Length of day governed by Earth's core processes

From the University of Liverpool , something I found interesting because a few years ago, former State Climatologist Jame Goodridge said he saw correlations between length of day and other atmospheric processes.

Variations of Length of Day

Research reveals Earth’s core affects length of day

Research at the University of Liverpool has found that variations in the length of day over periods of between one and 10 years are caused by processes in the Earth’s core.

The Earth rotates once per day, but the length of this day varies. A yeas, 300million years ago, lasted about 450 days and a day would last about 21 hours. As a result of the slowing down of the Earth’s rotation the length of day has increased.

The rotation of the earth on its axis, however, is affected by a number of other factors – for example, the force of the wind against mountain ranges changes the length of the day by plus or minus a millisecond over a period of a year.

Professor Richard Holme, from the School of Environmental Sciences, studied the variations and fluctuations in the length of day over a one to 10 year period between 1962 and 2012. The study took account of the effects on the Earth’s rotation of atmospheric and oceanic processes to produce a model of the variations in the length of day on time scales longer than a year.

Professor Holme said: “The model shows well-known variations on decadal time scales, but importantly resolves changes over periods between one and 10 years. Previously these changes were poorly characterised; the study shows they can be explained by just two key signals, a steady 5.9 year oscillation and episodic jumps which occur at the same time as abrupt changes in the Earth’s magnetic field, generated in the Earth’s core.

He added: “This study changes fundamentally our understanding of short-period dynamics of the Earth’s fluid core. It leads us to conclude that the Earth’s lower mantle, which sits above the Earth’s outer core, is a poor conductor of electricity giving us new insight into the chemistry and mineralogy of the Earth’s deep interior.”

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The research was conducted in partnership with the Université Paris Diderot and is published in Nature.

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ShrNfr

Gosh, that almost looks like a temperature graph with the AMO. Please, please, please, do not tell that to Mann. He will blame ADLC (Anthro Day Length Change) on CO2 and want to ban fossil fuels so that one side of the earth does not stay faced toward the sun at all times.

DirkH

Imagine, only 7 hours of sleep a day. It would kill me.

clipe

‘A yeas’, needs fixing
delete me afer..

RichardLH

I believe that anything that ‘plays’ with the Earth, Moon, Sun gravity fields effects on the others causes a modulation ofn the Climate that we see. Gravity is the way that energy is interchanged between non-radiating bodies in an orbital paths. That very slow release of ‘frictional energy’ on the other body that acts as a ‘spring’ to allow the other to get away.
I mean, what other way is there to do it? Interesting?

Ian W

It would be interesting to see if there is any relationship between the 60 year LOD cycle and the 60 year PDO cycle. Could ENSO events be due to ‘slopping’ Kelvin waves as well as winds?

DirkH

FAO has used LOD – or at least a model with 55 yr cycles – for temperature (and fish catch) forecasts.
ftp://ftp.fao.org/docrep/fao/005/y2787e/y2787e08.pdf

Robert of Ottawa

Needs editing, incomprehensible:
A yeas, 300million years ago,

RichardLH

Ian W says:
July 11, 2013 at 3:43 pm
“It would be interesting to see if there is any relationship between the 60 year LOD cycle and the 60 year PDO cycle. Could ENSO events be due to ‘slopping’ Kelvin waves as well as winds?”
I thin you may have to account for what looks like a 24 year cycle as well as 60 years.
That would at least split the enregy left to be distributed into more sensible RMS values.
http://i1291.photobucket.com/albums/b550/RichardLH/UAH-Comparisonofcascadedlowpassfilteroutputmonthsrunningaverage_zpsf1883e44.png

Robert of Ottawa

Why is the Earth’s rotation and orbital period slowing (over billions of years of course)?
Is it due to work between Earth and Solar magnetic fields? … Lief?

