From techno-science.net This tip came in on our tip & notes page, and at first I was quite surprised because I could not see a possible mechanism for it. Then as I read the translation (from French) it started to make more sense. I’ll point out my friend Jim Goodridge published an essay on WUWT about correlation of the PDO and rainfall with LOD: California Climate, PDO, LOD, and Sunspot Departure
Here’s the graph from the current article of interest:
And here’s some excerpts describing possible mechanisms:
Some authors, notably Bourget et al (1992), had begun to reveal correlations between solar activity and the length of day, and more recently, Abarca del Rio et al (2003) and Winkelnkemper (2008) in his thesis noted that the amplitude of the component semi-annual (6 months period) of the length of day and atmospheric angular momentum were anti-correlated with changes in the same period of the ” solar constant (the solar constant expresses the amount of solar energy (actually a lighting power) which would be one …) “.
What could be the link between certain changes in day length, the zonal winds and solar activity? To help answer this question, The Mouël and colleagues analyzed a series of 48 years (from 1962 to 2009) of daily measurements of the length of day, the service provided by the International Earth Rotation and systems reference located at the Observatoire de Paris. They have extracted the component of period 6 months and showed significant variations in the amplitude of this component, about 30%, they compared the one hand the number of sunspots (the Wolf number, a traditional indicator of solar activity measured for several centuries) and also the flux of galactic cosmic ray.
The authors show a good correlation between these three parameters, more precisely (Figure), it is the evolution of cosmic rays and the amplitude of the semi-annual day length are correlated (correlation coefficient the order of 0.7), and are in phase. The correlation is improved when we remove the curve (In geometry, the word curve or curved line designates certain subsets of the plan, the usual space. ,…) example of day length linear trend which could be related to phenomena occurring in the nucleus. It is established also that variations in cosmic rays are out of phase with sunspots and shifted about a year (this is attributed to the mechanism of modulation of galactic cosmic rays by the solar wind (solar wind is a stream plasma consisting essentially of ions and electrons are ejected from the high …) and its magnetic field).
How the speed of rotation of the Earth can it be sensitive to the modulation of cosmic rays?
The answer is in the system of winds. Those who contribute most to the seasonal variations of angular momentum are the winds of relatively low altitude (Altitude is the vertical elevation of a place or object relative to a baseline.) below 30km . Taking an average over a year (A year is a unit expressing the duration of time between two occurrences of an event linked to the revolution …), the difference between radiation (Radiation is energy transfer under form of waves or particles, which can occur by radiation …) received from the Sun ((weight percent)) and one that is emitted by the Earth outward into the great length of wave (A wave is the propagation of a disturbance occurring on its passage a reversible variation of properties …) (IR) is positive towards the equator and negative beyond 40 degrees latitude (Latitude is an angular value, expression north-south position of a point on Earth (or another …).
This latitude gradient must be balanced by a flow of energy (in the common sense energy means anything that allows a work, making the heat, …) from the equator to the poles: the transportation (transport, from the Latin trans, beyond, and portare wearing is wearing something, or someone one, a place …) is provided by the Southern movements (that is to say along the geographic meridians) of the atmosphere, averaged in longitude (Longitude is an angular value, expressing the position east-west from a point on Earth (or another …), and eddies. The zonal winds are the result of this transport because of conservation of angular momentum: going to the poles is approached the axis of rotation of the Earth and changes in this distance must be compensated by changes in speed. The seasonal variations in insolation lead to variations of the same period of the carriage along the meridians and, from there, the mean zonal winds.
…
There is another route by which clouds can be affected: the atmosphere is indeed penetrated by a vertical electric current of a few nano-Ampere per square meter (the meter (the meter (symbol m, the Greek metron, measure) is the basic unit of length in the International System. … It is defined) square (a square is a regular polygon with four sides is a quadrilateral that is both a rectangle (it a. ..) ( symbol m) is the unit area of the international system.), which fluctuates with the ionospheric currents and therefore the solar activity. These vertical currents electrically charged clouds and, again, change their micro-physical state. Both mechanisms can indeed co-exist. What characterizes them is that those variations induced by solar activity is measured in tenths of a percent and not in parts per thousand. That’s where the important niche amplification (We are talking about force amplifier for a whole range of systems that amplify the efforts: mechanics ,…) of the phenomenon.
