I Picked this comment up on a recent WUWT sea level thread. LOD is Length of Day, a measurement of the Earth’s speed of rotation, which varies for several reasons. For some reason yet to be fully explained, its variation seems to correlate well with the changing disposition of mass in the solar system above and below the solar equatorial plane (SSBz), and detrended global average temperature.
agfosterjr says:
Jens Bagh says:
May 16, 2012 at 1:03 am
Were sea levels to be rising this would slow down the rotation of the earth. Has any change been noted in the rate of change of rotation and if so how does this compare to the present study?
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Oddly enough, LOD responds to sea level rise differently depending on whether the source is thermal expansion or melting ice. Of course thermal expansion adds no mass, but it does move it further from the center of gravity so that it flows toward expanding shallow coasts. It just so happens that shallow coasts are concentrated nearer to the poles than would be expected at random, much reducing the rate at which thermal expansion increases LOD or even reversing it, whereas rise due to melted ice should increase LOD by about .1ms per cm. So to determine the overall effect we have to know what fraction of rise is due to which source, when in fact the rise is so miniscule that neither satellites nor gauges can measure the combined effect accurately.
Still, LOD places limits on possible ice mass transfer, but core/mantle coupling is suspected of having a greater decadal effect on earth rotation. The earth’s loss of angular momentum can be calculated by measuring the rate of lunar recession. Secular deceleration of earth rotation can be calculated from ancient astronimical observations. The former gives a rate of 2.3ms/century and the latter yields 1.7. The difference is attributed to isostatic adjustment. The past couple of years have seen LOD hang around 1ms over the 1800 standard, meaning .5ms/century, a third of the normal. And since the advent of the atomic clock LOD has hardly increased at all, though it fluctuates on a number of time scales.
The core/mantle excuse is only good up to a point–time wise and amplitude wise: catastrophic sea level rise would certainly increase LOD to an easily measured rate, and this is not happening. J2 –a measure of earth curvature–can theoretically distinguish between core angular momentum contribution and sea level contribution to LOD, hence between thermal and mass expansion of the sea, but as with temperature and tide gauge measurements, noise predominates.
I might add that the LIA and MWP can be roughly inferred from reconstructed LOD. –AGF
World ocean heat content and thermosteric sea level change (0–2000 m), 1955–2010
http://www.agu.org/pubs/crossref/2012/2012GL051106.shtml
“The heat content of the World Ocean for the 0–700 m layer increased by 16.7 ± 1.6 × 1022 J corresponding to a rate of 0.27 W m−2 (per unit area of the World Ocean) and a volume mean warming of 0.18°C. ”
My estimate made three years ago was 0.15°C. Not bad considering the vagueness of the XBT/ARGO splice.
This study confirms that the ocean retains heat on long timescales. That confirms that the long period in the C20th when the solar activity level was higher than the long term average over the period of record from 1749 has a lot more to do with global warming than minor changes in minor atmospheric constituents.
http://tallbloke.wordpress.com/2010/07/21/nailing-the-solar-activity-global-temperature-divergence-lie/
The principle issue to be addressed is the linkage between solar activity and cloud amount in the areas that matter in terms of insolation. The reduction in low level tropical cloud measured by ISCCP from ~1980-1998 confirms that sunshine hours over the oceans are the important metric. Sunshine hours correlate with temperature far more closely than co2.
http://tallbloke.wordpress.com/2012/02/13/doug-proctor-climate-change-is-caused-by-clouds-and-sunshine/
The other issue is TOA energy balance. We need to know about energy levels leaving the planet as well as arriving at its surface.
http://tallbloke.wordpress.com/2010/12/20/working-out-where-the-energy-goes-part-2-peter-berenyi/
Conclusions.
The ‘missing heat’ is somewhere past Alpha Centauri by now.
The ARGO data is being fudged to show continued increase in ocean heat content. The Satellite altimetry is calibrated to the co2 driven theory instead of actual measurements made by tide gauges.
http://tallbloke.wordpress.com/2011/12/02/sea-level-scare-stories-simply-scandalous/
Greetings, Tallbloke, and thankyou for your attention. What immediately caught my attention here was your remark on the displacement of the sun from the barycenter–two solar diameters, I think–representing two million miles. I had never before considered variable earth-sun distance as affected by solar-barycenter displacement as a climate/weather driver. And I have never seen a graph of true earth-sun distance over time, taking into account the displacement. Maybe this just shows what a novice I am, but could you direct me to such a graph? Regards, –AGF
Hi AGF and welcome. I don’t think the Earth – Sun distance is affected by the Sun’s motion wrt the solar system barycentre to any important extent. This is because the Earth follows the Sun as the Sun moves. Otherwise the signal would easily be discerned in the TSI measurement.
The gas giants, especially Jupiter, are causing the changes in the Sun’s orbit predominantly, and so there will be changes in the Earth – Jupiter distance which relate to the Sun SSB changes. This gravitational effect may be small in relation to other forces which affect LOD.
My plot above is for the motion in the z axis, relative to the solar equatorial plane, rather than in the plane the planets orbit in. The correlation is much clearer and more direct here, than it is in the x,y plane, which was investigated by Ian Wilson a couple of years ago. Hopefully, he’ll provide a link to his study.
The big question mark for me, is how much these changes in LOD affect ocean currents and meridional flows, given the tantalising link with ~60 year oceanic cycles.
OK, first, does SSB mean “single side band”? If so, how was this measured in 1860, before Marconi?
As for LOD affecting sea currents, I’m aware that Axel-Morner made such a suggestion, but I find it impossible to believe that variation on the order 10 ^ – 8 will affect anything. LOD is the effect, not the cause, at least on millennial scales and shorter.
