What is the likelihood of another solar grand minimum occurring soon?

[davenn]

greeting all

Over the last 2 weeks I have noted the first sunspots of the new solar cycle 25.
How do I know they are spots of the new cycle ?
Because they are higher latitude and opposite magnetic polarity.

Before I show an image, a little history and science. Over the many observed solar cycles, a
feature of the sunspots and the 11 year cycle, is that the spots migrate from higher latitudes
down to the equatorial region of the sun as the cycle progresses. This process produces what is
known as the "butterfly pattern"...

Courtesy NASA

The graph shows approx. 120 years from cycle 12 to cycle 23
The top part of the diagram shows the butterfly pattern and below it, the peaks in each cycle can
be seen in relation to the percentage of the sun's surface covered in sunspots. Basically an
indication of sunspot numbers and the peaks in the numbers.

Now for the spots themselves. Spots and spot groups have magnetic polarities and these
polarities are opposite in the northern and southern hemispheres of the sun. And those polarities
reverse with each new solar cycle. This is known as Hale's sunspot polarity law ...

https://www2.hao.ucar.edu/Education/Sun/hales-sunspot-polarity-law

The left side of the diagram shows a magnetogram from cycle 21 and you can see with the magnetic
polarities that in the northern hemisphere the white areas lead the black areas and that is opposite
in the southern hemisphere.
The right side shows a magnetogram from cycle 22 and you can now see that the polarities in each
hemisphere have swapped. So now we have the big clue for detecting the start of a new solar cycle.
We are looking for high latitude spots in either hemisphere that have opposite magnetic polarities
compared to spots at lower latitudes in the same hemisphere.

OK, let's look at the current cycle 24 polarities. Daily, I download a number of the solar images
from https://umbra.nascom.nasa.gov/images/latest.html . The green and blue Fe ( ionised iron)
the red He, the magnetogram and the intensitygram ( visible light -- shows the actual sunspots)
Below is a magnetogram from the 11 Sept 2018. The left active region is just below the equator
and the right region is just above the equator. Note the magnetic polarities for the different
hemispheres. Southern hemisphere, white is leading the black and the opposite for the region to
the right that in in the northern hemisphere. This is the arrangement for cycle 24.

Come forward a couple of months to this last week and we see that there is now a higher
latitude ( northern hemisphere) active region that has an opposite polarity ...

The large region to the right, altho right on the equator, is part of the northern hemisphere set.
This can be confirmed when it is followed back in time and compared to other regions that are
definitely just on the south side of the equator, as in the previous image.

As the next months and years go by, more high latitude active regions, in both the northern and
southern hemispheres will be seen as the sun moves towards the next solar max in approximately
5 years time.Dave

EDIT: fixed a couple of typos

 

[jedishrfu]

Dave,

This is awesome. Perhaps you could make your post into an insights article for @Greg Bernhardt and get a $25 gift card(?) I think that was his offer for this November. Me, I'm holding out for the Xmas offer ;-).

Back to your post:

How does acoustics play into the sunspot activity? I remember a NOVA show where they mentioned that there were acoustical waves wafting across the Sun's surface and wondered if they played a role in these sunspot cycles.

Here's a link to the NOVA program (@ the 11:24 min mark they mention sound waves):



Here's a reference to Helioseismology:

https://en.wikipedia.org/wiki/Helioseismology

 

[StandardsGuy]

greeting all

Over the last 2 weeks I have noted the first sunspots of the new solar cycle 25.
How do I know they are spots of the new cycle ?
Because they are higher latitude and opposite magnetic polarity.

Now for the spots themselves. Spots and spot groups have magnetic polarities and these
polarities are opposite in the northern and southern hemispheres of the sun. And those polarities
reverse with each new solar cycle. This is known as Hale's sunspot polarity law ...

As the next months and years go by, more high latitude active regions, in both the northern and
southern hemispheres will be seen as the sun moves towards the next solar max in approximately
5 years time.

What is this expected to mean in terms of weather and communications?

 

[anorlunda]

Wow, great post @davenn , How do they measure those magnetic polarities?

 

[davenn]

How does acoustics play into the sunspot activity? I remember a NOVA show where they mentioned that there were acoustical waves wafting across the Sun's surface and wondered if they played a role in these sunspot cycles.