Thus, the Earth (specifically the mantle), the rotation is accelerated or slowed according to the fluctuations of cosmic rays under the influence of solar activity through the zonal winds, provide a wonderful device integration variations in atmospheric angular momentum and zonal wind circulation that it is difficult to measure directly.
Full article and translation here
h/t to WUWT reader Steward
Pour tenter de répondre à cette question, Le Mouël et ses collègues ont analysé une série de 48 années (de 1962 à 2009) de mesures journalières de la longueur du jour, fournies par le service international de la rotation de la Terre et des systèmes de référence situé à l’Observatoire de Paris. To help answer this question, The Mouël and colleagues analyzed a series of 48 years (from 1962 to 2009) of daily measurements of the length of day, the service provided by the International Earth Rotation and systems reference located at the Observatoire de Paris. Ils en ont extrait la composante de période 6 mois et ont mis en évidence de fortes variations de l’amplitude de cette composante, de l’ordre de 30%, qu’ils ont comparé d’une part au nombre de taches solaires (le nombre de Wolf, un indicateur traditionnel de l’activité solaire mesuré depuis plusieurs siècles) et d’autre part au flux de rayon cosmiques galactiques. They have extracted the component of period 6 months and showed significant variations in the amplitude of this component, about 30%, they compared the one hand the number of sunspots (the Wolf number, a traditional indicator of solar activity measured for several centuries) and also the flux of galactic cosmic ray.
Les auteurs mettent en évidence une bonne corrélation entre ces trois paramètres, plus précisément (Figure), ce sont les évolutions des rayons cosmiques et de l’amplitude de la composante semi-annuelle de la longueur du jour qui sont corrélées (coefficient de corrélation de l’ordre de 0,7), et qui sont en phase. The authors show a good correlation between these three parameters, more precisely (Figure), it is the evolution of cosmic rays and the amplitude of the semi-annual day length are correlated (correlation coefficient the order of 0.7), and are in phase. La corrélation est améliorée quand on retire à la courbe de la longueur du jour une tendance linéaire, qui pourrait être liée à des phénomènes se produisant dans le noyau. The correlation is improved when we remove the curve (In geometry, the word curve or curved line designates certain subsets of the plan, the usual space. ,…) example of day length linear trend which could be related to phenomena occurring in the nucleus. Il est établi par ailleurs que les variations des rayons cosmiques sont en opposition de phase avec les taches solaires et décalées d’environ un an (ceci est attribué au mécanisme de modulation des rayons cosmiques galactiques par le vent solaire et son champ magnétique). It is established also that variations in cosmic rays are out of phase with sunspots and shifted about a year (this is attributed to the mechanism of modulation of galactic cosmic rays by the solar wind (solar wind is a stream plasma consisting essentially of ions and electrons are ejected from the high …) and its magnetic field).
Comment la vitesse de rotation de la Terre peut-elle donc être sensible à la modulation des rayons cosmiques ? How the speed of rotation of the Earth can it be sensitive to the modulation of cosmic rays?
