Solar cycle #24

[William]

Archibald provides an estimate of how much the earth will cool, due to the delay in the start of solar cycle 24, in this presentation. Archibald’s estimate is a rapid return to planetary temperatures similar to the little ice age.

Archibald notes planetary temperature shows a correlation to solar cycle length. (Solar cycle length is only a proxy method to measure the specific solar magnetic cycle changes that modulate planetary cloud cover. The papers in the comments above provide a description of the detailed hypothesized mechanism.)

http://www.youtube.com/watch?v=DbAe_g41Zl4

Comment/Aside
Archibald also discusses the affect higher CO2 has on C3 plants. Besides growing faster, C3 plants require less water with higher CO2 levels. There were crop failures in northern regions during the little ice age, due to early and late frosts. I believe Archibald’s point is increased food production due to higher CO2 will help offset the negative affects of a rapidly cooling planet.

[Jens]

Sorry, I don't have sufficient knowledge to really comment, but just as a question, is this something that is being discussed by solar researchers in general? I mean, do scientists in general see something abnormal, or is it just one person?

[orionjim]

Sorry, I don't have sufficient knowledge to really comment, but just as a question, is this something that is being discussed by solar researchers in general? I mean, do scientists in general see something abnormal, or is it just one person?

There are quite a few people predicting a weak solar cycle 24; but the guy I would put my money on is Dr. David Hathaway, the sunspot expert from NASA. And what does he say?

"What's wrong with the sun? (Nothing)
http://science.nasa.gov/headlines/y2...ycleupdate.htm


Jim

[William]

In reply to orionjim's comment:

There are quite a few people predicting a weak solar cycle 24; but the guy I would put my money on is Dr. David Hathaway, the sunspot expert from NASA. And what does he say?

Hathaway does say cycle 24 will be a weak cycle. A weak solar magnetic follows a long solar cycle. Solar cycle 23 is a long solar cycle. Solar cycle 22 and 23 were short solar cycles.

Hathaway has also noted that the solar conveyor speed has decreased by 50% which is the lowest ever observed. An abrupt 50% reduction in the solar conveyor speed would indicate that something was changed in the sun. The level of solar magnetic cycle activity in the 20th century was the highest in 10,000 years, so it does seem reasonable that based on the historical record that the period of high solar magnetic cycle activity will abruptly end, particularly as the solar conveyor speed has suddenly abruptly changed. Also there were three papers published in the last five years predicting an imminent Dalton or Maunder like solar minimum. (One paper based on timing found in the paleo record of past solar magnetic cycle minimums, a second paper used a physical solar model, and a third based on past correlation of Dalton and Maunder like solar magnetic cycle minimums on the position and velocity changes of the sun as it moves about its barycenter.)

Archibald makes the statement in his presentation that based on past correlation of planetary temperature on solar cycle length that the planet is about to cool 1.6C. Yes other scientists who studied and publish papers on how the solar magnetic cycle affects planetary cloud cover would support Archibald's statement.

Shivav published an estimate that 75% of the 20th century warming was due to solar magnetic cycle changes. Svensmark in an interview estimated that 85% of the 20th century warming was due to solar magnetic cycle changes. Palle's satellite analysis of planetary cloud cover and his analysis of changes in the earth's albedo by studying the changes in moonshine supports the assertion that roughly 75% of the 20th century warming was due to solar magnetic cycle changes.

[Diamond]

There are quite a few people predicting a weak solar cycle 24; but the guy I would put my money on is Dr. David Hathaway, the sunspot expert from NASA. And what does he say?

"What's wrong with the sun? (Nothing)
http://science.nasa.gov/headlines/y2...ycleupdate.htm


Jim

He's one of many who say there's nothing "wrong" with the Sun (and I agree with him), but one of a very small number of solar scientists who think that SC24 will be as large or larger than SC23.

I am very skeptical of commentators claiming a "Maunder Minimum" style collapse, since the MM took a great many cycles to happen and those cycles happened over the course of a century or more.

Here's the list of predictions for SC24 and beyond. The best you can say about it, is there is "no consensus".

Someone's going to be right (by chance?) and a lot of people are going to be wrong. But that's the fun of science!

[orionjim]

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Hathaway does say cycle 24 will be a weak cycle. A weak solar magnetic follows a long solar cycle. Solar cycle 23 is a long solar cycle. Solar cycle 22 and 23 were short solar cycles.
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I follow the sunspot cycles rather closely and I don’t remember seeing Dr. Hathaway suggesting cycle 24 would be weak. Can you point me to a place where he says that? The link I provided in my post shows his prediction for cycle 24 and he is predicting something like cycle 23 or a strong cycle. If you look at the date on the link it is July 11th of 2008.

Now cycle 25 is another story, Hathaway is predicting will be off the charts to the low side.

Jim

[orionjim]

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Here's the list of predictions for SC24 and beyond. The best you can say about it, is there is "no consensus".

Someone's going to be right (by chance?) and a lot of people are going to be wrong. But that's the fun of science!

Yes I agree; we are going to learn a lot about the sun in the next two solar cycles.

