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North Pole notes

I always find it interesting as to why some stories get traction in the mainstream media and why some don’t. In online science discussions, the fate of this years summer sea ice has been the focus of a significant betting pool, a test of expert prediction skills, and a week-by-week (almost) running commentary. However, none of these efforts made it on to the Today program. Instead, a rather casual article in the Independent showed the latest thickness data and that quoted Mark Serreze as saying that the area around the North Pole had 50/50 odds of being completely ice free this summer, has taken off across the media.


The headline on the piece “Exclusive: no ice at the North Pole” got the implied tense wrong, and I’m not sure that you can talk about a forecast as evidence (second heading), but still, the basis of the story is sound (Update: the headline was subsequently changed to the more accurate “Scientists warn that there may be no ice at North Pole this summer”). The key issue is that since last year’s dramatic summer ice anomaly, the winter ice that formed in that newly opened water is relatively thin (around 1 meter), compared to multi-year ice (3 meters or so). This new ice formed quite close to the Pole, and with the prevailing winds and currents (which push ice from Siberia towards Greenland) is now over the Pole itself. Given that only 30% of first year ice survives the summer, the chances that there will be significant open water at the pole itself is high.

The actuality will depend on the winds and the vagaries of Arctic weather – but it certainly bears watching. Ironically, you will be able to see what happens only if it doesn’t happen (from these web cams near the North Pole station).

This is very different from the notoriously over-excited story in the New York Times back in August 2000. In that case, the report was of the presence of some open water at the pole – which as the correction stated, is not that uncommon as ice floes and leads interact. What is being discussed here is large expanses of almost completely ice-free water. That would indeed be unprecedented since we’ve been tracking it.

So why do stories about an geographically special, but climatically unimportant, single point traditionally associated with a christianized pagan gift-giving festival garner more attention than long term statistics concerning ill-defined regions of the planet where very few people live?

I don’t really need to answer that, do I?


827 Responses to “North Pole notes”

  1. 701
    Cobblyworlds says:

    #699 Phil,

    The last NSIDC (14 July) Sea Ice News makes reference to the wind conditions that open that lead showing pressure patterns (fig 3 I think). The period they show average pressure, revealing a high over the Archipelago, was another negative excursion of the AO. The NOAA link (AO index) I gave above is a useful shorthand for when to expect the opening there. It’s called the Circum Polar Flaw Lead – a term I don’t really like, Trans Polar would be better (as it doesn’t go round the pole!).

    #697 Dan C.
    If you check out my post #696 above your post you can open up the link to the image from Terra. That enables you to see the scale of the area, try opening the image as a 250 or 500 metre per pixcel (i.e. 250X250 or 500X500). And then consider the size of an ice breaker. As the other posters have said – that impact is negligible.

    I was looking at more Terra/Aqua images last night, along the Siberian coast and by Svalbard are some of the most beautiful images I’ve ever seen. Fractal like vorticity patterns in the ice.

  2. 702
    Dan C. says:

    Thanks all,

    #701 Cobblyworlds,
    Is it possible to link me/us to the images you refer to:
    “along the Siberian coast and by Svalbard”?

    Thanks

  3. 703
    Hank Roberts says:

    Note Dan and others, when you look at Cobblyworlds’ image link for the TERRA and AQUA imagery (which is truly wonderful) — note the choices and be careful on a slow download phone line link — the “250 meter per pixel” images are huge(!) image files, because each pixel on them represents a 250-meter resolution on the ground.

    There are lots more services using their imagery. For example, I watch my local N. California air quality change several times a day as the winds shift:
    http://activefiremaps.fs.fed.us/imagery.php?op=fire&fireID=ca-north-000

  4. 704
    CobblyWorlds says:

    Very Sorry!
    I forget not everybody has 8Mb broadband. The 250×250 metre per pixcel images are of the order of 6.7Mb when saved to my hard-drive. Thanks Hank.

