Guest post by David Archibald
This is a little bit amusing. In February, I had a post on the solar – sea level relationship which quantified the sea level fall to come to the end of Solar Cycle 25:
http://wattsupwiththat.com/2012/02/03/quantifying-sea-level-fall/
The site “Skeptical Science” has to date carried two pieces in response to that February post: http://www.skepticalscience.com/Why_David_Archibald_is_wrong_about_solar_sea_level.html
and http://www.skepticalscience.com/Why_David_Archibald_is_wrong_about_solar_sea_level_1B.html
My February post was 624 words and 6 figures. The Skeptical Science responses to date total 3,446 words and 17 figures. The relationship I found between solar activity and sea level is 0.045 mm per unit of annual sunspot number. The threshold between rising and falling seal level is a sunspot amplitude of 40. Below 40, sea level falls. Above that, it rises.
So let’s apply that relationship to the know sunspot record back to the beginning of the Maunder Minimum and see what it tells us. This is the result:
Figure 1: Back-tested Sea Level from 1645
The figure shows sea level falling through the Maunder Minimum due to the lack of sunspots and then fluctuating in a band about 60 mm wide before increasing rapidly from 1934. It then shows sea level peaking in 2003 before declining 40 mm to 2040.
That is pretty much in agreement with the data from the last 150 years, as per this figure combining coastal tide gauge records to 2001 and the satellite record thereafter:
Figure 2: Sea Level Rise 1850 with a Projection 2040
The glaciers started retreating in 1859, with sea level responding with a rise of 1 mm per annum up to 1930. There was an inflection point in 1930 with the rate of sea level rise almost doubling to 1.9 mm per annum. Sea level also stopped rising from 2003. So the back-tested model and the sea level record are in agreement for at least the last 150 years.
Jevrejeva et al (http://www.psmsl.org/products/reconstructions/2008GL033611.pdf) reconstructed sea level back to 1700:
Figure 3: Global Mean Sea Level Reconstruction since 1700
This longer term reconstruction shows the rise of sea level once the glaciers started retreating. It also shows the acceleration of sea level rise from the early 1930s. As Solanki noted in 2004, the Sun was more active in the second half of the 20th Century than at any time in the previous 8,000 years: http://earthobservatory.nasa.gov/Newsroom/view.php?id=25538 A sea level response to that would be expected.
In summary, the sea level trend fluctuations driven by the internal variability of the ocean-atmosphere coupled system were overprinted by higher solar activity from 1933 to 2003. The period of best fit within that, from 1948 to 1987, has allowed the solar component of sea level rise to be elucidated.
@P Solar
“In reality the uncertainty is greater than the effect.”
I am not sure how you will fare bringing real science and engineering into the climate discussion. You will see the occasional call for error bars and if they were put on the charts, a debate would ensue about which ones to show. It could be a calculation of a 95% confidence band, or 90%, or anything else that made things look more accurate than they really are.
People want their work to appear to be precise and accurate. Often climate work is neither. Claims for precision often far outstrip the instrument, as I feel you pointed out.
Claims for demonstrated effects that are well inside the experimental error bars are a dime a dozen: witmess the outrageous forecasts of future climate based on computer modelling.
@Leif
Your presentation http://www.leif.org/research/Rudolf%20Wolf%20Was%20Right.pdf on the lack of variation of TSI seems to be contradicted by the paper on your site http://www.leif.org/EOS/muscheler07qsr.pdf which says in the conclusion.
“Regardless of these uncertainties, the cosmogenic radionuclide records indicate that the current solar activity is relatively high compared to the period before 1950 AD. However, as the mean value during the last 55 yr was reached or exceeded several times during the past 1000 yr
the current level of solar activity can be regarded as relatively common.”
