Paper: Evidence for distinct modes of solar activity

Posted: February 22, 2014 by tchannon in Astrophysics, cosmic rays, Geomagnetism, Solar physics

This solar reconstruction uses a combination of 14C and “archeomagnetic field models” (Licht) to show strong solar activity modality.


Fig 3 from paper

Evidence for distinct modes of solar activity
I. G. Usoskin, G. Hulot, Y. Gallet, R. Roth, A. Licht, F. Joos, G. A. Kovaltsov, E. Thébault and A. Khokhlov
A&A 562 L10 (2014)

Abstract conclusion

Conclusions. The Sun is shown to operate in distinct modes – a main general mode, a Grand minimum mode corresponding to an inactive Sun, and a possible Grand maximum mode corresponding to an unusually active Sun. These results provide important constraints for both dynamo models of Sun-like stars and investigations of possible solar influence on Earth’s climate.

Posted by Tim

  1. tallbloke says:

    Thanks Tim, Stuart and I were just reading this when you posted it.
    Here’s how the 30 out of 180yrs minimum mode appears to operate:

    This plot shows a few different things which in combination may offer an explanation. The orange curve is the sunspot numbers since 1749 averaged over the period of the solar cycle. The blue curve is the integrated disposition of the planets (predominantly the gas giants) above and below the solar equatorial plane, averaged over the period of two Jupiter orbits (to simulate the damping of large fluid bodies like the Sun). The grey curve is the proximity of the centre of mass of the system to the solar centre. The horizontal yellow band covers +/-0.05 solar radii. The crash into solar minimum mode (strong divergence of the orange sunspot curve from the blue curve) seems to be related to the occasions on which the grey curve stays within the yellow band for an extended period (marked by the black vertical tick marks near the x-axis).

  2. Quote : “a Grand minimum mode corresponding to an inactive Sun, and a possible Grand maximum mode corresponding to an unusually active Sun.”

    Physical enigma !
    In particularly, I think in the deep solar minimum i say big electrical and small magnetic.

  3. E.J. Mohr says:

    The idea of a bimodal sun has intrigued me for a long time. I wonder if there is even more to it than what these authors have in mind. Bimodal activity can explain the ups and downs of the Holocene, but I wonder if there may be a larger step down mode that runs during the Ice Ages.

  4. E.J. Mohr says:

    In particular I am wondering if more work has been done on Robert Ehrlich’s ideas:

  5. markstoval says:

    @ E.J. Mohr

    I am convinced that the sun drives climate change on earth. The great mystery is what drives the sun. The cycles are plain to see if one looks with open eyes. Ah, but the causes of the cycles, now that subject is worth billions to investigate.

  6. E.J. Mohr says:

    There’s no doubt the sun drives climate. Where things get interesting is how constant the so called solar constant is. For many years TSI was assumed to be constant – end of story. Since the satellite era we have seen that the constant does vary. Those in the ACRIM camp, the fans of data, tell us that TSI wiggles more than those who like the data to conform to a model.

    For those of us with a geology background the evidence of enormous climate change during the last 20,000 years makes us ponder the fact that the sun may have other activity modes that we have not seen. Perhaps, if Ehrlich is right, the sun’s nuclear furnace has resonant diffusion waves that operate on 41ky and 100ky cycles. Maybe the barycenter heretics are on to something if this resonance is part of a solar system resonance. I’m out of my depth on this, but it makes me wonder. Certainly it is important enough to look into since a full-on Ice Age, if caused by the sun, would be a catastrophe. It’s the kind of thing you’d want to know about, if it could be predicted.

  7. […] Paper: Evidence for distinct modes of solar activity | Tallbloke's … […]

  8. Bruce Binion says:

    This is a particularly great discussion! Thank you all and thank you Michelle Casati for suggesting I tune in!

    Tonight, my folks and I were discussing the last two ice ages and the glaciers that moved down into Central Illinois USA. The boundary layer around Bethany Illinois between the present and time before the last glacier is about 42′ down.

    Anyway, my comment concerns the time period around 1811 in the graph. I am trying to pull together all things concerning the New Madrid Missouri USA area earthquakes that began in December of 1811. If you would please, discuss the implications of the period marked by “black vertical tick marks near the x-axis” centered around 1811. One reason I ask is the weather, starting in January of 1811 and leading up to the December quake was similar to that of 2012 except for the noticable lack of lightning in 1811 and another reason is the accounts from that period indicate a possible severe magnetic disturbance may have travelled from New Madrid to the East coast the night of the first quake.
    Thank you.