La réponse est dans le système des vents. The answer is in the system of winds. Ceux qui contribuent le plus aux variations saisonnières du moment angulaire sont les vents de relativement basse altitude , en dessous de 30km. Those who contribute most to the seasonal variations of angular momentum are the winds of relatively low altitude (Altitude is the vertical elevation of a place or object relative to a baseline.) below 30km . Prise en moyenne sur une année , la différence entre le rayonnement reçu du Soleil et celui qui est réémis par la Terre vers l’extérieur dans les grandes longueur d’ onde (infra-rouge) est positif vers l’équateur et négatif au delà de 40° de latitude . Ce gradient en latitude doit être équilibré par un flux d’ énergie de l’équateur vers les pôles: ce transport est assuré par les mouvements méridionaux (c’est-à-dire le long des méridiens géographiques) de l’atmosphère, moyennés en longitude , et les tourbillons. Les vents zonaux sont la conséquence de ce transport à cause de la conservation du moment angulaire: en allant vers les pôles on se rapproche de l’axe de rotation de la Terre et les changements de cette distance doivent être compensés par des changements de la vitesse. Les variations saisonnières d’insolation entraînent des variations de même période du transport le long des méridiens et, partant de là, de la moyenne des vents zonaux. Taking an average over a year (A year is a unit expressing the duration of time between two occurrences of an event linked to the revolution …), the difference between radiation (Radiation is energy transfer under form of waves or particles, which can occur by radiation …) received from the Sun ((weight percent)) and one that is emitted by the Earth outward into the great length of wave (A wave is the propagation of a disturbance occurring on its passage a reversible variation of properties …) (IR) is positive towards the equator and negative beyond 40 degrees latitude (Latitude is an angular value, expression north-south position of a point on Earth (or another …). This latitude gradient must be balanced by a flow of energy (in the common sense energy means anything that allows a work, making the heat, …) from the equator to the poles: the transportation (transport, from the Latin trans, beyond, and portare wearing is wearing something, or someone one, a place …) is provided by the Southern movements (that is to say along the geographic meridians) of the atmosphere, averaged in longitude (Longitude is an angular value, expressing the position east-west from a point on Earth (or another …), and eddies. The zonal winds are the result of this transport because of conservation of angular momentum: going to the poles is approached the axis of rotation of the Earth and changes in this distance must be compensated by changes in speed. The seasonal variations in insolation lead to variations of the same period of the carriage along the meridians and, from there, the mean zonal winds.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Paul Birch says:
October 5, 2010 at 7:32 am
Have you visited the earth’s core lately, how is it?
Paul Birch says:
October 5, 2010 at 7:17 am
But the feedback from the rest of the solar system to the sun is very, very weak
That was believed long ago, in the epoch of the “Flintstones’ Universe conception” ( a kind of “pebbles universe” where only rounded stones existed and also where there were some extravagant sky wanderers made of Ice-Cream and stars’dust, called by the famous physicist Fred Flintstone, “comets”).
I am old too but I use to refresh my mental windows once in a while: Ask your grand children!
Paul Birch says: October 5, 2010 at 7:32 am
………….
Yes indeed I do (and frequency factor, and 1/e). Even so electric currents are induced by ionosphere to depths up to several hundred kilometres of lithosphere!
But it is not the induced currents, that reach the core, it is their magnetic field, which works against the geomagnetic field, resultant as vector sums of two, as a result is reduced. As an indication of this effect I offer suggestion that there is an inverse correlation between GMF and solar output, in the Arctic region’ where such electric currents are strongest:
http://www.vukcevic.talktalk.net/LFC9.htm
However other readers may be interested to know that NASA has an ongoing project investigating possible link solar wind – ionosphere currents – earthquakes.
The variation of the horizontal component H of the geomagnetic field is the crucial parameter in the Magneto-Seismic Effect MSE to be discussed in a companion paper. The connection of earthquake activity to possible solar or solar wind drivers is not well understood; many authors have attempted correlations in the past with mixed results. We will use data from the S3C Great Observatory and from ground-based magnetometer arrays to show long term trends near solar minimum for ultra low frequency (ULF) fluctuations, specifically the Pc5 (˜1 – 8 mHz) band.
The role of ionospheric currents will be highlighted in a companion paper.
R. Kessel, F. Freund & G. Duma
Lab for Solar and Space Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 [ramona.l.kessel@nasa.gov
Department of Physics, San Jose State University and Ecosystem Science and Technology, NASA Ames Research Center, MS 242-4, Moffett Field, CA 94035-1000
For anyone interested in matching LOD changes to known weather or other terrestrial events I’ve done a higher resolution GRAPH
Not sure were all the data in the header comes from but this is the plot I get for LOD and SSN
http://img692.imageshack.us/img692/387/lodsunspot.png
There seems to be no correlation worthy of note.
LOD here
http://hpiers.obspm.fr/eop-pc/
SSN here
ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/MONTHLY
vukcevic says:
October 5, 2010 at 11:46 am
“Yes indeed I do (and frequency factor, and 1/e). Even so electric currents are induced by ionosphere to depths up to several hundred kilometres of lithosphere!
