Sun said to be “bi-modal”
While many, including the IPCC, suggest the modern Grand Maximum of solar activity from 1950-2009 has nothing to do with the 0.4C global warming measured over that time frame, it does seem to be unique in the last three millennia.
from CO2 Science: A 3,000-Year Record of Solar Activity
What was done
According to Usoskin et al. (2014), the Sun “shows strong variability in its magnetic activity, from Grand minima to Grand maxima, but the nature of the variability is not fully understood, mostly because of the insufficient length of the directly observed solar activity records and of uncertainties related to long-term reconstructions.” Now, however, in an attempt to overcome such uncertainties, in a Letter to the Editor published in the journal Astronomy and Astrophysics, Usoskin et al. “present the first fully adjustment-free physical reconstruction of solar activity” covering the past 3,000 years, which record allowed them “to study different modes of solar activity at an unprecedented level of detail.”
What was learned
As illustrated in the figure below, the authors report there is “remarkable agreement” among the overlapping years of their reconstruction (solid black line) and the number of sunspots recorded from direct observations since 1610 (red line). Their reconstruction of solar activity also displays several “distinct features,” including several “well-defined Grand minima of solar activity, ca. 770 BC, 350 BC, 680 AD, 1050 AD, 1310 AD, 1470 AD, and 1680 AD,” as well as “the modern Grand maximum (which occurred during solar cycles 19-23, i.e., 1950-2009),” which they describe as “a rare or even unique event, in both magnitude and duration, in the past three millennia.”
Further statistical analysis of their reconstruction revealed the Sun operates in three distinct modes of activity – (1) a regular mode that “corresponds to moderate activity that varies in a relatively narrow band between sunspot numbers 20 and 67,” (2) a Grand minimum mode of reduced solar activity that “cannot be explained by random fluctuations of the regular mode” and which “is confirmed at a high confidence level,” and (3), a possible Grand maximum mode, but they say that “the low statistic does not allow us to firmly conclude on this, yet.”
What it means
Usoskin et al. (2014) write their results “provide important constraints for both dynamo models of Sun-like stars and investigations of possible solar influence on Earth’s climate.” They also illustrate the importance of improving the quality of such reconstructions, in light of the fact that previous reconstructions of this nature “did not reveal any clear signature of distinct modes” in solar activity.
Unfortunately, it was beyond the scope of this paper to address the potential impact of solar activity on climate. Yet the reconstruction leaves a very big question unanswered — What effect did the Grand maximum of solar activity that occurred between 1950 and 2009 have on Earth’s climate? As a “unique” and “rare” event in terms of both magnitude and duration, one would think a lot more time and effort would be spent by the IPCC and others in answering that question. Instead, IPCC scientists have conducted relatively few studies of the Sun’s influence on modern warming, assuming that the temperature influence of this rare and unique Grand maximum of solar activity, which has occurred only once in the past 3,000 years, is far inferior to the radiative power provided by the rising CO2 concentration of the Earth’s atmosphere.
Reference
Usoskin, I.G., Hulot, G., Gallet, Y., Roth, R., Licht, A., Joos, F., Kovaltsov, G.A., Thebault, E. and Khokhlov, A. 2014. Evidence for distinct modes of solar activity. Astronomy and Astrophysics 562: L10, doi: 10.1051/0004-6361/201423391.
Abstract
Aims. The Sun shows strong variability in its magnetic activity, from Grand minima to Grand maxima, but the nature of the variability is not fully understood, mostly because of the insufficient length of the directly observed solar activity records and of uncertainties related to long-term reconstructions. Here we present a new adjustment-free reconstruction of solar activity over three millennia and study its different modes.
Methods. We present a new adjustment-free, physical reconstruction of solar activity over the past three millennia, using the latest verified carbon cycle, 14C production, and archeomagnetic field models. This great improvement allowed us to study different modes of solar activity at an unprecedented level of details.
