Below is a GRACE satellite map. The Earth looks like a warty ball, with red bumps and blue pits that represent measured fluctuations in the planet’s gravity. Note Greenland in the red. We’ve covered GRACE before, suggesting it may not be a good tool to measure ice loss in Greenland. See this WUWT story.
The red spots represent measurements where Earth’s gravity is stronger. The blue ones are where it is measured to be weaker. The universal force of gravity itself does not vary, but the pits and bumps are a local indication that Earth’s mass distribution isn’t smooth and uniform. As seen on the image above, tectonic mountain building in South America produces red zones; elsewhere, tectonic movements produce thin, blue, ones.
Even more interesting is the fact that the map changes over time, Earth as we know is not static.
CO2 science reviews this new paper, which suggests that for sea level rise and ocean mass, the signal to noise ratio is high low and adjustments further complicate the issue. It also suggests some studies aren’t appropriately correcting for these issues. For example, GRACE measurements related to Greenland and West Antarctica (which we also criticized in WUWT here and here):
“…non-ocean signals, such as in the Indian Ocean due to the 2004 Sumatran-Andean earthquake, and near Greenland and West Antarctica due to land signal leakage, can also corrupt the ocean trend estimates.”
Ocean Mass Trends (and Sea Level Estimates) from GRACE Reference
Quinn, K.J. and Ponte, R.M. 2010. Uncertainty in ocean mass trends from GRACE. Geophysical Journal International 181: 762-768.
Background
The authors write that “ocean mass, together with steric sea level, are the key components of total observed sea level change,” and that “monthly observations from the Gravity Recovery and Climate Experiment (GRACE) can provide estimates of the ocean mass component of the sea level budget, but full use of the data requires a detailed understanding of its errors and biases.”
What was done
In an effort designed to provide some of that “detailed understanding” of GRACE’s “errors and biases,” Quinn and Ponte conducted what they describe as “a detailed analysis of processing and post-processing factors affecting GRACE estimates of ocean mass trends,” by “comparing results from different data centers and exploring a range of post-processing filtering and modeling parameters, including the effects of geocenter motion, PGR [postglacial rebound], and atmospheric pressure.”
What was learned
The two researchers report that the mean ocean mass trends they calculated “vary quite dramatically depending on which GRACE product is used, which adjustments are applied, and how the data are processed.” More specifically, they state that “the PGR adjustment ranges from 1 to 2 mm/year, the geocenter adjustment may have biases on the order of 0.2 mm/year, and the atmospheric mass correction may have errors of up to 0.1 mm/year,” while “differences between GRACE data centers are quite large, up to 1 mm/year, and differences due to variations in the processing may be up to 0.5 mm/year.”
What it means
In light of the fact that Quinn and Ponte indicate that “over the last century, the rate of sea level rise has been only 1.7 ± 0.5 mm/year, based on tide gauge reconstructions (Church and White, 2006),” it seems a bit strange that one would ever question that result on the basis of a GRACE-derived assessment, with its many and potentially very large “errors and biases.” In addition, as Ramillien et al. (2006) have noted, “the GRACE data time series is still very short,” and results obtained from it “must be considered as preliminary since we cannot exclude that apparent trends [derived from it] only reflect inter-annual fluctuations.” And as Quinn and Ponte also add, “non-ocean signals, such as in the Indian Ocean due to the 2004 Sumatran-Andean earthquake, and near Greenland and West Antarctica due to land signal leakage, can also corrupt the ocean trend estimates.”
Clearly, the GRACE approach to evaluating ocean mass and sea level trends still has a long way to go — and must develop a long history of data acquisition — before it can ever be considered a reliable means of providing assessments of ocean mass and sea level change that are accurate enough to detect an anthropogenic signal that could be confidently distinguished from natural variability.
References
Church, J.A. and White, N.J. 2006. A 20th-century acceleration in global sea-level rise. Geophysical Research Letters 33: 10.1029/2005GL024826.
