From the European Geosciences Union
New research suggests that Antarctic sea ice may not be expanding as fast as previously thought. A team of scientists say much of the increase measured for Southern Hemisphere sea ice could be due to a processing error in the satellite data. The findings are published today in The Cryosphere, a journal of the European Geosciences Union (EGU).
Arctic sea ice is retreating at a dramatic rate. In contrast, satellite observations suggest that sea ice cover in the Antarctic is expanding – albeit at a moderate rate – and that sea ice extent has reached record highs in recent years. What’s causing Southern Hemisphere sea ice cover to increase in a warming world has puzzled scientists since the trend was first spotted. Now, a team of researchers has suggested that much of the measured expansion may be due to an error, not previously documented, in the way satellite data was processed.
“This implies that the Antarctic sea ice trends reported in the IPCC’s AR4 and AR5 [the 2007 and 2013 assessment reports from the Intergovernmental Panel on Climate Change] can’t both be correct: our findings show that the data used in one of the reports contains a significant error. But we have not yet been able to identify which one contains the error,” says lead-author Ian Eisenman of the Scripps Institution of Oceanography at University of California San Diego in the US.
Reflecting the scientific literature at the time, the AR4 reported that Antarctic sea ice cover remained more or less constant between 1979 and 2005. On the other hand, recent literature and the AR5 indicate that, between 1979 and 2012, Southern Hemisphere sea ice extent increased at a rate of about 16.5 thousand square kilometres per year. Scientists assumed the difference to be a result of adding several more years to the observational record.
“But when we looked at how the numbers reported for the trend had changed, and we looked at the time series of Antarctic sea ice extent, it didn’t look right,” says Eisenman, who set out to figure out what was wrong.
Scientists have used satellite data to measure sea ice cover for 35 years. But the data doesn’t come from a single instrument, orbiting on a single satellite throughout this period. Instead, researchers splice together observations from different instruments flown on a number of different satellites. They then use an algorithm – the most prevalent being the Bootstrap algorithm – and further processing to estimate sea ice cover from these data.
In the study published in The Cryosphere, Eisenman and collaborators compare two datasets for sea ice measurements. The most recent one, the source of AR5 conclusions, was generated using a version of Bootstrap updated in 2007, while the other, used in AR4 research, is the result of an older version of the algorithm.
The researchers found a difference between the two datasets related to a transition in satellite sensors in December 1991, and the way the data collected by the two instruments was calibrated. “It appears that one of the records did this calibration incorrectly, introducing a step-like change in December 1991 that was big enough to have a large influence on the long-term trend,” explains Eisenman.
“You’d think it would be easy to see which record has this spurious jump in December 1991, but there’s so much natural variability in the record – so much ‘noise’ from one month to the next – that it’s not readily apparent which record contains the jump. When we subtract one record from the other, though, we remove most of this noise, and the step-like change in December 1991 becomes very clear.”
With the exception of the longer time period covered by the most recent dataset, the two records were thought to be nearly identical. But, by comparing the datasets and calculating Antarctic sea ice extent for each of them, the team found that there was a stark difference between the two records, with the current one giving larger rates of sea ice expansion than the old one in any given period.
If the error is in the current dataset, the results could contribute to an unexpected resolution for the Antarctic sea ice cover enigma.
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This research is presented in the paper ‘A spurious jump in the satellite record: has Antarctic sea ice expansion been overestimated?’ to appear in the EGU open access journal The Cryosphere on 22 July 2014.
The scientific article is available online, free of charge, from the publication date onwards, at http://www.the-cryosphere.net/recent_papers.html. *A pre-print copy of the paper is available for download at http://www.egu.eu/news/118/is-antarctic-sea-ice-cover-really-setting-record-highs/*.
The team is composed of Ian Eisenman (Scripps Institution of Oceanography, University of California at San Diego, USA), Walter Meier (NASA Goddard Space Flight Center, USA) and Joel R. Norris (Scripps).
