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.
milo, the Samara signal in the ice cores is nearly 6 years long, meaning that ash and sulfur continued to fall out at the poles. There are very few volcanos with ash fallout signals that last more than 3-4 years in ice cores. The volcanos that have multi-year (IE greater than 4) deposits also coincide with cold periods in the temperature records. And again, please understand that stratospheric volcanic signals in ice cores at both poles points to global veiling. There are volcanos that may have spewed more ejecta, but unless that ejecta gets into the stratosphere with enough material to stay aloft till it eventually falls out at the poles, the effects will be local or regional, not global.
re: the ad hominem
I read all the papers I link to before putting them here. Further, I rarely link to just an abstract of a paper behind a paywall. And I consider it bad form if I do.
A recent paper describes correlation between historic Ireland records (written annuls) of cold spells with volcanic ice core records. Ireland is in the direct path of regional volcanos as well as tropical and Southern Hemisphere stratospheric volcanic events due to its proximity to warm oceanic currents and of course local volcanically active regions. It certainly appears that during a rather long period of volcanic activity, the people of Ireland withstood a weather pattern regime shift that brought on noticeably colder weather. The conclusion asks that further information be collected on oceanic/atmospheric teleconnections and systems active prior to these events. I wonder why they would think that was important? Note: That was a rhetorical question just in case you wonder why I would ask whether or not it was important.
http://iopscience.iop.org/1748-9326/8/2/024035/article
milo: I read the paper before I posted the link, in case you worry about that sort of thing. And I have read other papers about Ireland chronicles. Both sides of my family trace their ancestors back to Ireland and the written chronicles completed by religious orders go way back. It is a real treasure trove of information.
Pamela Gray says:
August 10, 2014 at 7:47 pm
Samalas did not happen during the Maunder Minimum but at the height of the Medieval Warm Period.
The effect on insolation of even the biggest volcanic eruptions is orders of magnitude less important than the fluctuations in UV component of the irradiance spectrum & magnetic flux, not to mention the effects of orbital & rotational mechanical modulation & clouds, not least because the volcanic effects are of such short duration. Noticeable effects on weather last a few years at most, not six, even if sulphates be detectable for six years. Best evidence is that even Toba, as has been repeatedly pointed out here, affected weather for only about six years.
Why do you keep speculating so wildly when all the evidence shows that there was no climatic effect from Samalas or any other eruption during the Medieval Warm Period, or for that matter the LIA, Modern WP or any other of the regular cycles preceding them? The guy upon whose now outdated sulphate data you rely himself admits as much, although he does say that Toba might have produced a climatic effect, but of too short a duration to show up in the proxy data. But that’s pure speculation, too.
Pamela Gray says:
August 11, 2014 at 7:51 am
Does it come as a surprise to you that temperature records are derived from historical sources such as chronicles? I guess you’re as new to data reconstruction as Mosher, who pooh-poohs historical records.
How do you think the CET set has been extended back 800 years from its thermometer data? This is what researchers like our own Tony Brown do every day.
The Irish chronicle indeed records the effect on weather of volcanic eruptions, as do other sources. No one ever denied that big eruptions can affect weather. What you haven’t shown, because you can’t, is that they also affect climate, whether through your already repeatedly falsified ENSO conjecture or some other means. After a few years at most, the effect ends as the aerosols get rained or snowed out, drift down on their own, attached to particles or by other means. This indisputable fact has been demonstrated over & over.
PS: I know of only one or two possible VEI 6 eruptions during the Maunder Minimum (using conventional dates of 1645-1715, which are debatable), & both were early in it, if within it at all. Santorini burped in 1650 & Long Island, NE of New Guinea, in 1640-80, most likely c. 1660. There were none at all after those not only during the rest of the Maunder, including its depths, but way into the 18th century. Laki went off in 1783 after over a century of volcanic drought.
Volcanos are a part of my theme for overall cooling going forward, but they are but one part of the big picture and are likely tied into solar activity if past historical data is reliable.
Anyone that tires to equate one item as the item that controls the climate is barking up the wrong tree.
The sun is an exception because it drives the climate and when something that drives something else changes it will have an effect. But the sun needs secondary effects in addition to primary changes in the sun itself to accomplish this.
I don’t think anyone disagrees with that premise. The disagreement comes as to what degree does solar variability change the climate and to what degree does the sun vary by.
Know one really knows the answer I will admit that. However from my point of view the recent solar lull suggest solar variability is more then what many expect. Two reasons for this is it came (2008-2010) no where near the peak of a Grand Minimum Solar period ,and solar activity although severe was quite short in duration in contrast to the MAUNDER MINIMUM.
This suggest that the Maunder Minimum was probably a much weaker solar period then the recent solar lull but even if it were similar most if not all of my solar criteria would have been met during the Maunder Minimum to promote climate change.
The solar parameters during the recent solar lull did meet my criteria on balance other then duration of time not being long enough, and solar wind being a little high.
