500,000 km2 Discrepancy Between NSIDC and NORSEX

NOTE: there are some animated GIF’s in this post that may take time to fully load. Patience please.

By Steve Goddard

Monday’s NSIDC Arctic ice extent graph took a turn downwards, and is now showing 2010 a little more than 500,000 km2 higher than 2007.  The animation below shows the change from May 1 to May 2.

By contrast, NORSEX shows something very different for May 2. They have no downwards turn, their ice extent measurement is right at the 1979-2006 average, and they show 2010 extent more than 1,000,000 km2 above 2007.

In order to look at this closer up, I superimposed the NORSEX 2010 data (red) on the NSIDC 2010 data (blue) at the same scale, and normalised to 2010, and saw some interesting things.  The first problem is that they started to diverge right around the first of April, and as of May 2 they disagree by nearly 500,000 km2.

The next image shows that the X-Y scaling is identical (but normalised) in the two graphs. The grid is from NORSEX. Other colors (besides red) have been removed through chroma keying.

The second discrepancy is that the two sources show a large difference in growth since 2007.  The image below normalizes the 2007 data – with identical horizontal and vertical scales.  Using this view, NORSEX shows twice as much ice growth as NSIDC since 2007.

The animation below begins normalised to 2010 and finishes normalized to 2007. This technique does not show that either source is in error or has changed their data, rather the animation is done by me to enhance visualization.What it does show is the significant differences between the two records.

I believe that both groups use SSMI so it is difficult to understand what the problem is. Last year we saw something similar. NORSEX has a history of making adjustments in mid-season, so my sense is that NSIDC is probably more accurate. Any ideas from readers?

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102 thoughts on “500,000 km2 Discrepancy Between NSIDC and NORSEX

  1. Excellent post, thanks as always. I’m sure it’s a total coincidence that the two records diverge right around the time the ice looked to exceed the ’79-00 average.

  2. If you have two watches, they will show two different times. And neither one is likely right.

  3. I think we all need to accept the normal variation in these early months and be patient. The key will be to see what happens at two seminal points; late June and late August. By September we will know whether we continue to rebuild multi-year ice or are running low again.

    I’d be interested in seeing how things change over time with regard to the wind direction as correlated to the area of ice loss. It would provide a better predictor than just comparing today with yesterday’s coverage, and would give the less patient of us something more useful to think about.

    d.

  4. While they both use SSMI it’s not clear that they use the same satellite. Last year when the SSMI on one satellite (F15?) went down it affected CT, NSIDC and NORSEX and they all took steps to fix it, CT switched to JAXA, NSIDC switched to SSMI on another satellite (F18?) and completed cross calibration, I don’t recall that NORSEX actually said what they did. Since that time the ArcticROOS data seems to do some strange things and be the ‘odd man out’ when compared with the other sources, so I don’t regard it as reliable any more. JAXA, Uni-Bremen, and NSIDC (smoothed) are consistent despite using different platforms.
    http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

  5. Les Johnson says: “If you have two watches, they will show two different times. And neither one is likely right.”

    Yes, and these curves are nowhere near as accurate as a watch. They’re more like wrist sundials–lots of guesswork. Maybe a lot of wishful thinking, too, in the case of ice extent. .

  6. Steven: Thanks for this post. I have noticed the relatively sudden drop in the AMSR-E Ice Extent graph that Anthony displays, similar to the NSIDC plot. I cannot imagine why there should be such a discrepancy, however, it amounts to only 3.8%. Is this so significant? I would be more concerned to see such a difference after the Summer melt. I have also noticed that the AMSR-E plot exhibits a sizable blib on 1st June each year from 2002 to 2009, inclusive. What happens in the Arctic ever 1st June? Independance Day?

  7. “Last year we saw something similar. NORSEX has a history of making adjustments in mid-season, so my sense is that NSIDC is probably more accurate.”

    Based on last year’s observations and abjustments by NORSEX which of the two was the most accurate?

  8. I’ve noticed that NSDIC sometimes shows open ocean (concentration = 40%, but sometimes >=80%). I’m guessing that Cryosphere Today creates composite images that contain data from several days earlier (as must NSIDC), but I’ve seen the discrepancies linger consistently for protracted periods of time. Discrepancies can be both on the Pacific and Atlantic sides. The biggest difference I’ve seen recently has been in the Sea of Okhotsk (sp?) where NSIDC has consistently shown major open ocean along the coast and in the north that hasn’t existed in the Cryosphere pictures. The difference was even more glaring a week ago, but still exists. It looks as if there is some inconsistency in algorithms that I don’t believe can be explained by differences in binning/smoothing/interpolation.

  9. NSIDC does some average-ing to generate their graphics. If ASME data is any indication, the NSIDC curve will trend towards being less steep in the days to come.

  10. All I really know is my wife says the ice in the freezer is on the decline and I think it is well within the norm…course she drinks Margaritas and I bourbon…neat.

    perspective is all lets try balancing today against an average from 1980 to 2010?? neat

  11. I think unless the two systems have been calibrated against each other, one should expect them to be different. The important thing will be the trends when comparing data from each source. It would be like time keeping – any two watches will keep different time. But if I am measuring hours, the differences wouldn’t matter.

    I expect the trends are more important than the exact daily number, and we need to look at NSIDC versus NSIDC and NORSEX versus NORSEX. DMI for example is quite different since they use 30% ice, but I still like it for trending but it is DMI compared to DMI.

    Wayne

  12. Interesting find Steve. With sea ice really falling way down in the Barents Sea, I tend to think that NSIDC has it correct, but the reason for the large difference is curious.