But it is not the induced currents, that reach the core, it is their magnetic field, ”
I suggest you go and read up on the skin effect again. It prevents varying magnetic fields from penetrating a conductor. Neither the magnetic field, nor any induced currents, could penetrate the Earth’s core (on this time scale, ie, at these frequencies).
“Several hundred kilometres” is less than a tenth the depth the fields would have to penetrate, even to reach the outer regions of the magnetic core, let alone into its dynamo, where the conductivity will be much higher and the skin depth correspondingly smaller.
Enneagram says:
October 5, 2010 at 5:44 am
Thank you for the link, I had seen this and am sure it is edifying, however, my original question @ur momisugly October 4, 2010 at 3:28 am was on how a reduction in braking force can cause an acceleration. Its a ‘laws of motion thing’ I thought but links kindly supplied by Vukcevic & yourself suggest I need to involve myself in Unified Field Theory! Well, very kind of you but I am a little bit busy what with the twins and the roof problem and all !-)
Paul Birch says: October 6, 2010 at 3:26 am
………….
And perhaps you can explain how the core’s electric currents generated magnetic field penetrates trough the same skin effect of the lithosphere in the opposite direction !
Also you may wish to consider effect of geomagnetic field on instability in anarcho-capitalism- Paul Birch
E.M.Smith says:
October 5, 2010 at 5:05 am
I got pulled into the idea of “Spin Orbit Coupling”
Some may call it “resonance” or whatever, however yours it is not “Oh, and one distraction”, it is really the same phenomenon: We do not need to divide reality in so many details, which differ only in frequency and wavelength (“the devil is in the details”, rather it makes simple things obscure by multiplying it to infinite quantities). The field is one. (see above link). We should return to the simplicity of numbers and elemental geometry or music in order to comprehend reality.
Richard Holle says:
October 4, 2010 at 5:40 am
There are three unstoppable things in nature, truth, true love, and an Idea whose time has come.
Great!. The time is due; changes, if resisted, cause pain, a pain which only affects our cherished ego, then we could get rid of that “suffering” if we just wanted to, but this is the harder task a man can accomplish: to die in order to resurrect.
Stephen Wilde says:
October 4, 2010 at 5:39 am
All too speculative so far I fear and unlikely to be a large enough forcing agent.
A back of the envelope SWAG calculation, dK= I w dw (rotational kinetic energy change with a change in the angular speed) shows that the potential “forcing” has a maximum of about 0.1 Watts/m^2 for the maximum difference in angular speed.
vukcevic says:
October 6, 2010 at 5:24 am
“And perhaps you can explain how the core’s electric currents generated magnetic field penetrates trough the same skin effect of the lithosphere in the opposite direction !”
I don’t have to, since it is you, not I, that is promoting the relevance of changes in the core. I have made no such claim. However, points to note include the longer timescales (lower frequencies) and greater energy densities. The core is the dog, the magnetosphere the very tip of its tail.
Do you still not understand that the skin effect attenuates imposed magnetic field variations exponentially with depth, and that this poses very grave problems for your “alternative” theory? If you want to rescue your theory the onus is on you to show how this difficulty can be overcome – with hard physics, not merely by handwaving or attacking other people’s ideas.
You already contradicted yourself in your statements. Neither you or I or anyone else has a theory how geomagnetic field is generated. It is only a hypothesis (there is a difference between two !).
My ideas are new and controversial , I do not have to prove anything to anyone, you can take it or leave it. There is a long queue of people and scientists ready to rubbish what I write, you are more then welcome to join.
Paul Birch says:
October 6, 2010 at 9:15 am
You speak about the “skin effect”, however if you could see a skin like Oppenheimer saw his conference table, as moving energy, you would see an “electric double layer” : That’s music you know, waves, and each crest of those waves is that “skin” you like so much. The fact of the matter (literally) is that earth’s skin, that surface you walk on, it is a transient congealment of energy,, composed of several layers or “skins” which interact with the environment, with its “mother liquor”, An aggregation of cathode deposits arranged according to its potential: the more negative ones the last to be deposited on (that is why the earth’s surface is called SIAL -aluminum silicate-) that sea of energy it is not a dead universe of “rounded stones” but a vibrant and live spectacle to behold.
vukcevic says:
October 6, 2010 at 11:21 am
“You already contradicted yourself in your statements.”
