A climate science bombshell: New proposal from NASA JPL admits to “spurious” errors in current satellite based sea level and ice altimetry, calls for new space platform to fix the problem.
People send me stuff. Today it is a PowerPoint presentation from NASA JPL that touts the new GRASP (Geodetic Reference Antenna in Space) satellite project. I’d say it is more than a bit of a bombshell because the whole purpose of this new mission is to “fix” other mission data that apparently never had a stable enough reference for the measurements being made. This promises to rewrite what we know about sea level rise and acceleration, ice extent and ice volume loss measured from space.
What is most interesting, is the admissions of the current state of space based sea level altimetry in the science goals page of the presentation:
The difference between tide gauge data and space based data is over 100% in the left graph, 1.5 mm/yr versus 3.2mm/yr. Of course those who claim that sea level rise is accelerating accept this data without question, but obviously one of the two data sets (or possibly both) is not representative of reality, and JPL’s GRASP team aims to fix this problem they have identified:
TRF errors readily manifest as spurious sea level rise accelerations
That’s a bucket of cold water reality into the face of the current view of sea level rise. It puts this well-known and often cited graph on Sea Level Rise from the University of Colorado (and the rate of 3.1 mm/yr) into question:
What’s a TRF error? That stands for Terrestrial Reference Frame, which is basically saying that errors in determining the benchmark are messing up the survey. In land based geodesy terms, say if somebody messed with the USGS benchmark elevation data from Mt. Diablo California on a regular basis, and the elevation of that benchmark kept changing in the data set, then all measurements referencing that benchmark would be off as well.
In the case of radio altimetry from space, such measurements are extremely dependent on errors related to how radio signals are propagated through the ionosphere. Things like Faraday rotation, refraction, and other propagation issues can skew the signal during transit, and if not properly corrected for, especially over the long-term, it can introduce a spurious signal in all sorts of data derived from it. In fact, the mission summary shows that it will affect satellite derived data for sea level, ice loss, and ice volume in GRACE gravity measurements:
In a nutshell, JPL is saying we don’t have an accurate reference point, and therefore the data from these previous missions likely has TRF uncertainties embedded:
The TRF underlies all Measurement of the Earth
Without that stable Terrestrial Reference Frame that puts the precision of the baseline measurements well below the noise in the data, all we have are broader uncertain measurements. That’s why the plan is to provide ground based points of reference, something our current satellite systems don’t have:
To help understand the items in the side panels:
GNSS = Global Navigation Satellite System – more here
SLR = Satellite Laser Ranging – more here
DORIS = Doppler Orbitography and Radiopositioning Integrated by Satellite – more here
VLBI = Very Long Baseline Interferometry – more here
Taken together, these systems will improve the accuracy of the TRF, and thus the data. It’s rather amazing that the baseline accuracy didn’t come first, because this now puts all these other space based measurement systems into uncertainty until their TRF issues are resolved, and that’s an inconvenient truth. We’ll never look at satellite based sea level data or GRACE ice volume data in quite the same way again until this is resolved.
PowerPoint here: Poland 2012 – P09 Bar-Sever PR51 (PDF)
More info: http://ccar.colorado.edu/~nerem/EV-2_GRASP-final.pdf
UPDATE: Here’s an estimate of impacts:
Source: http://www.gps.gov/governance/advisory/meetings/2011-06/bar-sever.pdf
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Grasp promises 10x better
TRUTHS promisses 10x better
Nigel Fox of NPL with the TRUTHS project is promising a similar 10 fold improvement in satellite measurements by providing on board calibration.
‘NPL in Space’ – new calibration satellite required to make accurate climate change prediction
That similarly emphasizes shows how large the uncertainties (“errors”) are with current satellite measurements. See Fox’s lecture and paper.
Context:
“Well, yes, we did promise that the old satellite would settle the question of sea level trend, but now that we need more money, er, no, the old data are no good and we really, really need a new sooper-improved satellite. And we totally promise that THIS one will do the job–until we need more money.”
After all, the first clean years from Envisat showed how the others were biased…
There is a need for a Bishop Hill-style review of the sea level adjustments to the TOPEX/Posiden record. It’s important to recognize that it’s an extremely complicated job to try to figure out actual sea level rise on short time frames. There are enormous issues of measurement error, splicing of records, adjustments and corrections that would leave any reasonable person with some doubt about the ability of the current process to determine sea level changes to 0.1 mm. (For example see the special issue on sensors at http://www.mdpi.com/1424-8220/6/6 ).