The quibble remaining is that perhaps there has been a lot of variation in the level of solar activity but not accompanied by changes in TSI. Is that your position? It seems to me the purpose of the former link is to show that there is no long term trend in TSI and further that the solar activity in the late 20th century was not unusual, even relative to the early 20th century, as shown in your slide 14. It that correct? The lengthy paper on 10Be deposition and the 14C proxy used to affirm it holds to a different conclusion. The 10Be record shows an unusually active sun in the late 20th centruy, with even higher periods of activity 1000 years ago.
I felt the statement early on this topic that the sun was ‘more active than it had been in 8000 years’ is a mis-reporting of the more accurate, “The sun has recently been more active that is has been for 80% of the past 8000 years.” which is quite a different claim.
I have seen the claim several times with variations on the % value given, but all between 80%and 90%. From what I can see, it is not possible to reconcile the claim that the sun has recently been pretty much the same as it was for centuries, with the 10Be record.
Perhaps I am misreading the main claims in your Wolf Was Right presentation.
Crispin back in Waterloo says:
April 23, 2012 at 9:02 am
The quibble remaining is that perhaps there has been a lot of variation in the level of solar activity but not accompanied by changes in TSI. Is that your position?
The Muscheler 2005 paper in Nature states: “our reconstruction indicates that solar activity around AD 1150 and 1600 and in the late eighteenth century was probably comparable to the recent satel-
lite-based observations.”
There are now mounting evidence that the 10Be data has to treated with some caution as the relationship with solar activity is not so simple as first thought. For example, the deposition of 10Be depends on atmospheric circulation and thus climate [danger of circular reasoning here!]. Also the calibration of the data in terms of solar activity is model dependent and the Group Sunspot Number has been used for that, but the Group sunspot number is not really all that good: http://www.leif.org/research/What-is-Wrong-with-GSN.pdf
the situation is so dire that the experts involved in both the cosmic rays and solar activity will assemble next month for two workshops to try to see what can be done: http://www.leif.org/research/Svalgaard_ISSI_Proposal_Base.pdf and http://ssnworkshop.wikia.com/wiki/Home
The direct observations of sunspots, geomagnetic activity, and aurorae the past three hundreds years are believed to give a truer picture than the indirect cosmic ray proxies. But eventually we’ll learn how to calibrate the cosmic rays proxies and arrive at time series that we can use with confidence.
I’m not trying to discourage you, David, I’m trying to encourage you to look at and investigate this scientifically.
To add to this, you are repeating a mistake that was made long, long ago, and that has long since been addressed in the literature. The problem with solar coincidence is that single factor solar correlation that works consistently over long time periods is fairly rare in the climate game. Monsoons, droughts, and so on correlate, but the correlation isn’t perfect or persistent, which means that it could either be noise (no real correlation) or multifactorial — TWO things have to be right for the causal signal to resolve, not just one.
It is the curse of regression. There are good ways and bad ways to look for predictive relationships. For single or independent multiple variables with expected logistic or gaussian sorts of dependences, regression is peachy — given lots of data and low N (number of variables). For general nonlinear multivariable dependences that aren’t “simple”, regression sucks and parametric methods suck. All of this is well known in predictive modeling on complex landscapes or in computational pattern recognition (same thing).
The bad thing about THIS is that humans are pretty good at understanding “smoking causes cancer”. Don’t smoke, lower your risk. They aren’t as good at understanding “mothballs are harmless unless you have sickle cell anemia or parents of mediterranean descent and are older than 34 years of age — and male”. Where part of that isn’t even just made up. Nor is at as easy to accumulate the data to make the latter inference. And this is still a simple inference compared to inferences concerning patterns in a chaotic turbulent system.
So you could be right. The data could contain a compelling correlation — but absolutely not as a single-factor cause, and you haven’t identified the other important dimension that would permit the correlation to be observed or the causality — maybe — to be inferred.
rgb
I’m curious, though, how you extend the conclusion that the 20th century was exceptional in solar activity back over the entire Holocene.
I was trying to say it was NOT exceptional.
Is this junk science? If so, how do we know — what is wrong with the reconstructions?