Results. The distribution of solar activity is clearly bi-modal, implying the existence of distinct modes of activity. The main regular activity mode corresponds to moderate activity that varies in a relatively narrow band between sunspot numbers 20 and 67. The existence of a separate Grand minimum mode with reduced solar activity, which cannot be explained by random fluctuations of the regular mode, is confirmed at a high confidence level. The possible existence of a separate Grand maximum mode is also suggested, but the statistics is too low to reach a confident 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.
vukcevic says:
August 7, 2014 at 2:13 am
Based on the observational evidence, NASA has come to recognise some distinct properties of even and odd cycles (see second part of this video link
There is no such difference between even and odd cycles. There is a difference in geomagnetic activity between cycles from maximum to maximum. This is a purely geometrical effect and is an effect felt by the Earth, not a property of the Sun, see the discussion in section 9 of http://www.leif.org/research/suipr699.pdf
In addition, it is wrong to say that ‘NASA’ has recognized something.
philjourdan says:
August 7, 2014 at 4:11 am
“the repetition of five strong cycles over the last 60 years (cycles 17 to 22, with the exception of cycle 20) still marks a unique episode in the whole 400-year record.”
So one expert says we had a grand maxima, and one says we did not. But I would like to see Dr. Svalgaard discuss the above observation more.
Every sequence of cycles is unique. The low cycle 20 divides the cycles from 17 to 23 into two pieces [17-19 and 21-23] none of which is particularly special: http://www.leif.org/reseach/New-Group-Numbers.png and the phrase ‘the repetition of five strong cycles’ is simply wrong as there are six cycles in that period [I have co-authors who have a hard time giving up some ingrained ideas].
@Leif Svalgaard – I appreciate the response.
http://www.leif.org/research/New-Group-Numbers.png
Isn’t the importance of this paper in the “bimodal” nature of the sun? Whether there is a grand maximum or not cannot be ruled out by this paper, but it cannot be supported either.
However, a “bimodal” sun is significant because all sorts of statistical analysis gives spurious results when applied to a bimodal distribution. The bimodal sun tells us that we should reject statistical conclusions about the sun that do not account for a bimodal distribution. Which likely means that many past papers about the sun are now in question.
vukcevic says:
August 7, 2014 at 2:13 am
Based on the observational evidence, NASA has come to recognise some distinct properties of even and odd cycles (see second part of this video link
More on their misunderstanding:
section 5 of http://www.leif.org/research/Semiannual-Comment.pdf and section 6.2 of http://www.leif.org/research/2007JA012437.pdf
http://en.wikipedia.org/wiki/Bimodal_distribution
Summary statistics
Bimodal distributions are a commonly used example of how summary statistics such as the mean, median, and standard deviation can be deceptive when used on an arbitrary distribution.
http://en.wikipedia.org/wiki/Bimodal_distribution
Occurrences in nature
Examples of variables with bimodal distributions include the time between eruptions of certain geysers, the color of galaxies, the size of worker weaver ants, the age of incidence of Hodgkin’s lymphoma, the speed of inactivation of the drug isoniazid in US adults, the absolute magnitude of novae, and the circadian activity patterns of those crepuscular animals that are active both in morning and evening twilight. In fishery science multimodal length distributions reflect the different year classes and can thus be used for age distribution- and growth estimates of the fish population.[4] Sediments are usually distributed in a bimodal fashion.
ferdberple says:
August 7, 2014 at 6:40 am
However, a “bimodal” sun is significant because all sorts of statistical analysis gives spurious results when applied to a bimodal distribution.
In addition, it seems to me that the notion of a bimodal sun is not supported by the data. There is a continuum of cycle sizes from small to large. What Usoskin et al. probably mean is simply that Grand Minima are special, somehow. And we slide smoothly into and crawl smoothly out of a Grand Minimum, not abruptly [Vaquero et al.].
How is ozone sensitive to ionizing radiation? Sufficient seen a huge increase in 14CO2 in the 60’s. Nuclear Explosion in the stratosphere can destroy a tremendous amount of ozone by producing 14C with nitrogen. This isotope is very active and immediately react with oxygen.
http://oi60.tinypic.com/33vf57p.jpg
http://epic.awi.de/20620/1/Lev2009b.pdf
Again, Greg Goodman’s comments seem apropos. To amplify:
* There seems to be little disagreement that the sun is at least bimodal, with a phase/state where surface sunspots are heavily suppressed, solar magnetic activity in general is greatly reduced, and the length of the solar cycle extended, exemplified by e.g the Maunder minimum. It seem harmless, if a bit grandiose, to label these low activity periods “grand minima”. There is also at the very least a “normal” phase of solar activity, with moderate numbers of sunspots, a shorter solar cycle, and substantial solar magnetic activity.