    Dan,
    Funny you should ask for that, I just posted a link to one at Hot Topic.From my fourth paragraph down. The page for that at smallest size is here. From there you can select 4km/1km/500m/250m per pixcel as appropriate for people’s ISP connections.

    If you like that one, here is another one of the Siberian coast.

    I’ve followed the moods of Morecambe Bay and the East Lancashire fells for years. But I’ve never done the same thing via remote sensing for a place I’ve never even been to! Actually I know more scientifically about the Arctic than I have ever done about any part of the UK (which isn’t saying much as I’m just an amateur who’s degree is in Electronics).

  5. 705

    Cobbly, real cool link, thanks, a point to make, July 4 the big lead got bigger (new moon), July 18-19-20, a mega lead event SW of the Archipelago (full moon), Today New moon, mega activity along the coast again. Also Ward Hunt Island Ice shelf is almost toast:

    http://www.theglobeandmail.com/servlet/story/RTGAM.20080729.wice29/BNStory/National/

    all that open water is having nefarious effects. I am not surprised by this years melt, just a little
    startled by how its going on. Winds are playing a major role as well, with stong winds reported in the Arctic:

    http://www.climate.weatheroffice.ec.gc.ca/climateData/hourlydata_e.html?timeframe=1&Prov=XX&StationID=1776&Year=2008&Month=7&Day=22

    93 Km/hr winds

    wow, in the summer. Some remember Lorenz butterfly, I remember the Polar vortex of last winter
    with 200 MPH winds, a little bigger event than a wing flap.

  6. 706
    Hank Roberts says:

    http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?A082101525

    I love this stuff. What a beautiful world.

  7. 707
    Jim Galasyn says:

    Canadian Arctic sheds ice chunk

    A large chunk of an Arctic ice shelf has broken free of the northern Canadian coast, scientists say.

    Nearly 20 sq km (eight sq miles) of ice from the Ward Hunt shelf has split away from Ellesmere Island, according to satellite pictures.

    It is thought to be the biggest piece of ice shed in the region since 60 sq km of the nearby Ayles ice shelf broke away in 2005.

    Scientists say further splitting could occur during the Arctic summer melt.

    The polar north is once again experiencing a rapid ice retreat this year, although many scientists doubt the record minimum extent of 4.13 million sq km (1.59 million sq miles) of sea-ice seen in 2007 will be beaten.

    Nonetheless, dramatic changes are occurring in the region, affecting the ice both in the open ocean and the ice which is attached to the coast.

  8. 708
    Phil. Felton says:

    Re #705 et seq

    Comparing the Nasa pic from yesterday and the image in the BBC report leads me to believe that much more of the shelf has gone, perhaps I’m misreading the the images? Can any one familiar with the area confirm my interpretation (Wayne)?

    http://newsimg.bbc.co.uk/media/images/44876000/gif/_44876731_ice_ellesmere_sat_466_3.gif
    http://i302.photobucket.com/albums/nn107/Sprintstar400/IceSheet.jpg

  9. 709

    #708. Phil, The Globe and Mail article is better, it is based on site observations coupled with remote sensing images. It may be no coincidence that the shelf gets battered by powerful lunar tidal waves, could they be more effective when there is less pack ice? Its a question of ice and sea interface physics. THe Globe’s article cite an important opinion, which is the disintegration
    is not being followed by some form of mending, the destruction of the old shelf is relentless,
    again an indication of global warming, the contrarians cant possibly explain it any other way.

    Also doubts about whether 2008 will exceed Arctic Ocean 2007′s melt should be tempered by actual ice thickess, many vast areas of thin ice are left , but the melting continues at a furious pace now, the surprise of this year may be the way the ice melts given a greater extent from a colder winter in some Polar sectors. It seems that even thin Ice needs larger areas of open water
    to accelerate melting. once there is such an area established, melting feedbacks accelerate.

  10. 710
    Peter Ellis says:

    It seems that even thin Ice needs larger areas of open water
    to accelerate melting. once there is such an area established, melting feedbacks accelerate

    Is it even that, or is it simply that if an expanse of ice is of a more or less homogeneous thickness, you’d expect it to melt evenly across the entire area. Thus you won’t see any large changes in ice extent until it all melts out quite suddenly.