The recent sunspot record is used to calibrate the radionuclide proxies so any problem with the recent data feeds into the reconstructions. This is such an important problem that I’m convening a workshop in a couple of weeks to study this: http://www.leif.org/research/Svalgaard_ISSI_Proposal_Base.pdf
The cosmic ray experts also disagree as to what the proxies show, e.g. http://www.leif.org/EOS/muscheler07qsr.pdf
Yes, I understand/understood, but the radionuclide proxies are at the very least proxies for themselves, are they not? One can argue about what they mean in units of sunspot number, but how can one argue about what they mean in terms of themselves?
As you say, the sun has significant surface magnetic activity during Maunder minima, but that doesn’t mean that its major multipoles are similarly active. From your own data, it appears that they are not — that as solar activity in the form of sunspots diminishes, the dipole field strength at peak appears to be diminishing.
The Bravo paper I posted on another thread indicates that the surface magnetic field is completely dominated by high-order multipoles, so a diminishment of the background major multipoles associated with the interior dynamo would not necessarily mean that surface magnetic activity would cease or that a filamentary corona would not be visible during a Maunder minimum. It is the major (low order) multipoles, however, that reflect the interior state, and it is their field that dominates the far field. So it is entirely reasonable to believe that during a Maunder minimum, the bulk solar magnetic field in the vicinity of the Earth could be very seriously reduced even though highly structured surface magnetism on the Sun might be maintained.
rgb
rgbatduke says:
April 23, 2012 at 9:41 am
Yes, I understand/understood, but the radionuclide proxies are at the very least proxies for themselves, are they not? One can argue about what they mean in units of sunspot number, but how can one argue about what they mean in terms of themselves?
Yes, of course, but they are the result of convolving production and deposition, each of which again depends on several factors [e.g. the Earth’s magnetic field and Atmospheric circulation].
So it is entirely reasonable to believe that during a Maunder minimum, the bulk solar magnetic field in the vicinity of the Earth could be very seriously reduced even though highly structured surface magnetism on the Sun might be maintained.
The cosmic ray modulation depends on the magnetic field in interplanetary space [e.g. near the Earth], so since the cosmic ray modulation was still present during the Maunder Minimum we [at least I] believe that the interplanetary [and hence low-order solar] field was not severely reduced. Data sometimes trumps reason.
Thanks Leif “But eventually we’ll learn how to calibrate the cosmic rays proxies and arrive at time series that we can use with confidence.”
I agree with rgbatduke that the 10Be are without interpretation a proxy for themselves. The simplest and most direct, useful thing they have to say is that 10Be is inversely corellated with temperature. Blaming the weather for 10Be deposition rates is going to rank in my books alongside ‘the MWP was a local event” explanation of higher temperatures 800 years ago.
I believe 10Be is what set people in motion looking for ‘why’ re the temps. There is a pretty good chart of thsoe two going back 530m years as I recall, plus CO2. The 10Be led to the cosmic rays which led to the heliosphere and the spiral currents flowing in it which led to the solar connection which led to the cyclical nature of it which led to the observations that the planetary gravitational sum also matched some of the cycles observed in the sun, and the rest is blogs as you know.
The SSN is far less direct a forecast of temperature, however I find myself convinced that the SC length is so well correlated with the temps immediately following that it deserves a status similar to the 10Be:Temp relationship for the very reason you cite: data trumps reason(ing) [or ‘explaining’ as some are wont to do].
Crispin back in Waterloo says:
April 23, 2012 at 12:44 pm
Blaming the weather for 10Be deposition rates is going to rank in my books alongside ‘the MWP was a local event” explanation of higher temperatures 800 years ago.
This is not ‘blaming’, but an established fact. Most of the 10Be is created elsewhere and then brought to the polar regions by atmospheric circulation and precipitation.
and the spiral currents flowing in it which led to the solar connection which led to the cyclical nature of it which led to the observations that the planetary gravitational sum also matched some of the cycles observed in the sun, and the rest is blogs as you know.
