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North Pole notes (continued)

Filed under: — gavin @ 22 August 2008

This is a continuation of the previous (and now unwieldy) post on the current Arctic situation. We’ll have a proper round up in a few weeks.


638 Responses to “North Pole notes (continued)”

  1. 401
    Clarence says:

    Current raw (unsmoothed) NASA/NSIDC Arctic ice data:

    F15 data:

    Date Extent Area / 10³ km²
    2008-08-26   5038 -72 3287 -44
    2008-08-27   5067 +29 3328 +41
    2008-08-28   5074 +7 3361 +33
    2008-08-29   5036 -38 3373 +12
    2008-08-30   5032 -4 3393 +20
    2008-08-31   4974 -58 3328 -65
    2008-09-01   4818 -156 3279 -49
    2008-09-02   4729 -89 3246 -33
    2008-09-03   4724 -5 3281 +35
    2008-09-04   4656 -68 3176 -105
    2008-09-05   4658 +2 3201 +25
    2008-09-06   4662 +4 3153 -48
    2008-09-07   4615 -47 3122 -31
    2008-09-08   4577 -38 3091 -31
    2008-09-09   4568 -9 3126 +35

    F13 data:

    Date   Extent Area / 10³ km²
    2008-08-26   5099 -79 3298 -39
    2008-08-27   5064 -35 3321 +23
    2008-08-28   5089 +25 3360 +39
    2008-08-29   5076 -13 3381 +21
    2008-08-30   5008 -68 3373 -8
    2008-08-31   4956 -52 3303 -70
    2008-09-01   4871 -85 3282 -21
    2008-09-02   4758 -113 3243 -39
    2008-09-03   4739 -19 3274 +31
    2008-09-04   4695 -44 3186 -88
    2008-09-05   4696 +1 3197 +11
    2008-09-06   4665 -31 3138 -59
    2008-09-07   4617 -48 3115 -23
    2008-09-08   4614 -3 3092 -23

    2007 (F13):

    Date   Extent Area / 10³ km²
    2007-08-27   4840 +29 3202 -14
    2007-08-28   4726 -114 3234 +32
    2007-08-29   4714 -12 3278 +44
    2007-08-30   4593 -121 3233 -45
    2007-08-31   4545 -48 3192 -41
    2007-09-01   4521 -24 3193 +1
    2007-09-02   4497 -24 3128 -65
    2007-09-03   4479 -18 3139 +11
    2007-09-04   4490 +11 3113 -26
    2007-09-05   4446 -44 3080 -33
    2007-09-06   4349 -97 3063 -17
    2007-09-07   4341 -8 3053 -10
    2007-09-08   4348 +7 3072 +19
    2007-09-09   4331 -17 3069 -3
    2007-09-10   4295 -36 3075 +6
    2007-09-11   4257 -38 3064 -11
    2007-09-12   4305 +48 3080 +16
    2007-09-13   4284 -21 3096 +16
    2007-09-14   4187 -97 3063 -33
    2007-09-15   4216 +29 3081 +18
    2007-09-16   4222 +6 3116 +35
    2007-09-17   4197 -25 3144 +28
    2007-09-18   4203 +6 3101 -43
    2007-09-19   4254 +51 3158 +57
    2007-09-20   4249 -5 3180 +22
    2007-09-21   4259 +10 3190 +10
    2007-09-22   4320 +61 3204 +14
    2007-09-23   4251 -69 3163 -41
    2007-09-24   4186 -65 3133 -30
    2007-09-25   4249 +63 3170 +37
    2007-09-26   4278 +29 3201 +31
    2007-09-27   4334 +56 3259 +58
    2007-09-28   4315 -19 3251 -8
    2007-09-29   4378 +63 3324 +73
    2007-09-30   4523 +145 3416 +92

    The unsensored area around the pole (311·10³ km²) is fully included in both extent and area. Other missing data filled in by me with temporal linear interpolation of concentration (or persistence at the end). F15 data are mostly complete, F13 data do have some missing values. The final 2007 data have missing values already filled in by NASA/NSIDC. Lakes and ice with less than 15% concentration are excluded. Other than that, no manipulation of the data has been applied (no obviously spurious coastal ice removed). [data source]

    The requested ice volume based on GDAS/GFS data (GDAS 2008-09-09 12Z, full resolution): Arctic 4.4·10³ km³, Antarctic 15.3·10³ km³. But note that this is even more a rough estimate than the ice thickness, because it also depends on ice concentration, which tends to be analyzed too low (on the other hand there is some spurious ice).

    Other figures based on the same data (in million km²):
    Extent: 4.1 (Arctic), 17.6 (Antarctic)
    Area: 3.3 (Arctic), 15.8 (Antarctic)

  2. 402
    Nick Barnes says:

    CT area today: 3.098 Mkm^2.

  3. 403
    Timothy Chase says:

    Chris wrote in 387:

    The NSIDC map you refer to took its data from, and only from, the Arctic buoys I have referred to many a time.

    http://www.crrel.usace.army.mil/sid/IMB/newdata.htm
    It portrayed how much they had melted SO FAR THIS SEASON. To get context, you need to compare to them to their status at the same point last year (if available), and take into account drift, positioning and what type of ice they were installed in.

    I already explained the context of the NSIDC map at e.g. #330.

    But that wasn’t what you were speaking of in the post that I was responding to.

    You had written in 373:

    Almost…. Just read #372. You need to put thickness in context, not to mention the limitations of using satellite data to estimate it. Even taking the data at face value, the central Arctic area looks pretty much unchanged since a month ago, with thickness still greater than 1.5m throughout, and losses of no more than 0.2m.

    As such it seemed as if you were downplaying the melt that had occured this year by means of a fairly selective stale piece of data, and the proper response was to point out that the melt that had occurred from the beginning of the melt season until some time more recent had been greater, oftentimes much greater throughout most of the Arctic. That is precisely what I did in 375.

    But if what you are now claiming is that there hasn’t been much loss of ice thickness relative to last year, then point taken.

    Chris wrote:

    You seem very confident that net melt/compaction will continue until much later than last year.
    Let’s see what’s happened so far in September.

    I gave an estimate earlier on which was bullish with regard to the duration and extent of this year’s melt — based upon a form of trending.

    Please see 261 (30 August 2008 at 10:08 PM):

    Starting with June 1, 2008, I calculated the sea ice loss for each day relative to the preceding day, then I did a quadratic trendline for the sea ice loss…

    But I made it clear that I didn’t know how long the trend would hold or how accurate it would be.

