From UCAR: Extended solar minimum linked to changes in Sun’s conveyor belt
BOULDER—A new analysis of the unusually long solar cycle that ended in 2008 suggests that one reason for the long cycle could be a stretching of the Sun’s conveyor belt, a current of plasma that circulates between the Sun’s equator and its poles. The results should help scientists better understand the factors controlling the timing of solar cycles and could lead to better predictions.
The study was conducted by Mausumi Dikpati, Peter Gilman, and Giuliana de Toma, all scientists in the High Altitude Observatory at the National Center for Atmospheric Research (NCAR), and by Roger Ulrich at the University of California, Los Angeles. It appeared on July 30 in Geophysical Research Letters. The study was funded by the National Science Foundation, NCAR’s sponsor, and by NASA’s Living with a Star Program.
The Sun goes through cycles lasting approximately 11 years that include phases with increased magnetic activity, more sunspots, and more solar flares, than phases with less activity. The level of activity on the Sun can affect navigation and communications systems on Earth. Puzzlingly, solar cycle 23, the one that ended in 2008, lasted longer than previous cycles, with a prolonged phase of low activity that scientists had difficulty explaining.
The new NCAR analysis suggests that one reason for the long cycle could be changes in the Sun’s conveyor belt. Just as Earth’s global ocean circulation transports water and heat around the planet, the Sun has a conveyor belt in which plasma flows along the surface toward the poles, sinks, and returns toward the equator, transporting magnetic flux along the way.
“The key for explaining the long duration of cycle 23 with our dynamo model is the observation of an unusually long conveyor belt during this cycle,” Dikpati says. “Conveyor belt theory indicates that shorter belts, such as observed in cycle 22, should be more common in the Sun.”
Recent measurements gathered and analyzed by Ulrich and colleagues show that in solar cycle 23, the poleward flow extended all the way to the poles, while in previous solar cycles the flow turned back toward the equator at about 60 degrees latitude. Furthermore, as a result of mass conservation, the return flow was slower in cycle 23 than in previous cycles.
In their paper, Dikpati, Gilman, and de Toma used simulations to model how the solar plasma conveyor belt affected the solar cycle. The authors found that the longer conveyor belt and slower return flow could have caused the longer duration of cycle 23.
The NCAR team’s computer model, known as the Predictive Flux-transport Dynamo Model, simulates the evolution of magnetic fields in the outer third of the Sun’s interior (the solar convection zone). It provides a physical basis for projecting the nature of upcoming solar cycles from the properties of previous cycles, as opposed to statistical models that emphasize correlations between cycles. In 2004, the model successfully predicted that cycle 23 would last longer than usual.
According to Dikpati, the duration of a solar cycle is probably determined by the strength of the Sun’s meridional flow. The combination of this flow and the lifting and twisting of magnetic fields near the bottom of the convection zone generates the observed symmetry of the Sun’s global field with respect to the solar equator.
“This study highlights the importance of monitoring and improving measurement of the Sun’s meridional circulation,” Ulrich says. “In order to improve predictions of the solar cycle, we need a strong effort to understand large-scale patterns of solar plasma motion.”
About the article
Title: Impact of changes in the Sun’s conveyor-belt on recent solar cycles
Authors: Mausumi Dikpati, Peter Gilman, Giuliana de Toma, and Roger Ulrich
Publication: Geophysical Research Letters
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Clearly, it’s caused by CO2.
As has been pointed out (correctly) time and again, a “cold” object can cause a nearby “hot” heat source to get hotter. Man, with his universe-destroying CO2 emissions, is increasing the temperature of the earth which radiates some of its heat back towards the sun.
This causes a small, but significant, heating of the solar surface above what Mother Nature intended and disrupts the natural circulatory systems there. Worryingly, although the effect is tiny, there will be feedback involved which will amplify the effect in time – more heating of the sun = more heating of the earth = more heating of the sun…..
Having done some rough calculations on a postage stamp I estimate that, if we continue to produce CO2 at current rates, the end result will be for the sun to explode in about 5 billion years. But that’s assuming that our emissions stay constant. In fact they’re increasing so this catastrophe could happen at any time!!!!
Hey Dikpati, groping in the dark?, what if grid voltage has lowered?
Ken,
I also am no expert on solar physics.
My prospective is that once the study of nature goes beyond what is directly perceivable via the evidence of the human senses, then you get to the most interesting part of science because it is more challenging. Human nature being what it is then I think no mystery of the universe, especially the sun, will withstand the human mind’s ability. My pro-human cheerleading ends. : )
I estimate that the current situation wrt to unraveling the sun is it is a ‘constantly developing work-in-progress”. And probably the result of the effort is going to be non-linear with the amount of time or money spent.
John
These Birkeland words, speaking about his terrella EXPERIMENT (not a model) which applies also to the Sun, says it all:
“if the globe is magnetised, even very slightly, the patches from which the disruptive discharges issue, arrange themselves then in two zones parallel with the magnetic equator of the globe; and the more powerfully the globe is magnetised, the nearer do they come to the equator “
So, the “power” varies during the cycle and during bigger cycles.