The 10Be is caused by cosmic rays that do not follow the spiral [as they are much too energetic], and the planets have nothing to do with 10Be.
The SSN is far less direct a forecast of temperature, however I find myself convinced that the SC length is so well correlated with the temps immediately following
You may believe that, but it is not the case.
Some valid comments by rgb and Crispin.
Two important points raised, when considering climate or the temperature record it is foolish to see solar forcing as the be all and end all that needs to match with precision. The PDO and other factors perhaps playing an even larger role outside of grand minima events. Also the necessity of recognizing the importance of maintaining the isotope records. When matching 14C and 10Be it can be seen both records are in good agreement when overlaid.
http://tinyurl.com/2dg9u22/?q=node/51
In time other markers will be recognized that show the isotope records are correct over the short term, but perhaps begins to stray around 5000 years BP.
Geoff Sharp says:
April 23, 2012 at 5:51 pm
In time other markers will be recognized that show the isotope records are correct over the short term
Hardly. compare
http://arxiv.org/abs/1004.2675
“We have compared the yearly production rates of 10Be by cosmic rays in the Earths polar atmosphere over the last 50-70 years with 10Be measurements from two separate ice cores in Greenland. These ice cores provide measurements of the annual 10Be concentration and 10Be flux levels during this time. The scatter in the ice core yearly data vs. the production data is larger than the average solar 11 year production variations that are being measured. The cross correlation coefficients between the yearly 10Be production and the ice core 10Be measurements for this time period are <0.4 in all comparisons between ice core data and 10Be production, including 10Be concentrations, 10Be fluxes and in comparing the two separate ice core measurements. In fact, the cross correlation between the two ice core measurements, which should be measuring the same source, is the lowest of all, only ~0.2. These values for the correlation coefficient are all indicative of a "poor" correlation. The regression line slopes for the best fit lines between the 10Be production and the 10Be measurements used in the cross correlation analysis are all in the range 0.4-0.6. This is a particular problem for historical projections of solar activity based on ice core measurements which assume a 1:1 correspondence. We have made other tests of the correspondence between the 10Be predictions and the ice core measurements which lead to the same conclusion, namely that other influences on the ice core measurements, as large as or larger than the production changes themselves, are occurring. These influences could be climatic or instrumentally based. We suggest new ice core measurements that might help in defining more clearly what these influences are and-if possible-to correct for them."
http://arxiv.org/abs/1003.4989:
Using new calculations of 10Be production in the Earths atmosphere which are based on direct measurements of the 11-year solar modulation effects on galactic cosmic rays and spacecraft measurements of the cosmic ray energy spectrum, we have calculated the yearly average production of 10Be in the Earths atmosphere by galactic and solar cosmic rays since 1939. During the last six 11-year cycles the average amplitude of these production changes is 36%. These predictions are compared with measurements of 10Be concentration in polar ice cores in both the Northern and Southern hemisphere over the same time period. We find a large scatter between the predicted and measured yearly average data sets and a low cross correlation ~0.30. Also the normalized regression line slope between 10Be production changes and 10Be concentration changes is found to be only 0.4-0.6; much less than the value of 1.0 expected for a simple proportionality between these quantities, as is typically used for historical projections of the relationship between 10Be concentration and solar activity. The distribution of yearly averages in the 10Be concentration level in the data from the Dye-3 ice core in Greenland for the time period 1939-1985, contains a "spike" of high concentration one year averages which is not seen in the production calculations. These and other features suggest that galactic cosmic ray intensity changes which affect the production of 10Be in the Earths atmosphere are not the sole source of the 10Be concentration changes and confirm the importance of other effects, for example local and regional climatic effects, which could be of the same magnitude as the 10Be production changes.
14C and 10Be are in good agreement, two different deposition methods that form a proxy record that should not be compared to sunspot activity precisley.The outstanding outcome is there is no flat floor, that no doubt you will attempt to hammer down.