I don’t think I have. Please quote the alleged contradiction.
“Neither you or I or anyone else has a theory how geomagnetic field is generated. It is only a hypothesis (there is a difference between two !).”
I don’t care whether you call it a hypothesis, theory, conjecture or view; it still has to obey the laws of physics.
“My ideas are new and controversial , I do not have to prove anything to anyone, you can take it or leave it. There is a long queue of people and scientists ready to rubbish what I write, you are more then welcome to join.”
If you refuse to subject your ideas to scientific test, or wantonly ignore basic physics, then you are merely fabricating a fantasy. All right for science fiction, perhaps, but not for science. And if you pretend it’s real, while turning your back on reality, then it’s rubbish (and old, rehashed rubbish at that).
Paul Birch says:
October 6, 2010 at 2:29 pm
If you refuse to subject your ideas to scientific test, or wantonly ignore basic physics, then you are merely fabricating a fantasy.
Which is what Vuk does, so let’s just treat it as entertainment.
Thanks doc for coming to my defence, despite being solar scientist, you are still on ‘terra firma’; you may be also entertained by ideas of ‘moving planet Mars with mirrors’.
http://www.paulbirch.net/MoveAPlanet.pdf
http://www.paulbirch.net/SpinAPlanet.pdf
by curtsey of the above
P.s. Have you given any further thought to
http://www.vukcevic.talktalk.net/CET-Mc.htm
vukcevic says:
October 7, 2010 at 12:50 am
P.s. Have you given any further thought to
http://www.vukcevic.talktalk.net/CET-Mc.htm
You still need to add 1.7 nT to McCracken’s values before ~1950.
vukcevic says:
October 7, 2010 at 12:50 am
“Thanks doc for coming to my defence, despite being solar scientist, you are still on ‘terra firma’; you may be also entertained by ideas of ‘moving planet Mars with mirrors’.”
He wasn’t coming to your defence, and the planet-moving technique in those JBIS papers uses high-velocity mass-streams, not solar sails (which is one of a variety of suggestions from previous workers, but which is unfortunately unable to transfer sufficient momentum to accomplish significant orbit modification within reasonable timescales <1Myr). Mirrors are required only to provide the initial energy from a solar-orbiting light-sail windmill, and could be replaced by any other suitable energy source. The technique is entirely consistent with known science and engineering principles.
Leif Svalgaard says: October 7, 2010 at 3:28 am
You still need to add 1.7 nT to McCracken’s values before ~1950.
I hope your Euro-vacation was enjoyable.
Graph is now corrected.
http://www.vukcevic.talktalk.net/CET-Mc.htm
I think there is still good reason for concern regarding the pre 1930 svalues.
(CETs are normalised to corrected McCracken).
Vuk etc. says:
October 7, 2010 at 4:27 am
I think there is still good reason for concern regarding the pre 1930 values.
Don’t know what you are talking about.
There are various indications that the dips in the ‘HMF’ [actually in the cosmic ray flux] are caused by climate/weather effects, so the correlation [if any] may just be climate with climate.
vukcevic says:
October 5, 2010 at 11:46 am
Yes indeed I do (and frequency factor, and 1/e). Even so electric currents are induced by ionosphere to depths up to several hundred kilometres of lithosphere!
But it is not the induced currents, that reach the core, it is their magnetic field, which works against the geomagnetic field,..
..However other readers may be interested to know that NASA has an ongoing project investigating possible link solar wind – ionosphere currents – earthquakes..
..The role of ionospheric currents will be highlighted in a companion paper..
Good stuff Vuks.
How do the ionspheric field currents communicate with the surface fields and how do the surface fields, commuicate with core fields. Maybe through a series of cylinders which they are now suggesting exist based on current studies.
This graph Vuks is interesting..
http://www.vukcevic.talktalk.net/Daily%20LOD.htm
Made me start thinking about this again..since you had about 50 years up there..