    Please see for example:
    283 (31 August 2008 at 7:35 PM)

    Is the trendline for 2008 realistic? So far, yes. But it has to break down at some point. And personally I expect it to break down when the internal dynamics nears the projected minima — due to outside forces that overwhelm those dynamics: hurricanes that extend the melting season with poleward oceanic heat advection.

    … and:293 (1 September 2008 at 1:40 PM)

    In any case, I think the projection is an improvement upon the straight trend lines some were trying or impressions of what should happen simply based on what had happened in previous years on the same dates.

    Then I pointed out that the method I was using didn’t really seem to provide that stable an “answer.”

    Please see:
    351 (4 September 2008 at 2:07 AM)

    There are now two projections using the same method. However, the first uses a quadratic trendline based on the actual daily reduction in sea ice extent for the period 6/1/2008-8/27/2008, whereas the second uses a quadratic trendline based on the actual daily reduction in sea ice extent for the period 6/1/2008-9/3/2008.

    However, I have done a little more investigation since then with an “ensemble”-like approach. For each day from 8/12/2008 to 9/9/2008, I calculated a similar quadratic trendline fit for sea ice extent loss for the period from 6/1/2008 to to that day, then did a running total of sea ice extent loss and subtracted that from the sea ice extent from 5/31/2008. The following chart gives the daily values and the five-day running averages.

    Projections of Sea Ice Extent for 2008
    http://i37.tinypic.com/ezjyma.jpg

    For daily values, the maximum was 4,620,035, the minimum 3,924,920, and the average 4,372,151. For five-day running averages, the maximum was 4,550,031, the minimum 4,155,389, and the average was 4,360,168. The most recent value was 4,484,226, and the most recent five-day average was 4,469,356.

    A ten-day average of the projected day of sea ice extent minima gives 9/22/2008.

  4. 404

    #401 Thank you very much so Clarence! Do you have a few more crucial number estimates: Last years peak volume at extent maxima, this years peak volume at ice extent maxima, and last years volume at extent minima, around September 20 2007. These are big questions, mainly left for us to guess.

    #402 Nick is this equal to last year?

  5. 405
    Chris says:

    #404 Wayne: today’s figure is 3.107 Mkm^2. For last year’s figure see:

    http://www.realclimate.org/index.php/archives/2007/08/arctic-sea-ice-watch/#comment-53760

    I think you’ll find today’s is ~6.4 per cent more

    Today’s JAXA sea ice extent figure is 4,729,688 km2, that’s ~8.9 per cent more than last year’s figure

  6. 406
    Pekka Kostamo says:

    RE 399: Although this topic may be OT: You can start unraveling the U.S. regulations from i.e. http://www.gao.gov/new.items/d04654.pdf. In the U.S. the limit per reactor seems to be about $300 million, further details being rather complicated. Similar arrangements exist elsewhere as purely commercial full liability cover is nowhere available. The damage levels at which national Governments start carrying the risks are variable. Liability related to other forms of pollution releases are another area of law hotly disputed both in the courts and in politics.

  7. 407
    Pekka Kostamo says:

    RE 399: You may start unraveling the nuclear insurance issue from http://www.gao.gov/new.items/d04654.pdf .

  8. 408
    Chris says:

    Re: volume.

    Ice area figures are more volatile than ice extent figures, and have varied between 6 and 10 per cent above last year’s figures during September so far (going by CT). Extent figures have varied between about 7 and 9 per cent above last year’s (going by JAXA). So let’s say surface ice area is ~7.5 per cent more than a year ago.

    In terms of thickness, we have very little real information. There appear to be only 2 buoys which both (a) can be used to compare today with a year ago and (b) have remained within the surface ice area referred to above.
    They are:
    http://www.crrel.usace.army.mil/sid/IMB/2006C.htm which shows exactly the same ice thickness (1.15m), and
    http://www.crrel.usace.army.mil/sid/IMB/2007J.htm which shows a 0.5m increase in thickness (2.8 m to 3.3m)
    (This isn’t cherry picking, it’s simply the only relevant data I have. I fully accept it could be wildly out, and that it is of very limited use.)
    The mean of the data is a 0.25m increase in thickness, or 12.7 per cent increase.

    Since volume = surface area times thickness, my best guess of volume change would be 1.075 times 1.127 = 1.21

    i.e. a 21 per cent increase.

  9. 409
    Martin Vermeer says:

    Mark #399

    So how come paying for the insurance of a private company is not a subsidy? If it is because it isn’t worth much then why not get the company to pay it?

    It is not a subsidy if the pricing of the re-insurance offered is realistic, i.e., the money collected from policies corresponds to risk probability times accident size, computed as is common in the insurance business.

    The point is not the money involved, but the huge size of the insured event. What would happen if the unthinkable happened, is that the insurance company would go bust and the policy takers would remain without their money. The same applies to hurricane, earthquake and other natural disaster insurances. No private company acting responsibly would offer such an insurance. The only entity capable of carrying such a risk (tiny in probability, huge in size) is the state. And the wish by citizens to have these risks insured at a realistic cost price is IMHO reasonable.

  10. 410
    LG Norton says:

    This comparing of this year to last year ice in a percentage basis is misleading.

    Lets look at a worst case scenario.

    Say one year the ice is almost wiped out and is reduced to just 100,000 sq km.

    The next year, the weather sucks, and the ice recovers to 1,000,000 million sq km.

    Are we going to say that ice have increased by a thousand percent, and the crisis is over. No.

    Whatever difference between this year and last year is just statistical noise due to weather.

    The trend is still the same; an accelerating downward trend, with a few outliers throw in every few years, just to give a false sense of hope.

  11. 411
    Chris says:

    #400 Wayne: “Despite what appears to be significant temperature shifts, the melt for the entire pack is similar to last year (not just one coast or another), indicating thinner ice, and also suggesting some stable under observed warm source.”

    (1) The melt for the entire pack was similar to that of pre-2007 years up until early August (despite the much thinner initial ice)

    (2) The rapid surface-led melt of August is no mystery – see for example NSIDC News, Sep 4th: “A pattern of high pressure set up over the Chukchi Sea, bringing warm southerly air into the region and pushing ice away from shore. August air temperatures in the Chukchi Sea (at 925 millibars pressure, roughly 750 meters [2,500 feet] in altitude) were 5 to 7 degrees Celsius (9 to 13 degrees Fahrenheit) warmer than normal. Ice loss in the Chukchi and East Siberian Seas averaged 14,000 square kilometers (5,400 square miles) per day faster than in 2007.”
    Not surprising that such a heatwave should melt a lot of ice, especially ice that had started the season at such thin levels.