Jim

[William]

In reply to orionjim’s comment:
[QUOTE]I follow the sunspot cycles rather closely and I don’t remember seeing Dr. Hathaway suggesting cycle 24 would be weak. Can you point me to a place where he says that? The link I provided in my post shows his


As David Archibald notes in this presentation and Christensen and K. Lassen state in the below linked paper other the last 300 years there is a direct correlation of solar cycle length and planetary temperature. The shorter the solar cycle the warmer the planet and visa versa when the solar cycle is longer the planet is colder. The solar cycle length is only a proxy to the specific solar magnetic cycle changes that are actually causing the planetary temperature changes. The changes in the earth’s temperature are hypothesized to be due to changes in cloud cover, not due changes in the sun’s output. (i.e. The sun doe not get hotter or colder, but rather causes an increase or decrease in planetary cloud cover which in turn affects planetary temperature.)

http://www.youtube.com/watch?v=DbAe_g41Zl4

Length of the Solar Cycle: An Indicator of Solar Activity Closely Associated with Climate Friss-Christensen and K. Lassen

http://www.sciencemag.org/cgi/conten...t/254/5032/698


As solar cycle 23 is suddenly becoming longer and in the past a longer solar cycle meant an abrupt drop in the earth’s temperature, we can predicted that solar cycle 24 will be a low amplitude cycle.

From a physical standpoint, moving back to the sun, the sudden reduction in the solar conveyor speed means that the magnetic flux from the last solar cycle which moves down from the poles of the sun through the solar convection region slowly so there is time for it be torn to pieces before it can reach the tacholine region (The tacholine region is the term for the narrow region that separates the solar radiative zone and the solar convection zone). The tacholine region is where the new solar magnetic ropes are formed. This explains why a long solar cycle is followed by a very low number of sunspots. The next question is why does a low number of sunspots result in a colder planet earth.

It is not the reduction in the number of sunspots but the reduction in the solar heliosphere (the solar plasma that carries knots of magnetic field out to about the orbit of Saturn.) and the reduction in the solar large scale magnetic field (the longer the cycle the greater is the time for the large scale magnetic field to decay) a decay in the solar large scale magnetic field and less solar wind bursts cause an increased in Galactic cosmic ray (GCR) to strike the earth. (The solar heliosphere deflects the high speed cosmic rays, from striking the earth.)

An increase in GCR causes an increase in cloud forming ions, particularly over the oceans which are ion poor. More clouds colder planet, less clouds warmer planet.

So we know the solar cycle has increased from solar cycle 22, 9.6 years which is the shortest cycle in the twentieth century. Solar cycle 23 is predicted to be around 13.5 years which will, if correct, be the longest cycle since 1786.

While it is correct that only time will tell, paleoclimatic researchers (for example Bond) have found a record of over 70,000 years of this cyclic climatic change. It therefore seems quite likely as we now know what is causing the changes and the solar conveyor speed has abruptly slowed down, that solar cycle 24 will be a very low cycle. A very low, very weak cycle will lead to a weaker and lower cycle which will lead to Maunder minimum.

The key to what starts the Maunder minimum is the specific abrupt motion of the sun that interrupts the tacholine and which causes the solar conveyor to slow down. Solar motion change is caused by the relative position of the large planets, which explains why the occurrence of the cooling events is semi-periodic. (i.e. To predict the solar magnetic cycle changes it is therefore necessary to understand and to take into account the planetary orbits and planetary positions vs the current position and velocity of the sun, not just a simple cycle based on the sun and time.)

[William]

(This piece was missed when I pasted in my comment to orionjim. See above.)

In reply to orionjim’s comment:

I follow the sunspot cycles rather closely and I don’t remember seeing Dr. Hathaway suggesting cycle 24 would be weak. Can you point me to a place where he says that? The link I provided in my post shows his prediction for cycle 24 and he is predicting something like cycle 23 or a strong cycle. If you look at the date on the link it is July 11th of 2008.

Hi orionjim,

I think we can use current solar observations and recent solar research, to predict how the solar magnetic cycle will change. Solar cycle 23 has suddenly increased in length. It was originally predicted to end March, 2007. That date was extended to March, 2008. Solar cycle 23 is predicted to last at least 13.5 years as opposed to cycle 22 which as 9.7 years.

As David Hathaway notes something is and has changed with the sun.

http://science.nasa.gov/headlines/y2..._longrange.htm

May 10, 2006: The Sun's Great Conveyor Belt has slowed to a record-low crawl, according to research by NASA solar physicist David Hathaway. "It's off the bottom of the charts," he says. "This has important repercussions for future solar activity."

"Normally, the conveyor belt moves about 1 meter per second—walking pace," says Hathaway. "That's how it has been since the late 19th century." In recent years, however, the belt has decelerated to 0.75 m/s in the north and 0.35 m/s in the south. "We've never seen speeds so low."

Obviously some large physical force is causing the solar cycle to abruptly increase in length. (See last comment, the physical reason for the sudden change in solar conveyor speed is hypothesized by some researchers to be due to changes in the motion of the sun about its barycenter.)

As others have noted there are cyclic warming and cooling periods in the paleoclimatic record. This paper and the lecture by David Archibald (See last comment) notes the data for the last 300 years shows a correlation of planetary temperature with the length of the solar cycle.

