Tim Lambert (deltoidblog AT gmail.com) is a computer scientist at the University of New South Wales.
The Register, an occasionally accurate online IT newspaper, has been running a series of warming denial pieces, by one Steven Goddard. Goddard has been trying to cast on temperature and ice data. Unfortunately, he does a whole lot of cherry picking. For example:
A second important issue with NASA's presentation is that they use the time period of 1951-1980 as their choice of baseline. This was a well known cold spell, as can be seen in the 1999 version of the NASA US temperature graph below.
Why use a graph of US temperatures instead of world temperatures? The "cold spell" is more pronounced in the US graph. In fact, the average for 1951-1980 is almost the same as for the 20th century so it is misleading to call it a cold spell. Goddard prefers to use satellite data, with a baseline that is significantly warmer than the 20th century average, to try to making warming seem less. He does some more cherry picking when he presents a map of GISS temperatures leaving out the sea data and using 250km smoothing (even though the NASA used 1200km smoothing for the temperature graphs) in order to make it look like there are significant gaps in NASA's coverage. He compounds this by picking a month where this makes it look like there is a warming bias in NASA's temperatures.
But his most recent effort was even worse, claiming that the NSIDC's graph of Arctic sea ice extent was wrong and that there was 30% more sea ice than at the corresponding time last year.
But it was Goddard who was wrong, as NSIDC's Walt Meier explained to the Register:
He appears to derive his estimate by simply counting pixels in an image. He recognizes that this results in an error due to the distortion by the map projection, but does so anyway. Such an approach is simply not valid.
If you correct Goddard's error, you get the same number as the NSIDC. Meier adds:
Besides this significant error, the rest of the article consists almost entirely of misleading, irrelevant, or erroneous information about Arctic sea ice that add nothing to the understanding of the significant long-term decline that is being observed.
Goddard admitted he was wrong but, as noted by Joseph Romm, Kevin Grandia and James Hrynyshyn, the numerous denialists who claimed that Goddard had shown that the ice wasn't melting have mysteriously failed to correct things.
There are too many to list, so I'll just point to the Australian bloggers: Jennifer Marohasy "Arctic Sea Ice Refuses to Melt", Tim Blair "Arctic ice seems to be growing somehow." and Andrew Bolt "Tim Blair rounds up the local anecdotes of coldening.". No corrections from any of them.
Incidently, in the graph above, 2005 was the record melt until 2007. 2008 has already passed 2005 and whether or not it ends up setting a new record, it's clear that the melt in 2008 is similar to 2007 rather than anything ever seen before.
Update: Bolt referred to Goddard more than once:
Steven Goddard checks those predictions that the North Pole could melt clear away this summer, and finds we can (yet again) relax.
Environment
Comments
never excuse, never correct, unless forced at gunpoint. so no surprise, that most denialist sources will not change or correct their stories.
remember, their mission is to confuse and to mislead. while spreading the false Goddard claims, they have fulfilled this mission.
and it wont matter how much below the average or 2005 that line might drop.
as long as it doesn t drop below 2007, the denialist blogosphere will howl in triumph.
Posted by: sod | August 28, 2008 3:20 AM
Correct their mistakes? Bah! Denialists feed on their own errors. Being wrong just makes them stronger.
Well, if it's not Jen Miss Socratic Irony! What Miss Irony might have said:
Of course I'm refusing to correct the error merely to observe how angry those darn Alarmists™ will get over this. My own inaction says more about them than it does about me, goo goo g'joob.
What Blair might have said:
The totally ineffectual liberal hippie anti-war movement have concocted a gigantic worldwide hoax known as al-Goracular Global Warmism!
What Bolt might have said:
Today in Malaysia, Anwar Ibrahim has been sworn in as Parliament Member for Permatang Pauh.
What an apt metaphor!
Like the Abdullah government, the phantom edifice of Global Warmism is slowly falling like a slowly falling deck of cards! Merdeka!