    The Arctic ice pack this year must be much more even in thickness than previous years, since there’s so little thick multi-year ice left. The big question is whether that thin single-year ice will hold on till the end of the melt season, or whether we’re due for a very sudden collapse in extent as the last couple of feet melts through across the whole Arctic more or less simultaneously.

  11. 711

    The NW passage seems to be be open, if you relly on

    http://iup.physik.uni-bremen.de:8084/amsr/arctic_AMSRE_nic.png

    going through Peel Sound, and circumnavigating King William Island a la Amundsen or perhaps even not so, and the trick is done.

  12. 712
    Dan C. says:

    Hi All,

    Yes, I agree it seems to be negligible the effect of icebreakers on the “whole” north polar ice cap.

    Only 50 high-capacity icebreakers in the world and only a portion
    (?%) of these are in the north.

    My nagging thought is still present. In the 1940’s and for decades since, not many people thought about what man could do to the earth’s atmosphere as relating to having an effect on earth’s weather- good or bad outside of nuclear war: The assumption was- We are too small.

    Well into the 2000’s, some still think man is too small to effect earth’s weather. Today there is volumes of data, 1000’s of reports and studies that allow us to form a consensus that we have in the past and currently are indeed effecting our weather.

    Has or can anybody study specifically: IF and WHAT effect these icebreakers have on polar ice? What do satellite images which have known icebreaker activity in it show? Over time- a day after it passes- how does the broken ice move/flow knowing wind and current data? How plastic is sea ice and shelf ice (assuming there is some difference)? Is any agency tracking all movement through polar ice?

    Is north pole ice more fragile/sensitive than assuming we are too small to negatively impact it? Has somebody already looked at data/ measurements regarding icebreakers impact? By studying it in this way (by breaking ourselves into the artic), have we influenced the system being measured?

    I personally don’t think we broke it, but is it just possible we’re helping nudge it’s demise along?

    Please accept my apology if I offend, it is not my intent. I only wish to know.

    http://upload.wikimedia.org/wikipedia/commons/6/61/Polarstern.gif

    http://www.awi.de/de/infrastruktur/schiffe/polarstern/wo_ist_polarstern/

    http://www.nowpublic.com/russian_ships_reach_north_pole
    -old news but enlightening :-(

    Dan C.

  13. 713
    CobblyWorlds says:

    Phil Hunt,
    You’ve marked the wrong island, that’s Meighen Island. Ward Hunt is off Ellesmere, not to it’s west, and it’s pifflingly small in the context of the region. It’s importance is as a time-marker, it’s been there for thousands of years. It’s at Lat 83deg 4′ 35.94″N Long 74deg 12′ 12.64″W, if that helps

    The best graphics are on the BBC and other media may well follow.

    But for those who want to see it on the images from NASA, this image is recent.

    You really need to open at 250 or 500 metres resolution, the chunk of ice that’s broken off is tiny on a regional scale.

    Go right down to the bottom left corner of the image.
    Go right until you can see the ice to the right of the north coast of Greenland, with a stretch of deep turquoiuse water leading up onto the image.
    Place the mouse curser midway between the ice and water on the bottom on the image and scroll upwards until you meet more land, there’s an inlet with sparse ice just where the curser hits land (with a single berg to the right).
    Now follow the coast up past an inlet blocked with ice until you can see 2 islands in an inlet, the islands are horizontal to each other. The bigger of the 2 islands is Ward Hunt Island itself.

    On this image you can see the time just after it broke off. Ellesmere island is just right of centre, the orientation of the 2 islands mentioned above is vertical (not horizontal as in the image above.