I need to dig a bit deeper to see what I can find out

Here's a link to the NOVA program (@ the 11:24 min mark they mention sound waves):

I hadn't seen that particular doco before, tho am aware of most of what was presented ...
a great video for anyone who wants a good introduction into the workings of the sun and space weather

What is this expected to mean in terms of weather and communications?

It has it's good and bad effects on communications ... a general improvement of long haul (worldwide) HF communications but intense
solar maximums and large flares also cause HF propagation blackouts. With the increased energy input to the Earths atmosphere,
it heats the atmosphere causing expansion and increasing drag on satellites ... Skylab was lost partly for that reason.
more sunspots equals more energy output from the sun which generally relates to a warming of the Earth. Long periods of / deep solar minimums,
eg. the Maunder Minimum is recognised to have produced a mini ice age in the northern hemisphere.

 

[Vanadium 50]

How do they measure those magnetic polarities?

Polarization of atomic spectral lines.

 

[Vanadium 50]

the Maunder Minimum is recognised to have produced a mini ice age in the northern hemisphere.

Is that true? They were certainly coincident, but was it cause and effect?

 

[davenn]

Is that true? They were certainly coincident, but was it cause and effect?

well I did recently see an argument against the Maunder Minimum being the main cause including the wiki quote below ...

from Wiki
https://en.wikipedia.org/wiki/Maunder_Minimum

Little Ice Age
The Maunder Minimum roughly coincided with the middle part of the Little Ice Age, during which Europe and North America experienced colder than average temperatures. Whether there is a causal relationship, however, is still controversial.[13] Research at the Technical University of Denmark and the Hebrew University of Jerusalem has linked large solar eruptions to changes in the Earth's cloud cover and clouds are known to affect global temperatures.[14] The current best hypothesis for the cause of the Little Ice Age is that it was the result of volcanic action.[15][16] The onset of the Little Ice Age also occurred well before the beginning of the Maunder minimum[15], and northern-hemisphere temperatures during the Maunder minimum were not significantly different from the previous 80 years ,[17] suggesting a decline in solar activity was not the main causal driver of the Little Ice Age.

The correlation between low sunspot activity and cold winters in England has recently been analyzed using the longest existing surface temperature record, the Central England Temperature record.[18] They emphasize that this is a regional and seasonal effect relating to European winters, and not a global effect. A potential explanation of this has been offered by observations by NASA's Solar Radiation and Climate Experiment, which suggest that solar UV output is more variable over the course of the solar cycle than scientists had previously thought.[19] In 2011, an article was published in the Nature Geoscience journal that uses a climate model with stratospheric layers and the SORCE data to tie low solar activity to jet stream behavior and mild winters in some places (southern Europe and Canada/Greenland) and colder winters in others (northern Europe and the United States).[20] In Europe, examples of very cold winters are 1683–84, 1694–95, and the winter of 1708–09.[21]

The term "Little Ice Age" applied to the Maunder minimum is something of a misnomer, as it implies a period of unremitting cold (and on a global scale), which was not the case. For example, the coldest winter in the Central England Temperature record is 1683–1684, but the winter just two years later (both in the middle of the Maunder minimum) was the fifth-warmest in the whole 350-year CET record. Also, summers during the Maunder minimum were not significantly different from those seen in subsequent years. The drop in global average temperatures in paleoclimate reconstructions at the start of the Little Ice Age was between about 1560 and 1600, whereas the Maunder minimum began almost 50 years later.[original research?][citation needed]

Maybe they are right ? and the Maunder Minimum just intensified that cooling period ?

On the other hand there was little telescopic observations of the sun prior to them MM period ... The telescope had only been around for
~ 40 years at that time, so maybe the minimum or at least lower activity stretched back even further and can still be directly linked ?
I see graphs showing a maxima of spots prior to the MM period, yet other text states what I said in the first sentence of this paragraph
So who isn't telling the truth ??