Posted by: bi -- IJI | August 28, 2008 3:46 AM
"... the rest of the article consists almost entirely of misleading, irrelevant, or erroneous information about Arctic sea ice that add nothing to the understanding of the significant long-term decline that is being observed. ..."
Yeah but Al Gore is still fat.
Posted by: Ian Gould | August 28, 2008 3:48 AM
Careful, there. Goddard has retracted his original claim that there was something wrong with the NSIDC numbers, and now acknowledges that those numbers are in fact correct. This is welcome.
But there does seem to be some discrepancy with the images (from UIUC) and it is not just because of the projection. In fact, correcting for the projection actually makes the discrepancy with NSIDC worse. It's likely, I think, that the two images Goddard was comparing were actually using different notions of extent. I'm not sure; but it is definitely NOT just an issue with the projections.
Posted by: Duae Quartunciae | August 28, 2008 3:56 AM
Yes, ther ewas also an issue with comparing different things. Meier wrote:
Posted by: Tim Lambert | August 28, 2008 4:14 AM
It's a shame that The Register has become as reliable on environmental issues as former members of the UK Revolutionary Communist Party.
Posted by: Naadir Jeewa | August 28, 2008 5:52 AM
The Register should just stick to what they know: technical IT stuff.
Posted by: David | August 28, 2008 8:36 AM
Thanks for this. I generally enjoy the Register, but they've taken on a ridiculous global warming denialism in recent months.
Posted by: unicow | August 28, 2008 9:03 AM
I have tried a number of times to leave a post on Bolt's blog over the last several days asking when the under-reported truth about his inaccurate piece would be acknowledged, and when a retraction would be duly penned.
I seem to have been lost in moderation...
Posted by: Bernard J. | August 28, 2008 9:04 AM
Hi Tim, #5. The issue of area vs extent is different from the issue with images. UIUC does report ice area; but the pixel counting exercise is still a way of estimating an extent; not an area. Meier has been very helpful indeed in all of this, but his remark about UI plots being area don't make any sense. You get area by weighting each region with its percent ice cover; but the plot has pixels added for a certain extent. There is a 30% difference (or more than 30%, if you take projections into account) between the extent in the two images Goddard was comparing, when the data indicates it should be much less than this. It looks to me a bit like the 2007 image was showing the extent of 50% ice, while the 2008 image was showing the extent of 30% ice.
The comments from William Chapman of UIUC conflict with this; but it still looks wrong to me. The 2007 image at UIDC sure as heck looks a lot like the extent of 50% ice cover. It's strange.
Posted by: Duae Quartunciae | August 28, 2008 9:25 AM
@David, The Register's IT coverage is little more accurate. It's best described as an IT gossip column.
Posted by: Craig | August 28, 2008 9:40 AM
Which is why any analysis ought to be done on the UNDERLYING DATA, not an image generated from it.
Goddard's claim was that the NSIDC graph - generated from DATA - was wrong based on a computer-generated image that among other things had been JPEG'd once.
Idiocy. If Goddard weren't a climate science is a left-wing conspiracy denialist scum, he might've said something like "there's something interesting about the IMAGE".
Regardless, pixel counting the generated image is just wrong. There's a reason for the link that says "download the historic sea ice dataset here".
Posted by: dhogaza | August 28, 2008 9:50 AM
Hey D.Q. #4, #10
Assuming the UIUC images are a perspective view from above the North Pole I would guess the viewing height to be 1 Earth radius. You can just see the S. end of Japan, which is at 31 N. This height gives a tangent view at 30 N which would seem like a natural choice. Then it should be possible to calculate ice extent from the images by counting pixels and correcting for distance and viewing angle, using the factor
distance^2/cos(surface tilt)
to scale each pixel. I tried this but still cannot get any agreement with the IARC-JAXA figures for ice extent. The calculation overestimates the area, by an increasing amount as the ice extent gets larger. Just as Goddard discovered.