  14. 714
    Phil. Felton says:

    Re #709

    Thanks Wayne, I’d also noticed that the inner passage looked close to passable. Was I correct in my identification of Wayne Hunt here?
    http://i302.photobucket.com/albums/nn107/Sprintstar400/IceSheet.jpg

  15. 715
    Hank Roberts says:

    Dan, the diesel exhaust from Arctic shipping will have far more effect on the ice. That’s actually been estimated. This isn’t the paper I recalled, but it’ll do as a start: http://www.sklog.labs.gov.cn/atticle/B07/B07004.pdf

    I think if there were any significant effect of using icebreakers, we’d have seen them used to open up shipping channels months earlier than they normally melt out, in the many places where ice stops freighter use during winter months. There would be a strong economic incentive to use them if it would work.

    And if icebreakers can’t even keep a channel clear, I’d guess there’s little basis to imagine they could make the whole ocean melt out faster.

  16. 716
    Mark says:

    Dan C #712

    Take an ordinary plank.

    Seat on top of it a 1kg weight.

    It is fine.

    Seat another. Still fine. Keep on putting one more kilo.

    Will it always be fine?

    No.

    CO2 doesn’t go out of the system unless there’s a sink for it. And so it continues to grow.

    So what was true in 1940 is not always going to be true.

  17. 717

    #714 Phil, Yep, distinguishing fast ice and the ice shelf may be a problem.. This is why its always better to have a guy there doing field work. Further so, the passage, impassible even in September, for so many years, is now open for shipping.

  18. 718
    Phil. Felton says:

    Re #713

    Thanks Cobbly Worlds, I thought that I probably had it wrong, I was looking for something bigger!
    Great pictures.

  19. 719

    Phil, 00ps ya, Meighen Island looked like it, but after closer inspection was off by 400 miles. Me bad…

  20. 720
    Jim Eager says:

    Links to images of the underlying topography of both Greenland and Antarctica have been posted before, I thought I had bookmarked them but apparently I did not and now I can find neither the comment with the links nor the images using a google search.

    Does anyone have those links bookmarked or recall the thread where they were posted?
    TIA

  21. 721
    Nick Barnes says:

    Wayne: It’s not clear to me that Simpson Strait (between KWI and the mainland) is clear, or that the route up James Ross Strait and Peel Sound is clear enough for shipping. Do you have better images than I can find on MODIS (mostly obscured by cloud) or QuikSCAT? Amundsen would make it through, without a doubt, but I wouldn’t take a yacht up there yet. Another week or two and it’ll be blue water.

  22. 722
    Cobblyworlds says:

    #712 Dan C,

    “How plastic is sea ice and shelf ice (assuming there is some difference)?”

    Shelf ice is pretty static, being buttressed by immobile land. Check out the link in Hank’s post #706, where you can see the ‘circum polar flaw lead’ along the Candian Archipelago coast (a dirty great crack in the ice). That’s caused by the movement of sea ice against the fixed ice shelves along the coast. It’s worse now than it seems to have been in the past because of the thinner ice along that coast.

    You may find this .avi video interesting: http://www.homerdixon.com/download/arctic_flushing.html The sea ice is mobile, it will be more mobile now than it once was as it’s thinned significantly. But given it’s mobility any tracks of disruption by ice-breakers will be “fixed” (mixed away) relatively quickly. The mechanisms behind how the ice cap got into it’s current poor state are more vast in scale and are associated with:

    * changes in wind forcing (Arctic Oscillation tending to a more positive mode likely due to CO2 stratospheric cooling) mainly since the 1990s. (Fram Strait Outflushing – as seen in the movement of ice past Greenland in the above .avi movie)

    * a general warming since the 1950s, likely compounded by soot.

    * ice processes themselves e.g. preferentially reducing the thickness of the thicker ice. Thick ice grows more slowly than thin so over time (given a general warming trend) this amplifies the loss of thick ice as compared to thin.

    Overall it’s a very complex process (what in nature isn’t?).

    Phil/Wayne,
    Here is a recent Aqua image of the North West Passage in McClure Sound & Viscount Melville Strait.