Ramillien, G., Lombard, A., Cazenave, A., Ivins, E.R., Llubes, M., Remy, F. and Biancale, R. 2006. Interannual variations of the mass balance of the Antarctica and Greenland ice sheets from GRACE. Global and Planetary Change 53: 198-208.
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Robert
That article made no attempt to address my question about claimed recent losses far away from the coast. He did set up lots of strawman arguments, supposedly in response to my articles.
Jantar says:
July 21, 2010 at 5:37 am
“… according to my Physical Chemistry Book … ( g ) is 9.80665 and THAT IS AN EXACT VALUE ! ( ms^-2 )”
Reading this imediately had me reaching for my year 1 physics text book. College Physics by Weber manning & White pp 56 (yes I still have it, and it dates me). It shows g in St Michael, Alaska as 9.822 m/s^2, and Key West Fla as 9.79 m/s^2. Both of these at 1 m elevation. So it appears that back in 1965 g was accepted as not being an exact value.
_______________________________________________________________________
Standard gravity, commonly labelled g, is defined as exactly 9.80665m/s2. However, over the Earth’s surface the acceleration due to gravity varies slightly from the standard value; the approximate value is given by:
g(lat,alt)/(m/s2)=9.80615-0.025862cos(2lat)+0.000059cos2(2lat)-0.000003alt.
@ur momisugly John Trigge July 21, 2010 at 12:35 am
‘As predictable as the tide’ is a saying I come across reasonably frequently. In addition to having two satellites with accelerometers at each of their centre of mass the grace measurement data is compared to an idealised model which accounts for predictable influences such as the tide but assumes that the mass distribution in the earth is equal. In this way the background influences such as the tides can be subtracted from the grace data and then other corrections can occur.
Of course if you keep going like this you will find something that the GRACE satellite currently doesn’t correct for or doesn’t correct for very well and there are definitely such things out there. The big point to mention is that the GRACE mission is one of exploration as is all science. It is on a mission of discovery. There are plenty of papers out there which deal with early mistakes of the GRACE project and evolved understanding due to new data and analysis. The GRACE mission is a very elegant experiment but it is still an experiment, it is a learning experience. Science is about evolution. In evolution a lot of mistakes occur before a useful advancement is made. A mistake in science isn’t a bad thing; there are plenty of papers out there detailing early mistakes of the GRACE project. You learn from the mistakes and move on. That’s why scepticism is so important in science because it searches for mistakes. Unfortunately some scientists don’t accept obvious mistakes very well and refuse to evolve.
Once again, calculate the expected sea level rise from the estimated mass loss from Antarctica and Greenland and see whether they are inconsistent with sea level changes.
Your initial statement Yet GRACE interpreters delude themselves into believing that the earth is steady and fixed over vast distances underneath the ice and oceans. was false. Admit it.
They don’t assume that the Earth is fixed and steady.
“”” DirkH says:
July 21, 2010 at 11:06 am
George E. Smith’s g seems to be called the standard gravity according to the wikipedia and is well-defined:
http://en.wikipedia.org/wiki/Standard_gravity “””
You chaps will have to be a whole lot faster on the uptake; to keep up with this old codger.
I usually do not make this stuff up. I also never go to wikiwonderland to look for stuff either; but I’m happy to hear they are awake too.
The same Text book also cites exact values for the Calorie (4.184 Joules), one Atmosphere (101.325 kPa = 760 Torr) and also for the centigrade zero point (273.15 Kelvins).
If you read the scientific article that you pretend to critique then you would see that they do not make the claim about mass loss far from the coast.
Vince Causey says:
July 21, 2010 at 5:03 am
Zeke the sneak,
Challenge by all means, with all scientific rigor. But earlier in your post you asserted the electric dipole theory of gravity as if it was a fact, when it is clearly only a conjecture.
Now you are stating that it is conjecture as if that was a fact.
🙂 The words I quoted are “an obvious line of enquiry,” taking up where Michael Faraday left off.