Length of the Solar Cycle: An Indicator of Solar Activity Closely Associated with Climate Friss-Christensen and K. Lassen

http://www.sciencemag.org/cgi/conten...t/254/5032/698

See comment above which is then a summary of other researchers work that provides a mechanism as to how solar magnetic cycle changes are hypothesized to affect planetary temperature. Now following the pattern where the planet cools when the solar magnetic cycle is long. To explain the past cooling a weak magnetic cycle is required to cause the planet to cool. (i.e. Reasoning backwards from the pattern in last 300 years.)

Another factor to explain why the planet is colder when the solar cycle is long is that solar large scale magnetic field decays when the solar cycles are longer. The solar large scale magnetic field has doubled in the 20th century.

“Doubling Sun’s Coronal Magnetic Field in Last 100 years” by Lockwood et al.

http://www.nature.com/nature/journal.../399437a0.html

Here we show that measurements of the near-Earth interplanetary magnetic field reveal that the total magnetic flux leaving the Sun has risen by a factor of 1.4 since 1964: surrogate measurements of the interplanetary magnetic field indicate that the increase since 1901 has been by a factor of 2.3.

As noted in the Lockwood et al's paper the doubling of the large scale solar magnetic field is hypothesized to be due to short solar cycles in the 20th century. So inverting the effect, a longer solar cycle will result in the solar large scale magnetic field decaying and returning to pre 20th century values.

As noted in this paper by Solanki et al. solar magnetic cycle activity was very high in the 20th century as compared to the past.

From Solanki, Usokin, Kromer, Shussler, Beer's, 2004 paper "Unusual activity of the Sun during recent decades compared to the previous 11,000 years"

"According to our reconstruction, the level of solar activity during the last 70 years is exceptional, and the previous period of equally high activity occurred more than 8000 years ago. We find during the past 11,400 years the Sun spent only of the order of 10% of the time at a similar high level of magnetic activity and almost all of the earlier high-activity periods were shorter than the present episode."

[orionjim]

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I think we can use current solar observations and recent solar research, to predict how the solar magnetic cycle will change. Solar cycle 23 has suddenly increased in length. It was originally predicted to end March, 2007. That date was extended to March, 2008. Solar cycle 23 is predicted to last at least 13.5 years as opposed to cycle 22 which as 9.7 years.

As David Hathaway notes something is and has changed with the sun.

http://science.nasa.gov/headlines/y2006/10may_longrange.htm
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If you go to the NASA link in your post and look at the chart labeled: “Sunspot Cycles: Past and Future” you will see Hathaway’s prediction for cycle 24 along with Mausumi Dikpati's prediction. Hathaway’s prediction is a little less than Dikpati’s, but both are high; both predictions are based on the Sun’s Meridional flow but Dikpati’s also factors in magnetic memory of past cycles making hers higher.

If you check out this NASA site:
http://solarscience.msfc.nasa.gov/predict.shtml you will see predictions that factor in the Earth’s magnetic field are among the most reliable.

Among the most reliable techniques are those that use the measurements of changes in the Earth's magnetic field at, and before, sunspot minimum. These changes in the Earth's magnetic field are known to be caused by solar storms but the precise connections between them and future solar activity levels is still uncertain.

I found the link that Diamond had in his post to be most helpful:

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Here's the list of predictions for SC24 and beyond. The best you can say about it, is there is "no consensus".

Someone's going to be right (by chance?) and a lot of people are going to be wrong. But that's the fun of science!

The list shows 33 different methods that solar scientists have used to calculate what solar cycle 24 will look like. Most on the list are predicting solar cycle 24 will be average or above in strength.

As Diamond said: “Someone’s going to be right (by chance?) and a lot of people are going to be wrong.”

The great thing is; in the next 10 – 13 years we will learn a lot. It’s going to be fun to watch.

Jim

[William]

In reply to orionjim's comments

If you go to the NASA link in your post and look at the chart labeled: “Sunspot Cycles: Past and Future” you will see Hathaway’s prediction for cycle 24 along with Mausumi Dikpati's prediction. Hathaway’s prediction is a little less than Dikpati’s, but both are high; both predictions are based on the Sun’s Meridional flow but Dikpati’s also factors in magnetic memory of past cycles making hers higher.

The list shows 33 different methods that solar scientists have used to calculate what solar cycle 24 will look like. Most on the list are predicting solar cycle 24 will be average or above in strength.

Hathaway’s prediction for cycle 24 does not take into account the physical fact that the tacholine (Tacholine is the name for the narrow region which is the transition from the solar radiative zone to the solar convection zone) has been interrupted. As noted in this paper by Hathaway published in Dec. 1993, Hathaway’s prediction model is not a physical based model and will fail if there are physical changes in the sun.

Some of the 33 solar prediction methodologies in Diamond’s list are of the same type as Hathaway (non-physical models) the non-physical models incorrectly predict cycle 24 will be a moderately high cycle.