    Nice update today on the NSIDC site for current conditions in the arctic. They focus on the warmth the artic has been seeing this year:

    http://nsidc.org/arcticseaicenews/index.html

    But they also focus on something I think is even more interesting, and that’s the pick up in ice flow out through the Fram Strait since the winter. A nice map is included showing the ice motion:

    I think the most accurate data today would show that we are now slightly below 2009’s level for sea ice extent for the same date, and getting very close to 2008’s level. I think with the heat, the rate of melt, the increased flushing through the Fram Strait, and the generally thin ice conditions because the winter was mild in the arctic, we are headed for a summer low near 2007’s record low (or slightly above, as I predict).
    Most importantly, the sea ice volume anomaly continue downward:

    Lower volume, higher temps, increase Fram Strait flushing…probably the only thing to prevent a near record summer minimum would be Katla in Iceland behaving very very badly…and there is a reasonable chance of that as well.

  13. Are you sure that NORSEX uses SSMI? The NORSEX curve looks very similar to the ASMR-E curve in the time frame in question.

  14. Got caught in formatting. Should have said that NSIDC shows open ocean where Cryosphere Today shows ice. And not just near the concentration boundary of 15 percent.

  15. Ice coverage algorithms can produce different although consistant results. Consistancy is the key, compare apples to apples each year, but comparing apples to oranges is a waste of time.
    For a more accurate ice coverage you should use the AMSR-E data (6.75Km resolution v’s 25Km for SSMI). Incidently this also shows the drop on the 3rd May caused by the melt of thin ice in the Sea of Okhotsk. Link is in the Live Weather Roll on this page or for a different algorithm here http://www.iup.uni-bremen.de:8084/amsr/ice_ext_n.png

  16. I think someone forgot to turn off an Aprils fool Joke.
    Aren’t there any sattelite pictures to compare? 500.000 km of ice isn’t likely not to “dissapear” on those.

  17. The missing ice went off to hide with the missing heat. This will result in a missing sea level rise.

  18. At Bob
    “I have also noticed that the AMSR-E plot exhibits a sizable blib on 1st June each year from 2002 to 2009, inclusive. What happens in the Arctic ever 1st June? Independance Day?”

    They change algorithms to account for melt pools forming on the surface of the ice. This prevents underestimating sea ice area.

  19. Les Johnson says:
    May 4, 2010 at 10:58 am

    If you have two watches, they will show two different times. And neither one is likely right.

    Not a good analogy in this day and age; consider Radio Controlled Wristwatches; “A look at radio controlled wristwatches, including those that synchronize to WWVB.”

    .
    .

  20. “The map is not the territory”

    “If the map shows a different structure from the territory represented — for instance, shows the cities in a wrong order. . . . then the map is worse than useless, as it misinforms and leads astray.”

    Alfred Korzybski

  21. Perhaps someone saved a big chunk of ice for all the Daiquiris (Ice+Rum+Lemon juice) which will be prepared in the next Cancun Climate Change Summit, just to relax all climate scientists, who have worked so hard, during the year, inventing all kind of convenient theories about a wide variety of armageddonian scenarios, providing all his excellencies-politicians and most holy prophets of the New Age climate change creed with the needed input in order for them to wiseacre about the necessity of a world “governance” which will empower them so as to govern upon our destiny without any hindrance whatsoever.

  22. My husband has been reading a book on Global Warming by Claude Allegre called ‘L’imposture climatique’ . Unfortunately I don’t read French, but he translates interesting bits. M. Allegre describes how difficult it is to decide what global temperature is, as temperature varies so much between equator and pole, mountain and plain, day and night, winter and summer, and a great deal of adjusting goes on. The same must be true for sea ice extent.

    Which is perhaps why there is so much dispute going on about whether there is warming or not. The whole subject is difficult to pin down. M. Allegre is on the sceptic side of the fence.

  23. Well in this case they hide the increase in ice and make it look like a decline.At ant rate the ice is right at the normal since these records begin 1979 and we’ve been in a warm cycle now watch as were entering a cold cycle.GROW ICE GROW!

  24. Well, since NSIDC uses a 5-day average, you’d think they’d be “sticky down” just like they are “sticky up”.

    But both seem to be using 15% and 25km2 grid cells, so you really wouldn’t think they’d get that far out of whack.

    I consider May 1-July 1 to be a bottleneck in extent that happens yearly, and really the extent numbers by themselves have very little meaning in that period, high or low, compared to recent averages. During this bottleneck period, the concentration levels of the central core is much more interesting (and indicative, IMO) of what happens after July 1.

  25. Someone would rather make graphs with conventional style line-widths that we see here rather than the truer smear of a line that would reflect the inherent uncertainties?

  26. Dave Wendt says:
    May 4, 2010 at 12:35 pm

    “The map is not the territory”

    “If the map shows a different structure from the territory represented — for instance, shows the cities in a wrong order. . . . then the map is worse than useless, as it misinforms and leads astray.”

    Alfred Korzybski

    Yes, I’ve been thinking about Korzybski on the model vs data options. And Lavoisier: “It isn’t a stone fallen from the sky, because there are no stones in the sky.” Wrong maps.

  27. R. Gates says:
    May 4, 2010 at 11:53 am

    There’s another possibility: Last year around February, we witnessed the degradation and failure of a satellite-based ice detector. It started off exactly as Steve has outlined. Some agencies jumped on the catastrophic decline only to find themselves embarassed.
    Let’s see what transpires.