Many others still aim in the other direction

http://www.stsci.edu/stsci/meetings/lisa3/beckmanj.html

http://www.solarstorms.org/BerkeleyMaunder.html

for anyone with access to Researchgate ( I don't)
https://www.researchgate.net/publication/234317458_The_Maunder_Minimum_and_Climate_Change_Have_Historical_Records_Aided_Current_Research The big problem is that there is so much sensationalising by various sources

https://www.livescience.com/51597-maunder-minimum-mini-ice-age.html
https://www.livescience.com/61716-sun-cooling-global-warming.html

----------------------

https://earthobservatory.nasa.gov/images/7122/chilly-temperatures-during-the-maunder-minimum
https://www.historicalclimatology.c...r-minimum-new-perspectives-on-an-old-question
http://ossfoundation.us/projects/environment/global-warming/maunder-minimum

a good one...
http://lasp.colorado.edu/sorce/news/2010ScienceMeeting/doc/Session2/2.01_Feulner_ClimateChange.pdfDave

 

[davenn]

Wow, great post @davenn , How do they measure those magnetic polarities?

Here's a page about the instrument that does the imaging of the magnetic field ...

http://hmi.stanford.edu/
This pdf file has detailed info on the actual imaging components ... it gets pretty technical
http://hmi.stanford.edu/doc/Tech_No...ification_HMI_Michelson_Interferometer_DS.pdfDave

 

[jim hardy]

Dave

last night i stumbled across Professor Valentina Zharkova's interesting lecture.

EDIT i see it's picked up by too many "sensationalists" for me to trust.

An amateur's mistake

i apologize

old jim

She has developed a math curve fit for sunspot activity that appears to pretty well match past data as far back as it goes.

What startled me was when she added Rhodes Fairbridge's planetary influence to what she'd calculated with 'dynamo theory' ,
her match got a lot better. (i don't pretend to be well versed in either)

Her presentation is a full hour

and i wouldn't ask you to invest that much time in my amateur question
so if you've not heard of her just dismiss this whole post.

i guess the best way to phrase my question is:
as a layman
i'm curious
Is Ms Zharkova an esteemed solar phycisist ?
Is her premise
of two very stable circulations inside the sun
whose beat frequency,
modulated by solar tides from the planets' gravitational pull,
and manifesting as sunspots and solar system's magnetic field
considered by you folks who've actually studied the sun,
likely ?

My total exposure to solar astronomy is i read Clark's "The Sun Kings" , a history of solar observations and observers ..
So as i said it's an amateur question and an off the cuff response will satisfy me.

We'll see anyway in just a couple years whether she was on to something.

thanks for reading

old jim

 

[davenn]

Dave

last night i stumbled across Professor Valentina Zharkova's interesting lecture.
She has developed a math curve fit for sunspot activity that appears to pretty well match past data as far back as it goes.

.....

old jim

Thanks Jim

I will watch and read through and comment when I get home from work

Dave

 

[jim hardy]

I will watch and read through and comment when I get home from work

dave that's a whole hour presentation and i wouldn't ask you to invest that sort of time .

if you do watch it i'd value your take on it.

I read some of Fairbridge's papers about ten years ago and remember thinking he was on to part of a bigger picture
This i thought might be one more piece
but if it's a wild goose chase , well for me it was an interesting one and no harm done.

It is an honest question with no intent to hijack your thread..

old jim

 

[sophiecentaur]

@davenn
Brilliant thread, thanks for kicking it off.
The other good news is that you will have a chance to use your new kit in anger and not just in hope!

 

[davenn]

Brilliant thread, thanks for kicking it off.

thanks

The other good news is that you will have a chance to use your new kit in anger and not just in hope!

for sure ... I think it's been at least a month since my last imaging session

 

[davenn]

EDIT i see it's picked up by too many "sensationalists" for me to trust.

An amateur's mistake

i apologize

old jim

Hey Jim

no problems ...
I only got to see a little bit of it last nite ( had end of month invoicing to do) and I tend to agree with your commentsD

 

[Genava]

a good one...
http://lasp.colorado.edu/sorce/news/2010ScienceMeeting/doc/Session2/2.01_Feulner_ClimateChange.pdf

If you are more interested about the subject, here the original publications of Feulner:
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010GL042710
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL048529

Another expert on the subject is Mike Lockwood, here two of his recent publications:
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011JD017013
https://link.springer.com/article/10.1007/s10712-012-9181-3

 

[Marisa5]

@davenn

I was curious to get your opinion on the next solar grand minimum. This paper suggests they happen on average every ~400 years and the last one was at the end of the 16th century, so another may occur soon if the proxy methods are strong.

The origin of grand minima in the sunspot cycle
https://arxiv.org/abs/1208.3947