Solar Wind Loses Power, Hits 50-year Low
“The average pressure of the solar wind has dropped more than 20% since the mid-1990s,” says Dave McComas..
..Curiously, the speed of the million mph solar wind hasn’t decreased much—only 3%. The change in pressure comes mainly from reductions in temperature and density. The solar wind is 13% cooler and 20% less dense..
..In addition to weakened solar wind, “Ulysses also finds that the sun’s underlying magnetic field has weakened by more than 30% since the mid-1990s,” says Posner. “This reduces natural shielding even more.”
Unpublished Ulysses cosmic ray data show that, indeed, high energy (GeV) electrons, a minor but telltale component of cosmic rays around Earth, have jumped in number by about 20%..
http://science.nasa.gov/science-news/science-at-nasa/2008/23sep_solarwind/
hmmm heliosphere shrunk, Earth’s atmosphere “lowered.” (could say magnetosphere shrunk) and the core field has decreased.
Don’t tell Leif, but I am starting to feel delusional .. hahahha
If we have a contact point with the radiation belts showing a visible weakened “depression,” in the earths surface field and an adjacent ..
Then there’s Jupiter losing the S. Hemi stripe thingy..
Jupiter loses a stripe
21:49 11 May 2010 by David Shiga
Jupiter has lost one of its prominent stripes, leaving its southern half looking unusually blank. Scientists are not sure what triggered the disappearance of the band.
Jupiter’s appearance is usually dominated by two dark bands in its atmosphere – one in the northern hemisphere and one in the southern hemisphere.
But recent images taken by amateur astronomers show that the southern band – called the south equatorial belt – has disappeared.
The band was present at the end of 2009, right before Jupiter moved too close to the sun in the sky to be observed from Earth. When the planet emerged from the sun’s glare again in early April, its south equatorial belt was nowhere to be seen.
http://www.newscientist.com/article/dn18889-jupiter-loses-a-stripe.html
And there’s that equatorial belt thingy again..
Leif Svalgaard says:
October 7, 2010 at 4:46 am
…..so the correlation [if any] may just be climate with climate.
I am the one who usualy jumps into conclusions, not this time.
I did a quick look at period of your ‘special interest’ 1780-1840, subtracted my not so perfect North Atlantic precursor (I am well aware of your scepticism on this, still in the process of trying to interpret data) and got this:
http://www.vukcevic.talktalk.net/SSN-Mc.htm
a perfectly respectable CR’s graph.
Hi Carla, for the above I have to come back when I look at data available if any, but for time being, it is all a bit of speculation
vukcevic says:
October 7, 2010 at 9:45 am
a perfectly respectable CR’s graph.
You can see the effect of volcanoes. Does not look like respectable CR. And forget about the silly NAP.
1) The HMF deduced by McCracken is based on what he calls a “pseudo-Climax neutron monitor record”. In constructing this record he merges 10Be with neutron monitor data. But he is mixing oranges and apples. He forgets (or does not know – although Beer should) that the 10Be data lags 2 years behind the sunspots and the HMF (mainly because of the residence time of 10Be in the atmosphere). Thus all his data from before ~1980 (where the 10Be series from Dye-3 in Greenland stops) should be shifted 2 years earlier. This louses up any detailed comparisons of single years. I discovered this by painstakingly making a large magnification (3 feet across) copy of his Figure showing HMF as a function of time.
2) When shifting the HMF(10Be) data 2 years it becomes evident that they are too low before ~1950 by 1.7nT. When adding 1.7 nT before 1950, his data now agrees well with S&C, RL&F, and L&S.
3) There is a strong disagreement 1883-1896 (the “crack” in the floor). There are other cracks 1809-1820, 1694-1710, and a smaller one ~1766. 10Be is deposited by adhering to stratospheric aerosols which then drift down and rain out. The amount of aerosols in the stratosphere is controlled mainly by volcanic eruptions. There were such strong eruptions in 1693 (Hekla on Iceland, having large effect on nearby Greenland), 1766 (Hekla), 1809 (see Dai JGR 96, 1991), 1814 (Mayon), 1815 (Tambora), 1883 (Krakatoa). I suggest (although will have to study the mechanism) that these events are the reason for the cracks.