* What is at double issue is whether or not there is sufficient organization to consider the peak regions of solar activity, which might be characterized in several ways, as a third “mode”, and to recognize the distinct organization of that activity and its “unusually high” level of large numbers of sunspots, the shortest observed cycles, and very substantial solar magnetic activity as “grand maxima”. After all, if we assume that solar activity is distributed in almost any way you like between “grand” minima and some maximum level and varies completely randomly/chaotically without the slightest hint of actual internal reorganization beyond that associated with chaotic dynamics at some level, we can always draw lines at corresponding to the top 10% and bottom 10%, call anything that falls into this 10% “unusual” (which by definition it is!) and label them “grand” maxima and minima. By the same token rolling double sixes or a six and a five on a pair of dice could be labelled a “grand maximum” and snake eyes or an acey-deucey could be labelled a “grand minimum”.
* As I understand it, there is some reason to think that unusually low solar maxima are in some way internally structurally distinct from its normal operation, although I could of course be wrong, not really my field. Hence the assertion of bimodality, although I’ve never heard an explicit detailing of the differences in structure associated with internal dynamics sufficiently compelling to be called a separate “mode”. The greatest evidence lacking this is autocorrelation — unusually low solar maxima appear to come in packs. I think Lief would even agree, here, since he has been predicting lowered solar activity over an extended series of cycles, presumably on the basis of an understanding of internal organization with greater temporal persistence than a single cycle.
* Ushokin’s work (as well as some evidence, e.g. length of solar cycle) strongly suggests that “unusually high” solar maxima (note the lack of the term “grand”) also come in “packs”. If I understand Lief’s objections to applying the term “grand” to these collections of maxima, they are twofold: first, and most important, there is nothing that differentiates the solar state structurally during these periods from the “normal” operation of the sun where there are always a mix of slightly stronger and slightly weaker cycles, with a limited (say 1-2 cycle) autocorrelation and more or less random trends. (Again, I wonder to what extent the same is true of “grand” minima, but…); second, the relative magnitude of the 20 century peaks is exaggerated compared to the overall record and, while “high”, is high only in the sense of rolling a few sets of double sixes in a row, not high in the sense of rolling double sevens on normally six-sided dice (where Maunder-type minima could be characterized as rolling double zeros on six-sided dice, perhaps — having the dice land perfectly on a corner and refuse to fall).
Put this way, there might be some possibility of coming to agreement. The late 20th century was a period of high solar activity compared to our best guess of a “mean level” of normal solar activity. The peaks were not necessarily the highest in the record, but there was a stretch of several cycles in a temporally correlated group of higher than mean activity. Such stretches are to be expected even if the sun literally rolls dice to determine the strength and length of the next cycle, so this is insufficient evidence that this stretch was a “mode”, and reasonable scientists can agree to disagree about whether or not the evidence suggests that their magnitude per se was extraordinary, or merely statistically unlikely but not unexpected in a “random” (chaotic) system. Over time, perhaps they’ll come to a consensus. Or not. Given that they are trying to reconstruct and repair past data — a process fraught with error and opportunities for bias to subtly enter the result — at the very least, the reconstruction should have greatly amplified error bars that probably (should!) leave substantial room for doubt and disagreement. There is less room for formal disagreement on the interpretation of proxy results, provided that they are uniformly and correctly presented across the entire record without high frequency/low frequency mixing, and provided (as always) that they are openly and frankly obtained and subjected to proper scientific doubt and error analysis.
If we do this, we can stop worrying about whether or not a “grand” maxima caused 20th century warming, whether a series of comparatively high (but not that unusual individually) maxima caused 20th century warming, whether or not the Maunder minimum caused the LIA, etc, and simply sit here, with popcorn, and wait and see what happens if the Sun decides to — as several people I have no reason to doubt (or particularly strongly believe) have asserted it will — pop out a series of extremely low/long solar cycles. We don’t even need to wonder whether or not this series should be called a “grand” minimum — it is what it is. We don’t need to assert that this will definitely affect climate because we have no modern, trustworthy, observational evidence to prove the argument one way or the other. We lack working models for the climate even when we use enormous computers to try to build them. Do people really think that you can outguess these computers when the computers are failing? Your guesses are all built on the linearization fallacy — that in a complex, chaotic, nonlinear system you can examine an apparent linear correlation (even one with a physical argument to support it!) and extrapolate it.