Going forward questions will be answered as follows:
Will there be another severe solar lull?
If so how severe will it be?
If so how long will it last in duration of time?
If it materializes will it have a climate impact?
My best estimate by looking at past historical data is yes to al the question while others will say no.
Time will tell.
Salvatoree Del Prete says:
August 11, 2014 at 9:06 am
However from my point of view the recent solar lull suggest solar variability is more then what many expect.
The Lockwood et al. papers you have been peddling claim that solar variability is LESS that previously thought…so ‘your point of view’ may not amount to much. And a ‘lull’ is just ‘less’ than something, isn’t it?
Check out the image of El Chichon’s sulfur cloud on page 28. It is sitting right over the high pressure cell component of the Walker Circulation that maintains the neutral to La Nina condition allowing solar energy transfer into the ocean water column. When that Walker cell circulation is disrupted, Kevin waves and El Nino conditions are triggered which themselves can led to decreased insolation due to additional clouds. Obscuring the Sun with a sulfur cloud over that high pressure cell, in addition to El Nino cloudiness could easily disrupt the Walker Cell system and severely reduce solar insolation, leading to weather pattern regime shifts on a global basis.
The 1257 event was far larger and resulted in far greater sulfur signals in the ice core record, extending over multiple years. So keep that cloud over the high pressure cell for years and let’s see what happens in our thought experiment. There would be a significant reduction in solar insolation in the one area that is drastically important in terms of ENSO processes that teleconnect on a global basis, which includes larger decadal oscillations like the PDO and AMO.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CDUQFjAC&url=http%3A%2F%2Fwww.agu.org%2Fbooks%2Fgm%2Fv116%2FGM116p0025%2FGM116p0025.pdf&ei=6uPoU73xBcHXiwKYt4G4DA&usg=AFQjCNGT9jTgG6bQRYZ8xRO5c0OgKZdcWA&sig2=VxGEJMebmv5r2KUuSsDprw
In fact, well known volcano-climatologists subscribe to such climatic effects resulting in decadal and even century long temperature drops (not just weather affects):
“The largest volcanic perturbation was estimated to be that from the 1259 Unknown. Together with four other moderate to large sulfate injections during the century, 1228, 1268, 1275 and 1285, this particularly large eruption caused a clear temperature decrease of several tenths of a degree Celsius for the entire thirteenth century. This suggests the role of these temporal closely spaced eruptions may have in century-scale climate variation of that period.”
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCkQFjAB&url=http%3A%2F%2Fclimate.envsci.rutgers.edu%2Fpdf%2FGao2008JD010239.pdf&ei=Uu3oU_GlEcKKjALPqIFw&usg=AFQjCNEsYW1lx-Dpn_rn3ncKWQhQ5xOglw&sig2=MEUMpzyJELpKaV2CXYRosg&bvm=bv.72676100,d.cGE
Milo, in case you wonder, not only have I read these papers but they also sit on my desk top so I can read them again. Thought you would want to know.
Again my point of view to the dismay of some is not an isolated point of view. There are many that share the same point of view.
Lockwood is supporting the view that solar variability is much greater then what many keep trying to convey. I am on board the Lockwood train.
If one looks at the data one will see that over 80% of al major volcanic eruptions have been associated with prolonged minimum solar periods or minimum solar activity. A fact like it or not.
I would say this supports solar variability . I am in agreement..
Abstract
From the variation of near-Earth interplanetary conditions, reconstructed for the mid-19th century to the present day using historic geomagnetic activity observations, Lockwood and Owens (2014) have suggested that Earth remains within a broadened streamer belt during solar cycles when the Open Solar Flux (OSF) is low. From this they propose that the Earth was immersed in almost constant slow solar wind during the Maunder minimum (c. 1650–1710). In this paper, we extend continuity modeling of the OSF to predict the streamer belt width using both group sunspot numbers and corrected international sunspot numbers to quantify the emergence rate of new OSF. The results support the idea that the solar wind at Earth was persistently slow during the Maunder minimum because the streamer belt was broad.
View Full Article with Supporting Information (HTMLTO VARY MORE
Salvatoree Del Prete says:
August 11, 2014 at 9:34 am
Lockwood is supporting the view that solar variability is much greater then what many keep trying to convey.
No, the traditional, mainstream notion is that the solar magnetic field [as measured by HMF B] was less than 1 nT during the Maunder Minimum versus some 5 nT right now. Lockwood’s model claims that HMF B was 2 nT. The variation from 5 nT down to 2 nT is LESS than the old value of from 5 nT down to 1 nT, so Lockwood [latest] claims just the opposite of what you believe… Are you ready to jump on that new ‘less variability train’?
I am fine with 2nT. That proves solar variability..
2 nT would be more then enough to have the kind of solar variability I think is needed to promote climate change.