My mention of short term accuracy applies to the carbon dating aspect.
Geoff Sharp says:
April 23, 2012 at 7:20 pm
14C and 10Be are in good agreement, two different deposition methods that form a proxy record that should not be compared to sunspot activity precisely.
Not even the 10Be records agree among themselves as the two links I provided show [did you even read them]. Nevertheless, the 14C and 10Be do have much in common [slide 6 of http://www.leif.org/research/The%20long-term%20variation%20of%20solar%20activity.pdf ] with the exception of recent data. The main point is that there is no support for the Grand Modern Maximum in the 10Be record as you can see for yourself on the slide, by comparing the 10Be and Usoskin records.
The outstanding outcome is there is no flat floor, that no doubt you will attempt to hammer down.
There is growing suspicion that the deep dips at grand minima are not correct [the reconstructions often yield unphysical negative values, see http://www.leif.org/research/HMF-B-Steinhilber.png ]. This is what we’ll examine at our workshop in May and try to see where the error in the reconstruction of the low values comes from – my own hunch is that the error stems from the [wrong] assumption that the heliosphere is spherically symmetric at low solar activity; we shall see.
Geoff Sharp says:
April 23, 2012 at 7:20 pm
The outstanding outcome is there is no flat floor, that no doubt you will attempt to hammer down.
Here is the agenda for this sub-topic at our ISSI workshop:
Reconstructions based on Cosmic Rays:
Beer, McCracken, Steinhilber, Usoskin (devil’s advocates: Lockwood, Solanki, Cliver):
(1) 11-yr modulation during the Maunder Minimum: What does the modulation look
like if no filtering is applied? Was modulation strong or weak during this period in
relation to the Spoerer minimum and later periods such as the Dalton minimum,
the Gleissberg minimum around 1900 or the recent period of high activity? Is
there any evidence for a 22-yr cycle (e.g., Jokipii in the Sun in Time (1991) and
Hiroko Miyahara at a recent IAU Symposium in Argentina)? How did solar wind
B vary at high time resolution? The auroral record (Siscoe, 1980) indicates a
diminution of solar activity during the MM. Do you see evidence for this in the
cosmogenic nuclide data?
(2) Dip in B centered on 1895: How consistent is the ice core (i.e., seen in both
hemispheres? multiple cores?) evidence for this depression? Is the dip
supported by geomagnetic data? By sunspot number data? Could Krakatoa
have contributed?
(3) Drop outs to B ~ 0 nT beginning with the Spoerer Minimum: Supported by 14C?
Observed in multiple 10Be cores? Time scale of drop-outs? Contribution from
volcanos?
(4) Comparison of Caballero-Lopez (2004), McCracken (2007), and Steinhilber et
al. (2010). Evolution of time series. Consideration of the sensitivity of the B
reconstructions to the local interstellar spectrum (LIS) used.
——
Take note of the people involved.
Leif Svalgaard says:
April 23, 2012 at 8:03 pm
The main point is that there is no support for the Grand Modern Maximum in the 10Be record as you can see for yourself on the slide, by comparing the 10Be and Usoskin records.
While not agreeing with all of your points I do agree that Solanki/Usoskin are over the top with their modern reconstruction. SC19 would most likely get close to a solar ceiling that has the capacity to repeat every 172 years but see the level of grand minima during an epoch as the restrictive component. In that respect we did have a very good run in the last 200 years.
http://tinyurl.com/2dg9u22/images/powerwave3.png
Leif Svalgaard says:
April 23, 2012 at 9:29 pm
Take note of the people involved.
Definately some talent involved, but perhaps missing those that might contribute with alternative views.