  28. I am not seeing the 500,000 km2 difference between NSIDC and NORSEX. If you look at the timeseries plots individually you see they both have around 13.7 million sq. km of ice extent. When you normalize the NORSEX to 2010 on the third plot, the May data never goes below 14 million sq. km, am I missing something? I understand you want to put them on the same scale, but did this normalization not arbitrarily bump up the NORSEX extent? And of course the NORSEX is closer to its mean line than NSIDC because the means are derived from two different periods..NORSEX containing 2001-2006 data and its lower values. What should be analyzed is the slope of correctly normalized data from late April-May 2 or 3, or whatever the newest data is. I know you can download NSIDC SSMI gridded sea-ice concentration…and probably NORSEX, is it too difficult to calculate the extent yourself (with and without their averaging at NSIDC)? The issue I see is no independent/external analysis of the data or comparison to the multiple other algorithms out there.

    That being said, the last 5 days in NSIDC have shown a very large drop in extent, but I have not seen too much sea-ice go away on any retrieval system…NASA Team2, Bootstrap, NORSEX, Bremen, EUMETSAT or even mine in-house which is SSMIS-based. Qualitatively they all compare favorably. There has been ice loss around Svalbard and Novaya in the Berents sea, and west of the Korean pennisula…but 100,000-150,000 sq km in a day? It only went at a rate of 16,000 sq km/day in April…the rate shouldn’t increase that rapidly.

  29. We will see, IMHO, we may end up with more extend than previous year.

    Inbetween (old song from the Doors):

    Wintertime winds blow cold the season
    Fallen in love, I’m hopin’ to be
    Wind is so cold, is that the reason?
    Keeping you warm, your hands touching me

    Come with me dance, my dear
    Winter’s so cold this year
    You are so warm
    My wintertime love to be

    Winter time winds blue and freezin’
    Comin’ from northern storms in the sea
    Love has been lost, is that the reason?
    Trying desperately to be free

    Come with me dance, my dear
    Winter’s so cold this year
    And you are so warm
    My wintertime love to be

    La, la, la, la

    Come with me dance, my dear
    Winter’s so cold this year
    You are so warm
    My wintertime love to be

    Regards

    KlausB

  30. What became Chaos Theory was first discovered by a weatherman. I’m surprised you don’t see more such divergence.

  31. well Steve it looks as if the ice extent max was delayed by about one month from normal. That is kind of weird; because everything I have seen this year as a harbinger of spring, seems to have been delayed by about that same amount of time.

    The tree from Hell, that grows on my front lawn (Liquid Amber) has only just spread its leaves, and that normally seems to happen way back in March. All the blossoms on fruit trees ad the like seem to have been similarly delayed.

    Now I know that all of that is purely anecdotal; and I would not expect to see the same thing happen next year; but it has been dramatic enough this year to not ignore. And of course; that is just weather anyhow.

    But it does demonstrate to me; that significant shifts in timing can occur; all as part of the natural variability of the climate system; and talk of evrything wandering to the north is nothing to be upset about; there’s lots of good land area up north to grow stuff, if conditions up there improve.

  32. I would think differences in algorithms is the likely culprit for differences in the displayed extent and area. This may be the result even when the same data source is employed.

    With regards to the “blip” around june 1st, I think it is related to compensation algoritms for the yearly appearing fresh-water melting pooles on the ice on this time.

    Cassanders
    In Cod we trust

  33. O.T. The UK paper ‘Daily Express’ yesterday(May 3rd) had a full page article under a banner headline ‘GLOBAL WARMING IS A LOAD OF HOT AIR’ quoting former NASA climate scientist Dr Roy Spencers’ theory that current warming is not man made but the result of natural forces and intimating that the current global mass hysteria is “driven more by quasi-religious beliefs and financial and political motives than by an objective assessment of the science” To keep getting funding, scientists need to support Gores’ “consensus” that CO2 is evil and man made CO2 is an abomination. It goes on to point out the Dr Spencer has had great difficulty getting any kind of media coverage for his research and that warmists instead of attempting to disprove his theories scientifically resort to personal attacks and smears. Just one newspaper coming out of the consensus but a start. The article can be read at http://www.dailyexpress.co.uk under james dellingpole ‘global warming is a load of hot air’

  34. @King of Cool

    That’s very interesting, since there hasn’t actually been any increase in Oz uranium mining. There’s been a lot of hype in the news and on the sharemarket but the same ‘three mines’ have been operating at about the same capacity for a couple of decades (with Beverley, an in situ leach replacing an open cut in the Northern Territory – so even less dust).

    Be interesting to see the isotopic ratio, lots of depleted uranium dust has been put into the atmosphere in the last 20 years.

    On the other hand there’s quite a lot of uranium in other materials. Garden soil typically has more uranium in it than high grade gold ore has gold in it. There’s been a vast increase in (dusty) iron ore mining, so maybe the U comes from that.

    No surprise that the Oz ABC carry the story, they are very left wing, highly warmist, anti mining and anti nuclear power. Plus they like to support the government, who is in a tax war with the miners this week.

  35. I have a suggestion! Get the data in numerical form, like jaxa’s data rather than using their graphs, where the data is possibly being put through different ‘smoothing’ functions.
    Bah, I’m fed up of suggesting this. You spend so much time messing with their graphs. I’m going to ask them. Do you think they’ll give me it or will I have to use the FOIA?

  36. ok, I’ve sent off requests to cryo and nansen for starters. Hopefully the (date- quantity ) form of the data I asked for will help resolve the disparity.

    This is what I wrote to them. Feel free to use it as a template for informal emails requesting data from ice monitoring groups.

    ***
    Hi, I’ve been looking for time seriesdata for arctic sea ice extent and
    area in numeric form. Ideally it would be in a simular form to the jaxa
    sea-ice data here.
    http://www.ijis.iarc.uaf.edu/seaice/extent/plot.csv
    i.e. Date and a value for the ice area on that date.