    (3) Therefore to argue that such warmth may have become a permanent feature, I’d have thought you’d have to explain the atmospheric mechanisms which result in such weather patterns, and how any “stable under observed warm source.” may have caused such mechanisms to develop and stick around.

    Personally, I think it’s too early to tell. If the ice grows back earlier this year as I suspect, and thus the small recovery already seen starts to gain momentum, then a lot depends on what happens next summer. If the summer starts with thicker ice (than this summer did), and weather patterns shift to more benign conditions, then conceivably we might not just be waiting until mid-August for the ice melt to exceed the pre-2007 years, but we might be waiting all summer (in vain). Once that happens, a lot depends on what global temperatures do, but that’s for other threads………

  12. 412
    Chris says:

    #410: LG Norton

    “This comparing of this year to last year ice in a percentage basis is misleading.”

    It is what it is. Everyone’s comparing this year to last year in their own way, myself included. At least percentages are facts, rather than opinions.

    “Lets look at a worst case scenario.
    Say one year the ice is almost wiped out and is reduced to just 100,000 sq km.
    The next year, the weather sucks, and the ice recovers to 1,000,000 million sq km.
    Are we going to say that ice have increased by a thousand percent, and the crisis is over. No.”

    That’s not the scenario we face this year. If we did, yes there would be no problem with us saying the ice had increased by 1000 per cent – that’s a statement of fact. And no we wouldn’t say “the crisis is over”. What does this prove? I haven’t said anything about a crisis being over.

    “Whatever difference between this year and last year is just statistical noise due to weather.”

    That’s a statement of opinion. Another might be “changes in underlying factors between this year and last year show a turning point towards a strong and sustained recovery in Arctic ice” (this isn’t my opinion by the way). But what does either statement prove?

    “The trend is still the same; an accelerating downward trend, with a few outliers throw in every few years, just to give a false sense of hope.”

    The trend is what it is. The question is what happens next. I’m not saying I know more than anyone else (though you’re assuming 100 per cent you know more than me). All I’m trying to do is engage with the detailed debate about what might be happening, both short and longer term.

    Sorry if my attitude seems really frustrating to you, but what’s wrong with considering all perspectives? I actually find it frustrating myself when my contributions are repeatedly tarred with expressions like “misleading”, “cherry picking”, “not seeing the wood for the trees”, “flawed analysis”, “cheap rhetorical trick” etc.

  13. 413
    Chris says:

    LG Norton – on reflection, sorry if I got too wound up with my last post, you were only voicing your thoughts after all……

  14. 414
    Andre Grz, Brisbane says:

    To Pekka Kostamo (#398 & #406) and Martin Vermeer (#409): Thanks for the insights on the Finns’ point of view and insurance issue/web site. Appreciated.
    To Barton Paul #396: I was only kidding, man. No offense intended.

  15. 415
    Phil. Felton says:

    Re #397

    Meanwhile, latest thickness data (9th Sep) from buoys used to create NSIDC map of August 20th:

    2008E – 1.3m (First year ice, Lat: 83.127 N Long: 3.562 E)
    [Showed as 1.32m on NSIDC map]

    2008C – 2.7m (Multiyear ice, Lat: 85.114 N Long: 75.591 W)
    [Showed as 2.39 on NSIDC map – wrongly?]

    Why do you suggest that the real time data marked in red as:
    “Caution: Data presented on this page are provisional.”
    are correct and the processed data presented in a report are the ones that are wrong? You get frustrated when things don’t behave the way you think they should and appear to be projecting your beliefs onto the data!

    2008B – 1.95m (First year ice, Lat: 85.640 N Long: 89.317 W)
    [Showed as 1.35 on NSIDC map – wrongly?]

    As above.

    2006C – 1.1m (Multiyear ice, Lat: 84.900 N Long: 137.556 W)
    [The thickness shown by buoy 2006C is exactly the same as in Sep 07. Melt has been ONE METRE LESS this year, since thickness was 2.1m at the beginning of summer 08, compared with 3.1m at the beginning of summer 07]
    [Showed as 0.43m on NSIDC map – wrongly?]

    I’ve been watching this data for some time and I don’t believe it for the following reason: last summer the max was flat at -1.1, perfectly flat even the noise, my experience in experimental measurements leads me to distrust behavior like that.
    This summer it did exactly the same thing, perfectly flat at the same value, doesn’t look realistic! The data from the paper makes more sense.

    2007J – 3.3m (Multiyear ice, Lat: 79.269 N Long: 128.851 W)
    [This is an INCREASE IN THICKNESS of 0.5 metres since the same date last year]
    [Showed as 2.01 on NSIDC map – wrongly?]

    2008F – 3.1m (Multiyear ice, Lat: 75.967 N Long: 138.515 W)
    [Not shown on NSIDC map]

    New buoy, lost ~0.5m in just over a month.

    2007E – 0m (Multiyear ice, Lat: 74.013 N Long: 142.161 W)
    [This buoy had been on a 3m thick ice floe which drifted into open water in the Beaufort Sea and melted completely. Thus I’m not claiming it’s all good news!)
    [Showed as 1.37 on NSIDC map]

    There you are projecting again.

    2007F – On edge of Beaufort, data erratic (appears to show increase in ice from 3m last year to 4m this year, but I wonder if the ice underneath has in fact melted causing data to go haywire)
    [Not shown on NSIDC map]

    Rapid melt from June until early Aug when it was closing in on 0.0m when all of a sudden it does a flip to 3.5m and another to 4m at the same time the snow gauge shoots from 2.5 to -1.5! Ice break-up or flip sideways or something similar, there’s no way this is a correct reading and given its location doubtful if there’s any ice left.

    2008D – NSIDC showed as 2.01m but no sign of line on graph since initial thickness of 2.95m in April. Graph only goes down to 3m so I wonder if thickness is still below 3m?)
    Could be anything, the legend says the data is missing, seems most likely.
    An overall look at ice thickness throughout the basin gives cause for concern as it shows a continued loss in multiyear ice and a continued loss in ice mass.
    http://nsidc.org/images/arcticseaicenews/20080717_Figure5.png

  16. 416
    Timothy Chase says:

    Chris wrote in 412:

    The trend is what it is. The question is what happens next. I’m not saying I know more than anyone else (though you’re assuming 100 per cent you know more than me). All I’m trying to do is engage with the detailed debate about what might be happening, both short and longer term.