My conjecture is that the projection used in the images does not correspond to a photographic/perspective view, although the way the images are presented against a star background suggests this is the case. Perhaps this is the trap Goddard fell into. (Or perhaps my calculation is wrong).
Posted by: dipole | August 28, 2008 11:28 AM
So now we have dipole making guesses as to what the image is, and analyzing based on his guess.
Dude: it's a waste of time. The Auditors are always screaming about the need for raw data. In this case, despite it's availability, you guys are tripping on images whose provenance you don't even understand (the folks there have explained the history of the images, you can't even be bothered to learn it rather than guess?)
Posted by: dhogaza | August 28, 2008 12:38 PM
dhog:
So now we have dipole making guesses as to what the image is, and analyzing based on his guess.
This is all they have.
Give dipole a break: if they didn't have this, what would they comment about? Brangelina's twins?
Best,
D
Posted by: Dano | August 28, 2008 1:42 PM
Anyone comparing pixels in a jpeg deserves to be laughed at.
http://en.wikipedia.org/wiki/Compression_artifact
Think of it as the digital equivalent of impressionist art.
Posted by: pough | August 28, 2008 3:43 PM
meanwhile, back here in reality:
For the first time ever, both the Northwest and the Northeast Passages are free of ice.
http://www.spiegel.de/international/world/0,1518,574815,00.html
and
New satellite measurements show that crucial sea ice in the Arctic Ocean has plummeted to its second lowest level on record.
http://ap.google.com/article/ALeqM5gU8J3xEhFmRPw87tPfwb-oXa5h9gD92QNA480
will jennifer bother with the facts?
or simply ignore them, again?
Posted by: sod | August 28, 2008 4:29 PM
Dipole, why guess?
You can look this stuff up.
Look on the page next to the maps. See the little rectangle for searching the site?
Know what the map thingumabob is called? It's a "projection" -- so put into the Search box: map projections and tell it to look it up:
http://nsidc.org/data/atlas/news/newmapprojections.html
Seriously, a few minutes talking with the librarian at the reference desk at your local library could save you a world of trouble, and you'd get far less attention from people in the blogosphere if you got it right the first time.
Oh, wait. Is that what you want?
Posted by: Hank Roberts | August 28, 2008 4:50 PM
Arrrgh. I forget this blogging software doesn't take what's pasted into it literally.
You want underscores before and after the word 'map' in that link for it to work properly.
For this blogging software, put a backslash before the underscore to display it literally:
http://nsidc.org/data/atlas/news/new_map_projections.html
Posted by: Hank Roberts | August 28, 2008 4:58 PM
Actually, the image in question doesn't come from the nsidc site, so it might not be the same projection ...
Posted by: dhogaza | August 28, 2008 5:06 PM
People; I am not one of the AGW skeptics, and I am not casting any doubt in the reporting of the sea-ice figures. I did put a bit of work into sorting out the subject, in an attempt to deal with Goddard's article; but when Goddard retracted, the urgency went out of it and I moved on to other things.
But in the meantime, when other people bring up the subject and make errors in describing the matter, don't you think it is appropriate to supply a correction? Is it only when denialists make mis-statements that we should speak up?
I don't think so! Furthermore I am confident that Tim won't object at all. He does a great job with this blog; and part of what makes our side stand out is that we tend to be better at dealing with errors, big or small. Usually.
And, by the way, credit to Steve Goddard for acknowledging that he was wrong to think the NSIDC figures were wrong. It was incredible just how quickly his original remarks got picked up and spread around the denialist sites; and how few of the them have acknowledged it was all for nothing. But Steve at least has retracted.
The whole thing was intrinsically implausible from the start. The images are a highly processed diagnostic of the data; without knowing all the processing involved or the dataset used, it was surreal to take pixel counts as trumping actual satellite data. And yet, and yet. There really is a 30% difference in extent between two UIUC images. That this is a lousy basis for disputing NSIDC figures does not actually absolve our side from all scrutiny.