If you look Diamond’s list of 33 model predictions, the models that predict cycle 24 will be a low magnetic cycle; do not just look at last the cycle to make their prediction. As noted above (See the link to the three papers that are predicting cycle 24 will the start of either a Dalton or Maunder like minimum.) based on long term solar cycle behavior or based on changes in solar motion as it moves about its barycentre (The change in solar barycentre motion is probably the forcing function that has caused the interruption at the tacholine.) solar cycle 24 will be very weak which is a lead in to a Dalton or Maunder minimum.


http://solarscience.msfc.nasa.gov/pa...chmann1994.pdf

The Shape of the Sunspot Cycle By David Hathaway, Robert Wilson, Edwin Reicheman, Dec, 1994

The temporal behavior of a sunspot cycle, as described by the International sunspot numbers, can be represented by a simple function with four parameters: starting time, amplitude, rise time, and asymmetry. Of these, the parameter that governs the asymmetry between the rise to maximum and the fall to minimum is found to vary little from cycle to cycle and can be fixed at a single value for all cycles. …

Ideally, a theoretical model of the solar dynamo should provide the basis for observations of the physical processes on the Sun that are relevant to the workings for the dynamo itself. Observations of the rotation, magnetic field, and velocity field of the Sun would then provide the initial conditions for calculations of future solar activity levels. However, good working models of the solar dynamo have not yet been developed. Furthermore, if the dynamo is concentrated at the base of the convection zone (my comment: The tacholine), the observations themselves may be difficult to obtain. Nonetheless, preliminary work in that direction shows some promise.

Specifically how quickly the sun can move to a Maunder minimum is not known. There is however in the paleoclimatic record semi-periodic severe planetary cooling events. There is in the paleoclimatic records evidence of cosmogenic isotopes which indicate the sun was in a deep solar magnetic minimum at the same time as those events. It was only in the last 7 years that a mechanism as been developed to explain how an interruption in the solar magnetic cycle could cause the planet to abruptly cool.

Supporting my comments that the fact solar cycle 23 is suddenly lengthening, is an indication of a cycle event which is precursor for a Dalton or Maunder minimum, is this paper by Rogers and Richards.

“Long-term variability in the Length of the Solar Cycle” By Michael Rogers, Mercedes Richards, July 2006

http://arxiv.org/abs/astro-ph/0606426v3

Detailed models of the solar cycle require information about the starting time and rise time as well as the shape and amplitude of the cycle. However, none of these models includes a discussion of the variations in the length of the cycle, which has been known to vary from ~7 to 17 years. The focus of our study was to investigate whether this range was associated with a secular pattern in the length of the sunspot cycle. To provide a basis for the analysis of the long-term behavior of the Sun, we analyzed archival data of sunspot numbers from 1700 - 2005 and sunspot areas from 1874 - 2005. The independent techniques of power spectrum analysis and phase dispersion minimization were used to confirm the ~11-year Schwabe Cycle, and to illustrate the large range in the length of this cycle.

The median trace analysis suggested that the cycle length had a period of 183 - 243 years, while the more precise power spectrum analysis identified a period of 188 ± 38 years. We found that the 188-year cycle was consistent with the variation of sunspot numbers and seems to be related to the Schwabe Cycle. We found a correlation between the times of historic minima and the length of the sunspot cycle such that the length of the cycle was usually highest when the actual number of sunspots was lowest. The cycle length was growing during the Maunder Minimum when there were almost no sunspots visible on the Sun. This information can now be used to improve the accuracy of the current solar cycle models, to better predict the starting time of a given cycle.

[orionjim]

Hi William,
My concern with your posts was you were saying that Hathaway is predicting a weak cycle 24. I try to keep up with what’s going on and have never seen where Hathaway predicted a weak cycle 24.

Hathaway does say cycle 24 will be a weak cycle. A weak solar magnetic follows a long solar cycle. Solar cycle 23 is a long solar cycle. Solar cycle 22 and 23 were short solar cycles.
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You and I aren’t going to decide if cycle 24 will be weak or strong, only time will tell. Who’s right or wrong in 11 to 13 years doesn’t matter; what matters is what was learned. We are all going to learn a great deal about how the solar dynamo works and the effects it has on climate.

Jim

[John-X]

Greetings everyone.

Something I haven't seen mentioned in the posts so far, and something that is quite relevant, is the strength of the magnetic field at the solar poles.

At this point in the cycle (very near solar minimum), the magnetic field strength should be concentrated at the solar poles. (It can concentrate at the poles because of solar differential rotation - the poles are a "safe harbor," away from rotational effects). From the poles it descends, is carried toward the equator, with eruptions along the way appearing as sunspots.

Direct observations of the magnetic field strength at the solar poles are available beginning in 1976 - see Stanford's Wilcox Solar Observatory graph of this series

http://wso.stanford.edu/gifs/Polar.gif

The recent polar field is significantly lower than during the previous 3 solar cycles, and the weakest ever directly observed.

So, since in the solar dynamo model, the source of sunspots at solar maximum is the magnetic field strength that accumulated in the poles at solar minimum, and the solar polar magnetic field is now the weakest ever directly observed, just where are the Cycle 24 sunspots going to come from?

see Ken Schatten's paper, "Solar Cycle #24 and the Solar Dynamo," which includes his prediction and explains his methodology

http://ntrs.nasa.gov/archive/nasa/ca...2007033016.pdf

[orionjim]

Hi John,
Welcome to BAUT.

Greetings everyone.
Something I haven't seen mentioned in the posts so far, and something that is quite relevant, is the strength of the magnetic field at the solar poles.
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You're right about that; the fact Schatten's method was ranked number one on the list provided by Diamond should mean something:

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Here's the list of predictions for SC24 and beyond. The best you can say about it, is there is "no consensus".

Someone's going to be right (by chance?) and a lot of people are going to be wrong. But that's the fun of science!