Robert of Ottawa

Richard III July 11, 2013 at 3:42 pm
I mean, what other way is there to do it? Interesting?
The interaction of magnetic fields

rogerknights

Robert of Ottawa says:
July 11, 2013 at 3:51 pm
Needs editing, incomprehensible:
A yeas, 300million years ago,

“yeas” should be “year”

“The rotation of the earth on its axis, however, is affected by a number of other factors – for example, the force of the wind against mountain ranges changes the length of the day by plus or minus a millisecond over a period of a year.”
*
The force of wind? This sounds to me a bit like blowing on your own sail or trying to hold up a swing with your own hands. A bunch of you who are more learned than I might jump on my conclusion there, and so be it, I won’t argue back. Another point, though, is that while mountain ranges seem big to tiny little creatures like us, on scale with the planet they are hardly there at all.
It doesn’t ring true to me that the wind can push the planet around, even by minute amounts.

Uh, the Y scale here is in milliseconds, to the human eye it might as well be hours. In other words there isn’t much variation in the length of the day, but this chart make it look like there is. Most of this chart is below average so what does average really mean here? Personally I like have longer days, I can get a lot more done in an extra 4 milliseconds or so. This is another example of research money well spent, if we can figure out a way to get 5 more milliseconds out of the day that would really be something.

RichardLH

Robert of Ottawa says:
July 11, 2013 at 3:58 pm
Richard III July 11, 2013 at 3:42 pm
That’s not be . Take that poster down!
“The interaction of magnetic fields”.
Indeed. But the magnitudes of energy available are very different. I would call gravity first.

PaulH

I would have thought tidal forces would have a greater impact than wind against mountains, but I’ve guess I learned something today. 🙂

RichardLH

Tom Trevor says:
July 11, 2013 at 4:01 pm
“Uh, the Y scale here is in milliseconds, to the human eye it might as well be hours.”
So you consider that styudying the minute oscilations, that show up here as variations in the msecs, are in now way connected to that beautfull dance that the orbits show?

SCheesman

Most of the change in the length of day is due to the transfer of angular momentum from the earth to the moon due to tidal forces. The moon is accelerated by the tidal bulges into a higher orbit, at the same time the earth’s rotation slows by an equivalent amount to balance the energy. I would expect that settling of heavier elements (Ni and Fe) into the core would tend to counteract the decrease in rotation rate by a lesser amount.

SCheesman

I am of course speaking of long-term changes, over the full history of the earth, not short term changes discussed in the article above.

Ian Wilson

Unfortunately, I believe that Anthony has chosen the wrong horse in this case.
http://astroclimateconnection.blogspot.com.au/2013/02/do-you-think-that-moon-might-have.html

Bill Illis

This parametre is carefully studied by a number of different international organizations including the International Earth Rotation and Reference Systems Service, the Special Bureau for the Atmosphere and the Earth Orientation Centre.
Yes, the length of day actually changes and this can be caused by the wind-drag (very short-term), ocean-drag (short-term), moon-gravity-drag (millions of years), core and mantle rotation processes (medium-term), and the gravity from the other planets in the solar system (long-term).
http://www.iers.org/nn_10896/IERS/EN/IERSHome/home.html?__nnn=true
http://www.aer.com/science-research/earth/earth-mass-and-rotation/special-bureau-atmosphere
http://hpiers.obspm.fr/eop-pc/index.php?index=mission&lang=en

RichardLH

Bill Illis says:
July 11, 2013 at 4:38 pm
“this can be caused by the wind-drag (very short-term), ocean-drag (short-term), moon-gravity-drag (millions of years), core and mantle rotation processes (medium-term), and the gravity from the other planets in the solar system (long-term).”
I think that the ‘frictional effects’ of Lunar/Earth interaction are underestimated. How the Moon’s gravity ‘plays’ with our Climate by that effect and thus ‘gains’more energy to get away.

Streetcred

This cannot possibly be so … ask any old timer (me too) … the days seem to be rocketing by much faster nowadays.