    I looked for the data on your website but in was in graphical form, with some of the data abstracted as an average.
    http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic

    My use for the data is purely as a hobby, spured by the mass-media focus
    arctic sea ice.

    Can you make available to me the numeric data in (
    date – quantity ) format from 1978 to present on arctic sea-ice extent and
    area please?

    Thanks
    James Grist
    ***

  37. Wouldn’t the data be more suspect if there were no variation whatsoever? The difference in TMDE calibration and eyeball density due to variation in barametric pressure differences between the two sites would account for most of the difference. (Is that redundent?)

    Einstein once said, “Ve are not as smart as ve dinks ve are, are ve?”

  38. I don’t know why you bother, the Arctic will be ice free in three years time and your graph will flatline.

  39. “”” Bruce of Newcastle says:
    May 4, 2010 at 3:24 pm
    @King of Cool

    That’s very interesting, since there hasn’t actually been any increase in Oz uranium mining. There’s been a lot of hype in the news and on the sharemarket but the same ‘three mines’ have been operating at about the same capacity for a couple of decades (with Beverley, an in situ leach replacing an open cut in the Northern Territory – so even less dust).

    Be interesting to see the isotopic ratio, lots of depleted uranium dust has been put into the atmosphere in the last 20 years.

    On the other hand there’s quite a lot of uranium in other materials. Garden soil typically has more uranium in it than high grade gold ore has gold in it. There’s been a vast increase in (dusty) iron ore mining, so maybe the U comes from that.

    No surprise that the Oz ABC carry the story, they are very left wing, highly warmist, anti mining and anti nuclear power. Plus they like to support the government, who is in a tax war with the miners this week. “””

    So just how much of that Uranium dust would you expect to find in the atmosphere now. Uranium is not the densest of materials; but it is denser than anything that is available in quantity (I didn’t say readily available). I think Tungsten is 19.3 or there abouts; and I thing the max is around 22.5 for Osmium. Apparently either Iridium or Osmium is the densest but nobody knows which for sure (as of 1968); well I guess uranium is only 18.95 ; so i guess it would just float like a feather for ages, in the atmosphere.

  40. Yeah I know, but what else they gonna call em? ‘hide the lack of decline’ functions?

  41. This is a question I have never once seen brought up before. For many many years, I have seen the question about the June blip on the ice chart. And I have seen it patiently explained many many times. Since the june blip is explained by a change in algorythm each year on that date, that implies to me that they change the algorythm back on some other day. My question is…why is there not two blips per year?

  42. In relation to this comment:

    This is a question I have never once seen brought up before. For many many years, I have seen the question about the June blip on the ice chart. And I have seen it patiently explained many many times. Since the june blip is explained by a change in algorythm each year on that date, that implies to me that they change the algorythm back on some other day. My question is…why is there not two blips per year?

    If you are referring ot the IJIS Website extent linked on this website on the side panel, there is both an explanation and has been pointed out that there are two blips:

    The current version of data processing produces an erroneous blip of sea-ice extent on June 1 and October 15, which is seen in the graph of sea-ice extent as a small peak on these dates. The apparent blip arises due to switching of some parameters in the processing on those dates. The parameter switching is needed because the surface of the Arctic sea ice becomes wet in summer due to the melting of ice, drastically changing the satellite-observed signatures of sea ice. We will soon improve the processing to make the graph much smoother.

    The second blip is there, however while the first one is a slight bump making it stand out, the second is a slight leveling off and is harder to see unless you know exactly the date to look for.

  43. When there is a positive AO most ice is transported out of the arctic through the Fram Strait. I think I’ve seen animations on this website showing the movement of the ice (quite psychedelic I remember).

    Given the strong negative AO that’s existed this year, and the fact that weather rotates in the opposite direction, does anybody know if the transport of ice is any different?

    I’d also like to see some sort of analysis of wind, especially this year. Ice concentrations in the central Arctic ocean area look unusually high and stable this winter using Cryosphere Todays comparative tool.

  44. I’ve seen animations on this website showing the transport of ice out of the Fram Strait. Given that the AO index has been strongly reversed this year I was wondering if anybody knows whether ice transport is affected.

    I ask because using Cryosphere Todays comparative tool it looks like ice concentration in the central part of teh Arctic Ocean is quite high and seems fairly stable through this winter.

    I’d also be interested in knowing whats going on with regerd winds and storms given the change in the AO index.

    Just some things i’ve been thinking about recently, any help would be appreciated.

  45. HR,

    The -AO does help hold the ice in as opposed to the +AO conditions. This is one reason I think we’re likely to see a rebound again on the minimum extent. The AO rose back to around neutral for a good chunk of March and early April, but then fell back negative for the latter half of April. But more importantly, the winter time AO was massively negative and that seems to have a larger correlation with year to year minimums than the temperatures. There’s still other factors that could prevent a rebound such as an extremely anomalous wind pattern that brings both warmth and accelerates ice through the Fram Straight which is what likely helped the 2007 minimum get as low as it did in addition to that 2006-2007 hugely +AO in the winter leading up to that fateful summer.

    People are tracking each fluctuation this spring in the ice extent, but it doesn’t mean much as there is a bottleneck in ice extent for all years in late May and early June. Unless we see an obvious outlier from that bottleneck this year, then the real tracking will not begin until late June or July. The extreme -AO this past cold season has kept more multi-year ice in the Beaufort Sea and adjacent Arctic basin than any of the past few years which is why I (and some others who may have mentioned this) are arguing for a decent chance at another increase. A lot of ice was caught up in the Beaufort Gyre this past winter.

