Article published on Nature.com predicts new Maunder Minimum

[Emilio Petrozzi]

What do you think of this article published on Nature.com?

Article Published: 24 June 2019
Oscillations of the baseline of solar magnetic field and solar irradiance on a millennial timescale
V. V. Zharkova, S. J. Shepherd, S. I. Zharkov & E. Popova

... Until recently, solar activity was accepted to be one of the important factors defining the temperature on Earth and other planets. In this paper we reproduced the summary curve of the solar magnetic field associated with solar activity5,6 for the one hundred thousand years backward by using the formulas describing the sum of the two principal components found from the full disk solar magnetograms. In the past 3000 years the summary curve shows the solar activity for every 11 years and occurrence of 9 grand solar cycles of 350–400 years, which are caused by the beating effects of two magnetic waves generated by solar dynamo at the inner and outer layers inside the solar interior with close but not equal frequencies6.

The resulting summary curve reveals a remarkable resemblance to the sunspot and terrestrial activity reported in the past millennia including the significant grand solar minima: Maunder Minimum (1645–1715), Wolf minimum (1200), Oort minimum (1010–1050), Homer minimum (800–900 BC) combined with the grand solar maxima: the medieval warm period (900–1200), the Roman warm period (400–10BC) etc. It also predicts the upcoming grand solar minimum, similar to Maunder Minimum, which starts in 2020 and will last until 2055.

https://www.nature.com/articles/s41598-019-45584-3

Edited August 1, 2019 by Emilio Petrozzi

[Alva3]

At first glance, the most striking thing to me is the > 550 yr. increase to the forecast made by the author about 4 years ago (https://www.nature.com/articles/srep15689 

--  and  --  http://computing.unn.ac.uk/staff/slmv5/kinetics/zharkova_iau335_paper1.pdf)  despite use of the double dynamo model in both. 

[theartist]

Evaluation of the planetary positioning over time does indicate that there is a recurring cycle of ~360 years (your cited source says "350-400 years and calls it a "grand solar cycle").  But the similarity between planetary positions of adjacent "grand solar cycles" is not exact; with each successive "grand solar cycle" advancement into the future, there is some clocking advancement of Neptune/Uranus, and some recession of Pluto. This is clearly seen looking at the following two figures.

As I recently posted in this thread, here is the planetary positioning at the Jupiter/Saturn conjunction ~360 years ago: 

 

Below is the positioning in contemporary times, with the Jupiter/Saturn conjunction to occur on 21 December 2020:

 

However, the recurring planetary positioning discussed above actually can be seen every ~180 years (and it may account for the 'Suess-DeVries cycle').  We can see at the time of the Jupiter/Saturn conjunction ~180 years ago (figure below), Uranus is not as far clocked rearward as it was ~360 years ago, and Pluto is not as far recessed as it is today:

Here are facts to consider:

1. our planetary positioning was closer to that observed ~180 years ago than it was to that observed ~360 years ago;
2. the Smoothed maximum ISN in the solar cycle ~180 years ago, i.e., SC8, was 244.9 (and was 219.9 soon thereafter in SC9).

In light of those factual considerations solely with regard to planetary positioning (apart from other considerations, like the most recent Bremen Composite record being discussed in this thread), it is difficult (if not implausible) to draw the conclusion that our current planetary positioning will result in Maunder Minimum conditions.

Edited August 2, 2019 by theartist

[theartist]

On 8/2/2019 at 4:12 AM, theartist said:

Here are facts to consider:

1. our planetary positioning was closer to that observed ~180 years ago than it was to that observed ~360 years ago;
2. the Smoothed maximum ISN in the solar cycle ~180 years ago, i.e., SC8, was 244.9 (and was 219.9 soon thereafter in SC9).