It has been said that the UI calculates area, not extent. This is irrelevant; the image comparison was dealing with extent. It has been said that it is about the projection used. That's flatly false; the projection makes the discrepancy larger; not smaller. Lots of comments refer to the NSIDC images. Pay attention people, it is the UIUC images that have a discrepancy. If you want to ignore the whole thing as trivial, fine! But if you want to comment on the subject and your comments are wrong; you get the same kind of scrutiny that Goddard received and eventually took into account.
By the way, dipole, the UIUC projection seems to be a vertical perspective projection from an altitude substantially more than Earth radius. I get very close with the tangent from the viewpoint touching latitude 27. This is a viewing altitude of about 7700 km. It could also be using an ellipsoid rather than the sphere.
The UIUC images are for 12-Aug-2007 and 11-Aug-2008. There's no link for the second, because the image archive only goes to 2007. But you can "compare" images using this link. I did email William Chapman. I might try to sort it out a bit more one day; but it's not a priority. In the meantime, I'm just noting for those who comment on the matter... there is a bigger difference in extent apparent in the UIUC images between these dates than what you should expect from data, and this is not an artifact of projections.
Posted by: Duae Quartunciae | August 28, 2008 6:29 PM
http://www.google.com/search?hl=en&q=NASA+SMMR+SMMI+%2B%22map+projection%22&btnG=Search
That's searching on the words found in the lower right corner of the UIUC sea ice images.
Of the two hits, the first one http://www.ccpo.odu.edu/SEES/pdf_files/pi_i2k_ex.pdf
seems to me most likely to be a description of how those images are made.
It begins:
Exercise 1--Generating North and South Pole Geographic Reference Maps
File type and file name description
Displaying sea ice concentration (SIC) data images
Adding color to the images
Understanding display windows and images
Creating North and South Pole geographic reference maps
Calibrating pixel values to SIC in percent using NASA Image2000 ...
And its discussion explains:
"The set of exercises that follow were designed to explore characteristics of polar ice processes using satellite data. These exercises introduce students to basic image processing skills for displaying and analyzing images. Each exercise has scientific discussions explaining what the student is observing. Students will use NASA Image2000, a version of NIH Image, to display and analyze the data sets. The exercises are inquiry based and designed for advanced high school or introductory level undergraduate Earth science classes and associated Macintosh computer labs. They were designed to be used in concert with an electronic lecture that contains scientific background information on polar sea ice and its satellite observations ...."
Looks like it explains the process. Whether it's exactly the one used by UIUC, I dunno.
Beyond that, I see Duae has already wisely inquired of Dr. Chapman at the UIUC site.
Good method.
Posted by: Hank Roberts | August 28, 2008 6:49 PM
When images don't match the data they're generated from, it is obvious which has a problem. The images aren't generated with the notion that anyone would attempt to do pixel-by-pixel comparisons, who in their right mind would expect that any one would do this? Especially when the raw data's available via a link on the same page?
There are all sorts of possibilities for the discrepancies. Maybe one set was JPEG'd, the other not. Maybe colors were assigned slightly differently, maybe not. Maybe different image generation software was used, maybe not.
But - who cares? Seriously - who cares? Sure, e-mailing Chapman can help solve the mystery, Watts has done so, others, too. But ... if this where anything other than AGW-related, would anyone be bothering the image maker? Wasting their time? Making them spend their time on something that, in any objective sense, is meaningless?
Demanding that he remove a quote of Al Gore from the website, as Watts very publicly did? (sheesh - worse, they obeyed their denialsphere masters).
Posted by: dhogaza | August 28, 2008 7:12 PM
The raw data is NOT available at the same page. Check and see. The historical data available is actually only monthly, and it is much coarser than the images. The UIUC is not actually very clear about precisely what data source they use for the images being compared here.