    But as mentioned before, there’s always other factors to consider, and if they conspire enough against the more dominant -AO factor, then we could see it negated and a drop this year from 2009.

  46. Thrasher says:
    May 4, 2010 at 8:38 pm
    HR,

    The -AO does help hold the ice in as opposed to the +AO conditions. This is one reason I think we’re likely to see a rebound again on the minimum extent.

    Except that the actual observations this spring show that the flow out of the Fram has been strong not ‘held in’.

    The extreme -AO this past cold season has kept more multi-year ice in the Beaufort Sea and adjacent Arctic basin than any of the past few years which is why I (and some others who may have mentioned this) are arguing for a decent chance at another increase. A lot of ice was caught up in the Beaufort Gyre this past winter.

    Again the observations contradict this, multi-year ice has been broken up and pushed out of the gyre into the trans-polar drift.

  47. Haven’t see Rush Limbaugh speaking to the fact that the arctic sea ice is now below last year’s level, yet he was so quick to report on the March “bump up” and touted the sea ice was still growing in early April when the winter maximum had been reached on the last day of March. What gives? Could he be biased? :)

    REPLY: I dunno, could you be?

  48. @George E. Smith “well I guess uranium is only 18.95 ; so i guess it would just float like a feather for ages, in the atmosphere”

    Yep. Half life for ordinary dust is about 1 year at 20 km altitude. Depends how high up it goes and how small the particle size it is. Likewise it depends on what the U is in – if in iron ore particulates, or in dirt (we also had a few big dust storms late last year), then the specific gravity of the particles is a lot lower, so they’d stay up longer.

  49. Phil,

    I’d need to see good evidence of your claim before taking it to heart. You might be right, but I have a hard time believing that one month of neutral AO conditions negated a record -AO winter which was 3 months. The report from the NSIDC said that the flow of ice out of the Fram Straight increased in March compared to February…but that is not saying much since February had such little flow out of the Fram Straight…so of course there was an increase. But overall, I didn’t see anything like the flushing that occurred in 2007, 2008, or even 2009 (which was definitely less than the 2 prior years….coincidence that the ice extent increased again?).

    You’ll have to provide me a good source of multi year ice that shows that March brought us all the way back down to levels seen in 2008 before I take your claims seriously. This is not a knock on you, but just simple quality check on data claims. Its almost impossible impossible for multi year ice that got caught up in the Beaufort Gyre in February to be flushed out of the Fram Straight by now…it doesn’t work that fast which is likely why the hugely -AO winters have produced higher extent minimums like 2001 and 1996. There are other factors too, but assuming those are fairly “normal” this summer, then we’ll expect a bump back up in extent.

    The beauty of this debate is we do not need to wait a decade to see the results, we just need to wait a couple months to see the wind patterns and the ice extent numbers to see what it happening. And no, I don’t think that volume graph from UWAS is very reliable since its a model and not an observation. But regardless, we’ll find out soon enough…I think roughly 3 months time we’ll know about the state of this year’s ice.

  50. R. Gates:

    Please continue your posts about this year’s ice issues. As I have mentioned before, I am struck by the absoluteness of your projections based upon near term data.

    Please let us collectively know if you have considered longer term natural temperature variations as part of your prognostications. I’m referring to the loss of ice in the late 30’s – early 40’s (as pointed out by Anthony’s most recent post on this topic https://wattsupwiththat.com/2010/05/02/catastrophic-retreat-of-glaciers-in-spitsbergen/#more-19179) as well as the early 1900’s, not to mention our 20 + periods of glaciation, as part of the current ice age, going back 2.5 million years.

    Early humans please admit your role in these flagrant climate changes and flagrant CO2 changes.

    I’ve asked this before, and I patiently await your response.

  51. There are several problems associated with the current satellite sea ice measures, apart from sensor degradation. The raw data from the sensor is processed multiple times before the final graph is produced and each process step involves assumptions about what the the expected result should be. Particular problems exist at the fractal sea/land boundary, and during the annual melt season, when liquid water on the surface of the ice distorts the results.

    As in many thing related to climate metrics, none of the production sea ice area and extent graphs are absolute metrics, rather they are best estimates of what is happening in a highly chaotic, multi-variant system at a moment in time. No surprise, perhaps, when differences to the various estimates disagree.

  52. I also own two wrist watches, one of them does not run, but it is perfectly accurate,twice a day. There is nothing that man measures accurately, it is always a guesstimate. One can only be sure that something exists by bumping into it physically. The Arctic ocean ice, waxes and wanes, history is full of less and more ice. The arctic is not a barometer, it is subject to many nefarious variations, for the fact that the north pole, is not land based. AGW retoric on the waning of the Arctic ice is nonsense. The creeping southward of the cold would be great concern, not the creeping north of warm. Proving the Arctic is warming would be a bonus to all mankind.
    Thank you for your blog Anthony and to all those with real knowledge who have stopped the propaganda on the global stage. The next step is for all like myself to stop the brainwashing of children in our schools by the useful idiots. Wayne

  53. I ain’t no genius but having worked as a Test Engineer in high end technology I will postulate that a single sensor reading with multiple corrections will pick up an error tolerance (in ALL circumstances) of at least 3%. I believe ice data is ‘measured’ by pixel count? Best guess at such a ropey technique 5%. So you are studying noise. Fascinating how it goes up and down and down and up and up and up and down.

    Suggest you stick the alarmists in a canoe and tell them to paddle the Northwest Passage this summer. Should have a very pleasant and quiet winter without them.