Jimbo

Ahhhh, length of day affected by man-made greenhouse gases.
Here is the peer reviewed literature. As I said before, we must insist on the science. 🙂 Haaaa haaa.
Earth’s rotation to slow down
Earth’s rotation to speed up

skorrent1

Interesting concentration on short-term variations. However, over longer periods (millions of years) the earth-moon tidal system is more determinative. The moon is observed to move to a higher, more energetic, orbit (about 1 inch/year) as a result of the earth’s rotation/tidal forces. That energy is subtracted from the earth’s rotation, therefore it slows down.
Incidentally, that presents a dilemma over a long period. Assuming that Newton’s Laws remain constant, and that the oceans are relatively unchanged, over billions of years, you can back the earth-moon system up. As the moon gets closer, the tidal forces get larger and the process speeds up. Accordingly, about one and a half billion years ago the moon was close enough to cause tides higher than the continental mountains, and the earth is spinning like a top. What’s wrong with this picture?

Bart

Robert of Ottawa says:
July 11, 2013 at 3:53 pm
“Why is the Earth’s rotation and orbital period slowing?”
Mainly tidal friction, creating heat which radiates the energy of motion away into space.
PaulH says:
July 11, 2013 at 4:14 pm
I expect ocean tides dominate.

Bart

Robert of Ottawa says:
July 11, 2013 at 3:58 pm
“The interaction of magnetic fields”
Needs to be a dissipative force. Perhaps electrical eddy currents could be set up in the core due to magnetic field interactions. That would create resistive heat, which could then radiate away.
Somehow, the kinetic energy has to be converted to a form which can be transferred out of the local system.

Bart

Jimbo says:
July 11, 2013 at 4:57 pm
That is choice 🙂

Louis Hooffstetter

Since plate tectonics began, the earth has been differentiating, with heavier materials sinking toward the core. As a result, the earth should be rotating much faster now, like a spinning skater who pulls their arms closer to their body. It’s obvious the moon’s increasingly higher orbit has counter acted this effect, and has a pronounced effect on the length of day.

KitemanSA

I would note that the 5.9 year oscillation is almost exactly 1/2 the period of Jupiter around the sun. Don’t know if it MEANS anything, but it is interesting.

Katherine

Oh, it’s a model. I was wondering how they knew the variation in length of day in 1890—down to fractions of a millisecond.

Gary Hladik

A.D. Everard says (July 11, 2013 at 3:59 pm): “This sounds to me a bit like blowing on your own sail”
Funny you should mention that. 🙂

scarletmacaw

One other (tiny) effect is an annual change caused by snow depositing on higher elevations slightly slowing the rotation rate, which speeds up again when the snow melts. I wonder how much longer the day was during the last ice age.

RoHa

This is why an oil-based economy is such a bad idea. By removing the oil from the Earth, we are taking away the lubricant for all the gears and things in there. When it has all gone, the innards of the Earth will seize up, and the rotation will stop. Then we’ll be really doomed.

Now didn’t we have a story about the “faint young sun” problem a few days ago?
If this is correct “A year, 300million years ago, lasted about 450 days and a day would last about 21 hours. As a result of the slowing down of the Earth’s rotation the length of day has increased.” I wonder what the LOD and year were 3 billion years ago? Sure doesn’t sound like the temperature of the Earth then was determined primarily by CO2.

Go Home

“theoretical calculation of how the Japan earthquake—the fifth largest since 1900—affected Earth’s rotation. His calculations indicate that by changing the distribution of Earth’s mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).
“In comparison, following last year’s magnitude 8.8 earthquake in Chile, Gross estimated the Chile quake should have shortened the length of day by about 1.26 microseconds and shifted Earth’s figure axis by about 8 centimeters (3 inches). A similar calculation performed after the 2004 magnitude 9.1 Sumatran earthquake revealed it should have shortened the length of day by 6.8 microseconds and shifted Earth’s figure axis by about 7 centimeters, or 2.76 inches”
“Earth’s rotation changes all the time as a result of not only earthquakes, but also the much larger effects of changes in atmospheric winds and oceanic currents,” he said. “Over the course of a year, the length of the day increases and decreases by about a millisecond, or about 550 times larger than the change caused by the Japanese earthquake.”
http://www.nasa.gov/topics/earth/features/japanquake/earth20110314.html

Rod

Another way to slow the Earth’s rotation is to collect dust and asteroids from space. Tens of thousands of tons of dust hit the earth each year (Internet search found a wide range of numbers, but 50K is representative). Extra mass on the surface has same affect as ice skater holding their arms out: it slows the spin rate.