If you don't care, dhogaza, that's fine. I agree that actual data (available at NSIDC) is clear on the real changes going on. Feel free to ignore issues with the UIUC images. I also stopped doing anything on them once Goddard retracted his original claims about data.
In the meantime, I'm still going to correct errors of fact being made, thanks all the same. From anyone. I didn't bring the matter up. I'm just correcting some erroneous statements in relation to UIUC images.
Posted by: Duae Quartunciae | August 28, 2008 7:52 PM
's 14,15,16,18,22
What's your problem? Everyone, including Goddard, agrees Goddard was wrong. Wm. Chapman from UIUC/Cryosphere Today posted a rather vague rebuttal on Watts' site involving projection error. I asked him there what projection the CT maps used. No reply. Rather than pester him further by email, phone, or flying over to visit him I did a few fun calculations.
DQ #21 did email him, apparently without success.
Walt Meier of NSIDC (quoted above) talks about "error due to the distortion by the map projection".
OK, it's just a mathematical/cartographic question, but my curiosity is aroused. Is curiosity now something to be frowned upon? Just tell me what projection I need to use to reconcile the CT images with the raw data.
Posted by: dipole | August 28, 2008 9:16 PM
On the issue of Ice disappearing faster than denialist credibility, one wonders the ramifications of the rapid collapse of the West Antarctic Ice Sheet (due to collapse of suppportive ice shelves over the next twenty years, max.). One ramification no one wants to touch is rapid Isostatic rebound and the ensuing Super Volcano.(Increased Volcanic activity due to rapid isostatic rebound recently proven, http://environment.newscientist.com/article/dn13583-melting-ice-caps-may-trigger-more-volcanic-eruptions.html)
As the WAIS depresses 750000 square kilometers of Plate up to 1 kilometer, resultant Volcanic activity will be catastrophic. A Volcanic winter lasting hundreds of thousands of years, collapse of the EAIS, further sea level rise and vast increase in Isostatic rebound and associated Tectonic activity.
One wonders what the sudden release of Trillions of tonnes of Ice from the axis of rotation of the Planet will do.
Posted by: 4 billion | August 28, 2008 9:46 PM
Hapgood!
Posted by: Gareth | August 28, 2008 10:37 PM
Ha, ha, ha. Go to Marohasy's blog. Right. Now.
http://www.jennifermarohasy.com/blog/archives/003365.html#comments
Posted by: CK | August 28, 2008 10:57 PM
If you really meant this, you'd just stick to saying ...
Pixel-to-pixel count comparisons of various images of unknown provenance which, in at least, one case has been JPEG'd is ...
There's really nothing else to say, no matter which side of the supposed AGW debate you're on.
WHO GIVES A FUCK IF IMAGES PUT UP FOR YOUR VIEWING PLEASURE AREN'T RELIABLE DATA FOR ANALYSIS?
The people who put them up never made that claim for them.
It's just butt-fucking stupid.
Posted by: dhogaza | August 28, 2008 11:09 PM
No one who gives a shit about science, the data, the real world, gives a rusty fuck about the images.
Why? Honest question. Why? Whatever the result of your query will not mask the fact that ice extent in 2008 is already the second worst on record and is likely to soon become the worst, by NSIDC data. UICT may hold it as the second.
Neither of these statements will be based on the images.
Bottom line here: UIUC was stupid to put images that approximate the data up on their site. It should be limited to a link to a dump of the raw data, no commentary, nothing.
Because gosh, if they once JPEG an image ... holy fucking shit! All of climate science is proven false!
That's the denialist meme, and those of you who claim to be "on the right side" are just playing into their game.
Posted by: dhogaza | August 28, 2008 11:14 PM
dhogaza says:
"Why? Honest question. Why?"
Because I'm interested in map projections. Here's a nice book for you.
Posted by: dipole | August 28, 2008 11:28 PM
Looking again at the thread intro I see Tim notes that:
If you correct Goddard's error [due to projection distortion], you get the same number as the NSIDC.