Leif Svalgaard says:
April 23, 2012 at 9:29 pm
Speaking of Usoskin, did you see the Vaquero paper that he and 2 others contributed to that show the Maunder Minimum started earlier than the established date. More sunspot records found suggesting 1610 as the start point. This now agrees with the 14C record and with Carl’s graph.
http://iopscience.iop.org/2041-8205/731/2/L24/fulltext/apjl_731_2_24.text.html#apjl386754r35
Thanks to Ian Wilson for the link.
Geoff Sharp says:
April 23, 2012 at 9:48 pm
Definitely some talent involved, but perhaps missing those that might contribute with alternative views.
We are talking science here. Alternate views are like alternate medicine. They are alternate because they are not sound.
Geoff Sharp says:
April 24, 2012 at 1:48 am
Speaking of Usoskin, did you see the Vaquero paper that he and 2 others contributed to that show the Maunder Minimum started earlier than the established date. More sunspot records found suggesting 1610 as the start point.
more like 1617.
Yes, of course, but they are the result of convolving production and deposition, each of which again depends on several factors [e.g. the Earth’s magnetic field and Atmospheric circulation].
Right, but then one either has to make an assumption of maximum ignorance (a.k.a. “all things being equal”) and assume that on average they vary with solar activity because that is what they are observed to do on average now or one has to systematically try to identify and correct for those factors. For times in the remote past especially, I would think that the former would be a lot safer than the latter. This makes the conclusion uncertain but not unsound, does it not, much like the (your) next paragraph which makes inferences on very similar evidence.
Doesn’t radiometric carbon dating depend on similar assumptions, ones that aren’t always correct but that usually work pretty well, except when relatively rare confounding events occur? I mean, one has to make one’s best guess given the data and wrap the ignorance up into the error estimate as honestly as possible. But error estimates seem anathema in climate research, which is very strange as it seems to prevent a reasonable person from assessing whether or not a supposed “fit” or “trend” should be taken seriously.
The cosmic ray modulation depends on the magnetic field in interplanetary space [e.g. near the Earth], so since the cosmic ray modulation was still present during the Maunder Minimum we [at least I] believe that the interplanetary [and hence low-order solar] field was not severely reduced. Data sometimes trumps reason.
Since my personal goal is education more than argument, I would like to understand this. Your own graph here:
http://www.leif.org/research/Solar-Polar-Fields-1966-now.png
(also on Anthony’s solar reference page) shows the amplitude of the polar field of the sun diminishing strongly over the last three solar cycles. This is presumably directly proportional to the magnetic dipole moment that should be far-field dominant out at Earth orbit. At the same time, the SSN — by any counting method or formula — has diminished in a way that to my untrained eye appears to be very strongly correlated with this dipolar field strength, with the current magnetic field weak, the current SSN for the cycle low, with a clear downward trend in umbral field intensity. Neutron counts (also on the solar reference page) show a less strong and somewhat geographically correlated countervariance with the field strength and SSN, one that if I recall correctly actually goes back longer than the satellite era.
If we assume that observations of the Maunder minimum were correct, and that sunspot counts were indeed extremely low — perhaps not “zero” by modern telescope-driven standards but low enough to be completely remarkable, much lower than any other solar era for which we have historical records — then would we not expect the principle field components to be similarly low? I’m trying to understand your reasoning here — SSN seems to be a very sound proxy for dipolar field strength (and I would bet for quadrupole as well) at least over the cycles for which we have good data. As you say, proxy-inferred cosmic ray modulation is less reliable because proxy deposition can depend on geomagnetic field and weather, and the latter at least might well be different during a “little ice age” (where sure, this does make untangling cause and effect more difficult). Given a choice between the two, I’d certainly trust the former (SSN-dipole) more than the latter (inferred cosmic ray counts 400 years ago) in part because I find the former easier to understand.
Surely something was very unusual about the Sun during the Maunder minimum — something very unusual seems to have happened to the turbulence and other factors that give rise to sunspots.