DirkH says:
July 21, 2010 at 10:52 am
I have difficulty grasping the concept that there is a gauge theory for gravity like for the other 3 forces yet gravity is said to create a curvature of spacetime.
Why don’t the other 3 forces bend spacetime – or is the curvature of spacetime an obsolete concept when we talk about gravity as quantum gravity?
IOW, what’s special about gravity when it’s a force transmitted by some bosons just like the others?
The holy grail of present theoretical aspirations is to unify all forces.
The way string theories do it, at very large energies there is only one”force” ( rather interaction) and one gauge boson and one type of “particle”, the string. This has vibrational modes and each vibrational mode has zero mass and the quantum numbers of the symmetries that have been documented. As the energy goes down from the Planck mass, there is symmetry breaking and mass is acquired by the individual vibrational modes.
There are surprising predictions: mini black holes for example.
There is a plethora of extra dimensions that could accommodate many science fiction scenaria , let alone dark matter.
The relevance to our reality has to be proven, maybe at the new LHC experiments in CERN.
When one quantizes gravity space and time are quantized (gaps between seconds and gaps between cms 🙂 ). All energy/mass bends space time “macroscopically”.
anna v says:
July 21, 2010 at 12:04 am
In a nutshell, from string theories the standard particle model comes out naturally and at the same time gravity is included and quantized.
Simplified, each particle is a vibrational mode on a string ( the music of the spheres).
There is a long way to go until this string dream is verified, but at least there is no contradiction with existing data from the start.
In the Electric Gravity model, each particle is a resonant object, made up of smaller charged subtrons orbiting within the classical radius of that particle. “It is maleable and can be pushed out of shape, and by these simple deformations, you can explain magnetism and gravity” (radio interview, Thornhill). Really it is a return to classical physics.
Now I could listen to a physicist talk about string theory all day. 🙂 That is an interesting possibility. But I think the atom is probably not a ghostly imaginal world of possibilities, altered by the observer, as Einstein had it. And so no more “rest for the wicked,” the search for gravity continues.
Anthony, sorry for the delay in getting back to this conversation…
“Just a short question, do you spend most of your time at WAU with the “Skeptical Science” blog now? It seems like it has become full time.”
By WAU, do you mean the Uni of Western Australia (UWA)? No, I’m based in Brisbane on the other side of the country – I came over for a brief 4 day visit but due to poor timing, wasn’t actually there on the night of your talk in Perth or I would’ve attended. I’m not doing Skeptical Science full time – well, sometimes it feels like I’m spending full time hours on it but my efforts are not funded apart from the occasional paypal donation.
“Also, who funded those handouts in Perth?”
I created the handouts off my own bat (eg – unfunded as usual), UWA coughed up the $150 to get them printed.
REPLY: Thanks for the response. No worries. I had thought maybe you had switched to UWA since you had a “presence” there. – Anthony
You people are seriously arguing about the exact value of a standard gravity? And referring to chemistry textbooks?
Does no one still use the CRC Handbook of Chemistry and Physics? That was THE reference when I was in college. There’s even an online version these days. Why, I still have my own then-current copy… somewhere.
stevengoddard says:
July 21, 2010 at 1:41 pm
>>That article made no attempt to address my question about claimed recent losses far away from the coast. He did set up lots of strawman arguments, supposedly in response to my articles.<<
The article shows these losses are occurring based upon multiple sources of evidence. Just because you don't understand the mechanism doesn't mean that it can't happen, especially when all the forms of evidence shown dispute your theory. Secondly, we both know very well that inland propagation of glacier velocities can occur very quickly if there is a large disturbance at the glacier terminus. This has been shown in Rignot et al. 2004 and Scambos et al. 2004 with respect to changes after ice shelve removal. Grounding line retreat can have a similar effect on the force balance at the downstream portion of the glacier. I don't think it is very difficult to understand why losses are occurring in the regions mentioned. There are large outlet glaciers which originate from those regions (shown in Allison et al. 2009) and they are carrying more and more ice from these regions which explains why the elevation is reducing (Gunter et al. 2009) based upon extremely accurate icesat data.