  54. “”” Bruce of Newcastle says:
    May 4, 2010 at 10:57 pm
    @George E. Smith “well I guess uranium is only 18.95 ; so i guess it would just float like a feather for ages, in the atmosphere”

    Yep. Half life for ordinary dust is about 1 year at 20 km altitude. Depends how high up it goes and how small the particle size it is. Likewise it depends on what the U is in – if in iron ore particulates, or in dirt (we also had a few big dust storms late last year), then the specific gravity of the particles is a lot lower, so they’d stay up longer. “””

    I believe the post said that “lots of depleted Uranium” had been blown up into the atmosphere. Would you explain how it is that depleted Uranium becomes entangled with iron particles ?

  55. Thrasher says:
    May 4, 2010 at 11:12 pm
    Phil,

    I’d need to see good evidence of your claim before taking it to heart. You might be right, but I have a hard time believing that one month of neutral AO conditions negated a record -AO winter which was 3 months. The report from the NSIDC said that the flow of ice out of the Fram Straight increased in March compared to February…but that is not saying much since February had such little flow out of the Fram Straight…so of course there was an increase. But overall, I didn’t see anything like the flushing that occurred in 2007, 2008, or even 2009 (which was definitely less than the 2 prior years….coincidence that the ice extent increased again?).

    To see something you first have to look for it, where have you been looking? I’ve posted on here showing flow out of the Fram since at least January and what was in this month’s NSIDC report agrees with what I posted here.
    A factor in the 2007 loss of multi-year ice (particularly the oldest) was the early opening of the Nares strait and the outflow through it. Well that happened again this year but the ice to the north is much more fragmented than in 2007 so if anything the loss of multi-year ice via that route will be higher this year.
    Composite showing the Nares strait over the last 4 days:

    Comparison from May 2007 (note the lack of fragmentation):

    It’s not a coincidence that the extent increased because that was inevitable with the outflow of ice through the Fram and also into the Barents sea, note that the area did not increase at the same time.

    You’ll have to provide me a good source of multi year ice that shows that March brought us all the way back down to levels seen in 2008 before I take your claims seriously. This is not a knock on you, but just simple quality check on data claims. Its almost impossible impossible for multi year ice that got caught up in the Beaufort Gyre in February to be flushed out of the Fram Straight by now…it doesn’t work that fast which is likely why the hugely -AO winters have produced higher extent minimums like 2001 and 1996. There are other factors too, but assuming those are fairly “normal” this summer, then we’ll expect a bump back up in extent.

    The multi-year ice normally resident on the Canadian archipelago coastline has continued to be flushed through the Beaufort gyre and out into the transpolar flow where it will either melt or be pushed out of the Fram. It’s been replaced by 2 or 1 year old ice, hence thinning in the only region where thick MY ice remains.
    This is shown very clearly in Steve Goddard’s post: https://wattsupwiththat.com/2010/04/28/disconnected-computer-modeling/
    The same image shows the outflow of the MY ice to the north of Greenland through the Fram.

  56. So we have conflicting data. This does not surprise me. Techniques for measurement of climate change are inadequate. Sure, the climate will change; it always has, especially through this last ice age. But if we don’t have hard data, predictions are futile. Combine that with our lack of knowledge of how the climate is driven and our predictions are little better than guesswork. Given the past record of climate, all we can say with some reasonable confidence that the next Ice Age is heading towards us. Will it be in this century or in the next 500 years or maybe not for a couple of thousand years? We don’t know but my bet is that it is coming. What happens in the immediate future will have no real impact – we can adapt to a slightly warmer world. Adapting to an Ice Age will be a serious problem.

  57. Policyguy says:
    May 4, 2010 at 11:46 pm
    R. Gates:

    Please continue your posts about this year’s ice issues. As I have mentioned before, I am struck by the absoluteness of your projections based upon near term data.

    ——

    I have no problem remaining completely behind my projections that this year’s summer sea ice minimum will fall below 2008 & 2009, but not quite as low as 2007. I have stated that 4.5 million sq. km. will be about right (based on JAXA data), which would put it just slightly higher than 2007. I base this on:

    1) The warmth of the arctic winter
    2) The negative AO index during much of the winter which caused the warmth and forced a lot of the cold south out of the arctic to places like Florida for example
    3) The low sea ice volume (even the multi-year ice ice thinner than normal
    4) Projected record warmth during the heart of the melt season
    5) The end of the solar minimum

  58. Thrasher says:
    May 4, 2010 at 11:12 pm
    Phil,

    I’d need to see good evidence of your claim before taking it to heart.

    Well I did put together a detailed post in response together with some graphics, but as happens frequently these days it didn’t make it through.

  59. [Note: Image tags removed. There is no need for IMG tags to post links, and they make the link un-clickable. ~dbs]

  60. Dropping. Like. A. Rock.

    Nobody could have seen this coming.
    The ice was completely recovered in April.
    Just one of those things.
    Natural variability.
    Chaotic clouds.
    This happens every 60 years or so. Maybe 80.
    Sunspots are up.
    El Nino, PDO, AO are all just right.
    Huh.

  61. thanks dbs. The image illustrates a 1 million sq km descrepancy between the monthly averages of NSIDC and JAXA AMSR-E.

  62. R. Gates says:
    May 5, 2010 at 10:54 am.

    I’m struck by your comment about “The low sea ice volume (even the multi-year ice ice thinner than normal”. What is your source that the multi-year ice is thinner than normal? I don’t believe the new European satellite has been up long enough for such a statement and other measurements are mostly lacking. What is “normal” anyways? Even with the new satellite measurements that are hopefully forthcoming, there’s been a multi-year gap.