So why precisely do you doubt this? I have no doubt myself that you have excellent reasons, perhaps reasons and graphs I am unaware of entirely, but I would certainly like to learn of them if you don’t mind teaching me. In particular I would like to know why you reject the simple SSN-dipole strength correlation apparent in the era of modern instrumentation and what you think the dipole/quadrupole moments of the magnetic field of the Sun looked like during the cycles of the Maunder minimum.
rgb
We are talking science here. Alternate views are like alternate medicine. They are alternate because they are not sound.
Begging to differ, but as a scientific philosopher I must. First of all, not all alternative medicine is unsound. My wife is a physician, and absolutely compulsive about double blind data supported therapy, but she openly acknowledges that a lot of so called “alternative medicine” survives double blind analysis — while a lot does not. Sadly, precisely the same things is true of non-alternative medicine. I presume you are familiar with the recent study published in Science, I believe, where a pharmaceutical company set out to reproduce published results in cancer therapy preliminary to launching an effort to develop a new drug and was unable to reproduce 47 out of 53 peer-reviewed, published results.
Second, the research phase of science openly encourages alternative views, iconoclastic views, wild surmises, crazy talk, and so on — although it is (or should be) all modulated with a certain degree of common sense and eventually subjected to the rigorous process of experimental validation plus critical examination for consistency with the greater body of experimentally validated scientific belief (e.g. the laws of physics to the extent that we believe them). During this phase Ockham’s Razor (also known as maximum entropy) is very important, as is the notion of burden of proof. It isn’t that alternative views are not sound, it is that they have not yet been shown to be sound, that until they are simple pictures are the best, and that the burden of proof is ultimately on the author of the alternative theory or hypothesis to demonstrate both empirical and theoretical consistency (and ideally, that the new explanation has greater explanatory power). If we do not admit iconoclastic alternative views we miss things like quantum mechanics or relativity theory or any of the other scientific revolutions that (for a while) had scant empirical support and seemed to violate both common sense and the consistency requirement.
Don’t get me wrong, I spend a lot of my time pointing out that the climate does not violate the second law of thermodynamics and so on as well. There are plenty of unsound hypotheses. However, even then the best I can say is that they seem unsound to me and, if the author of the hypothesis wishes to convince me, the burden of proof is entirely on them to build a perpetual motion machine and completely explain how it works or whatever (or indicate why their climate theory does not permit the construction of a perpetual motion machine).
rgb
rgbatduke says:
April 24, 2012 at 6:26 am
Right, but then one either has to make an assumption of maximum ignorance (a.k.a. “all things being equal”) and assume that on average they vary with solar activity because that is what they are observed to do on average now or one has to systematically try to identify and correct for those factors. For times in the remote past especially, I would think that the former would be a lot safer than the latter.
We are a bit more ambitious as we want to [and think we can, eventually] understand the whole chain and calculate what the effects should be. You might call that the principle of maximum knowledge.
Your own graph here:
http://www.leif.org/research/Solar-Polar-Fields-1966-now.png
If we assume that observations of the Maunder minimum were correct, and that sunspot counts were indeed extremely low — perhaps not “zero” by modern telescope-driven standards but low enough to be completely remarkable, much lower than any other solar era for which we have historical records — then would we not expect the principle field components to be similarly low?
I actually think not necessarily. It is quite possible that the magnetic field was still present [the cosmic ray modulation shows it was] but that the sunspots were too small or too weak to be seen. We may have a similar situation arising today with the so-called Livingston & Penn effect.
As you say, proxy-inferred cosmic ray modulation is less reliable because proxy deposition can depend on geomagnetic field and weather
That would be true for the general level of the cosmic rays, but I was referring to the clear solar cycle modulation observed which is an unmistakably, relative effect on top of the overall trend.
but I would certainly like to learn of them if you don’t mind teaching me. In particular I would like to know why you reject the simple SSN-dipole strength correlation apparent in the era of modern instrumentation and what you think the dipole/quadrupole moments of the magnetic field of the Sun looked like during the cycles of the Maunder minimum.