I need to spend some more time on your site to get acquainted with your arguments. I’ll check in from time to time. But what’s SSB? –AGF
[reply] Solar System Barycentre
AGF: The point is, if the correlation in my graph above has any meaning, we can be sure it is the rest of the solar system’s movements causing the change in LOD, rather than the opposite. This LOD variation is around an order of magnitude larger than the semi-annual variation due to angular momentum exchange between the solid Earth and changes in atmospheric angular momentum. Those changes in winds strongly affect ocean currents, so why not the variation which is ten times bigger?
The LOD change vs the Solar-SSB motion looks to be affected by an overall inertial delay, compounded by some other factor that itself may be an inertial delay.
How does the Solar-SSB motion compare to the Earth-Sun distance? I expect the Earth-Sun distance has a complex sinusoidal variation with time, also, not just a simple variation due to a fixed elliptical orbit.
How about Solar-SSB with TOA TSI?
Since sunspots and solar flares are dominantly located in the +/- 35* (??) positions of the sun, does the changing position relative to the solar equatorial plane cause the cross-sectional capture area of the Earth relative to the source of solar emissions to change similarly to this? How about the solar wind: is there a strength distribution difference of a similar magnitude the Earth feels?
Solar-wind vs LOD?
Is there a solar system dust distribution difference between across the solar equatorial plane?
A total variation of 0.25 m/s in itself seems unimportant, more like a symptom of a common cause.
Still not sure what SSB z axis motion is, but it’s as good a fit as correlation between the earth’s magnetic field and LOD. As for AAM and LOD, the correlation is above 90% on a daily scale (tides modeled out) but useless on a decadal scale. Ocean currents have been proposed but rejected as contributors, but I suppose the circumpolar current shuts down during an ice age.
Doug, I was reading your paper between arguments with a local prof–I like your approach. Thanks to both of you. More later. –AGF
AGF;
my non-techie interpretation is the bobbing up and down of the center of gravity vis-a-vis the sun.
Brian: Almost. The green curve on the graph actually shows motion of the Sun’s equatorial plane relative to the centre of mass of the solar system in the up-down ‘z’ axis. The Sun is tilted at around 7 degrees to the average plane of the planetary orbits.
it’s most likely the precession of the equinox. if you use heliocentric coordinates instead the effect on the lod would probably disappear. the complication is geophysics bases their models on the motions relative to the so-called fixed stars which are themselves moving.
if I recall correctly, the ecliptic plane of the solar system is roughly perpendicular to the galactic plane of the milky way and the orbits of sun and the planets have a helix motion through the “arm” of the milky way.
since the velocity of the solar system has 3 fricken components (two of which oscillate) an undefined velocity projection which happens to have a correlation with a global temperature where both the data and the calculations used to generate index have been cooked is most likely coincidental.
Agile Aspect says:
May 19, 2012 at 5:31 pm
“it’s most… likely coincidental.”
Agile, I’ve been criticized (unfairly!) for this, but I don’t feel correlations are ever coincidences but may be non-causative without difficulty. What I think non-causative correlations are is indications of the impact of third-party actions on something that does have a causative impact on the second-party.
The correlation between pork belly and silver futures in the Chicago stock exchange (apocryphal or not) would be an example: whatever caused pork prices to rise later caused silver prices to rise, so that you could use the first to predict the second. That is how I would see any sea-level or temperature correlation with LOD.
The interesting thing about the solar positional data and the LOD is the tiny changes in the LOD that are correlated. That’s the weird thing. Despite all the fiddling with data and algorithms which I agree is considerable, you still get this robust correlation. That says two things. First, the fiddling must be internally consistent and/or correct, and the behind-the-scenes, causative action, hard-wired.
There is a third answer, of course, and one that I have no possibility of insight into: there is a circular reasoning somewhere in the calculations, such that if-then-if comes back on itself.
I suspect that most or all correlations with LOD are either by way of climate; or less likely by way of CAM. The severe 17th century rise is probably due to ice melt–LOD jumped 8ms in two decades:
http://hpiers.obspm.fr/eop-pc/earthor/ut1lod/lod-1623.html
(scoll to bottom)
–AGF
If the earliest telescopic data are reliable LOD increased by 8ms in a quarter century (between 1623 and 1648; see http://hpiers.obspm.fr/eop-pc/earthor/ut1lod/lod-1623.html
–scroll to bottom). I doubt that anything but climate phenomena could produce such drastic deceleration, and I think ice melt is the most likely candidate. Likewise I suspect that most pronounced correlations with LOD will be seen to have climate as the intermediate cause, with CAM coming in a distant second.
TB, could you post that graph here–or a better copy? –AGF
Glaciers advanced in the 1600′s, coincident with the Maunder minimum in solar activity. They did it again in the Dalton Minimum at the start of the C19th.
http://books.google.co.uk/books?id=okfCqYFfCdYC&pg=PA203&lpg=PA203&dq=glacial+advance+alpine+villages&source=bl&ots=cEdJ3jAINz&sig=X1dvUVDZF8vBqnktCUAQzSeVuKY&hl=en&sa=X&ei=gxq5T_6fJ_Cb1AXf5tjSBw&ved=0CGAQ6AEwBQ#v=onepage&q=glacial%20advance%20alpine%20villages&f=false
Maybe a big increase in unmelted snow in the northern hemisphere’s higher latitudes changed the mass balance sufficiently to alter LOD?
Rog, Google books won’t allow that.
Here have a maybe image from Michael Mann, Figure 1.
http://holocene.meteo.psu.edu/shared/articles/littleiceage.pdf
Various photos around but can’t put my hand on one.
I think you mean lower latitudes–lower than 63 degrees. That could do it.