Olaf Koenders

After reading some of the comments here I’m wondering if Earth’s core has some influence on spelling mistakes. Just sayin’ 🙂

Bruce

The earth rotates more than 360 degrees per day. The Sun is in the same place East to West each day at the same time, but the earth moves on the orbit so the Sun has to rotate a little more than 360 degrees to put the Sun in the same place.

Bart

Gary Hladik says:
July 11, 2013 at 6:10 pm
Neat! Makes sense, if you assume the fan is mostly drawing air equally from all sides (radially inward), redirecting it forward, and that flow is then being reflected so that net flow is balanced on the sides, but overall directed backwards.
Assuming Lambertian reflection, I get a net backward flow of about 16% max of what it would be if they turned the fan around. You’d probably lose 50% of that from luffing and edge losses, so about 8% relative efficiency overall. That seems about consistent with the speed they got.
So, the question becomes, is the “fan” (net atmospheric turnover being powered by the Sun) blowing against surface nonuniformities significant enough to significantly drive LOD.
I’m not convinced, but at least you’ve made me slightly more receptive to it.

dudleyhorscroft

Rod may be correct, but this is supposing that the dust is ‘stationary’. If the dust as it falls is moving at the same speed as the earth’s rotation speed in the relative latitude then the fact that there is added mass at the surface will not affect the rotational speed. More to the point, as the earth heats due to CAGW, the oceans and land will expand outwards. This is where the ‘ice skater’ effect comes into play, and so CAGW slows the earth!
BTW there seems to be an error in someone’s calculations. If the day, 300M years ago, was about 21 hours long then the year would be 365 x 24 /21 days long. This is about 417 days, not 450 days. The implication is that if the year was indeed 450 days long, the earth was in a different orbit, rather father out. Hence the earth must be spiralling into the sun. Once again, blame tidal friction. But if the earth is spiralling into the sun as a result of tidal friction, why is the moon spiralling out from the earth dud to tidal friction. Of course, my calculations could be wrong?

Bill Illis [July 11, 2013 at 4:38 pm] says:
Yes, the length of day actually changes and this can be caused by the wind-drag (very short-term), ocean-drag (short-term), moon-gravity-drag (millions of years), core and mantle rotation processes (medium-term), and the gravity from the other planets in the solar system (long-term).

Hear, hear, and really just to name a few of the known “randomizing” elements.
The biggest failure of imagination of all is that education always seems to put the cart before the horse. It starts with the definition of quasi-“constants”, here is the length of a day, a year, the orbit of this planet and that, etc, so that the student’s understanding comes from the opposite end of the logical spectrum. These quasi-constants are mere observations, snapshots of the sum of countless influences that total up to yield the current state of the observed universe. In reality the whole thing is as close to a random number generator as is possible, it is truly chaotic if we can just detach ourselves from our narcissistic point of view. Every passing comet and asteroid and interstellar event ( perhaps even inter-galactic event ), every new star, nova, supernova, even every change of radiative output of any and all stars will affect something. That is all on a huge macro scale which likely dwarfs the local climatic micro scale that we all obsess over every day.
You know how we have those astronomy models that show the positions of planets back into the past and forward into the future? Now try accounting for all the randomizing chaotic events that occur in real life out there. One glance at the surface of the moon should demonstrate that the influences that resulted in our current position and orbit, and length of day, etc, is truly unmanageable from a predictability point of view. Any model that says for example: ‘in 3975 years this is where Jupiter will be and this is where our moon will be’ should be accompanied by a disclaimer: ‘in 3975 years this is our best guess where we believe Jupiter will be and this is where our moon will be’. Now tell me again how weather and climate models work? They can’t work because they are constantly being rendered useless by discounted and unaccounted for variables on our tiny little ball of magma, dirt and water. It is like cooking up an Irish stew and predicting where the bubbles will appear and where the solid food will settle. Good luck with that.
Just imagine the torture future Scientists will experience if a few hundred or thousand years from now the “fringe” theory is verified that the speed of light is variable like the length of a day ( perhaps “C” only represents the maximum speed radiation can travel in the current configuration of the universe, change it and a different “C” is observed ). Anyway, whatever you do, don’t tell today’s Scientific elite that in the future their current textbooks will most likely appear as archaic as Ptolemaic musings do now. 😉