There are not any pantyhose´s loosen elastics here
Laughing at Tallbloke and Ken. Really funny.
Tallblokes site is worth visiting. I think that research into solar phenomena is going to take off in all directions following the unexpected (maybe not so) SC24 stall.
I know that Theodor Landscheidt is not a favourite of Anthonys but his ideas, although not as refined as such, hold more water and display more predictive power than the recent predictions of our current solar experts.
Ed Fix says:
August 17, 2010 at 2:58 am
Interesting bit of modeling, but it ultimately explains nothing. The hypothesis is that the stretched-out meridional flow prolonged Cycle 23. The un-asked question is: what stretched out the meridional flow?
Hi Ed I was interested in your graph that appeared in David Archibald’s latest book. We might be on the same page, I also ask the question why don’t they know why the conveyor belt changed.
Maybe they should ask us?
Mausumi…come on!, you already played and lost, it´s the turn for the other kids to play now!
You said this was gonna be a big cycle, don´t change it now!
H.R. says:
August 17, 2010 at 2:27 am
Geoff Sherrington says: “Sure beats me how you gather data to model the interior of the sun when you don’t even know its composition. Besides, if you look at it too long it hurts your eyes.”
“You do it at night ;o)”
That’s almost true. One of the standard techniques is to use an occulter disk (which could be the Earth or the Moon, or something much smaller and much closer) to block out the bright disk and let you see the interesting stuff going on at the rim.
Filing this one under “Wild A$$ed Guesses”, with the sub-heading “supported by pretty charts, some code that makes a computer do really cool tricks, and lots of public funding”.
Right? Wrong? Who knows. Can’t discount the ‘even a blind squirrel’ phenom.
Ken,
I think one important thing which is done is to measure the vibrations of the sun. Just as we use vibrations of the earth (from earth quakes) to determine the structure of the earth, so sun vibrations can be used to determine the structure of the sun.
Archonix,
Thanks for that link. Here’s another: click
Dave Dardinger says:
August 17, 2010 at 5:57 am
An electrocardiogram?….The Sun is the ER already!
Jim Hogg says
“These observations have no predictive value. That won’t come until they understand why the conveyor belt’s behaviour changes. Gravitational pull on the sun by the major planets might be the factor that controls the conveyor belt. Finding patterned connections between the two might go part of the way to explaining and predicting sunspot cycle minima and maxima and related weather on Earth.”
————
I agree.
Just a thought though…. As I believe it, ‘plasma reactions ‘ require not only hugh gravitational forces to operate at the atomic level but also attendant, immense, magnetic fields for general containment (as in the Sun) . As most of our solar system planets (and several satellites) have magnetic fields; might there also be an effect magnetically, in addition to any gravitational effect of planitary alignment? Could this effect possibly affect the ‘conveyor belt(s)’ enough to cause problems.
Katabasis says:
August 17, 2010 at 3:52 am
“For example – your model shows that 90% of the matter you were expecting to find isn’t there. What do you do? Instead of revising your model you postulate a ubiquitous, undetectable substance called ‘Dark Matter’. Right.”
The “dark matter” craze is mostly a media misunderstanding of some standard astrophysics. Galaxies rotate under gravity. Nothing fancy, just ordinary Newtonian physics. The orbital speed at a given radius from the centre tells you how much mass there is inside that radius. But, based on the observed luminosity, the total mass of visible stars (the “light matter”) is too low to account for the velocity curves. So there must be more mass we don’t see (the “dark matter” or “missing mass”). This comprises the interstellar medium of neutral gas, dust, dark nebulae, planetary bodies, brown dwarfs (stars and sub-stars too faint to see), ordinary stars hidden by dust, neutron stars, black holes, and other junk. There’s nothing particularly mysterious about it – we know it’s there – and we don’t have to rely on any weird quantum particles or strange fields (though they cannot be entirely ruled out). The motions of clusters of galaxies display similar shortfalls, but again, the intergalactic medium, loose stars, fragmented satellite galaxies and so forth can explain this without recourse to science fiction. Which isn’t to say that the science fiction is necessarily all wrong, mind.
Ken & Geoff,
As Dave says, you can learn something about what is going on inside the sun by looking at modes of vibration of the sun. Google “helioseismology” to find out more. It’s not an exact science, because you have to solve something called an ‘inverse problem’ that does not have a unique solution.
Also you can see the poleward flow at the surface, and deduce that there must be a return flow somewhere underneath.
Having said that, it is all a bit speculative – especially how this would lead to a long minimum – and the healthy skepticism expressed on this thread is justified.