    The short-term is interesting. It gives you a chance to be proven wrong a whole lot sooner. And I would especially like to understand the processes involved — atmospheric advection, the role of clouds which varies from the reduction of insolation to increased greenhouse effect, the role of oceanic advection and the role that hurricanes may play in that.

    Anyway, I can understand why someone might call this year a “minor recovery” (assuming we end up not setting new records but only taking a few second places — which seems highly likely at this point) but it pays to keep in mind that records usually aren’t broken year after year — given internal variability (La Ninas and the like), the experts themselves were divided on whether this year would set a new record for extent, this was a cooler summer for the Arctic with more cloud cover acting to reduce melt.

    And finally trends aren’t defined simply relative to the previous year but relative to a string of years. This year may have reversed the one year trend in sea ice extent loss just as 2006 did — given that we are going to reach a minimum that is higher than that of last year’s, but I believe it is a given at this point that the ten year trend will be higher than that of last year. It certainly was for August:

    Please see:

    Even though August ice extent was above that of August 2007, the downward trend for August ice loss has now gone from -8.4% per decade to -8.7% per decade.

    9/4/2008
    http://nsidc.org/arcticseaicenews/index.html

    In terms of volume, if every two years, we lose as much ice as we did going from 2005 to 2007, then we will see our first sea ice free Arctic by the summer of 2013. However, this is not the way the experts calculated it — Maslowski used a high resolution ocean circulation model that didn’t even take into account what happened in 2007. (Incidentally, I can certainly understand if others don’t buy into such an aggressive forecast.)

  17. 417
    Chris says:

    #415 Phil

    Re: the buoys. You’ve put your case that the raw thicknesses they show are wrong by a substantial margin. I disagree. We’ll just have to wait and see what the final results are.

    Re: the ICESat thickness estimates (NSIDC link). These compare Feb/Mar 06, Mar/Apr 07, and Feb/Mar 08.
    There is nothing surprising about a reduction in thickness between spring 07 and spring 08, since we had the record 2007 summer melt in between!
    What is surprising is how limited the reduction was. The real like-for-like reduction will be even less than that shown, since ice will be still thickening between Feb/Mar and Mar/Apr (i.e. Mar/Apr 07 should be compared with Mar/Apr 08, not Feb/Mar 08). Indeed all the buoys installed this year in April with available data were still showing continued thickness increases even into May and beyond:
    http://www.crrel.usace.army.mil/sid/IMB/2008B.htm
    http://www.crrel.usace.army.mil/sid/IMB/2008C.htm
    http://www.crrel.usace.army.mil/sid/IMB/2008E.htm
    Of course, they may all be completely wrong :)

    Thus, the “continued loss in multiyear ice and a continued loss in ice mass” you refer to is only demonstrated as far as a comparison of Feb/Mar 08 with Mar/Apr 07, which frankly doesn’t shed any extra light on the situation re: today vs a year ago.

    Meanwhile, the extent figures are continuing to defy many people’s expectations (including your own). Latest figure from JAXA is 4,751,563 km2, which is 423,594 km2 (or 9.8 per cent) more than a year ago. Hardly a massive change from the situation on 1st July, when the extent was 518,125 km2 (or 5.7 per cent) more than a year ago.

  18. 418
    Chris says:

    And yes, update from CT from a few mins ago puts latest area at 3.05 million km2 or a mere 4.5 per cent more than a year ago. Makes perfect sense to use this to reject the idea of any recovery this year. Personally I think the closeness masks concentration/surface melt issues with the area measurement, but I know most won’t believe me on this. But at least consider waiting until the end of the month to see how the area averages out (and if it shows a sharp rally, which might help to corroborate my suggestions about concentration/surface melt issues).

  19. 419
    Chris says:

    I guess I’d better spell out what I mean by “concentration/surface melt issues”.

    Re: concentration. Eyeball the following:
    http://www.iup.uni-bremen.de:8084/amsredata/asi_daygrid_swath/l1a/n6250/2008/sep/asi-n6250-20080911-v5_nic.png
    Anything purple is more than 90 per cent concentration, anything yellow is more than 70 per cent concentration. I don’t think anyone can reasonably argue that average concentration is less than say 80 per cent?
    JAXA ice extent is currently ~4.75 million km2. If you multiply this by 80 per cent, you get 3.8. Yet CT area is currently almost down to 3.0. Hence CT appears to have a higher concentration threshold for inclusion of ice coverage than the JAXA 15 per cent. Indeed, other sources of area data which are explicit about their cut-off being 15 per cent show significantly higher area for any given date than CT, e.g.
    http://www.nersc.no/~knutal/NORSEX_current.html
    and http://www.ifm.uni-hamburg.de/~wwwrs/seaice/amsr-e.html
    Thus I would suggest that in the last few days there has been no net melt; rather, a substantial area of ice has dispersed to below the CT inclusion threshold, but above 15 per cent. Hence CT may be understating the true total area of ice coverage insofar as the ice is less concentrated than a year ago.

    As for surface melt, consider the weather at the moment in Svalbard (78.2N), and note wind direction http://www.wunderground.com/global/stations/01008.html
    This shows that surface thaw is still very much possible at high latitudes. (It’s not a case of large areas of sea ice being turned into open sea – this is clear from a more detailed consideration of the satellite maps and relevant weather/SST etc data) Note: across the Arctic in general, the weather is freezing http://www.uni-koeln.de/math-nat-fak/geomet/meteo/winfos/synNNWWarctis.gif

  20. 420
    Phil. Felton says:

    Re #417

    Re: the buoys. You’ve put your case that the raw thicknesses they show are wrong by a substantial margin. I disagree. We’ll just have to wait and see what the final results are.

    Why wait you won’t believe them them either! You’ve already shown that you prefer to believe the preliminary raw data rather than the processed data in the report so why would you believe the final data (unless it happened to agree with your belief of course).

    Thus, the “continued loss in multiyear ice and a continued loss in ice mass” you refer to is only demonstrated as far as a comparison of Feb/Mar 08 with Mar/Apr 07, which frankly doesn’t shed any extra light on the situation re: today vs a year ago.

    Not true we know there was a major breakup of the multiyear ice during the winter and its subsequent dispersal into the Beaufort where it has been melting all summer, and that the outflow of multiyear ice continued via the Fram into June this year.

    Meanwhile, the extent figures are continuing to defy many people’s expectations (including your own).