I do not reject the notion that solar activity is very nicely related to the dipole strength. In fact, I originated that idea back in 1978, and fully expect it to hold at all times. My working hypothesis is that the dynamo was working normally during the Maunder Minimum, but that the process that compacts the magnetic field into visible sunspots was not effective enough during the MM. The observations by Livingston & Penn indicate that a similar loss of efficiency is beginning to operate recently. This is open to observational testing and will play out in a few years from now.
rgbatduke says:
April 24, 2012 at 6:41 am
Second, the research phase of science openly encourages alternative views, iconoclastic views, wild surmises, crazy talk, and so on
All generalization has problems. I was referring specifically to the alternate views championed by Geoff and others which are not science-based, reject known laws of nature, advocate astrology or unknown forces – new physics, and the like. Another cornerstone of science is falsification, which seems to me is also rejected by ‘the alternatives’. At our workshop I fully expect some of the views held be abandoned [as they cannot all be correct where they differ]. I very much doubt that any of the ‘alternative views’ would be abandoned when exposed to the harsh light of real science.
At our workshop I fully expect some of the views held be abandoned [as they cannot all be correct where they differ]. I very much doubt that any of the ‘alternative views’ would be abandoned when exposed to the harsh light of real science.
No argument here, as I said, I encounter a lot of the same thing. Please feel free to bop me upside the head if I depart from the path of reason in your field as I certainly expect that you know it a hell of a lot better than I do, although my knowledge of physics and the underlying math is adequate for me to understand it.
rgb
rgbatduke says:
April 24, 2012 at 8:20 am
Please feel free to bop me upside the head if I depart from the path of reason in your field as I certainly expect that you know it a hell of a lot better than I do
Although most of the ‘alternatives’ claim I know almost nothing… 🙂
Yeah, but I actually look back at the literature, and note that you’ve been working in the field at least since about the same time I graduated from Duke as an undergrad. Looking at some OF that literature, it seems highly unlikely that you are an idiot (although idiocy is not entirely unknown among the ranks of Ph.D. qualified physicists, see Mann, Michael as a possible example). Therefore if you don’t know a hell of a lot more than I do, and if your knowledge (universally correct or not) is not reasonably well founded, there is a serious problem with the Universe. Q.E.D.
I, OTOH, am entirely capable of being a flake in solar science, because I don’t know enough.
I will say that theory of knowledge suggests that it is sometimes good for flakes or outsiders to look in and ask to have things explained or challenge explanations, because in optimization theory it is always too easy to sit complacent on a local hilltop and note that all pathways away from the peak lead (locally) downhill. This can make it difficult to see a slope up to a much higher peak (better global explanation) that might be a far jump across an intervening valley away. So hopefully you will be tolerant of my mistakes (while by all means correcting them) in the off chance that I might have some sort of insight that my very naivety still permits but that is less likely to those that thing in well-established ways.
Presuming I have time to even get to where I can make even a naive hypothesis. I’m only insanely busy with my own stuff as it is (which is largely predictive modeling, Monte Carlo, teaching, and random numbers) although as I said I do know a fair bit about multipoles and E&M in general and a smattering of astronomy and astrophysics.
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LazTeenager says: @ur momisugly April 22, 2012 at 3:33 pm
But then again if you live in Venice or Bangkok or any other low lying city you may not. The time scales are very long so people will move. But a large amount of our cultural heritage will be obliterated.
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A lot of our heritage has been bombed, burned and otherwise destroyed. The plates of Congressman Lindbergh’s books were destroyed by US Government agents for example. (So much for free speech)
6 Real Sunken Cities
The lost city of Mahabalipuram (drowned)
Egypt’s lost pyramids: Spied from space by satellite, 17 tombs buried by sands of time
EGYPTIANS ARE SLOWLY UNCOVERING ANCIENT CITY BURIED UNDER SAND’
More telling still
It is hubris to think mankind can actually stay the winds of time.