However, as a counterpoint, something else to consider is where the timing of the sun's dynamo falls in relation to the planetary positioning.  ~180 years ago, the Saturn/Jupiter conjunction happened 1.4 yrs before the "Start" of SC9, so that when SC9 started, Jupiter had a decent angular advancement away from Saturn:

The Jupiter/Saturn conjunction in SC25 does not happen until December 2020, and it will be almost 2.5 years from now (in January 2022) before the angular advancement of Jupiter beyond Saturn is similar to what it was at the start of SC9:

On 8/2/2019 at 4:12 AM, theartist said:

it is difficult (if not implausible) to draw the conclusion that our current planetary positioning will result in Maunder Minimum conditions.

The above statement needs clarification. Absolutely, our current planetary positioning is similar (not exact) to what happened ~360 years ago.  Where the planetary positioning falls in relation to the phasing of the solar dynamo could possibly affect, maybe significantly, the consequent solar activity of the cycle.

However, I wish to separate the idea of solar activity ~360 years ago from the climatic conditions ~360 years ago.  There is a lot of scientific evidence to suggest that the 'Little Ice Age' started long before the Maunder Minimum, and volcanic activity may have been one significant contributor to causing cold conditions in the 'Little Ice Age'.

Edited August 16, 2019 by theartist

[theartist]

In addition, consider that if planetary positioning has been suppressing sunspot activity in recent years, then possibly this suppressing activity has 'turned-the corner', per discussion in this thread.

Edited August 16, 2019 by theartist

[theartist]

Over on the  Ap & aa Indices and Solar Minimum thread, we are kind-of seeing a 4-cycle repetition pattern showing up in the aa-Index plot. One might kind-of see it in the 400-yr Sunspot plot (source), too, annotated below:

Two of the 4-cycles is the duration (approx.) of a Gleissberg Cycle.   

'The Atmosphere Guy' was suggesting he saw a large sinusoid in the classic Butterfly Diagram, and in the aa-Index chart.  Consider a large sinusoid pattern in the 400-yr Sunspot chart, as follows:

 The chart above does kind-of suggest a repeating pattern, where the average sunspot number (SSN) of the first half-sinusoid of a full 16-Schwabe-cycle sinusoid is of lesser magnitude than the average SSN of the second half-sinusoid. The average SSN of the first full sinusoid (starting in ~1657) drawn above is less in magnitude than the average SSN of the second full sinusoid (starting in ~1833).

SC8 was the first Schwabe cycle in the second sinusoid drawn above, and SC24 was the first Schwabe cycle in the current 16-cycle sinusoid in progress.  The first sinusoid drawn above started out in the Maunder Minimum, and its first Schwabe cycle was (obviously) of less intensity than SC24, and SC24 was of less intensity than SC8.  It stands to reason that SC25 (the second cycle of the large sinusoid in progress) would be of intensity between that of SC9 and of the solar cycle starting in ~1668.  Also, since SC9 was of lower intensity than SC8, it might suggest that SC25 will be of lower intensity than SC24.

Edited August 31, 2019 by theartist
Added term "in progress" for clarification.

[theartist]

I just came across some information regarding the potential consequences to the Total Solar Irradiance in an era of lower sunspots.  The most shocking thing to me is that this is rarely, if ever, mentioned in the online debates regarding a potential impending Grand Solar Minimum.

The statement comes from Leif Svalgaard (probably one of the more recognized contemporary solar physicists) in the article, Solar activity – past, present, future, (J. Space Weather Space Clim. 3 (2013) A24 DOI: 10.1051/swsc/2013046):

"the number of visible spots in the next cycle (and perhaps beyond) may fall to values not seen since the Maunder Minimum, but without dramatic changes in the emerging magnetic flux. Without the dark spots, Total Solar Irradiance might even be a bit higher."

In the typical discussion on the matter, such as the article Global Warming vs. Solar Cooling: The Showdown Begins in 2020, this contrarian view is not discussed.

Any comment on this information, Emilio Petrozzi?

Edited September 17, 2019 by theartist