Why is it that virtually every single climate indicator that has been in favor of skeptics ends up having bad sensors or some math issue?
Richard M says:
July 22, 2014 at 3:46 pm
“The trend in extent in the Antarctic sea ice has been shown to be positive in different publications,” he said. “It is even more positive now than ever, and the Eisenman et al paper is providing a misinformation instead of a resolution.”
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Thanks Richard….I saw that too
…10 mins out of the gate….and already shot down
There is a dataset for Antarctica that goes even farther back to 1973. It is the orginal GSFC NasaTeam Bootstrap Algorithm.
It is virtually identical in the overlap period of October 1978 to December 2002, to the current NSIDC Antarctica Sea Ice Extent bootstrap algorithm measure.
Old 1973-2002 data here.
ftp://sidads.colorado.edu/pub/DATASETS/nsidc0192_seaice_trends_climo/total-ice-area-extent/esmr-smmr-ssmi-merged/
One can compare this to the current NSIDC sea ice extent data (bootstrap algorithm) here.
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/south/daily/data/
So if we look at these two datasets back to 1973, one finds that they are virtually identical. No step-change is evident in 1991. [Note that the Antarctic sea ice extent was actually higher in the early 1970s than today].
http://s30.postimg.org/y4m5qvgtd/Antarctic_SEI_1973_2014.png
Now we can also zoom-in on the infamous 1991 period here. There is no step-change evident.
http://s1.postimg.org/osfxzb5zj/Antarctic_SEI_1990_1992.png
Factual evidence that the claim in this paper is simply musing (with no basis in fact) and the paper should be withdrawn. Someone should send this comment to the authors.
Come on, expeditions have been plying down to the Antarctic by sea for over a hundred years.
Even Inspector Clouseau could work out from talking to craggy old Antarctic ship’s captains or looking at available voyage SITREP’s whether Antarctic sea ice is increasing or decreasing.
For example just a cursory glance of the Voyage SITREPs of the Australian Antarctic Division’s Aurora Australis gives a comparison of conditions between Dec 1999 and Dec 2013 at similar latitudes:
https://secure3.aad.gov.au/proms/public/schedules/display_sitrep.cfm?bvs_id=15576
https://secure3.aad.gov.au/proms/public/schedules/display_sitrep.cfm?bvs_id=19305
BTW that last voyage also contains details of how the ship was diverted to rescue of the Akademik Shokalskiy when Professor Chris Turney and his NSW Uni touring scientists got stuck in the ice at Commonwealth Bay a couple of days later.
If the Antarctic sea ice has NOT been increasing then I expect the AAD’s ship’s schedules for the coming season will be much the same. But without closely checking all their planning I have a strong feeling they will be put back a little.
Whatever, I will be watching with interest on how they get on this year and especially if the NSW Uni has some more entertaining reading for us of its adventure and survival trips to the Southern Ice.
Antarctica sea ice is diminishing US intelligence suggests: “There is an almost certainty that Antarctica sea ice is also diminishing and our Antarctica allies have indicated pockets of melting sea ice with torch blowers” says a Climate State Department official under the cover of anonymity.
Meanwhile satellites even with a slight correction do show rising Antarctica sea ice extent…
Back to you Candy.
Setting aside all the other inherent stupidity of this article, why should they be allowed to get away with this statement; “Arctic sea ice is retreating at a dramatic rate.”?
In the satellite records of arctic ice extent, it is plainly obvious that there was a decrease in ice extent from about 2000 to 2007, but that there has been no percievable decrease in ice extent from 2007 to present. 2014-2007 = 2007-2000; the arctic ice extent has been NOT shrinking for as long a period of time now as it WAS previously shrinking.
The only rational description is that while the arctic sea ice has retreated in the past, it is not presently retreating. It remains to be seen what it will do in the future, but the statement that “Arctic sea ice IS retreating at a dramatic rate” can be considered as nothing other than an outright lie of the most blatant and obvious sort, in which case the entire article is unworthy of consideration.