More on 1809:
Title: Ice core evidence for an explosive tropical volcanic eruption 6 years preceding Tambora
Authors: Dai, Jihong; Mosley-Thompson, Ellen; Thompson, Lonnie G.
Publication: Journal of Geophysical Research (ISSN 0148-0227), vol.
96, Sept. 20, 1991, p. 17,361-17,366.
Abstract: High-resolution analyses of ice cores from Antarctica and Greenland reveal an explosive volcanic eruption in the tropics in A.D. 1809 which is not reflected in the historical record. A comparison in the same ice cores of the sulfate flux from the A.D. 1809 eruption to that from the Tambora eruption (A.D. 1815) indicates a near-equatorial location and a magnitude roughly half that of Tambora. Thus this event should be considered comparable to other eruptions producing large volumes of sulfur-rich gases such as Coseguina, Krakatau, Agung, and El Chichon. The increase in the atmospheric concentration of sulfuric acid may have contributed to the Northern Hemisphere cooling observed in the early nineteenth century and may account partially for the decline in surface temperatures which preceded the eruption of Tambora in A.D. 1815.
Title: Two major volcanic cooling episodes derived from global marine air temperature, AD 1807-1827
Authors: Chenoweth, Michael
Publication: Geophysical Research Letters, Volume 28, Issue 15, p. 2963-2966), 2001
DOI: 10.1029/2000GL012648
Abstract: A new data set of global marine air temperature data for the years 1807-1827 is used to show the impact of volcanic eruptions in ~1809 (unlocated) and 1815 (Tambora, Indonesia). Both eruptions produced cooling exceeding that after Krakatoa, Indonesia (1883) and Pinatubo, Philippines (1991). The ~1809 eruption is dated to March-June 1808 based on a sudden cooling in Malaysian temperature data and maximum cooling of marine air temperature in 1809. Two large-scale calibrated proxy temperature records, one from tree-ring-density data, the other using multi-proxy sources are compared to the marine air temperature data. Correlation is highest with maximum latewood density data and lowest with the multi-proxy data.
Muscheler, R., F. Joos, J. Beer, S. A. Muller, M. Vonmoos, and I. Snowball, 2007: Solar activity during the last 1000 yr inferred from radionuclide records. Quaternary Science Reviews, 26, 82-97, doi: 10.1016/j.quascirev.2006.07.012.
Abstract: Four 10Be records from Greenland ice cores (Camp Century, GRIP, Milcent and Dye3) together with two 10Be records from Antarctic ice cores (Dome Concordia and South Pole). In general, the 10Be and 14C records exhibit good agreement that allows us to obtain reliable estimates of past solar magnetic modulation of the radionuclide production rates. Differences between 10Be records from Antarctica and Greenland indicate that climatic changes have influenced the deposition of 10Be during some periods of the last 1000 yr. The radionuclide-based reconstructions of past changes in solar activity do not always agree with the sunspot record, which indicates that the coupling between those proxies is not as close as has been sometimes assumed. The tree-ring 14C record and 10Be from Antarctica indicate that recent solar activity is high but not exceptional with respect to the last 1000 yr.
http://arxiv.org/abs/1004.2675
A Comparison Of New Calculations Of The Yearly 10Be Production In The Earths Polar Atmosphere By Cosmic Rays With Yearly 10Be Measurements In Multiple Greenland Ice Cores Between 1939 And 1994 – A Troubling Lack Of Concordance Paper #2
W.R. Webber, P.R. Higbie, C.W. Webber
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.
From the text: "Indeed this implies that more than 50% the 10Be flux increase around, e.g., 1700 A.D., 1810 A.D. and 1895 A.D. is due to non-production related increases!"
Dr. Svalgaard
Thank you for the extensive notes. I went through them twice, nothing in there is in any contradiction with my findings. At least it does indirectly confirm that the Dalton minimum activity was not be exceptionally low.
I have made that point on another thread
I have also referred to your reply
p.s. you may find eventually that NAP is not that silly at all, magnetic field is not the engine, just a rev-counter