Finally, I don't see too many strawmen. I see someone who dug himself into a hole (you) and is having trouble getting out. You said in the comments that glaciers can't flow at high velocities, this article showed you're wrong and showed you these regions had high glacier velocities, you claimed that ice losses wouldn't occur in the EAIS this showed you wrong. You claimed that surface melt was an important mechanism in Antarctica, this article proved you wrong. You claimed that Grace was inaccurate, this article shows you many other studies using different methodologies which match up.
You can make fancy rhetorical statements about "strawmen" all you like but the truth of the matter is that someone caught you and you are not willing to admit it.
Robert,
“So are we going to be as unbiased as we were then and give the cazenave paper a chance?”
I love Cazanave’s paper. It shows how the rate of sea level rise has declined since 2003.
Zeke,
“But I think the atom is probably not a ghostly imaginal world of possibilities, altered by the observer, as Einstein had it.”
Einstein most definately did not believe that. What you describe are quantum mechanics, a field that Einstein spent most of his life attacking.
I had thought maybe you had switched to UWA since you had a “presence” there.
Anthony, you should know having recently travelled the length and breath of Australia that Brisbane is the best city in the country, heckling oceanographers withstanding 🙂
From: Zeke the Sneak on July 20, 2010 at 4:01 pm
From: Zeke the Sneak on July 21, 2010 at 10:08 pm
There should be an experiment to test that. We know light can be bent by gravity (actually the path of the photons is altered by the gravitational field). Light would not have those dipole structures, it is energy, also as far as it is a particle at all (I hope “electric gravity” is smart enough to not argue against wave-particle duality) it has no smaller pieces. Gravitational attraction is universal, that which gravity attracts also has its own gravitational field.
So see if one beam of light causes another beam of light to bend. It’ll actually be mutual, they’ll bend towards each other. If bending is not detectable, then the lack of those dipole structures can be considered to be the reason. If bending is detected despite the lack, “electric gravity” loses.
Possible setup, two coherent beams running parallel in a vacuum. The force of gravity is inversely proportional to the square of the distance between objects, halve the distance and quadruple the force. So you measure the distance between the beams at fixed spatial intervals. Graphed out, one should see a curve, the distance between will get smaller faster over time, as the beams get closer they will bend faster. Even if not a perfect vacuum, with closely-spaced beams you should see the same rate of divergence for both. If the distance shortens by other than a linear rate, measuring from the edge of the beam, and shows a greater than linear decrease over time, then you have bending.
Now as these things go, one only has to figure out how to conduct the real-world experiment…
🙂
Quantum theory like general and special relativity actually does an excellent job of predicting experimental results to a certain level of statistical significance. Many issues, though, such as entangled particles and particles instantaneously traveling from one point to another under certain conditions are still not explained just like the missing graviton particle or the dark matter and accelerating expansion of the universe in general relativity. But since I have yet to see an explanation of how simple magnetism is propagated through space (graviton?) it just reminds us of how little we actually know with certainty. Prhaps the super colider will answer some of these questions but in the mean time, like climate.
kadaka (KD Knoebel) says:
July 22, 2010 at 9:14 am
you quote Actually “gravity is due to radially oriented electrostatic dipoles inside the Earth’s protons, neutrons and electrons.”
and say:
There should be an experiment to test that.
There are beautiful and accurate experiments that show that protons and neutrons are composed of quarks held together by gluons, and that electrons and other leptons are not composite.
The so called “standard model”, with the symmetries SU2XSU3XU1 cannot be in question by anybody who knows anything about the matter.
All the particle physics experiments of the last 20 years show not even an iota of evidence of compositeness, i.e that quarks and leptons are composite in a further internal level. There is no need for new experiments to disprove the proposition that there are “electrostatic dipoles” inside protons and electrons. It is pure science fiction.
Anna,
My last post was for you and I was interupted. Should have said:
In the mean time, like climate, we are still more in the dark than we like to admit.