Yeah it does seem that way, one would think that if it were an honest mistake the error would be as likely to go one way as the other, but for the most part the heavy-duty math libraries used by these programs are extremely well tested. Computer Software Engineers are well aware of the precision and limitations of these libraries some have been in developement for 60 years, post-grads with a couple hours of Comp Sci are more likely a “Your Millage May Vary” situation.
I’ll ask again… can anyone remember an example of either of the following…
1) errors or adjustments favoring cooling (or skeptic position)
2) model forecasts did not verify too warm
As a stats geekess, I would expect model verification and errors and data adjustments to fall randomly in a bell curve around the mean. But instead, they always seem to be on the same side of the mean in an amazing skewness.
Perhaps I’m missing something?
Mosher writes “not uncommon for processing sensor data from a satellite. ”
Yep but more generally its not uncommon when stitching together two datasets from different sets of measurements. For example there is a large jump in OHC at the time that Argo began measuring. However because that jump follows the party line, they dont take too much effort to reduce it.
“Arctic sea ice is retreating at a dramatic rate.”
It isn’t.
” What’s causing Southern Hemisphere sea ice cover to increase in a warming world”
Which world is that? Not this one for the last seventeen years.
“, a team of researchers has suggested that much of the measured expansion may be due to an error, not previously documented, in the way satellite data was processed.”
No chance that an error has lead to the ideas that Arctic ice is retreating and the world is warming?
For example there is a large jump in OHC at the time that Argo began measuring.
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I believe if you check Argo itself is questionable. Initially the trend was in the “wrong” direction, so buoys were eliminated until the desired trend was obtained. Links were posted here on WUWT some months ago to confirm what happened. My impression was that the researcher responded to “peer pressure” – he was concerned with the reception he would get from his peers if his findings did not conform to expectations.
John F. Hultquist says:
July 22, 2014 at 4:03 pm
“I love the snark . . . ”
snark – a very common characteristic of:
Barack Obama
Albert A. Gore, Jr.
…
long list follows
…
Joseph R. Biden, Jr.
John F. Kerry
————
Steven Mosher has provided very good comments here. Thanks.
=================================================
I’ll second that! I learned quite a bit from the comments here, and Mosher’s were quite helpful in pointing me in a useful direction.
Of course some comments can be frustrating, but patience Steve:), we are all learning from different starting points and at different rates, plus, separating the politics and the science isn’t always easy for us.
“May”, “could”, etc. Article is simply conjecture with no science and not evidence of anything anywhere. Most obviously, if there were a significant error then the record of the data would show it clearly, “noise” or no “noise”.
The only conclusion is that these warmists are looking for anything to cast doubt because the antarctic ice growth has embarrassed them so.
Lets not get too complicated, the simple explanation to “why”, might be the carve up of the profit cake that caused such a fight between NASA (Hansen) and NOAA (Schmidt) as to which part of the organization would control the multi Billion/Trillion operation to geoengineer the World Climate to fix, a problem, these same “men of science” insisted was happening then. Well before enquiring minds applied sceptical reasoning to their theories and behaviour.
Was that funding “cake” worth all that deceptive behaviour (the Hot Senate room adjustments, etc. etc. the hiding of data, biasing data) They say Hansen won the right to the program once authorised, but was it really worth it!! But you be the judge!