  63. Phil, I see the response now. Thanks for the write-up…though I have a couple issues. First, you mentioned the NSIDC report from this month. It states:

    “In February, the strongly negative phase of the Arctic Oscillation was associated with a strong Beaufort Gyre, enhancing ice motion from the western to the eastern Arctic. A weaker Transpolar Drift Stream also slowed the movement of ice from the Siberian coast of Russia across the Arctic basin, and reduced ice flow out of Fram Strait. The wind pattern changed in March, when the Arctic Oscillation went into a more neutral phase. As a result, the flow of ice sped up through Fram Strait and along the coast of Greenland.”

    In the previous month’s statement, they said:

    “the Arctic lost less ice the past two summers compared to 2007, and the strong negative Arctic Oscillation this winter prevented as much ice from moving out of the Arctic. The larger amount of multiyear ice could help more ice to survive the summer melt season.”

    It sort of states the obvious when putting the two together….March had an increase of flow through Fram compared to earlier because of the AO rising to near neutral. But I’m not sure how that proves this melt will be any greater than last year or the year before when they had a much heavier flow of ice going out of the Fram straight during the cold season than this year did. Heavily -AO winters have tended to precede higher extent minimums.

    Secondly, the other link is a computer model showing what the ice might do this summer. Its a nice illustration of what the ice looks like going out of the Fram Straight and its projected melting pattern, but I’m not sure I find much other use in it.

  64. Thrasher says:
    May 5, 2010 at 1:29 pm
    Secondly, the other link is a computer model showing what the ice might do this summer. Its a nice illustration of what the ice looks like going out of the Fram Straight and its projected melting pattern, but I’m not sure I find much other use in it.

    No comments on any of my post then?
    The figure I was referring to was the 4th in Goddard’s post, it’s not a model result.

  65. MikeP says:
    May 5, 2010 at 1:20 pm

    What is “normal” anyways? Even with the new satellite measurements that are hopefully forthcoming, there’s been a multi-year gap.

    Multi-year gap ?
    ICESat’s last laser failed on October 11, 2009, and they retired the satellite February 2010.
    CryoSat-2 was launched April 8, 2010.

    And “normal” is definitely > 0 in the summers.
    Once it reaches 0 some summer, we’re way out of “normal” territory.

  66. stevengoddard says:
    May 5, 2010 at 2:12 pm
    Anu

    The wind compacted some ice in the Barents Sea this week.

    I don’t think so.

  67. stevengoddard says:
    May 5, 2010 at 2:12 pm

    OK, thanks.
    I had been fooled by all the talk of the ice “recovering” in April.
    I guess we’re just back to normal – “way below average”.

  68. Although the Resident Doomsayer, I wish this Plunge was not occurring.

    But 2007’s Big Ice-Melt had 3 Parts:
    1. Warmth from an El Nino (April 2010 was still fading slower: ONI=1.2 cf 2007’s 0.1)
    see: http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml
    2 Wind pushing Ice out, and
    3. less Clouds (see:
    http://www.arm.gov/science/highlights/pdf/Roo143.pdf from Graeme L. Stephens at Colorado State University ).

    Does anyone know if Cloudiness is declining, as in 2007’s 16% ?

  69. We haven’t had an article (or I missed it) on NSIDC’s May Update, where they have to show April way above their trend line for the third year in a row. . . and strain for why a usually positive element (re the Beaufort Gyre) is actually going to be a negative element.

    Tho I’m beginning to get a bit more concerned about 2011 than 2010. But then a 4 year unbroken trend is pretty rare anyway, in either direction.

  70. @George E. Smith: “I believe the post said that “lots of depleted Uranium” had been blown up into the atmosphere.”

    George, I did not say that exactly. However if you turn U3O8 (or UO2 or etc) into nanometre sized particles they can be suspended in the atmosphere quite well. What I wrote was it depends on the particle size. The finer the size the easier to suspend. Fire a pyrophoric depleted U projectile at something hard and you get lots of fine oxide particulates suspended in the atmosphere.

    Search plutonium+ice for example. Plenty of hits. SG of Pu (19.8) is even higher than for U.

    My point is that U in Antarctic ice can come from lots of possible sources. U238 as a hypothesis is a nice falsifiable hypothesis because it is easy to test with a mass spec, and is not necessarily less plausible than if the U came from mining activity.

  71. Phil,

    The 4th post in Goddard’s link you sent me is the multi-year ice being held into the Beaufort Sea…I’m not sure how that is proof that multi-year ice is being flushed out of the Fram Straight faster than any of the previous few years. I assumed you weren’t even talking about that image. That is older ice making its way back into areas that have had significant melt the last 3 seasons. That is actually an image that supports the idea that the heavily -AO of this past cold season has held in multi-year ice. The Beaufort Sea has been a hostile place for ice the past few years, and that image shows it might make a comeback this year.

  72. Thrasher says:
    May 5, 2010 at 10:00 pm
    Phil,

    The 4th post in Goddard’s link you sent me is the multi-year ice being held into the Beaufort Sea…I’m not sure how that is proof that multi-year ice is being flushed out of the Fram Straight faster than any of the previous few years. I assumed you weren’t even talking about that image. That is older ice making its way back into areas that have had significant melt the last 3 seasons. That is actually an image that supports the idea that the heavily -AO of this past cold season has held in multi-year ice. The Beaufort Sea has been a hostile place for ice the past few years, and that image shows it might make a comeback this year.