    From current behaviour here’s what I am thinking at present:
    1) The area this year will end up being over about 0.6 million sqkm above last year. But will probably be a new second lowest area. The lag between 2007/08 of ~0.6 m kmsq has been persistent for weeks now as has the current rate of reduction (although that rate may reduce shortly).
    2) Nghiem’s measurement of perennial extent was massively down on a precipitous trend that has persisted for several years now. If next year’s March figure does not maintain that trend it may support the idea that 2007 was a “blip” not the start of a more intense drop. This may be seen to support the GCM projections.
    3) The results of studies such as Zhang 08 – suggesting that weather was the key factor last year, imply that the Arctic Basin is not yet able to sustain a seasonally ice-free state. We may need higher levels of GHGs (or cloud +ve feedback) to impede winter cooling and ice formation before we can expect the transition to a seasonally ice free state. Last year’s massive input of insolation energy in the newly open water delayed re-melt, but did not stop significant freeze once it had set in.
    4) I’ll stop rambling now…

  23. 723
    LG Norton says:

    #722

    Last winter was rather severe, and we started with 0.6 million km more ice, so given the unfavorable weather conditions this summer, roughly the same amount of ice will melt this year as last year, its just that we won’t reach a new minimun.

    I believe we have reached a tipping point, and we just need one mild winter globally and more favorable summer weather conditions, and we will have an ice free north pole, probably within the next five years.

  24. 724

    #723, LG, the surprise was really last year, no one that I know of, saw the great melt coming. Our skills with ice makes it quite favorable to expect another surprise this year, The apparent 2008 slower melt was leaning towards a mending of sorts, but that is falling apart daily now. Peter #710, is calling it more accurately. No one has observed such a great extent of first year ice melt, it is a learning experience for us all. However it is warm in the Arctic, I definitely will not call it over \until its over\.

  25. 725
    CobblyWorlds says:

    LG Norton / Wayne,

    Sorry for the length, but I want to be clear.

    In reading through the above to get my thoughts together I note I said “agreed” to LG Norton, that was wrong, what I had was a very specific agreement: I agree things are still not settled for this year, a surprise is still possible, however I now think the likelihood of that is small.

    By my reckoning, reading figures from Cryosphere Today’s “recent ice area” and “hemispheric ice area” plots, all in million square km:
    3/2007 13.3
    now 2007 4.5
    9/2007 3.0
    3/2008 13.9
    now 2008 5.2

    The lag between 2008 & 2007 at current date 4.5 – 3.9 = 0.6

    Melt up to now 2007 and 2008
    2007 13.3 – 4.5 = 8.8
    2008 13.9 – 5.2 = 8.7
    So the melt this year so far has been almost as much as this time last year (but not more), that’s without the weather of last year, but much of that area was at lower latitudes than the Arctic Basin.

    I am interested in the implications of Nghiem’s work on perennial ice extent, which I still view as the tipping point. That shows a precipitous drop every year after 2002 (at the same time area started reducing more quickly), and my reasoning was that once the perennial is gone we’d shortly after see a seasonally ice free state. However now I suspect that in a few years we could see the drop turn into a new regime of perennial extent randomly fluctuating at a low level until eventually a summer ice free state is reached (rather like a sigmoid – where we’re on the high rate of change slope and about reach the lower tail). I think the more usually considered total ice area/extent will change less, although become more responsive to weather, as last year showed. In effect I consider the perennial a “damper”, not as a prequisite for a perennial ice-cap (under the current IR regime).

    In short I think it’s too early to discount the idea that 2007 was the sort of outlier “blip” seen in models as noted by Bitz (and others). And that we may well see the more leisurely transition that the models show.

    When I factor in the loss of volume last year as implied by the drop of 1 million sqkm in perennial ice (Nghiem), and indications of thinner ice (NIC, NSIDC Sea Ice News 17/7/08 fig 5), I’d have expected more melt this year than is so far apparent. I am no longer so sure that thickness is as key a condition under current conditions. The top figure on Zhang’s summary of his teams modelling (here) is interesting, using the weather for 2001-2007 they find only last year’s weather gives a drop below last year’s minima using 30/9/07′s ice/ocean state as an initial condition. Note that their extent is for the Arctic Basin as used in PIOMAS, not comparable to Cryosphere Today’s Northern Hemisphere winter extent. And I am aware that Beaufort is ahead of all ensemble members over a month ahead of time.