The method of prediction used by NASA’s David Hathaway and NCAR’s Mausumi Dikipati both use Meridional Flow or the concept of a magnetic conveyor and they are #6 and #7 on Diamond’s list.

What makes them unique is they (hopefully) can predict two cycles ahead by analyzing the speed of the magnetic conveyor of the past cycles.

Dikipati’s theory is that this conveyor transports imprints of sunspots that have occurred over the previous two cycles. And I think Hathaway is using statistics rather than the theory of imprints (I could be wrong on this).

AFAIK Shatten’s method and the other methods only rely on the previous cycle.

Thanks for including Shatten’s paper, I enjoyed reading it.

Jim

[William]

Hello John X. I second Orionjim's comment and would recommend Schatten's paper, there are a number of interesting ideas in that paper. Schatten is proposing a different mechanism for the source of the solar magnetic field. I will compare it to Eugene Parker's mechanism, which has the magnetic ropes for the sun spots produced in the narrow region (tacholine) which is the region where the solar radiative zone changes to the convection zone.

In reply to Orionjim,

We should know by the end of the year, for sure by this time next year, if the end of cycle 23 is the beginning of a Maunder minimum. Maunder minimums require an abrupt sever interruption of the solar cycle. The sun does not gradually cycle by cycle slow down.

The solar cycle prediction methods which Schatten noted are none physical can work from time to time, when the sun is cyclically changing. When the sun has been interrupted, a physical based model is required to predict what will happen next, as the normal cycle mechanism is broken.

If what we are observing is the beginning of a Maunder minimum the large scale magnetic field will drop even further (I believe it the large scale magnetic field has an e-folding time of four years.) and there will be months upon months of no sunspots. After a specific length of extreme lows, the sun cannot restart its cycle using the normal mechanism and process.

I would expect if there is additional observational data to support a move to a Maunder Minimum, that one of the specialists in solar field will take a chance and make a prediction. I have seen a couple of papers noting recent asymmetry in the sun and there were the three paper that predicted a imminent Maunder minimum. Besides that, and Hathway's comment in 2006 concerning the abrupt slow down in the solar conveyor to the lowest level ever observed, the solar specialists have been silent.

The following is what I could find concerning the Maunder Minimum.

http://cc.oulu.fi/~usoskin/personal/Miyahara_AG06.pdf


The Solar Cycle at Maunder Minimum Epoch. By H.Miyahara, D. Sokoloff, and Ilya Usoskin

Let us summarize the main features of the Maunder Minimum (MM) according to the available data. The MM is considered as an example of Grand minima when the intensity of solar activity cycle diminishes drastically and a specific state of solar activity occurs. A Grand minimum epoch is substantially longer than a solar activity cycle, and therefore cannot be related to as an unusual cycle. Transition from normal activity to the MM was very abrupt compared to the typical time scale of the solar cycle.

On the other hand, the recovery of activity at the end of the minimum was gradual and took several decades. Because of the gradual recovery, the total duration of a minimum is not well-defined (Eddy defined the MM duration as 1645–1715). Roughly we can define the deep phase as 1645–1700, when sunspots occurred seemingly sporadically without an apparent cyclic behavior, while the whole minimum was extended until ca. 1712, including the very tiny but regular solar cycle 1700–1712. Cyclic activity did not completely disappear even during the deep minimum but was reduced to a level that is sub-threshold for sunspot formation.

The Maunder Minimum and the Solar Dynamo By D. Sokoloff

http://www.ingentaconnect.com/conten...00001/00004176

Based on archival observations of solar activity, we suggest a scenario for the Maunder minimum, and compare to what extent this is reproduced by dynamo models of Grand minima. In particular, we argue that the transition into the Maunder minimum was very abrupt, while the end of Maunder minimum was gradual, however, rather rapid as well.

[orionjim]

William,
Thank you, thank you, thank you.

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The following is what I could find concerning the Maunder Minimum.

http://cc.oulu.fi/~usoskin/personal/Miyahara_AG06.pdf
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That paper contained some information I’ve been searching for:

Another interesting fact is that it is possible to build butterfly diagrams for some periods of the MM, thanks to the archives of the French astronomy school. The butterfly diagram was strongly asymmetric during theMM with the majority of spots observed in the Southern solar hemisphere This fact is very important for understanding the Grand minimum scenario as discussed in Sec. 3.1.

I have been working on a solar dynamo model and like any model - the Maunder Minimum creates serious problems. For my model to work during the Maunder Minimum it would need to be asymmetric during that period of time (either favor the northern or southern hemisphere). The sun would also appear larger in diameter which I have found accounts that it did. I have been looking for information if the sunspot pattern was asymmetric and that paper points me in a direction to search.

My calculations show a minimum starting in 2020 which is close to Hathaway’s cycle 25 prediction. An interesting note my calculations missed the start of the Maunder Minimum by ~10 years; so if cycle 24 is the start of the minimum it will match the Maunder Minimum, meaning I will need to tweak my model a little.

Thanks for the link to the paper, it really helps.

Jim

[John-X]

Thanks to both orionjim and William for comments.

Of particular note in Schatten's paper is his Figure 7.

Where is solar minimum in this forecast? Somewhere in the "flat line" on the left (Schatten's latest estimate for Solar Minimum: July 2009)

When is Solar Max? Late 2013!