    It’s actually broken up MY ice from the canadian coast where it’s been stuck for a few years. Like the major breakup of Beaufort sea MY ice in 2008 it will either melt there or be transported in the transpolar drift and out the Fram. You should try reading what I actually wrote rather than just guessing, communication works better that way.
    Here it is try again:
    https://wattsupwiththat.com/2010/05/04/500000-km2-discrepancy-between-nsidc-and-norsex/#comment-383841

  73. Anu

    This is average :

    This is about one std dev below average

    i.e. statistically normal.

    Neither is “way below average.” What did you study at MIT, anyway?

  74. The sea ice volume data look very interesting to know.
    http://psc.apl.washington.edu/ArcticSeaiceVolume/IceVolume.php
    Yes part of it is a model, but they have had NASA ICESat satellite data from 2003 to 2007 mapped on it.

    If the sea ice extent is “normal” compared to the 30 year or so average but the volume (ie: thickness) is less today, does it mean that the arctic is showing warming despite the extent being not that bad?

    I was looking at the discovery channel last nigh and a NASA scientist was explaining how they use different kind of instruments aboard a plane to measure the volume of ice and according to their research, the loss of volume is still pointing to warming.

    I think this is the information:
    http://www.nasa.gov/centers/dryden/Features/G-III_uavsar_09.html

    But again, is this related in any way to man-made CO2 or part of a natural cycle?

  75. Simon Filiatrault

    Ice volume is low in the Arctic because most of the thick multi-year ice blew out into the North Atlantic during 2007-2008, and melted.

  76. NSIDC has explained this in their May Sea Ice News:
    http://nsidc.org/arcticseaicenews/

    While NSIDC primarily uses the Special Sensor Microwave/Imager (SSM/I) and Special Sensor Microwave Imager/Sounder (SSMIS) sensors to track long-term conditions, we also look at data from higher-resolution sensors to assess current conditions in more detail. An image from NASA’s Advanced Microwave Scanning Radiometer – Earth Observing System (AMSR-E) sensor from April 19 reveals numerous polynyas, or areas of open water in the pack ice in the Bering Sea, and broad areas of more scattered ice cover in the Sea of Okhotsk, Barents Sea, and Hudson Bay. Such conditions usually indicate that ice is about to retreat rapidly. Over much of the coastline in this image, there is an indication of low-concentration sea ice. This is an artifact of mixed pixel areas, which contain both water and land. The same effect is seen occasionally in the SSM/I record.

  77. stevengoddard says:
    May 5, 2010 at 11:27 pm

    This is “way below average”:

    Now look at this chart:

    The 2009 arctic sea ice extent as July started was “far below average” (about two std devs). By mid September, the 2009 ice extent was “very far below average”.

    Mid September 2008 sea ice extent was “far, far below average”.
    Mid September 2007 sea ice extent was “incredibly below average”.

    When it hits 3 million km^2, that will be “incredibly far below average”.
    The summer that hits 2 million km^2 will be “dangerously below average”.
    At 1 million km^2, we are “dangerously far below average”.
    And when it hits 0 million km^2, that will be “completely below average”.
    It’s important to speak precisely, Steven.

    Or, just use numbers and graphics.

  78. Nick says:
    May 5, 2010 at 2:57 am
    “NORSEX baseline is 1979-2006…NSIDC uses 1979-2000.”

    Awfully short periods to compare what is normal – but if we try to compare apples with oranges, what does “normal” look like if we do NORSEX 1985-2006 to make each 21 years?

    Also, normalization is not a panacea, and does have its own perils. For instance, the rate of melt is not linear with respect to ice thickness, but is higher order polynomial because of the tremendous heat capacity of ice. In other words, it takes a great deal more than three times the heat input to melt a three foot thick slab of ice than a one foot slab.

  79. RE:
    stevengoddard says:
    May 5, 2010 at 2:12 pm

    “Anu

    The wind compacted some ice in the Barents Sea this week. You can take a deep breath now, the Arctic is not melting down.”

    Well, that is a funny thing to say because the Barents is almost completely ice-free today…?

  80. jakers,

    The Barents Sea has about 350,000 sq km of ice cover. The winter max was around 750,000 sq km. I wouldn’t call that “almost completely ice free”.

  81. bubbagyro says:
    May 6, 2010 at 9:22 am

    For instance, the rate of melt is not linear with respect to ice thickness, but is higher order polynomial because of the tremendous heat capacity of ice. In other words, it takes a great deal more than three times the heat input to melt a three foot thick slab of ice than a one foot slab.

    Assuming you meant an ice slab of the same area, a slab three feet thick would need only three times the heat of a slab one foot thick to melt (it has three times the mass):

    Q = mL
    Q is the amount of energy released or absorbed during the change of phase of the substance (in kJ or in BTU),
    m is the mass of the substance (in kg or in lb), and
    L is the specific latent heat for a particular substance (kJ-kgm−1 or in BTU-lbm−1); substituted as Lf to represent as the specific latent heat of fusion, Lv as specific latent heat of vaporization.
    http://en.wikipedia.org/wiki/Latent_heat

    The rate of summer “heat input” should be roughly the same for both slabs of ice – sunlight/air temperature on the top, heat from warmer water on the bottom. But yes, it should take about three times longer for that rate of heat input to melt the three foot thick slab – hence thicker ice often survives the summer melt, thinner ice might accumulate enough heat to melt completely.

    Given a volume of ice, a small, thick lump should survive longer in the summer than a large, thin slab of the same mass – the energy required to melt both pieces of ice will be the same, but the ‘heat input’ will be higher for the ice with more surface area exposed to sunlight and underneath water.

  82. Just looked at NSIDC and NORSEX, and they’re virtually the same. NSIDC is at about 13.75m sq/km extent, and NORSEX is about 13.5m sq/km – a little bit lower than NSIDC. And NORSEX is usually a day or two behind with their updates.

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