    My expectations of the extent figures have not been defied since I have consistently preferred to follow the area measures. Those have come close to my expectations, last winter I thought that this year would easily make a second place behind 07, the events in the Beaufort sea over winter led me to believe that a new record was likely, presently we’re within 5% and a day or so could even surpass last year’s record. Given the cold winter and summer weather that’s quite remarkable, close to 11 Mm^2 of melt this season, far beyond last year’s.

  21. 421
    Phil. Felton says:

    Re #418

    But at least consider waiting until the end of the month to see how the area averages out (and if it shows a sharp rally, which might help to corroborate my suggestions about concentration/surface melt issues).

    You mean like it did last year?

  22. 422

    Clouds have been a factor all along with Polar ice this season, they have in essence prevented a more than massive melt from happening. However clouds play a different role now, they keep things warm, especially sea water; -0.5 C just measured a few moments ago in Resolute Bay, Canada. Contrasting clearly with last year when I measured -1 C at the same location . So its been cloudy with very little clear breaks around here, and it shows:

    http://www.weatheroffice.gc.ca/data/analysis/351_50.gif

    Notice the +3 C water North of Alaska and the Yukon. Clouds are delaying the end day of this year current melt.

  23. 423
    Timothy Chase says:

    People might want to check out Arctic Roos…

    An Arctic Regional Ocean Observing System (Arctic ROOS) has been established by a group of 14 member institutions from nine European countries working actively with ocean observation and modelling systems for the Arctic Ocean and adjacent seas.

    Welcome to Arctic ROOS
    Establishment of Arctic Regional Ocean Observing System
    http://arctic-roos.org

    … their time series for both area and extent…

    Daily Updated Time series of Arctic sea ice area and extent derived from SSMI data provided by NANSEN.
    http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic

    … and their forecasts…

    TOPAZ MODEL FORECAST
    http://arctic-roos.org/forecasting-services/topaz/topaz-model-forecast

  24. 424
    Chris says:

    #420: Buoys. Here’s the links for (1) the buoy data, and (2) the NSIDC News containing the thickness map up to 20th Aug.
    http://www.crrel.usace.army.mil/sid/IMB/newdata.htm
    http://nsidc.org/arcticseaicenews/2008/082508.html

    I’ve simply been reading off the snow-ice thickness plots shown for each buoy. Phil argues (reasonably, although i don’t like his repeated accusations about my “beliefs”) that the NSIDC map represents the correct/processed/final data, which implies that:
    – Buoy 2008B data over-stated thickness by 0.65m
    – Buoy 2006C data over-stated thickness by 0.75m
    – Buoy 2007J data over-stated thickness by 1.5m

    So who’s right? Unfortunately there may be no way of telling for some time. But I fully understand Phil’s view that the NSIDC map should be the final word on the matter. I’m just surprised that so much of the key buoy data could be so wrong, and think Phil is harsh in his assessment of my motives.

    Phil’s dismissive “Not true…” in his last post is highly disingenous. I’d pointed out that the map he linked to compared Mar/Apr 07 with Feb/Mar 08, which (1) is not quite a true comparison, and (2) more importantly, does not provide much help in proving that there has been a “continued loss in multiyear ice and a continued loss in ice mass” between Sep 07 and Sep 08, as opposed to between Mar/Apr 07 and Feb/Mar 08 (which obviously spanned the record 07 summer melt). Both of my points were 100 per cent true. He is making a different point.

    #421 “You mean like it did last year?” No, I mean faster than it did last year.

  25. 425
    Chris says:

    #422 Wayne – note that OLR anomalies in the Arctic area have been broadly positive for the last month, and merely neutral in the Resolute area
    http://www.bom.gov.au/bmrc/clfor/cfstaff/matw/maproom/OLR/m.lm.html
    Max temperatures in Resolute itself haven’t been above freezing since the 2nd Sep and have only reached 3C on four days since 12th August:
    http://www.weatheronline.co.uk/weather/maps/city?WEEK=08&MM=09&YY=2008&WMO=71924&LANG=en&SID=7192448f2928014abd83b43a4d9dea4035a21a&ART=MAX&CONT=namk&R=0&NOREGION=1&LEVEL=150&REGION=0013&LAND=NN
    Last year the AVERAGE maximum in Resolute for the month of 12th August-11th Sep was ~5.8C
    http://www.weatheronline.co.uk/weather/maps/city?WEEK=08&MM=09&YY=2007&WMO=71924&LANG=en&SID=7192448f2928014abd83b43a4d9dea4035a21a&ART=MAX&CONT=namk&R=0&NOREGION=1&LEVEL=150&REGION=0013&LAND=NN
    Average min temperatures there for the past month have also been significantly colder than a year ago.

    Of course, air temperatures need to be consistently below at least -2C for widespread refreeze to commence. This first happened last year from ~24th September. This year it’s starting as we speak:
    http://www.wunderground.com/global/stations/71924.html

    For each of the next five days, the forecast is “cloudy” with some snow flurries, yet even the max temperature is not forecast to rise above -4C! Those clouds sure aren’t keeping things warm……

  26. 426
    LG Norton says:

    Chris, I think you mean that water temperture needs to be below -2 for refreezing to start.

    Actually most of the ice that have formed at this time is Nilas which is basically loose ice crystals in water. This stuff is easily destroyed by storms due to mixing.

    Sure if calm conditions prevail, the surface layer of the ocean will drop below -2 and ice will start to form.

    However, the fall season is ussually very stormy, and a good portion of the top water colummn needs to get below -2 for sea ice to form.

    So September weather plays a major role in determining the date of the actual ice minimun

    IIJS has show a 50K increase in the past 5 days.
    NSIDC is still showing a steady small decline,
    and Cryosphere Today is very close to beating last years record.

    We may end this year, with diverging opinions, on if 2007 beat 2008 or not for ice lost, depending on the model you pick.

  27. 427
    D Price says:

    Looking at Cryoshere today and comparing it to last year the ice coverage last year appears to be a lot less than this year. Yet the loss is supposed to be nearly as great. Can anybody explain this.

  28. 428

    The record loss for 2008 was for the month of August only, not annual loss. Might this be what you are referring to?

  29. 429
    Jim Eager says:

    Re D Price @427; I would think total loss is defined as the difference between seasonal maximum and minimum, No? In that case, since maximum extent for winter 2007/2008 was higher than for 2006/2007, and since this summer’s minimum is so close to 2007, total loss for 2008 is much larger than comparing 2008 minimum to 2007 minmum would suggest.