So tell us the details Tim! What projection did you use?
Posted by: dipole | August 29, 2008 12:31 AM
Craig @ 11 - Jesus! They've even lost that! It's been a while since I've looked at it, but some of their hardware articles were OK back in the day.
Posted by: David | August 29, 2008 12:42 AM
Moral: Use PNG. :-B
Posted by: bi -- IJI | August 29, 2008 12:42 AM
Wrong question.
The real question is: Why is dipole so obsessed with
Al Goreusing projections?Posted by: bi -- IJI | August 29, 2008 12:45 AM
dipole, Goddard's error was counting pixels to get an estimate of the change in sea ice.
Posted by: Tim Lambert | August 29, 2008 12:57 AM
@ #27...'Hapy' may have the last laugh yet...anybody know a good medium?
Posted by: 4 billion | August 29, 2008 1:06 AM
Re: Tim Lambert #36
Sorry, but your mention of "Goddard's error" in the intro appears to refer the immediately preceding paragraph, where Meier attributes the error to mapping distortion. You also imply there that this error can be corrected, which I took to mean that the CT images have indeed been reconciled with the NSICD data.
I take it from your reply that you now agree that this is not the case.
Posted by: dipole | August 29, 2008 1:16 AM
dipole:
I'm in the process of writing up a story on the Real Reason™ that Steven Goddard issued his retraction. Other Deltoid readers probably have quite a good idea of what it is. Stay tuned.
Posted by: bi -- IJI | August 29, 2008 1:47 AM
At #39 bi -- IJI says:
the Real Reason™ that Steven Goddard issued his retraction.
You mean it wasn't just because he was wrong? Was he waylaid by a polar bear on his way home from work?
Posted by: dipole | August 29, 2008 2:06 AM
the discussion about the 2real reason for the error", is just another demonstration of the denialist smear machine in action.
reread my comment #1 above:
never excuse, never correct, never admit that you were wrong. as long as they can keep doubt about the reason for the error floating, they are fulfilling their mission.
Posted by: sod | August 29, 2008 3:46 AM
sod:
I was talking about the Real Reason™ for the retraction.
Now that's something which the inactivists won't want to touch with a 10-foot pole. :-B
Posted by: bi -- IJI | August 29, 2008 4:08 AM
sorry bi, i was not addressing you.
i am looking forward to yourtake at it :)
Posted by: sod | August 29, 2008 4:16 AM
Although it's off-topic, CK's link at #28 is curious indeed. Not long ago Marohasy apparated a disclaimer on her blog to the effect that the more bizzare wingnut theories on her blog were inspired by 'Socratic irony'. It now appears that she needs to (wisely) dissociate herself from the more overt fruitloops at P&E by the tried and true corporate strategy of dividing and rebranding her assets.
Anyone remember the APS 'affair', and Christopher Walter's outrage at being disclaimered?
I doubt that there will be any apology for the wrong-headed post she made on Arctic sea-ice either (Socratic irony aside), but the memory of the intertubes is a wonderful thing...
Posted by: Bernard J. | August 29, 2008 6:19 AM
Sorry Bernard, OT again, but that joint really is a circus tent. But all the same it's a great loss to irritainment.
She had no choice, really. Especially after her posts over the past week or so. Newtonian physics anyone?
Sounds like her overlords at IPA delivered some sound career advice.
Posted by: CK | August 29, 2008 6:42 AM
The Real Reason™ for Goddard's retraction, as discovered by yours truly. But you probably already know it, right? :)
Posted by: bi -- IJI | August 29, 2008 11:29 AM
Well done!
Posted by: dhogaza | August 29, 2008 11:51 AM
Looking at the UIUC images, it led to that SEES pdf file I linked above.