The "average" solar cycle of approximately 11 years is usually 4 years of "rise time" to solar max, followed by 7 years of "fall time" to solar minimum.

Cycle 23 officially began May 1996. Official max was June 2000, a near "perfect" 4 year rise. "Fall time" is now just over 8 years. According to Jan Janssens

http://users.telenet.be/j.janssens/SCtabellen/Dia2.GIF

in only 4 other cycles has fall time exceeded 8 years (96 months) - none in the last 100 years.

A July 2009 minimum would make Cycle 23 just over 13 years long (about 157 months).

Again from Janssens table, that would make Cycle 23 the 2nd longest in history - 2nd only to Cycle #4 (at 169 months) which preceded the Dalton Minimum.

Schatten's model admits a timing error of +/- 1 year. Therefore, if his model is correct, Solar Minimum could be as early as now-ish, or as late as mid 2010!

Schatten's model is indeed a physics-based model. The actual physics of the solar dynamo are still unknown, so all we have is models of how it is believed the physics of the real sun operates.

The original dynamo model proposed by the Babcocks was a more shallow model, similar to what Schatten and others have returned to, in an effort to resolve some of the inadequacies of the "deep" dynamo models developed subsequent to the Babcocks.

One very serious question, which all models must address, is where does the extra energy come from for particularly active cycles?

And where does it go, at particularly inactive periods, such as the one we now seem to be in?

Ken Schatten has noted the frequent appearance of low latitude coronal holes - very unusual at solar minimum - and has wondered if perhaps these features allow magnetic field strength, instead of being swept to the poles by normal meridional flow to become part of the next sunspot cycle, to instead reconnect at low latitudes, and through the coronal hole, "escape" into interplanetary space with the solar wind, leaving the sun "drained" of magnetic energy for the upcoming cycle.

[orionjim]

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The original dynamo model proposed by the Babcocks was a more shallow model, similar to what Schatten and others have returned to, in an effort to resolve some of the inadequacies of the "deep" dynamo models developed subsequent to the Babcocks.

One very serious question, which all models must address, is where does the extra energy come from for particularly active cycles?

And where does it go, at particularly inactive periods, such as the one we now seem to be in?
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You nailed the biggest problem any solar dynamo model has to overcome; does the sun just shut down? And if it does how does it get going again!

I think with the tools we have today when we hit another minimum we might be able to put more of the puzzle pieces together.

A site I found that has a good collection of these tools is (what else but) http://www.solarcycle24.com .

Another site I found that has a dialog between Lief Svalgaard and David Archibald is:
http://www.climateaudit.org/?p=2868

Lief had the 3rd rated prediction on the list provided by Diamond (see post #35 of this thread). Lief’s method uses the polar magnetic field and he is predicting a lower number than Schatten. And David Archibald is the person in the youtube video William posted in #31 on July 23 2008.

Jim

[William]

Thanks for the links orionjim.

The following is the NASA by month high and low solar forecast. The low forecast would have the sun spotless to around February, 2009.

http://www.swpc.noaa.gov/ftpdir/weekly/Predict_high.txt

http://www.swpc.noaa.gov/ftpdir/weekly/Predict_low.txt

[William]

Hello John X. and Orionjim,

I have re-looked at Jack Zircher’s discussion of the pros/cons of the different solar dynamo mechanisms from his book “Journey from the Center of the Sun”. (I would recommend Zircher’s book.)

Do you see a possible mechanism to create a Maunder minimum phase with Gene Parker's modification to the Babcock solar dynamo?

The following is paraphrased from chapter 13, Solar and Stellar cycles.

Bacock’s model:
Bacock’s model has the solar magnetic field starting with a weak polar field that lies in the convection zone and connects the sun’s poles in the solar corona. Differential motion of the convection zone wraps the north-south field lines around the solar equator, creating a band of toroidal magnetic ropes in each hemisphere. The wrapping process is hypothesized to reach some critical limit (around 3000 gauss) in a few years.

Gene Parker’s Criticism of the Bacock Mechanism, and his proposed Alternative:
As others had noted, the convection zone would tear up the weak polar to polar field. Computer modeling by Gary Glatzmeier using the Babcock mechanism did not match observation. Glatzmeier found sunspots in the simulations migrated toward the poles rather than toward the equator. In addition the helioseismic observations showed that for each solar latitude that the top and bottom of the convection zone had the same speed. (i.e. There was no radial variation in speed.)

Parker’s calculation indicated that the magnetic ropes formed would rise to the surface in much less than 11 years and would rise with a magnetic field strength much less than 3000 gauss. Also calculations showed that a magnetic field strength of 10,000 to 30,000 gauss is required to avoid being ripped to pieces as it rises through the convection zone.

Theorists’ calculations supported the assertion that a magnetic rope would remain submerged in the radiative zone/convection zone interface, if the convection zone slightly overshot the radiative zone, to create an active region. The theoretical calculations indicated a magnetic rope of up 100,000 gauss could be formed in that region.

As the radiative zone is believed to rotate as a single mass without differential rotation and the convection zone rotation varies with latitude there is a shearing motion at the interface to stretch and strength the magnetic field lines.

Parker’s modification to the Babcock model has to separate where the Alpha and Omega magnetic field line modifications take place, rather than have both field modifications hypothesized to take place in one region. The Omega affect has assumed to take place at the radiative zone to convection zone interface and the Alpha effect at the sun’s surface.