Salvatoree Del Prete says:
August 11, 2014 at 9:34 am
Lockwood is supporting the view that solar variability is much greater then what many keep trying to convey.
Let me remind you of what you quoted from Lockwood:
“Assuming S is proportional to R yields near-zero OSF throughout the Maunder Minimum. :
[This is the mainstream position]
“However, χ becomes negative during periods of low R, particularly the most recent solar minimum, meaning OSF production is underestimated”
[So Lockwood claims that the mainstream OSF is too low]
“This is related to continued coronal mass ejection (CME) activity, and therefore OSF production, throughout solar minimum, despite R falling to zero. Correcting S for this produces a better match to the recent solar minimum OSF observations. It also results in a cycling, nonzero OSF during the Maunder Minimum, in agreement with cosmogenic isotope observations.”
[So OSF was not near-zero as previously thought]
“These results suggest that during the Maunder Minimum, HCS tilt cycled as over recent solar cycles, and the CME rate was roughly constant at the levels measured during the most recent two solar minima.”
So the CME rate during the Maunder Minimum was on par with the recent observations, so LESS variability than previously thought.
You have all of this backwards. But, presumably it doesn’t matter what the data shows or what Lockwood claims, you have ‘your point of view’ which nothing can rock.
The solar variability issue is in a constant change of flux. This is why it is going to be very interesting going forward, but 2nT is much less then 4nT associated with this recent severe solar lull.
Which proves my point.
“These results suggest that during the Maunder Minimum, HCS tilt cycled as over recent solar cycles, and the CME rate was roughly constant at the levels measured during the most recent two solar minima
All you are saying is suggest which is fine . That is your point of view not the point of view of many others that have a complete different take on it. Time will tell.
The question that can’t be answered is where did all the sunspots go during the Maunder? Until that question is answered the Maunder is a mystery as to why it happened and what was the actual solar variability.
MORE QUESTIONS THEN ANSWES ARE OUT THERE.
And if this were not the case opinions today would not be so deeply divided.
Salvatoree Del Prete says:
August 11, 2014 at 9:56 am
“These results suggest that during the Maunder Minimum, HCS tilt cycled as over recent solar cycles, and the CME rate was roughly constant at the levels measured during the most recent two solar minima”
All you are saying is suggest which is fine . That is your point of view not the point of view of many others that have a complete different take on it.
No, that is not my view or suggestion, but that of Lockwood quoted by you. But you are correct, that many others have a completely different take on this than Lockwood.
Salvatoree Del Prete says:
August 11, 2014 at 10:01 am
The question that can’t be answered is where did all the sunspots go during the Maunder? Until that question is answered the Maunder is a mystery as to why it happened and what was the actual solar variability.
Before we get to that, you first have to admit that apart from that, solar variability was a lot less than previously thought [as Lockwood now realizes].
Then to the mystery: We know that sunspots form by magnetic fields assembling themselves into stronger concentrations which show a dark spots. It is likely that that process was somewhat less efficient during the Maunder Minimum [as is evidently observed]. Why that was so, is still a research problem.
I may have found Sigl’s reconstruction paper. Looking at the sulfur table on page 1158, the Samara 1257 eruption still stands out in the ice core as the largest in terms of bipolar deposit, and its location certainly would have driven a very large sulfur plume over at least the El Nino 3.4 region for quite some time, dwarfing El Chichon’s plume, even after evidence of deposition disappears in the ice cores (volcanic activity may have continued with regional outgassing for possibly years after the signal disappears from ice cores).
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=15&cad=rja&uact=8&ved=0CIABEBYwDg&url=http%3A%2F%2Fnora.nerc.ac.uk%2F502097%2F1%2Fjgrd50082.pdf&ei=GfToU-fHA-nNigKZmoCIAw&usg=AFQjCNEc3bKuIbs7FJ7ui1OCJ_wxKH_QRQ&sig2=C1p5glQHlzXPfDTcGxDBsw&bvm=bv.72676100,d.cGE
In any event I hope all the questions that are currently out there will be resolved one way or the other in the very near future. Watch and see where all of the data takes us going forward.
By the way milo, the guys with the “outdated” data? The current guys use a different calculation for the 1257 eruption. Both end up with an extremely large event. However, I would imagine the various groups of researchers have their proponents and detractors regarding this event. Who wouldn’t? The ice core raw data demonstrates the significance of this event. I consider it to be the holy grail of explosions in terms of mystery and stratospheric solar insolation affects. Apparently many researchers do too. Lots of papers out there. I have only provided links to a few (and have read them ;>).
It is only a matter of time before volcanically disrupted ENSO processes extending throughout the globe due to oceanic/atmospheric teleconnections come under the microscope when speaking of these Indonesian cataclysmic level eruptions. And I am betting that Bob Tisdale’s proposal involving a discharge/recharge process will be near if not on, the plate.
One more thing milo, I have linked to Irish chronicles several times in this blog. They are certainly not new to me.