Steve Nerem is a smart guy and I think may be descibed as the “godfather” of altemetry measurement of sea level (he’s been working on it for at least 30 years). In the relatively early days of T/P (1997) he published a correction in Science on an earlier paper that had “shown” the sea level increase to be 3.9 mm/year (Science, 1995, Nerem, 5 May, p. 708-710). In the 1997 “correction” he states “The corrected value of global mean sea level rise observed since the launch of TOPEX/POSEIDON in 1992 is close to 0 millimeters per year, although there is evidence of additional instrument drift (5), suggesting a preferred value of roughly +2 millimeters per year. The corrected TOPEX/POSEIDON observations for 1993–1996 are in statistical agreement with the historical tide gauge record, which shows mean sea level rising at a rate of approximately 1.8 millimeters per year over the last 50 years (6)”.
GPS is accurate to within a few inches, even with multiple satillites.
To get an accurate record of sea level rise, it will take years of multiple satillites to establish a base verses actual ground based measurements.
I see Mark Lynas denies he arranged the Maldives underwater cabinet meeeting, and also shows some appreciation of the risk of hype in relation to sea level rise (see http://www.marklynas.org/2012/04/where-sea-level-rise-isnt-what-it-seems/ ). It’s nice to see him pay attention to the real science. His swipe at Dr. Morner is uncalled for (as Dr. Morner knows more about sea level than Lynas ever will – he been publishing in the peer reviewed literature for over 40 years, including critical papers on isostasy and eustasy).
I always scratched my head wondering how these satellites (temp, sea level, ice extent) could achieve the claimed level of precision. Turns out they can’t.
Once again its worse than I thought.This iOS modern science?So what is left to the climate crybabies?The unprecedented temperature rise is now dead, demonstrated false ,a creation of bias, by one of the original Team, welcome back Briffa. The rise of the sea’s phoney or unmeasurable.Emissions by man of CO2 are still rising, temperatures are not.Refresh my memory here, we were advised to panic because??.
This is modern science?
Actually, technically they’re correct. “Accelerating” means “changing” in physics; the direction is not specified. Could be speeding up or slowing down. In common speech, “decelerating” is used for the latter, but not in scientific parlance.
1. Knee-jerk response – why would I support funding anything at NASA? Create a new agency to oversee collection of data only. Let some other agencies and academics analyze it.
2. What will be the margin of error of the new instrument? Is it worth doing – in other words, will the new data be so accurate as to be useful in the measurement ranges we think are needed? How confident are we of those answers and who will stake their careers on those answers – let’s have some real penalties for those leading the effort if their claims turn out to be false.
Kev-in-Uk says:
October 30, 2012 at 1:38 pm
I can understand that radio telemetry/altimetry is inaccurate for transmittal reasons. What I cannot understand is how they can then ‘work’ back to a supposed accuracy of 1/10s of mm per year on a moving irregular surface! Sorry, but it just doesn’t compute……..
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They are averaging a LOT of observations. As I recall about a million a day give or take. Assuming that all the errors are random, that presumably cuts their measurement error by a factor of 1000. I suspect that if you are a lot better at math than I am, you might have some questions about whether the averaging procedure really produces exactly that much improvement when applied to a time series of measurements of a moving target. But intuitively, it seems like it ought to help a lot.
So let me get this straight:
They have satellites passing over land and sea without any regular initialization and measurement against – on each pass or ten – a solid reference point? What could be more simple and obvious? The satellite orbit cannot be known without that, not to the necessary precision of what is being measured. The orbit may be (and likely IS) an elliptical orbit in the first place, even if only a few millimeters. And when it passes over high gravity masses that orbit has to be continually affected. It seems to be admitted here that there is no continual re-zeroing.
But Reg, they CAN achieve the proper level of precision – but only by being as thorough as possible. And then maintaining that thoroughness. It is amazing in the extreme that they let this go this long before recognizing the failure at such a fundamental level. The entire reference framework could be drifting all over the place. If this was in engineering, heads would roll.
Steve Garcia
If the problem is “spurious” errors in current satellite based sea level and ice altimetry, why is the tide gauge data (in the simulated graph included in the Key Science Goals) adjusted to show a faster sea level rise?
Berenyi, maybe the lost heat has been used up evaporating the lost water?
I noticed a couple of mistakes in the JPL image.
1: They have “Ice Loss”. This should be ice fluctuation or change.
2: Sea Level Rise. This should be Sea Level Change or Fluctuation.
These mistakes shows that this organization is biased.
Why bother getting the baseline correct when you’re throwing in totally bogus ‘corrections’ like the glacial isostatic adjustment (GIA). It’s just a way to get around the current rate decline and get it back up to what they’ve been reporting all these years.