If the climate had any simple linear correlate that worked to explain things like the MWP, the LIA, the modern warm period, the “pause”, etc, we would long ago have found it, to the extent that we can even trust the high-error-bar proxy-based assessments of probable past climate outside of the modern (post satellite) instrumental record. It doesn’t. Anybody who asserts that they “know” what the climate is going to do because (fill in the blank with your favorite linearized fantasy) is full of ca-ca. Cool? Maybe. Warm? Quite possibly. Stay the same (for at least a while)? Sure, why not.
We can’t even predict the local time evolution of a single supposed El Nino six months in advance after it has apparently started (as the ENSO meter sits pegged on zero once again). ENSO empirically affects the climate — or at least, the autocorrelated weather for an extended period. How can we predict the climate when we lack a theory that can predict ENSO, do not properly understand the factors that govern it, and even if we did do not have the data needed, at the spatiotemporal granularity required, to predict it given a perfect model?
rgb
Could it be that Gleissberg’s work on the supposed 100 year cycle is underpinning this tenacious refusal to address the issues with solar data, even in the face of well documented reasons for the issues and reasonable corrections? Belief trumps data. And sometimes especially so in scientific circles. It is hard to say no to the “fathers” of any particular scientific field of study.
Pamela Gray says:
August 7, 2014 at 7:37 am
even in the face of well documented reasons for the issues and reasonable corrections? Belief trumps data.
I think that clinging to the Modern Grand Maximum is motivated by an attempt to explain ‘global warming’ as a solar effect. It is inconvenient if the Grand Modern Maximum turns out not to be all that Grand.
rgb, you said, “If we do this, we can stop worrying about whether or not a “grand” maxima caused 20th century warming, whether a series of comparatively high (but not that unusual individually) maxima caused 20th century warming, whether or not the Maunder minimum caused the LIA, etc, and simply sit here, with popcorn, and wait and see what happens if the Sun decides to…”
I disagree. We can use equatorial band SST data to test this. We can put the change in TSI to a calculation (already done) for solar insolation (already done), and can calculate any change in SST heating from this energy difference under clear sky conditions (already done) into the only place on Earth it can be stored (oceans), and then determine whether or not this change in SST shows up (or indeed can show up) in the noisy data.
Here is the null hypothesis: The SST of the critical volume (top few hundred meters, see link) of equatorial band ocean, impacted by the change in insolation under clear sky conditions due to a lack of sunspots causing a change in TSI, will not change.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0CDMQFjAD&url=http%3A%2F%2Foptics.marine.usf.edu%2Freferences%2FLee_UV_penetration_JGR2013.pdf&ei=vZLjU4PiFMz5yQT7yoKIAg&usg=AFQjCNGwHlKUxsinyOQu3aQUf7JvBUndQg&bvm=bv.72676100,d.aWw
This commentary below makes so much sense . Nevertheless all of the data clearly shows solar activity and especially magnetic activity was very strong and increasing through out the last century.
The data post 2005 shows clearly the sun has changed from a very active state to a very quiet state. AP index a very good measure of this.
Now we have to see how deep this prolonged solar minimum gets and what impacts it has on the climate.
I expect a deep prolonged solar minimum will continue and it will have significant climatic effects.
Past history supports my thoughts. Look at the Dalton and Maunder Minimum and global temperature response.
If we do this, we can stop worrying about whether or not a “grand” maxima caused 20th century warming, whether a series of comparatively high (but not that unusual individually) maxima caused 20th century warming, whether or not the Maunder minimum caused the LIA, etc, and simply sit here, with popcorn, and wait and see what happens if the Sun decides to — as several people I have no reason to doubt (or particularly strongly believe) have asserted it will — pop out a series of extremely low/long solar cycles. We don’t even need to wonder whether or not this series should be called a “grand” minimum — it is what it is.
rgbatduke says:
August 7, 2014 at 7:23 am
because we have no modern, trustworthy, observational evidence to prove the argument one way or the other
When it comes to the Sun we actually do have trustworthy evidence, namely that provided by that great measuring device: the Earth itself: http://www.leif.org/research/What-Geomagnetism-can-Tell-Us-about-the-Solar-Cycle.pdf
Leif, do you then also think the present author is so inclined to believe in a grand maximum causing global warming?