The SEES site link has changed since that PDF was written. The link redirects now to: http://www.ccpo.odu.edu/SEES/polar/pi_data.htm
That says how to go about aquiring the data used in the SEES image files:
"The National Snow and Ice Data Center in Boulder, CO, is the source for information and data about high latitude Earth science, including sea ice. The Web site is http://www.nsidc.noaa.gov"
Posted by: Hank Roberts | August 29, 2008 1:14 PM
Lose the trailing quote on that last link, to get the data files -- but you knew that.
Here's the SEES image software page for Mac and Windows.
Reminder, I know nothing, I'm just backtracking from the attribution text in the lower right corner of the UIUC site's images, and guessing this software and the data files described may well be what they're using:
http://www.ccpo.odu.edu/SEES/polar/pi_comp.htm
If so, the confusion is from having two different imaging programs used for the same data set.
Time and the UIUC response will tell if I've guessed right.
Posted by: Hank Roberts | August 29, 2008 1:30 PM
Here's an alternative:
Sea ice map calculated from AMSR-E data using the ARTIST sea ice algorithem (ASI 5).
http://iup.physik.uni-bremen.de:8084/amsr/amsre.html
SSM/I and AMSR-E L1B from inside IUP : http://diana.iup.uni-bremen.de:8084/cgi-bin/index_ssmi_inside.html
All level 1A data are received from the National Space Development Agency of Japan. Distributed by: Boulder, CO, USA: National Snow and Ice Data Center.
The ASI sea ice concentration algorithm used here has been validated in several studies (Spreen et al. 2005, Spreen et al., 2008). [links provided on original page, see above] However, no warranty is given for the data presented on these pages.
Posted by: Hank Roberts | August 29, 2008 2:16 PM
dhogaza: ☺ ☺ ☺
Posted by: bi -- IJI | August 29, 2008 2:41 PM
That graph is looking a bit old and we are getting onto exciting times. Will it or wont it cross 2007. How about an active link which updates each day.
Posted by: sean egan | August 29, 2008 4:45 PM
Here's the daily graph from the NSIDC The big question is: will the rate of extent shrinkage flatten out before or after it crosses 2007. If before, the 2007 record is probably safe. If after ... this is about when things really started to flatten out in 2007, so a big change of pace this year would be needed to keep the minimum extent from crossing last year's record minimum.
It's a bit like watching a horse race ...
Posted by: dhogaza | August 29, 2008 5:56 PM
Hank Roberts #48,49
Thanks for your efforts but www.ccpo.odu.edu does not resolve to any IP address through my connection.
The Uni Bremen maps are great, and because they put on the lat/long grid lines it is easy to interpret the projection. As a bonus, they are lossless PNG images, so the colours should be undistorted.
Really I was just hoping for a simple answer about the production of the UIUC/CT images. Besides asking William Chapman on Watts' site, I also asked on RealClimate and now here. But it is like swimming through a dense shoal of red herrings.
Of course it is not a big deal, except that the UIUC/CT images are perhaps the most popular and commonly linked form of sea ice data. But the numbers just do not fit. I am sure there is a completely innocent explanation, and I am annoyed with myself that I cannot figure it out.
It is nothing to do with JPEG compression and pixel counting - everyone who has made a serious attempt agrees it is possible to separate out the sea-ice pixels.
I would be pleased if Tim either changed his comment that "If you correct Goddard's error, you get the same number as the NSIDC", or provided some information to back up that claim.
Posted by: dipole | August 29, 2008 10:39 PM
This is indisputable proof that polar ice is melting. http://www.theonion.com/content/node/56630 Note that this photograph has been peer* reviewed (*a member of the British 'mob'ility) and has been used by the IPCC as 'unequivocal' evidence of AGW.
Trolls, deniers, skeptical-type people who are being paid by big oil may claim that Al Gore was trying 'raise' the earth's temperature in order to boost box office receipts for An Inconvenient Truth.
Personally I think the picture speaks a thousand words!
Posted by: Lank | August 29, 2008 10:47 PM
dipole:
The address works for me. Try again.