GIA is 0.3mm/yr, which doesn’t sound like much, but that’s an additional 10% of the real rate. They purport to throw it in to account for volume changes, but you don’t measure volume in mm unless you have a straight-sided container, which we hardly have at the seashore. You end up with a neither-fish-nor-fowl-number that is useless for what we really measure sea level for, knowing when
Dr Hansen can go fishing from his office windowwe’ll need to raise our seawalls, or the Maldives are going under.0.3mm/yr ain’t much, but it adds up –
http://i50.tinypic.com/8zfndk.jpg
They’ve also applied an ‘inverse barometer.’ Given that the barometric pressure variation over 7/10ths of the earth’s surface should average out close to zero, that’s another avenue for mischief.
Jimmy Haigh says:
October 30, 2012 at 5:51 pm
“Are there any alarmists out there prepared to comment?”
No? Thought not…
I have had the impression that the altimeter data series was regularly recalibrated to adjust the fit to match a preconceived sea level rise trend. An alternative explanation is that satellite altimetry directly affects the time rate of rise of sea levels.
Hm, I wonder if I did this right (somebody please check).
If there is any noticeable sea level rise, it should come from thermal expansion. Here’s the basic data:
average depth of oceans: 3688,4 m
volume: 1.332.000.000 km3
surface: 361.132.000 km2
specific heat capacity of water: 4181,3 J/kg*°K (average in range 5-30 °C)
expansion coefficient: 0,02315% / °K (average in range 5-30 °C)
If my calculations are at least roughly correct, the sea level rise of 3,9 mm/year should correspond to heat input of 2,2893 W/m2 (which is close to the maximum of IPCC AR4 “assessment” of anthropogenic radiative forcing of 0,6 to 2,4 – 90% probability 1,6W/m2); the 2 mm/year rise should correspond to heat input of 1,174 W/m2 – is that a oblique climbdown from previously excessive estimates of climate sensitivity?
miso
Kev-in-Uk says: “To my mind – it would be like estimating the surface area of a the leaves on a large tree from a mile away, with a stiff wind blowing! (at thats just in the summer!)”
That’s a good analogy, but it’s more like trying to calculate the average postition of all the leaves on one side of the tree from 2000 miles away, with a force 9 gale blowing.
There are so many things that have to be corrected for, the outcome is determined not by the data but by which adjustments you chose to make.
At that point the desire to get published and secure funding quickly dominates all the other “forcings”.
I do not understand what you are trying to measure when folks talk about small sea level changes. The gauges give hight above/below land land. But the hight of the land is feet/metres “above mean sea level”. Is it referenced to the earths centre of mass? You can not just use satelite orbits as they are not uniform around the earth and are continously changing. Money inflation indexs and FT index have a basket of prices but the baskets change over time and you can not really compare dollars in 1912 to dollars in 2012 using indexes.
Mike says: “They’ve also applied an ‘inverse barometer.’ Given that the barometric pressure variation over 7/10ths of the earth’s surface should average out close to zero, that’s another avenue for mischief.”
Colerado can no longer be given any credibility. As well as the GAIA [sic] adjustment the data is no longer available without the barometer adjustment. This new lack of transparency conveniently prevents anyone seeing what effect it has globally, which indeed should be neglibible. Clearly it isn’t otherwise they would not include it in the global mean sea level data they put up front for public consumption.
What they are still calling mean sea level is not such thing, it hovers phantom like, several mm above the waves. It is some kind of “sea level global warming index”. Continuing to present this as mean sea level data is dishonest and intentionally misleading.
Since public concern about rising sea levels is related to the risk of flooding, it has nothing to do with the rigged data they are calling sea level.
Mišo Alkalaj says:
October 31, 2012 at 12:32 am
I recall muddling a similar type of calculation some years ago, but the main problem is that sea temp changes occur in zones, not ‘throughout’ the volume – and some may be going down as well as up.
I am sure I have mentioned in a previous post that sea volume change is affected by multiple things too – such as crustal movements (laterally, as well as up and down) and subsea volcanism, atmospheric water content, subterranean (land) water content, sea and land ice changes, etc, etc.
People tend to forget about the full hydrological cycle when thinking about sea level. I am sure most here have had some school tuition about the water cycle? You know,- ocean water evaporates – makes clouds, then rains on the land, then slowly flows back to the sea, etc, etc. Any ‘measurement’ of sea level change (whether accurate or not) is simply a measurement of one part of the system, not the change in ALL the other parts of the water cycle – and those parts of the cycle introduce time lag effects, etc. So, in truth, what the feck are they actually measuring in terms of sea level?
DR says:
What’s the next mission, STRAW? GRACE GRASP STRAW….sounds about right
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I guess the STRAW mission should be Manned…..