Here Mosher condescendingly obfuscates in personally insulting fashion the simplicity of white Antarctic ice pixel area counting by dragging in rounding error level complexity of perforated Arctic dynamics, shamelessly implying that simple measurement of ice area is yet another complex affair for experts alone to be able to judge, as *if*! It’s white pixels in a picture, folks. Learning to simplify after considering complexity is what sets too notch scientists from careerist hacks who always wallow in minutia. The whole point of sea ice extent is to offer a basic unnuanced year to year trend determination in which nitpicks about gloss and dirt and thickness are ruled out since hide are ice mass considerations and those average out to still provide a good trend estimate of growth versus loss which is what matters most. Is Antarctica not growing in ice extent, as clearly as day? Does Mosher’s comment about glossy film ice change the fact that Antarctic ice extent is growing by even a percentage point? If so, in what direction? Does he even offer a clue? No, he merely tries to confuse one if the most simple issues in the debate: Antarctic ice is growing in two dimensional area, now being at a record high value. This puts great doubt on models that claim ice volume is rapidly falling, given that sea ice growth comes from ice expansion out of the mainland via plastic flow.
iPhone impossibly small edit box typos:
too notch > top notch
hide are > those are
one if > one of
Yes, I’m saving up for a bigger pocket computer.
ferdberple writes “Initially the trend was in the “wrong” direction, so buoys were eliminated until the desired trend was obtained.”
Its true they eliminated “cold reading units” and I would hope they applied the same criteria to “warm reading units”. Josh Willis strikes me as an honest sort of guy. Either way, there wasn’t much trend left.
But that’s trend after Argo. I’m actually talking about stitching the XBT and Argo data together. There is a massive jump in OHC at the join.
The error is…the world is cooling and has been for a long time. What is it with there people?
Antarctic ice melting faster than expected
April 6, 2009
UP TO one-third of all Antarctic sea ice is likely to melt by the end of the century, seriously contributing to dangerous sea level rises, updated [un]scientific modelling on global warming shows. The evidence will be presented to an international meeting of Antarctic and Arctic scientists in the US tonight, at which US Secretary of State Hillary Clinton will speak.
http://www.theage.com.au/environment/antarctic-ice-melting-faster-than-expected-20090405-9t9v.html.
Antarctic ice spreading
April 23, 2009
It seems that global warming may actually be leading to an increase in sea ice in parts of the Antarctic. Scientists in the United Kingdom have produced a study which shows ice has grown by 100,000 square kilometres each decade in the past 30 years. And perversely the increase is being put down to the hole in the ozone layer.
http://www.abc.net.au/am/content/2008/s2550320.htm
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It appeared that there had even been demonstrations to thank Big Brother for raising the chocolate ration to twenty grammes a week. And only yesterday, he reflected, it had been announced that the ration was to be reduced to twenty grammes a week.
Was it possible that they could swallow that, after only twenty-four hours?
Yes, they swallowed it. Parsons swallowed it easily, with the stupidity of an animal. The eyeless creature at the other table swallowed it fanatically, passionately, with a furious desire to track down, denounce, and vaporize anyone who should suggest that last week the ration had been thirty grammes. Syme, too-in some more complex way, involving doublethink, Syme swallowed it. Was he, then, alone in the possession of a memory?
http://msxnet.org/orwell/1984
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I quote: “… Arctic sea ice is retreating at a dramatic rate. In contrast, satellite observations suggest that sea ice cover in the Antarctic is expanding – albeit at a moderate rate – and that sea ice extent has reached record highs in recent years. What’s causing Southern Hemisphere sea ice cover to increase in a warming world has puzzled scientists since the trend was first spotted….”
They would not be puzzled if they had bothered to read my 2011 article [E&E 22(8):1069-1083]. The ice at the two poles is regulated by two different mechanisms: while the Antarctic ice cover responds to the cold circumpolar atmospheric circulation in the Southern Ocean, Arctic warming is caused by ocean currents carrying warm Gulf Stream water into the Arctic Ocean. It started at the turn of the twentieth century, after 2000 years of slow, linear cooling. What happened is that there was a change in the pattern of North Atlantic currents that began to carry warm Gulf Stream water north. The original pattern of currents returned for thirty years in mid-century and was accompanied by cooling at the rate of 0.2 degrees Celsius per decade. Warming then returned about 1970 and has been active since then. There was no increase of atmospheric carbon dioxide at the turn of the century which rules out greenhouse warming as a cause of warming. Furthermore, It is quite impossible for greenhouse warming to suddenly change to cooling and then return to warming in thirty years’ time. From this it is clear that if it wasn’t for currents bringing Gulf Stream water into the Arctic both poles would now be cooling at the same rate. One more note: these guys refer to a “warming world” that does not exist. Someone ought to tell them that there is no greenhouse warming today and there has been none for the last 17 years. Their greenhouse theory is completely unable to explain this and belongs in the wastebasket of history.