Vince Causey,
I don’t disagree that the rate has lessened. I think the paper shows that the sea level rise currently ongoing is a result of less ocean warming but more contributions of glaciers and ice sheets. I think that with regards to this aspect the science is pretty understandable. I don’t understand why Goddard and co are repeatedly saying that ice losses cannot occur because the rate is not increasing when this paper outlines very well what happened.
Re: anna v on July 22, 2010 at 11:09 am
Darling, although my BA in physics is largely unused and left to gather dust, I did not earn it so long ago that such basics of particle physics were not taught way back then. Don’t worry, I myself am not questioning such basics. However, other people seem to be questioning them, and I just tossed up an experiment to test the “electric gravity” assumption I saw here where gravity was arising from only mass.
Although I will admit when you toss out lines like “…with the symmetries SU2XSU3XU1…” I am lost. The program was broad, somewhat directed towards engineering, with required amounts of electives in certain areas rather than a rigid program of practically everything being specific required courses. Analog and digital electronics, programming including Pascal and assembly (80286), yes. Accumulating enough math credits a mathematics minor was virtually automatic, picking up linear algebra, advanced calculus, even non-Euclidean geometry, did that. Memorizing quark flavors, no. And what is considered here to be basic statistics, eh, that’s something you picked up in graduate school if you needed it. 😉
kadaka (KD Knoebel) says:
July 22, 2010 at 3:58 pm
There was nothing wrong with the experiment you suggested and it would give limits for other composite theories , of which there are a good number that fell by the roadside as more and more data were accumulated from LEP at CERN. Others are still surviving but not popular.
I was just pointing out that the already existing experiments throw out such a primitive model as protons and electrons consisting internally of dipoles.
Jim G says:
July 22, 2010 at 11:22 am
In the mean time, like climate, we are still more in the dark than we like to admit.
Well, I had a high school teacher for ancient greek who was not very good, but he did say something from his philosophy courses which has remained with me:
“Draw a circle: knowledge is within the radius of the circle. The more you learn and
establish as knowledge, the larger the radius and content of the circle. But also the larger the periphery, so there is much more unknown.”
Now about the magnetic field and fields in general, the Feynman diagram organization of the perturbative solutions of the equations explains them. There are always two particles necessary for a field to manifest, and they exchange the carrier of what macroscopically is seen as a force. In the case of the magnetic field, the photon. The exchange transfers energy and momentum and thus the field of one particle is seen by the other. As all fields seen macroscopically are really the sum total of individual particles, as observed by another aggregate of individual particles, there is no mystery about fields in present day physics, though we do get into the many body problem.
For the general audience, here is a link from CERN with its aspirations: http://public.web.cern.ch/public/en/Science/Science-en.html
Vince Causey says:
July 22, 2010 at 6:25 am
Zeke,
“But I think the atom is probably not a ghostly imaginal world of possibilities, altered by the observer, as Einstein had it.”
Einstein most definately did not believe that. What you describe are quantum mechanics, a field that Einstein spent most of his life attacking.
Thank you. It would be better if I had said “as Einstein worded it.”
“In quantum physics, we do not deal with physical matter because we have no way of controlling it. If we go too deep in our search for matter, it begins to dissolve. Atoms appear to be not things, they seem like ghosts and we enter an imaginal world of theory.”
I had this written down somewhere and borrowed the wording from that. It is beautifully put, and I believe it is attributable to Einstein. (-?)
But this point touches on one of my real interests in atomic affairs, not being a physicist. It is that the real mysterious nature of the atom is, I think, not as much defined by its parts, but by the exquisitely tuned relationship between the parts. So I do not think that much will be proved and learned by smashing them up at CERN. If you want to study a watch or a living cell, you see how the parts communicate and work together.
In this model, a return to classical physics combined with computer technology can make “predictions for thousands of energies, distances, angles, and dipole moments that have been rigorously compared to experimental data.”
That is much better than wasting billions on collisions.