere solar insolation of the two planets. A similar relationship in atmospheric temperatures is found to exist, through insolation differences alone, between the atmospheric temperatures at 1 bar of the planetary bodies Titan and Earth, and Venus and Titan. This relationship exists despite the widely varying atmospheric greenhouse gas content, and the widely varying albedos of the three planetary bodies. This result is consistent with previous research with regards to atmospheric temperatures and their relationship to the molar mass version of the ideal gas law, in that this work also points to a climate sensitivity to CO2 – or to any other ‘greenhouse’ gas – which is close to or at zero. It is more confirmation that the main determinants of atmospheric temperatures in the regions of terrestrial planetary atmospheres which are >0.1 bar, is overwhelmingly the result of two factors; solar insolation and atmospheric pressure. There appears to be no measurable, or what may be better termed ‘anomalous’ warming input from a class of gases which have up until the present, been incorrectly labelled as ‘greenhouse’ gases.
    – – –
    Ref 4 in the paper:
    Nikolov, N., & Zeller, K. (2017). New insights on the physical nature of the atmospheric greenhouse effect deduced from an empirical planetary temperature model. Environment Pollution and Climate Change, 1 (2), 112.

  16. oldbrew says:

    Flashback to 2004:

    Sunspot Activity at 8,000-Year High
    October 27, 2004

    Sunspots have been more common in the past seven decades than at any time in the last 8,000 years, according to a new historic reconstruction of solar activity.
    . . .
    The new study, led by Sami Solanki of the Max Planck Institute in Germany, employed a novel approach to pinning down sunspot activity going back 11,400 years.

  17. ren says:

    Increase in magnetic activity in the southern solar hemisphere.

  18. oldbrew says:

    The era of low numbers of sunspot-free days was from solar cycle 17 to 22 (1933-1996).

    This is very obvious from the ‘Spotless days’ column here:

    We’re now back in the era of pre-1933 levels, when sunspots per cycle were always over 500, even over 1000 on one cycle. By contrast they never reached 400 in SC 17-22. Cycle 24 could reach 1000, currently 943.

  19. tallbloke says:

    Vote now!

  20. CP says:

    There is a HUGE error in this article, and I notice this HUGE error has been repeated in the online poll being taken. The error is trying to equate Zharkova’s prediction with that of Svaalgard’s. They are vastly different. Here are a couple of quotes from the Zharkova paper: ” …we predict a noticeable decrease of the average sunspot numbers in cycle 25 to ≈80% of that in cycle 24.” “We can conclude with a sufficient degree of confidence that the solar activity in cycles 24–26 will be systematically decreasing.”

  21. Geoff Sharp says:

    The plot of my forecast is probably a bit too low, the diagram in 2009 is meant to show SC24/25 would be the same as SC5/6, but later I learned the older counts are different to today. In my paper of 2010 I stated SC24/25 should be the same as SC5/6 but that the Layman’s Sunspot Count should be used as the modern count.

    According to the LSC SC24 was very close to SC5.

  22. Geoff Sharp says:

    The solar minimum values of my plot should also go down to the normal baseline.

  23. oldbrew says:

    Stefano Sello 2019 forecast, ‘using a revised nonlinear dynamics method’:

    The predicted peak amplitude for the monthly smoothed sunspot numbers in the next solar
    cycle #25 is near 107±10, peaking around July 2023±1 (see fig.1). This prediction confirms
    the current trend towards progressive reduced solar activity cycles.

    Click to access 1902.05294.pdf

    Fig. 1 gives a ‘Predicted evolution for the solar cycle #25’.
    – – –
    Hathaway 2006 was ‘dropped’ but there’s a newer forecast…

    An Updated Solar Cycle 25 Prediction With AFT: The Modern Minimum
    Lisa A. Upton David H. Hathaway
    First published: 06 August 2018

    Plain Language Summary

    After the exceptionally weak Solar Cycle 24 (SC24), there is considerable interest in accurately predicting the amplitude of the coming Solar Cycle 25 (SC25). In 2016, the Advective Flux Transport (AFT) Model was used to make such a prediction. We now have two additional years of solar data. Here we compare the results of the previous prediction to the observations that have since occurred. We then use the additional two years of data to create an updated prediction, with a much smaller uncertainty. We predict that SC25 will be about slightly smaller (∼95%) the strength of SC24, making it the weakest solar cycle in the last hundred years. We also predict that, like SC24, SC25 will be preceded by a long extended solar minimum. Finally, these results indicate that we are now in the midst of a Modern Gleissberg Minimum. [bold added]

    AFT = Advective Flux Transport model
    – – –
    Charbonneau et al ‘forecast a smoothed monthly international sunspot number (version 2.0) peaking at 89,+29−14 in year 2025.3,+0.89−1.05, with a 6 month onset delay in the northern hemisphere, but a peak amplitude 20% higher than in the southern hemisphere.’

    A Dynamo-based Forecast of Solar Cycle 25 [June 2019]

  24. Geoff Sharp says:

    Thanks for updating my prediction curve Steve, hopefully Roger can also update the plot here.

  25. oldbrew says:

    Miles Mathis weighs in again, pushing his galactic core theory. Looks interesting, haven’t read it all yet.

    The Next Maximum

    If I get hit by a bus tomorrow (knock wood), I want to be sure this data has been published
    with my name on it.

    Click to access corealign.pdf

    – – –
    MM is now predicting a higher solar cycle than most other forecasts. All testable of course, within a few years.

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