I was wondering what was going on with thr recent sea ice in Antarctica. As I correctly forecasted El Nino’s collapse on Jun 10th I know those GO people are going to be a bit disappointed in the coming months. Antarctic ice cap actually expanded during July not contracted significantly, when analyzing satellite. The pressure to change the record ice cap data this year must be amazing.
Anybody still remember the failed expedition last December to Antarctica led by Australia’s Professor Chris Turney? Remember how they all got stranded in all that ice?
I wonder what Chris Turney would have to say about this article?
Mosher has posted a lot of good comments in this thread.
Mosher is piling the BS up so high in this thread as to be a clown about it:
“Sensors in space do not measure temperature. They dont measure ice extent or area.
They measure brightness at the sensor at various frequencies. Those raw voltages are then
processed by models to create estimated “data” which try to represent things like temperature
of ice extent. The sensors change over time. The algorithms change.
People do agree on the math. 2+2 = 4. But when it comes to turning a raw voltage at the sensor
to a physical property… that’s more than simple math. It typically involves a physics model with
many assumptions.”
Dude, it’s white pixels on a perfectly dark background ocean. There simply *is* no sensor dilemma to this measurement in the Antarctic. It’s a five minute Photoshop job with nearly no error. Unlike the Arctic, the Antarctic satellite image is so clear about what is sea ice and what is ocean that there is no ambiguity whatsoever, no sensor calibration involved. An iPhone sent into space would do fine and you could send twenty smart phones up there on a small satellite and randomly choose one each day and still get the exact same ice area from each one since the contrast of the ice against ocean is ideal. Any camera will give the same result at nearly any exposure even with shadow or highlight blowout. It’s just like counting the relative pixels of white on a chess board after taking a picture of it. The type and condition of a the sensor has near zero impact on the simple act of finding the area of ice because the contrast is to incredibly high. Your detector or whatever imaging camera you want to use could vary all over the place and it will return the exact same high contrast determination of where the damn ice is. This is so trivial that if you haven’t applied the laugh test to claims of complexity then you are a willing dupe. No wonder skeptics can’t expose the overall scam. All it takes is one spin doctor and the whole crowd is wooed as if ice area was like complex ground thermometer records or whole Earth thermal sensors. No, it’s not like those at *all*. There is only some variation in mass in the Arctic and that’s about mass, not extent.
A smart phone camera *does* indeed measure white pixel area on a chess board, just using Photoshop on it to count pixels. There is no error here. You need distort the image of the chess board back to a square in fifteen seconds, then quick adjust the contrast in ten seconds, then select the highlights and do a pixel count in another fifteen seconds and you will always get 50% with a small error no matter what cell phone you use. With a team of programmers and rocket scientists with hundred million dollar equipment, you still get 50%, but more like 50.00% instead of just a couple percent variation. With either piece of equipment you never get more than a couple percent error.
What has happened to people’s reality detector versus BS detector? It’s disgusting to see a spin doctor make mashed potatoes our of your minds, dear skeptics. This is exactly how climate alarm still carries on. A bit of obfuscation turns skeptics into intellectual pacifists. Is ocean going to be classified as ice, ever? Can literal rocket scientists not time filter out cloud cover? Will ice ever really be classified as ocean? It’s a binary determination that is a clear as any system could ever be to measure properly. There is no error, no time that dark ocean is classified as white ice, ever. It’s simply not optically possible unless you smash the damn camera.
Isn’t the whole AGW hype a result of “processing error”s?