  30. 430
    CobblyWorlds says:

    #427, D Price,

    Take into account the information given by the different colours. There’s a lot more ice at concentrations below 70% for 12 Sept 2008 than there was 12 Sept 2007.

  31. 431

    There is clearly one thing different this year, its the size of the remaining ice pack approaching 80 degrees North. Which helps demonstrate the dynamics of the ice itself, load the last 15 days:

    http://seaice.bplaced.net/buoy-pos/

    extraordinary displacement of the buoy next to Ellesmere can be seen, note today is the full moon

    http://www.natice.noaa.gov/pub/east_arctic/Canadian_Arctic_East/2008/canecurrentcolor.pdf

    13 nautical miles a week on average for the entire coast. Still does not reveal Lunar spring tides spurts

    I am finally understanding better that the current may be stronger at this time of new and full moons and cause a significant further displacement. In the past, there was so much ice, that these spurts were incoherent, obstructed by ridging and multi-year ice formations, they were mostly highly localized, now they appear uniform. Seeing the full effects of spring tides, especially new moon one on Sept 1 just past, was quite instructive. This education comes at the expense of the destruction of the permanent ice cap, so no comfort in better knowledge here.

  32. 432
    Phil. Felton says:

    Re #425
    Of course, air temperatures need to be consistently below at least -2C for widespread refreeze to commence. This first happened last year from ~24th September. This year it’s starting as we speak:

    Rather more is needed than that, see the excerpt below:

    The addition of salt to the water lowers the temperature of maximum density, and once the salinity exceeds 24.7 parts per thousand (most Arctic surface water is 30-35), the temperature of maximum density disappears. Cooling of the ocean surface by a cold atmosphere will therefore always make the surface water more dense and will continue to cause convection right down to the freezing point – which itself is depressed by the addition of salt to about -1.8°C for typical sea water. It may seem, then, that the whole water column in an ocean has to be cooled to the freezing point before freezing can begin at the surface, but in fact the Arctic Ocean is composed of layers of water with different properties, and at the base of the surface layer there is a big jump in density (known as a pycnocline), so convection only involves the surface layer down to that level (about 100-150 metres). Even so, it takes some time to cool a heated summer water mass down to the freezing point, and so new sea ice forms on a sea surface later in the autumn than does lake ice in similar climatic conditions.

    From here: http://www.arctic.noaa.gov/essay_wadhams.html

  33. 433
    Chris says:

    “Of course, air temperatures need to be consistently below at least -2C for widespread refreeze to commence.”

    Whoa….. think i’ve been misunderstood here. It was in the context of replying to Wayne’s post, re: whether “Clouds are delaying the end day of this year current melt.”

    I wasn’t saying that air temperatures below at least -2C would by themselves cause widespread refreeze (I hope no one really thinks I was saying that, because it wouldn’t say much for my understanding of Arctic ice!). I was saying that they are a necessary condition. The colder the air, the quicker the sea cools, and the earlier the date of widespread refreeze will be. Thus the clouds currently over Resolute for the next 5 days, under which the temperature is not forecast to rise above -4C for the whole period, cannot be said to be delaying the end day of melt.

    I didn’t mean that widespread re-freeze in the Resolute area will necessarily happen quickly. What I was saying was that a necessary condition for it to happen has been met about 12 days earlier than a year ago (despite cloudiness!)

  34. 434

    Phil, would add the following as well, 2 meter temperature is quite high above the water. So today,
    -5.3 C at standard temperature height, sea water temperature again warm at -0.5 C measured at low tide in shallow water, air temperature immediately above the water -3.4 C. There is also and inversion
    several 100 meters above, with clouds to trap and reflect long wave radiation from escaping. So Chris -2 C would mean that the ice will never form! Since there should always be a warmer layer of air immediately above the sea surface. Over all it seems that the end day for the melt will rival last year, as I continue noticing some ice disappearing, and of course I was writing about clouds covering the entire Arctic ocean. This will continue unless there will be a greater drop in temperature in clear air, last year the ice set when sea water was -1 C and standard surface temperature was -11.

  35. 435
    Chris says:

    “So Chris -2 C would mean that the ice will never form!”
    – see #433

    “There is also and inversion several 100 meters above, with clouds to trap and reflect long wave radiation from escaping……..of course I was writing about clouds covering the entire Arctic ocean.”
    – see first link at #425

    Arctic ocean surface temperatures are significantly colder than last year overall:
    http://sharaku.eorc.jaxa.jp/cgi-bin/amsr/polar_sst/polar_sst.cgi?lang=e&mode=main&date=set&y=2007&m=9
    http://sharaku.eorc.jaxa.jp/cgi-bin/amsr/polar_sst/polar_sst.cgi?lang=e&mode=main&date=set&y=2008&m=9

    Whichever way you argue this, I don’t think you’re going to imply an anomalous greenhouse warming effect that is observable between this year and last year/recent years in the Arctic. SSTs are colder, surface air temperatures are colder, and lower troposphere temperatures are colder. In this situation, every possible combination of weather is likely to produce a cooling vs a year ago for the foreseeable future, clouds or no clouds.

    I’m NOT thereby disputing the greenhouse effect by the way. However, as long as global lower tropospheric temperatures at 25,000+ feet remain apparently colder than in any of the last 10 years, as they have done every month so far this year
    http://discover.itsc.uah.edu/amsutemps/execute.csh?amsutemps+003
    convection is likely to bring relative cooling. Higher SSTs over the NW Pacific and N Atlantic, not to mention in parts of the Arctic Ocean, with their knock-on effects on surface/near-surface temperatures, merely represent a greater release of heat from the oceans at high northern latitudes where winter is approaching and convection/subsequent radiation to space will be fast.

    If we then get another La Nina on top of this (which is the way the Pacific appears to be headed at the moment) as well as a return to neutral or even -ve NAO/AO, then cooling this winter could further eclipse last winter’s.

    [Dhogaza #320
    “Ah, the “La Niña will save us, as long as it happens every year and El Niño disappears” argument.
    Wanna lay odds on that?”]

    Of course, La Nina can be seen as a conservation of heat by the oceans. So maybe we’ll get another El Nino and the globe can release even more heat into the colder lower troposphere to radiate to space.

    Either way, if mean forecasts of the GCMs are correct in the longer term, I think reading too much of a greenhouse effect into 2007/8 ice melts could be dangerous, since if the situation in the Arctic reverses then such people who have done so could lose credibility in their longer term argument.