For clarification, we can calculate the change in SST, but under present measuring systems, we would not see the change in the data set as it is currently obtained.
As one can see by looking objectively at the historical climate data all increasing global temperature trends have been associated with prolonged maximum solar activity . While all decreasing global temperature trends have been associated with prolonged quiet solar activity.
This is due not only to primary solar effects but secondary solar effects.
I go by the data and nothing else and the data clearly supports what I have been posting.
Pamela Gray says:
August 7, 2014 at 7:59 am
Leif, do you then also think the present author is so inclined to believe in a grand maximum causing global warming?
It is good for funding if you can tie your research to the climate debate…
When it comes to the Sun we actually do have trustworthy evidence, namely that provided by that great measuring device: the Earth itself.
My commentary
And the data from the earth shows that it is clearly linked to solar activity. Again look at the historical global temperature data versus solar data.
This current prolonged solar minimum will prove this fact once and for all. We will know before this decade is out.
THE CRITERIA
Solar Flux avg. sub 90
Solar Wind avg. sub 350 km/sec
AP index avg. sub 5.0
Cosmic ray counts north of 6500 counts per minute
Total Solar Irradiance off .15% or more
EUV light average 0-105 nm sub 100 units (or off 100% or more) and longer UV light emissions around 300 nm off by several percent.
IMF around 4.0 nt or lower.
The above solar parameter averages following several years of sub solar activity in general which commenced in year 2005..
IF , these average solar parameters are the rule going forward for the remainder of this decade expect global average temperatures to fall by -.5C, with the largest global temperature declines occurring over the high latitudes of N.H. land areas.
The decline in temperatures should begin to take place within six months after the ending of the maximum of solar cycle 24.
NOTE 1- What mainstream science is missing in my opinion is two fold, in that solar variability is greater than thought, and that the climate system of the earth is more sensitive to that solar variability.
NOTE 2
This criteria was reached during the brief but sever lull form 2008-2010 for the most part.
The duration wiLl be longer the next time around.
That the 20th century was the time of a long term solar maximum is further demonstrated by Lockwood et al 2014. Fig 6 at
http://onlinelibrary.wiley.com/doi/10.1002/2014JA019973/pdf )
Lockwood et al 2014 in press say in their abstract: http://www.eiscat.rl.ac.uk/Members/mike/publications/pdfs/2009/Lockwood_ApJ_openflux_F1.pdf
“Cosmogenic isotope data reveal that this constitutes a grand maximum of solar
activity which began in 1920, using the definition that such grand maxima are when
25-year averages of the heliospheric modulation potential exceeds 600 MV.
Extrapolating the linear declines seen in all three parameters since 1985, yields
predictions that the grand maximum will end in the years 2013, 2014, or 2027 using VSW, FS, or B respectively”.
My own view ,based on the Ap index Fig 13 (see link below0 and the Oulu neutron count – Fig 14( Link below) is that the solar activity long term maximum peaked in about 1991.with the sharp decline beginning about 2005 – 6.
For further references and discussion on all this, with particular regard to the 970 year quasi- periodicity in the temperature record as a result of changes in solar activity see the latest post
at
http://climatesense-norpag.blogspot.com.
Forecasts of the coming cooling based on this millennial quasi-periodicity are also presented there.
To forestall useless discussion I’m quite happy to agree to differ with Leif in this matter and defer to Lockwood and Usoskin.
http://www.nature.com/nature/journal/v399/n6735/abs/399437a0.html
When solar activity is still low, the amount of ozone will be significantly reduced due to a decrease of UV radiation and increase of galactic radiation.
Simultaneously will increase significantly Cloudiness and increase pressure over the polar circles. Climate change will be drastic.
The above paper just like this article provides more conclusive evidence of the strength of solar activity last century which correlates to a global temperature increase.
Solar activity remaining strong until year 2005.