In the radiative zone there is no convection and little turbulence which allows the weak seed magnetic fields to build up, strengthened by the shearing motion of the convection zone as it moves across the radiative zone.

According to Zicker, two theorists MacGregor and Charbanneau have incorporated Parker’s ideas into a more sophisticated model, that takes into other complications. The simulations according to Zicker support the mechanism, although additional work needs to be done.

[John-X]

...
According to Zicker, two theorists MacGregor and Charbanneau have incorporated Parker’s ideas into a more sophisticated model, that takes into other complications. The simulations according to Zicker support the mechanism, although additional work needs to be done.

Charbonneau has an online mini-book - "Dynamo Models of the Solar Cycle"

http://solarphysics.livingreviews.or...5-2/title.html

Also, today is the first of the month, and the SIDC (Solar Influences Data Center) has updated the sunspot numbers for July - as a graph here

http://sidc.oma.be/html/wolfjmms.html

and as a table here

http://sidc.oma.be/products/ri_hemispheric/

The "harvest" of sunspots continues to be pitiful.

The drought goes on.

[William]

Thanks again John and Jim.

This appears to be an exciting time for solar research. There are a number of competing solar dynamo theories and there is indication the sun is moving to a Maunder minimum.

I am still working to understand the competing mechanisms and trying to understand what creates a Maunder minimum. I am going to read through Paul Charbonneau’s review summary that is linked to in Jim X’s above comment.

Recently published work seems to supports Jack Zirker’s 2002 comments in his book Journey from the center of the Sun that the magnetic ropes that form the sunspots are likely created in the solar tacholine. This paper outlines the hypothesized structure of the solar tacholine based on the most recent solar helioseismology observations and on theoretical calculations.

Specifically how a tachocline based mechanism functions and how what is happening in the tachocline is linked to observations on surface of the sun does not seem to resolved as of yet. The second paper linked to below discusses a hypothesis to explain the observed variance (if I understand the second paper) of the solar magnetic field along the axis of the sun.

Structure and Stability of the Solar Tachocline by G. Rudiger and L. Kitchatinov

http://www.iop.org/EJ/abstract/1367-2630/9/8/302

The strong rotational shear inside the tachocline is believed to be important for the solar magnetic activity (Hughes et al 2007). Even the solar cycle may originate from the tachocline or its vicinity (Rüdiger and Brandenburg 1995). Also other stars with convective envelopes will possess tachoclines. Strong differences in the magnetic activity between fully convective stars which cannot have tachoclines and solar-type stars with their convective envelopes can then be expected (cf Donati et al (2007)).

The solar tachocline parameters are well known from helioseismology. The tachocline thickness is about 4% of the solar radius, its midpoint radius is (0.692 ± 0.005)R⊙, and it is slightly prolate in shape (Antia et al 1998; Charbonneau et al 1999b; Kosovichev 1996). The tachocline is located mainly if not totally beneath the base of the convection zone at Rin = 0.713R⊙ (Basu and Antia 1997; Christensen-Dalsgaard et al 1991) in the uppermost radiative zone.

The presence of a meridional flow with an amplitude of a few metres per second at the bottom of the convection zone is shown as necessary for the magnetic tachocline model. The flow provides the confined geometry of the internal magnetic field (with field lines parallel to the outer spherical boundary) which is necessary for the tachocline formation. The bottom flow is also a key ingredient of advection-dominated dynamo models for the solar cycle (see Rüdiger and Hollerbach (2004) for detailed references). The flow is indeed predicted theoretically but its existence is not yet confirmed by observations. We hope, of course, that helioseismology will soon probe the deep meridional flow.

http://arxiv.org/abs/astro-ph/9812464v1

Transport Effects in the Evolution of the Global Solar Magnetic Field by K. Petyrovay, G. Szakaly

The time–latitude distribution of the axisymmetric component of the large scale solar magnetic fields is known to have a pronounced poleward branch at higher latitudes (Stenflo, 1988, 1991, 1994; Stenflo and Gudel, 1988; Ribes and Bonnefond, 1990; Mouradian and Soru-Escaut, 1991). This branch is also present in the butterfly diagram of a number of tracers of the magnetic field such as quiescent filaments, polar faculae, or the coronal green line (Callebaut and Makarov, 1992; Makarov and Sivaraman, 1989; Leroy and Noens, 1983). Several conflicting explanations exist for this polar branch. Noting that the separation latitude of the two branches, 30–40◦, approximately coincides with the latitude where the radial differential rotation changes sign according to helioseismology, one group of theories interprets it as the surface reflection of a high-latitude poleward propagating dynamo wave, coexisting with the low-latitude equatorward wave (Gilman, Morrow, and De Luca, 1989; Belvedere, Pidatella, and Proctor, 1990, 1991). The Parker–Yoshimura rule of sign (Belvedere, 1985) then naturally leads to the correct directions of propagation if α is negative, as expected in the lower overshooting layer where the dynamo should operate. (In fact this is only so for certain latitudinal profiles of α, cf. Schmitt, 1993.) The most modern version of these models, also incorporating some transport effects, is due to Rudiger and Brandenburg (1995). In what follows we will refer to these models as double wave models.