    Incidentally, the stratosphere continues even more anomalously cold than the lower troposphere, almost certainly as a result of the continued solar minimum
    http://discover.itsc.uah.edu/amsutemps/execute.csh?amsutemps+010
    which can only exert a further cooling effect on the atmospheric layers below.

  36. 436
    Chris says:

    “…if the situation in the Arctic reverses…”

    Note in this context that in summer 1944 Larsen sailed from the west coast of Greenland via the NW Passage (northerly route) to the Pacific in ~8 weeks http://www.ucalgary.ca/arcticexpedition/larsenexpeditions
    This was an ENSO-neutral year, and NH SST anomalies (wrt 1961-1990) were +0.142 for the year http://www.cru.uea.ac.uk/cru/data/temperature/hadsst2nh.txt

    By 1947, it seems the ice was back, and certainly NH SST anomalies for the year had dropped to -0.218C (that’s a drop of 0.360C from 1944)

    By comparison, NH SST anomalies for 2007 and 2008 (so far) are +0.355C and +0.310C respectively. Note: in the 20 months since Jan 2007, only 10 have crossed the Weak La Nina threshold and minimum ONI was -1.5C
    http://ggweather.com/enso/oni.htm
    (c.f. 24 consecutive months crossing Weak La Nina threshold between 1998 and 2000, and minimum ONI of -1.7C)

    In other words the recent La Nina was nothing special, and temperatures could easily go significantly lower still. (Not saying they WILL, just putting forward the possibility) Hence don’t rule out the possibility of a significant ice recovery.

  37. 437
    Chris says:

    Further note: I thought the recent “bucket correction” issue didn’t apply to my previous post. Just checked this and looks like although pre-1942 anomalies have already been adjusted, 1942-1945 SST anomalies may be awaiting downward revisions. If they end up being revised downwards enough to remove the drop in SST I referred to in #436, I guess I would take 1941 as the starting point instead (+0.167C) or 1937 (+0.137) since i understand an El Nino started in late 1941.

  38. 438
    Chris says:

    Alternatively, here’s a comparison of 1941-44 mean summer land temperatures (Jun-Aug) with those for 2007-08, for the only two GISS stations in the NW Passage area I can find with data for both then and now
    http://data.giss.nasa.gov/gistemp/station_data/

    Cambridge Bay and Coppermine combined summer mean temperature:
    1941-1944 7.10C
    2007-2008 7.03C

    Cambridge Bay
    1941-1944 average: 6.5C
    2007-8 average: 6.75C
    Coppermine
    1941-1944 average: 7.7C
    2007-8 average: 7.3C

  39. 439
    Phil. Felton says:

    Re #434

    Wayne, as I’ve noted before the weather station buoy while showing low SW radiation now as expected is still showing consistent ~300 W/m^2 IR ( http://www.arctic.noaa.gov/gallery_np_weatherdata.html),
    not your neck of the woods I know, but further North than you, and with the inversion and clouds you see I’d expect you’d see something similar.

  40. 440
    Chris says:

    Even I can’t dispute that CT area is now essentially no greater than this time last year: 3.004 million km2 as of latest update. Meanwhile extent is back to over 10 per cent greater. Something has to give………or does it?
    I think I’d now rather wait a few weeks than try to predict with any confidence what’s going to happen :)

  41. 441

    The Telegraph, is it known to be a poorly researched paper? Hiring journalists to spew lies in order to fill their contrarian needs?

    http://www.telegraph.co.uk/opinion/main.jhtml?view=DETAILS&grid=A1YourView&xml=/opinion/2008/09/14/do1402.xml

    “Much publicity was given, for instance, to Lewis Gordon Pugh, who set out to paddle a kayak to the Pole to demonstrate the vanishing of the Arctic ice. At 80.5 degrees north, still 600 miles short of his goal, he met with ice so thick that he and his fossil-fuelled support ship had to turn back.

    But this did not prevent him receiving a congratulatory call from Gordon Brown, nor boasting that he had travelled “further north than anyone has kayaked so far”.It took the admirable Watts Up With That blog, run by the American meteorologist Anthony Watts, to point out that in 1893 the Norwegian explorer Fridtjof Nansen found the Arctic so ice-free that he was able to kayak above 82 degrees north, 100 miles nearer the Pole than our hapless campaigner against “unprecedented global warming”

    The article fit for Monty Python news:

    http://www.montypythonnews.com/

    continues debating Hansen as a Gore sidekick of sorts, with the usual ignorant trappings designed to confuse readers about Global Warming. However, the Fram , Nansen’s ship was trapped by ice further southof 80 degrees, North of Siberia in 1894, eventually, Nansen beset and bored, took the said kayak as a sledge and tried to ski to the Pole , and was unsuccessful. The Fram was stuck on the Arctic Ocean ice for almost 3 years mostly exactly where there is open water now!

    Shall we give a comedy award to the writer or the paper? Or both?

  42. 442
  43. 443
    kfr says:

    Re the telegraph, there does certainly seem to be an agenda being pushed there (from the guardian)

    Bad Science Don’t let the facts spoil a good story

    Here is a cautionary tale for anyone working in research. “Captain Cook and Lord Nelson seem unlikely figureheads in the fight against climate change alarmists,” said the Sun. “Lord Nelson and Captain Cook’s ship logs question climate change theories,” announced the Telegraph. Oh that’s handy. So perhaps we can just keep on burning oil regardless then? “The ships’ logs of great maritime figures such as Lord Nelson and Captain Cook have cast new light on climate change by suggesting that global warming may not be an entirely man-made phenomenon.”

    I spoke to Dennis Wheeler, a geographer at Sunderland University and the man whose research triggered this coverage. Is he a leading figure in “the fight against climate change alarmists”?

    No. “But now I’ve had emails from cranks around the world thinking I’m some kind of anti-global warming conspiracy theorist and a friend to them. I’m most certainly not. The newspapers grossly and crassly misrepresented everything we are doing.”

    In fact, Wheeler had spoken only to the Sunday Times, which covered his work accurately. The rest of the newspapers copied the quotes, and the information, but rather grandly decided to change the purpose and the outcome of his research. “It was odd reading articles which were written as if a reporter had spoken to me – I wasn’t fully aware of the extent to which the media copy each other’s newspapers – but worse was the brazen way they distorted our work. Not a single one of the journalists from any other newspaper contacted us to see if their take on the story was correct.”