  9. c777 says:

    So all stars are probably variable stars including our Sun.
    Observable variable stars usually vary from days to months.
    How about years?
    Or centuries?
    Or millennia?
    Variable stars over longer periods would be far less likely to be observed.

  10. vukcevic says:

    Usoskin is getting hard time on the other blog.
    Purpose of solar reconstructions is in the main to quantify the solar influence on the Earth’s climate and to distinguish between the different forcings, so that climate model simulations can reproduce climate trends more accurately, or that is what they say.
    In this graph
    I compare Usoskin’s SSN, Steinhilber’s TSI and Loehle’s global temperature.
    You can make your own estimate of how good or adequate they are.

  11. E.J. Mohr says:

    In Hoyt and Schatten’s book: The Role of the Sun in Climate Change, they mention the Ca II K line Index of sun like stars, and show a graph on page 181. This graph shows that the observed Ca II index of the sun has only varied over the top portion of the range compared to sun like stars. So, the K line for the sun has varied from 17 Angstroms to just over 20 Angstroms. The full range expected from sun like stars is from 13 Angstroms to 21 Angstroms.

    At the time the book was written it was calculated that a 0.03 Angstrom change of the suns Ca II K line was equivalent to a 0.15% change in total irradiance. I’m not sure if these calculations are still valid today, or if more work has been done regarding this.

  12. E.J. Mohr says:

    Whoops – let me quickly correct one thing. The range of Ca II lines in sun like stars is from 0.13 Angstroms to 0.21 Angstroms. The sun has only varied from 0.17 A to just over 0.21 A.

  13. E.J. Mohr says:

    So, based on sun like stars, our local star may exhibit around a 0.4% TSI change between its most active phase, which we may have just lived through, and it’s more quiescent phases. Only time will tell, although we live in interesting solar times, and Nicola has made an interesting prediction.

    Meanwhile, about that New Madrid earthquake. It occurred on an so called “failed rift fault” that dates from the ancient supercontinent of Rodinia. The fault has been reactivated, as often happens with areas of weakened crust, and the reactivated fault has not only caused some quakes, but they have been massive. The reawakened rift is now known as the Reelfoot Rift – named after the lake that formed after the first big quake.

    All this near the center of the North American craton where you would expect relatively quiet seismic activity. From what I have read this area has lots of paleo-seismic data that indicates that it is wracked by infrequent but very large earthquakes. Presently GPS sensors indicate that there is little movement on the fault – good news? Perhaps not since a fault that exhibits no motion on its opposing sides may have locked tight and the pressure is building. Or maybe the fault is returning to being inactive and the strain is building elsewhere – but where?

    In any event the USGS is monitoring this area, and from what I can see it has had many small tremors and is active. It doesn’t fit in the standard model of faults, but it is known to be dangerous. Unlike AGW the science here is unsettled and geologists are actively debating – all of which is good.

  14. tallbloke says:

    E.J. M: Over what time period are sun-like stars observed to vary? Or are you referring to a range of stars that are constant?

  15. vukcevic says:

    TB: “I wonder how your plot here will go in the future”

    It all depends on the timing on the next SN minimum, calculation uses spiral formula. I might get back to it some time, once we approach SC24 minimum. Formula predicts a long SC24, more than 12 years, but last entry (dotted line on the graph), I deliberately shortened down and put it at the end of 2020.

  16. E.J. Mohr says:

    TB. The book does not specify the length of observation, but mentions Kitt Peak, and Sacramento Peak as some of observatories. The focus was on solar like variable stars whose ensemble was thought to represent sun like variation. Looking at the diagram there must be several hundred candidates. I see in an earlier chapter that P.R. Wilson of California Institute of Technolgy began observing solar like stars in the 1970’s.

    If memory serves, I vaguely recall reading that lately a dispute may have arisen over whether these solar like stars are in fact close facsimiles of the sun. In any event they have cycles like the sun.

  17. Brian H says:

    The “stays within” seems to consistently comprise a shallow double-dip episode.