There are two expert past studies on the subject of meridional flow modelling
done by Hulburt Center for Space Research (by Wang , Lean and Sheeley)
http://www.iop.org/EJ/article/1538-4357/577/1/L53/16614.text.html
and and Max-Planck-Institut ( Solanki et al)
http://www.aanda.org/index.php?option=article&access=standard&Itemid=129&url=/articles/aa/full/2004/42/aa1024/aa1024.right.html
I of course would also recommend a look at the PF equation numbers (2×11.862 and 19.859) in the formula http://www.vukcevic.talktalk.net/LFC17.htm
which is in excellent agreement with results of above studies, and
http://www.vukcevic.talktalk.net/LFC2.htm
Enneagram says:
August 17, 2010 at 5:47 am
These Birkeland words, speaking about his terrella EXPERIMENT (not a model) which applies also to the Sun, says it all
It does NOT apply to the Sun, so no need to dredge that up again.
——
The latest helioseismology data [presented at SHINE 2010] indicate that there does not seem to be a conveyor belt at all, but rather several cells, both in latitude and more importantly at depth. What we observe at the surface does not seem to reflect very well what goes on deep within the Sun. SDO will in the coming years tell us more about the circulation(s).
tallbloke says:
August 17, 2010 at 1:30 am
I ran the BBC article on this a few days ago. There seems to be some disagreement between the various people guessing what is going on inside the Sun.
“However, Dr David Hathaway, a solar physicist from Nasa’s Marshall Space Flight Center in Alabama, who was not involved in the latest study, argued that it was the speed and not the extent of the conveyor that was of real importance. The conveyor has been running at record high-speeds for over five years. Dr Hathaway said: “I believe this could explain the unusually deep solar minimum.”
If I remember correctly, before that it was thought that the conveyor was running a little slower!
Modelers really have a rough time in today’s politicized atmosphere (we have become such a jaded bunch). They are damned if they stick to their theories, and damned if they change mid way. I think this attempt at understanding the length of a cycle is worth putting out there and seeing what sticks to it and what falls away. I give her props, whether she is wrong or right.
A question:
If the conveyor system provides a thick, constant poleward flow on the surface of the sun, why is it that a given solar cycle’s spots tend to first appear far from the equator and then, over the length of the cycle’s active period [apparently] migrate toward the equatorial region?
Are the spots [some kind of equivalent of] bubbles coming up from the very deep counter-flow?
Of course, this still does beg the question of how the north and south polar regions are somewhat synchronized in their commencement of sunspot spot activities each cycle.
Mike
Leif Svalgaard says:
August 17, 2010 at 6:59 am
What is it that Dikpati and Hathaway observe at the surface, that tells them the solar converyor has speeded up or has greater reach to the poles? At what wavelength(s) of light do these observations come from?
wasn’t it Dikpati who predicted solar cycle 24 would be off the charts?
rbateman says:
August 17, 2010 at 7:34 am
What is it that Dikpati and Hathaway observe at the surface, that tells them the solar conveyor has speeded up or has greater reach to the poles? At what wavelength(s) of light do these observations come from?
They track the movement of magnetic fields on the surface [in visible light magnetograms, 525 nm and 602 nm, respectively].
MikeW says:
August 17, 2010 at 7:20 am
If the conveyor system provides a thick, constant poleward flow on the surface of the sun, why is it that a given solar cycle’s spots tend to first appear far from the equator and then, over the length of the cycle’s active period [apparently] migrate toward the equatorial region?
According to their model [and most solar physicists] the magnetic field is amplified during the travel on the belt at depth, Once it is strong some of it breaks out to the surface. As the belt continues its equatorward motion, the break-out will likewise.
Are the spots [some kind of equivalent of] bubbles coming up from the very deep counter-flow?
That is the idea.
Dikpati says. “Conveyor belt theory indicates that shorter belts, such as observed in cycle 22, should be more common in the Sun.” “Recent measurements gathered and analyzed by Ulrich and colleagues show that in solar cycle 23, the poleward flow extended all the way to the poles, while in previous solar cycles the flow turned back toward the equator at about 60 degrees latitude.”
Thought experiment: If the conveyor belt ‘normally’ turns back at 60 degrees, it should provide a large cross section for return flow and create a large ‘eddy’ at +60 to 90 degrees. In contrast, if the conveyor extends to near 90 degrees, the cross section area at the pole for return flow becomes constrained. Either the plasma return flows must really accelerate through the constrained sections at the poles or the average velocity of the outward flowing plasmas must decelerate to accommodate the constrained return flows. Think of it as an ‘orifice’ in a fluid flow pipe line. The higher the latitude, the smaller the diameter of the return orifice and vice versa.
Does a ‘slow’ outward conveyor flow to high latitudes correlate with low sunspot counts, low coronal mass ejections, and lower UV radiation? If so, why? If not, why not?
Or does the returning volume of plasma at the poles really accelerate to maintain steady state outward flows? This would seem to increase interior turbulence however, not conducive to the quiescent sun we are experiencing.
What makes the ‘conveyor’ flow to higher latitudes? Normal variability in a chaotic but somewhat periodic system? Microscopic black holes orbiting the solar mass center? };>)
And what does any of this mean for us mere earthlings? Stack up more dry firewood because the solar plasmas have headed for the poles??