    In fact, the journalists concocted all kinds of connections entirely for themselves. “Ships’ logs, and thousands more like them, have revealed that recent global warming is not so unusual after all.” Is that true? “No. As I pointed out to the Sunday Times, the ships’ log books I work with only give us information about wind force and wind direction, they basically do not give us information on temperatures, and if they do it’s very scant and unreliable. We’ve simply never claimed indirectly or directly to have any direct evidence on changing temperatures.”

    More from the Telegraph: “The records also suggest that Europe saw a spell of rapid warming, similar to that experienced today, during the 1730s that must have been caused naturally.”

    Wheeler? “Your heart just sinks. Well, the central England temperature series, for example, have shown us that the 1720s and 1730s are a period of fairly rapid warming, but that’s in recovery from the Little Ice Age, and we’d like to know more about that, but this has been known about since 1974. What we are trying to do is to shed a fresh light – a bit of background – on these long-known changes in temperature.

    “Somewhere at the end they do quote me, but by then the headlines have done their job, and the message is lost in the willingness of so many people to believe global warming is not a major issue. And by the end it was unclear what my quote meant anyway, in its new context.”

    How did the papers quote Wheeler? Thus: “Global warming is a reality, but our data shows climate science is complex. It is wrong to take particular events and link them to carbon dioxide emissions.” I could see how that quote might get misunderstood.

    “Only out of context. I wasn’t talking about the scientific community, I wasn’t talking about climate change theory being wrong, I was talking about the media and others getting things wrong. Any new weather event is currently explained away as yet another facet of global warming, but there has always been freak weather. Like most people, I find it hugely irritating when people draw too much from single events.”

  44. 444

    #443 I’d expect an apology or retraction from the Telegraph…. I am holding my breath now, :)…

    #439 Phil, How wonderful to have such numbers available. I need a little more context to see
    how significant they are though.

  45. 445
    Chris says:

    [I just can’t seem to get this past the filter so, in the extract from Nansen’s account below i’m going to omit various words and replace them with — in the hope my post will finally get through]

    Wayne #441: you accuse the journalist of “lies”, then go on to provide an extract from the article and a commentary which does not establish any “lies”. Can you be more specific?

    Here’s part of Nansen’s account of his travels

    link —

    … Wednesday, August 24th … It was at midnight between the 17th and 18th that we set off from our last — ground in — weather. Though it was cloudy and the sun —, there was along the horizon in the north the most glorious — glow with golden sun-tipped clouds, and the sea lay
    shining and — in the distance: a marvellous night … On the surface of the sea, smooth as a mirror, without a block of ice as far as the eye could reach, glided the kayaks, the water — off the paddles at every silent stroke. It was like being in a gondola on the C— G—. But there was something almost — about all this stillness, and the — had gone down rapidly. Meanwhile, we sped towards the headland … which I thought was about 12 miles off … I now thought I could safely conclude that we were on the west coast of F— J— Land, and were at this moment a little north of Leigh Smith’s most — point, Cape L—, which should lie a little south of 81° north latitude, while our observation that day made us about 81° 19′ north latitude …

    Re: the IR measurements, what wider significance are you implying that these have, beyond a representation of the local weather conditions which appear entirely within normal bounds?

  46. 446
    Chris says:

    Turns out it may have been removing the link that finally got my last post through after the nth attempt. So i didn’t need to remove all those words and break the flow, as well as cut out lots of my original post…..

    I’m now trying to find a way to post the link, but i can’t seem to do it even by breaking it up into fragments. So anyone interested will just have to find it via the link to the WUWT blog in the Telegraph article.

    By the way, I think the article is rather shoddily written in parts, it doesn’t get things exactly right re: Nansen (although the central point i.e. he paddled his kayak further north than Pugh, is correct) and is OTT in other parts. However, I think Wayne’s response is just as OTT, and doesn’t demonstrate the “lies” he claims.

  47. 447
    Hank Roberts says:

    > kfr 15 September 2008 at 5:21 AM

    This deserves to be permanently documented, if not here then somewhere appropriate for others to cite it. Has Dr. Wheeler written it up himself anywhere, or have any of the science journalism programs focused on this?

    It’s an incident that reveals a widespread bad practice in newspaper journalism — cautionary, to be watched for.

  48. 448
    Clarence says:

    I’ve made a new animation of NSIDC ice concentration data, going back to 2005:

    http://seaice.bplaced.net/nsidc/

    It also shows the (unsmoothed) values for extent and area for each day.

    Data for the last days:

    F15:

    Date Extent Area / 10³ km²
    2008-09-05 4658  +2 3201 +25
    2008-09-06 4662  +4 3153 -48
    2008-09-07 4615 -47 3122 -31
    2008-09-08 4577 -38 3091 -31
    2008-09-09 4568  -9 3126 +35
    2008-09-10 4545 -23 3162 +36
    2008-09-11 4531 -14 3159  -3
    2008-09-12 4501 -30 3172 +13
    2008-09-13 4511 +10 3158 -14
    2008-09-14 4532 +21 3204 +46

    F13:

    Date Extent Area / 10³ km²
    2008-09-05 4696  +1 3197 +11
    2008-09-06 4665 -31 3138 -59
    2008-09-07 4617 -48 3115 -23
    2008-09-08 4614  -3 3092 -23
    2008-09-09 4592 -22 3123 +31
    2008-09-10 4559 -33 3151 +28
    2008-09-11 4548 -11 3149  -2
    2008-09-12 4560 +12 3176 +27
    2008-09-13 4585 +25 3161 -15
    2008-09-14 4590  +5 3203 +42

    Area probably has passed the minimum, extent maybe too.

    Re: Ice thickness from buoy data:

    The upper ice edge in http://www.crrel.usace.army.mil/sid/IMB/2006C.htm surely isn’t at zero and the ice thickness values look like being clipped at the top. From the negative snow depth I’d guess that the ice was less than 50 cm thick last year and the ice temperature plot suggests about 20 cm now. But for meaningful interpretation you’ll need some knowledge about the buoy.

  49. 449
    k rutherford says:

    re 447 Hank. Don’t know how long the link will live but this is it’s current incarnation.

    http://www.guardian.co.uk/commentisfree/2008/sep/13/1 It’s part of a long running series of articles by a Dr Ben Goldacre who usually looks at the way medical issues are dealt with by the press but he asks for anybody with good (bad) examples of having dealt with the media to send them in, so no idea if Dr Wheeler did anything more than get in touch with him

  50. 450

    Gentlemen,

    Have you see this?

    Look at the ice north of Ellesmere Island.

    http://www.seaice.dk/iwicos/latest/envisat.GMM3d.n.20080915.gif


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