Posted by: bi -- IJI | August 29, 2008 11:57 PM
You mean like ... different image generation programs might yield results that, while totally sensible and compatible to the human eye, might yield different analytical pixel counting results if you assume the color-weighing for each pixel is the same, year after year?
You're still stuck in the paradigm that the generated image means anything when analyzed this way.
Please remember that human eyes are much more sloppy. Different generation algorithms might yield pixels that appear to differ greatly to a pixel-counting effort while not being significant to the human eye.
Tell that to Watts and others who see JPEG compression artifacts in the images.
It has nothing to do with pixel counting yet everyone agrees they can count pixels by separating out the sea-ice pixels?
That's bullshit at the basic level of self-contradiction.
Of course they can separate out the sea-ice pixels as represented in the inaccurate image which is processed from the real data.
All that means is they have an inaccurate count of sea-ice pixels.
These generated images aren't data. Why the HELL would you or anyone else think so?
The raw data is easily available. USE IT.
Posted by: dhogaza | August 30, 2008 12:24 AM
From bi -- IJI #56:
The address works for me.
% nslookup www.ccpo.odu.edu ;; connection timed out; no servers could be reached
% nslookup www.mit.edu Server: 61.9.195.193 etc...
dhogaza #57:
When you have examined and analysed the image data yourself you can start lecturing me on JPEG compression.
Would you like my source code (uses Python Image Library and Numeric extension)?
Should I post the pixel mask so you can check it against the original image (pbm format, bzipped and uuencoded, 62 lines)?
Otherwise I have no idea what point you are trying to make. If you can't answer my question you are quite free to ignore it.
Posted by: dipole | August 30, 2008 1:12 AM
So try surfing to
http://www.ccpo.odu.edu/SEES/polar/pidata.htm http://www.ccpo.odu.edu/SEES/polar/picomp.htm
Actually I do. Or has the source code been destroyed by the Bavarian Climatati? Veritas vos liberabit...
Posted by: bi -- IJI | August 30, 2008 2:45 AM
http://128.82.119.9/SEES/polar/pidata.htm http://128.82.119.9/SEES/polar/picomp.htm
Posted by: bi -- IJI | August 30, 2008 2:47 AM
And while we're at it, I've archived Jen Miss Socratic Irony's landmark posts:
Now, back to the Real Reason™ for Goddard making his retraction.
Posted by: bi -- IJI | August 30, 2008 3:01 AM
www.ccpo.odu.edu - Center for Coastal Physical Oceanography, right? Worked first time for me. I got a result with nslookup, too. Maybe dipole's closest copy of DNS is borked.
Posted by: David | August 30, 2008 3:27 AM
Hey thanks bi--IJI #60. The IP addresses work. Not sure it helps much. I can't see the connection with the UIUC images. The links describe the NASA2000 data vis. application. According to the user guide it can do a limited number of map projections including polar, which
shows the North or South poles of the Earth as viewed from deep space. The polar regions are often severely distorted by other projections.
and this is clearly not what UIUC use.
Sure you can have my source code. But how to post? Without 'pre' tags it gets mangled. With tags it is truncated, according to preview, although only 36 lines long.
Posted by: dipole | August 30, 2008 3:43 AM
And your totally wild guess is connected how?
Use markdown. Or, heck, take a screenshot of the source code and upload it onto ImageShack or something. Or you can continue with your insinuations.
Posted by: bi -- IJI | August 30, 2008 5:16 AM
Why would I want to do something idiotic and stupid like analyze an image meant as an aid to visualization as though it is significant data?
Sorry, you get to live in stupidville by yourself.
Posted by: dhogaza | August 30, 2008 11:10 AM
Look in the lower right hand corner of the UIUC images. Take what's there, put it into Google. That's -- until Dr. Chapman replies to Duae and we get word of it --- all the info available.
Dig, if you want more: http://www.google.com/search?q=what+software+does+UIUC+use+for+polar+images%3F
Posted by: Hank Robert