scarletmacaw

Dudley Horscroft says:
July 11, 2013 at 7:27 pm

The Earth’s orbit should increase with time as the sun loses mass.

Geoff Sherrington

Blade,
It means little in outcomes, but I derive comfort from equating the state of the globe’s temperature to the state of a human body temperature. Each object has multiple influences that can and do affect temperature. There are cycles, but the lengths of the cycles need not be related (think rate of respiration with rate of sleeping with pulse rate. Maybe rough correlations exist some of the time, but nothing you could model well).
It’s interesting philosophy to discard the constants as primary assumptions, then to do observations with adequate accuracy to derive constants or quasi constants. I’ve often wondered why so many physical equations (before relativity) ended up with exact powers, given that Nature is not supposed to be able to count 1, 2, 3, etc.

RoHa

And in fairness I should admit that I nicked that idea from Wellington in “The Perishers”.
http://www.theauthenticperishers.co.uk/

scarletmacaw

skorrent1 says:
July 11, 2013 at 4:57 pm

Incidentally, that presents a dilemma over a long period. Assuming that Newton’s Laws remain constant, and that the oceans are relatively unchanged, over billions of years, you can back the earth-moon system up. As the moon gets closer, the tidal forces get larger and the process speeds up. Accordingly, about one and a half billion years ago the moon was close enough to cause tides higher than the continental mountains, and the earth is spinning like a top. What’s wrong with this picture?

That’s an interesting observation. Before the Cambrian Explosion (a little more than a half billion years ago), life on Earth was just a bunch of single cells and algae, not something that couldn’t survive a rapidly spinning Earth with wild tides. But the algae started over 3 billion years ago. There must have been other factors that neutralized some of the energy transfer.

skorrent1

scarletmacaw misses the heart of the dilemma. Forget what “life” was like 3 billion years ago. Geologists tell us that some geologic formations date back 4 billion or more years. But no surface formation could withstand repetitive many-mile-high tidal waves beating at them every few hours. Conclusion: either geologists’ time measurements are way off, or the moon wasn’t around to be that close to the earth. Either way, it raises many more problems.

Not really new, JPL and Potsdam have papers on the subject.
What is new is that processes in the Earth core are synchronized with solar activity, as I have shown here some time ago:
http://www.vukcevic.talktalk.net/SSN-LOD.htm
Now, that should shake geo-solar science from its current slumber.

vukcevic says:
July 11, 2013 at 10:59 pm
What is new is that processes in the Earth core are synchronized with solar activity
==========
it is hard to see how the earth could generate a magnetic field without the sun. Everyone likes to think the molten core is the explanation, but that ignores the chicken and the egg problem, as well as the magnetic properties of iron as it is heated.

RichardLH

scarletmacaw says:
July 11, 2013 at 8:56 pm
Dudley Horscroft says:
July 11, 2013 at 7:27 pm
“The Earth’s orbit should increase with time as the sun loses mass.”
I would have thought that it was the ratio betwen the two that mattered. And if Earth can leave just a little more of its mass in the great mass deposit bank that is the SUn, then it wil be much lighter on any later jouneys outwards.

Henk Kraa

The earth rotation is causing the winds to blow, not the other way around. The earth and it;s atmosphere move freely and frictionless through the vacume of space.,The only influence on the speed of rotation is the spread of the mass within the earth, over it’s surface or within the earth moon system. Ocean currents may influence this, wind currents in much lesser values (more air mass around the equator should make a difference and may be you could measure that), but winds slowing down the earth rotation is a cause and effect swap, sorry.