In our axisymmetric model of the passive transport of the large-scale mean poloidal magnetic field in the solar convective zone we found that the latitudinal distribution of the field at the surface reflects the conditions at the bottom of the convective zone, i.e. in this regard the convective zone behaves as a “steamy window”. This is due to the fact that with realistic values of the transport coefficients diffusivity is prevalent over all other effects. Passive transport theories of the origin of the poleward branch of the solar butterfly diagram are thus not viable, while double wave models are supported by these results. Owing to the large diffusivity the phase delay of the surface poloidal field relative to the bottom poloidal field is minimal. Coupled with the approximately π phase difference between the toroidal and poloidal field components for negative value (Dikpati and Choudhuri, 1995), this could bring the double wave models to accordance with the observed phase relationship.

[orionjim]

[…]
This appears to be an exciting time for solar research. There are a number of competing solar dynamo theories and there is indication the sun is moving to a Maunder minimum.

I am still working to understand the competing mechanisms and trying to understand what creates a Maunder minimum. I am going to read through Paul Charbonneau’s review summary that is linked to in John X’s above comment.
[…]

I agree, it's going to be exciting (and maybe a little boring with no sunspots).

When thinking about the Solar Dynamo I found Hathaway’s NASA site listing what we don’t know about the Solar Dynamo helpful:
http://solarscience.msfc.nasa.gov/dynamo.shtml

Also about four years ago I attended NASA’s Sun Earth Connection seminar and one of the speakers was Pete Riley. Pete’s talk was about the “Currentsheet”; the largest single thing in our solar system. I was blown away. This is a NASA site that talks about it:
http://science.nasa.gov/headlines/y2...rrentsheet.htm

And this is a paper about it:
http://www.docstoc.com/docs/798430/M...cle-variations

The inward and outward flows shown in the SOHO’s Coronagraph 2 and Coronagraph 3 are part of the currentsheet. To me, this is one thing you want to watch if/when we do start into a minimum.

Jim

[orionjim]

[…]
Charbonneau has an online mini-book - "Dynamo Models of the Solar Cycle"

http://solarphysics.livingreviews.or...5-2/title.html
[…]

Thanks for the link John. It will keep me busy for awhile.

[…]
The "harvest" of sunspots continues to be pitiful.

The drought goes on.

Isn’t it strange how “nothing” can be so exciting?


Jim

[Atraveller]

Looks like a sunspot may be forming - finally.

http://www.spaceweather.com/

[Jens]

Is it forming? A look at spaceweather.com today shows the sun is blank apparently.

[Superluminal]

SOHO hasn't updated their images since the 21st, any thing wrong with SOHO?

[Swift]

SOHO hasn't updated their images since the 21st, any thing wrong with SOHO?

I recall from another thread that it is undergoing some sort of maintenance, like baking out the CCD.

[William]

This paper by Livingston and Penn is interesting. A group of solar researchers have been measuring sunspot magnetic field strength by spectral analysis. The sunspot magnetic field causes splitting of spectral lines (Zeeman effect). The spectral splitting varies depending on the strength of the sunspot magnetic field, so by measuring the amount spectral splitting in the sunspot, it is possible to determine the magnetic field in the sunspot and how the sunspots' magnetic field strength is changing.

What the researchers found is there has been a steady reduction in sunspot magnetic field strength. The last observation in the paper has for 2005. Extrapolating the graph from 2005 the sun will no longer be able to produce sunspots in 2015, as the magnetic ropes produced will not survive the trip through the convection zone.

Also as the authors note as the sunspot magnetic field weakens, the sunspot becomes warmer. As relative difference in temperature of sunspot to surrounding solar surface is reduced there will be no visual indication of a sunspot.

The paper in question has submitted to Nature and was rejected, possible as the paper provides no explanation as to why the sunspot magnetic field strength is linearly dropping, beyond the obvious that this type of event appears based on the analysis of cosmogenic varying isotopes on the earth appears to occur cyclically. The amount of cosmogenic isotopes increases when the solar magnetic cycle is weak. The Maunder minimum being but one example of a weak or interrupted solar magnetic cycle.


Sunspots may vanish by 2015, W. Livingston & M. Penn

Sunspot umbral magnetic fields also show systematic temporal changes during the observing period as demonstrated by the sample spectra in Figure 1. The infrared Fe 1564.8 nm is a favorable field diagnostic since the line strength changes less than a factor of two between the photosphere and spot umbra and the magnetic Zeeman splitting is fully resolved for all sunspot umbrae. In a histogram plot of the distribution of the umbral magnetic fields that we observe, 1500 Gauss is the smallest value measured. Below this value photospheric magnetic fields do not produce perceptible darkening. Figure 3 presents the magnetic fields smoothed by a 12 point running mean from 1998 to 2005. The ordinate is chosen so that 1500 G is the minimum. A linear fit to the changing magnetic field produces a slope of 77 Gauss per year, and intercepts the abscissa at 2015. If the present trend continues, this date is when sunspots will disappear from the solar surface. (Italics include in paper. my comment.)

http://www.astroengine.com/?p=678

The graph below is from the paper and was copied from the above link that discusses the paper.

[George]

That's interesting. Here is their paper.

Livingston is a solar veteran, and perhaps Penn is, too. I wonder if anything new has come forth since this 2006 work?