    This year is clearly behind last year as seen from Cryosphere Today. Further significant reduction is still possible (e.g. 2006) all things being equal, but all things are not equal as insolation is already falling off. So further inroads into the central Arctic will be fighting against reducing insolation and lowering angle of incidence. It would be interesting if this is the reason Zhang’s PIOMAS run using 2007 weather gives a further drop, but one which is nowhere near as low again as last year’s drop from the previous trend.

    At present the rate of drop has been maintained for the last 6 weeks or so, it’s notably straight in terms of the records of past years. Furthermore the concentration anomaly for this July is worse than any year save last year (NSIDC). These seem to suggest the effect of thinner ice than typical.

    However comparing SST anomalies for July 2007 and July 2008 shows that the ocean heating this July is not as marked as in July 2007 (source here). I suspect that as insolation falls there will not be such a “thermal momentum” as last year for the re-freeze to overcome. As the re-freeze starts it may start ealier than last year, we could see an increase in the perennial ice over this winter (Fram Strait allowing), possibly even a re-assertion of the post 2002 rate of reduction.

    Aside from the shock of last year, why do people think we are going through a Small Ice-Cap Instability (SICI) type threshold?

    Was 2007 just warning shot from a region that may well be able to unleash armageddon (CH4, rapid climatic shifts), or is it really too late?

    I’m already more interested in 2009 than 2008, especially Nghiem’s perennial figure for March 2009.

  26. 726

    Cobbly, Ice extent is mostly weather driven, nothing too much to do with how thick ice is. The images between 2007 and 08 cant be more clear, Ice in 07 was bunched up by Gyre current and winds compressing the last bits into a formidable fortress of ice. This year, a Low pressure is/was almost always present in the SW quad of North American side of the Pole, This gives the illusion of a much smaller melt, yet there is very little difference in extent compared to 07, there is a lot of loose thin ice, which may compress, and reveal the same open water surface as last year, but Highs North of Alaska/Yukon are rare this summer. The image changes, the melt is similar, whether it will exceed 2007 is a matter of happenstance, there is no evidence here of cooling, plenty of evidence that winds play with the eyes of the observer. Those persistent Lows cancel the effects of the Arctic Ocean Gyre current. But Russian side current melt seems to be a signature event of this moment.

  27. 727
    LG Norton says:

    It looks like this is the dive everybody has been waiting for.

    NSIDC ice area

    Also, we just dropped below the 2006 ice coverage for this date, and we are less than 100,000 km from droping below the 2005 ice coverage for this date.

    IJIS ice extent

  28. 728

    I would hazard a guess that the current main driver of Arctic Sea ice melt is the persistence of the 500-hPa height anomalies over the area of northeastern Greenland and Svalbard. See animation of the past 30 days here:

    http://www.cpc.noaa.gov/products/intraseasonal/z500_nh_anim.shtml

    Also, for a better look at the ice situation, the Danish Institute of Technology maintains a page, but it is often difficult to access — first click on the link that follows and then click on the left-most image to go to the page of up to date images:

    http://www.seaice.dk/latest-ice.html

  29. 729
    Phil. Felton says:

    Re #726
    Hi Wayne, enjoying the warm, sunny weather I hope? Thanks for your updates, regarding ice thickness this buoy data shows a quite dramatic picture of the last two melt seasons:
    http://www.crrel.usace.army.mil/sid/IMB/2006C.htm
    The latest IUP-Bremen images make it look like the southern route for the NW Passage is clearing rapidly as you commented a few days ago, looks like it would be a reasonable trip now.

  30. 730
    CobblyWorlds says:

    #726 Wayne,

    Ice extent is mostly weather driven, nothing too much to do with how thick ice is.

    Then how do you explain the trend in extent and last year’s crash in particular? Surely with the thicker ice of the 20th century that wouldn’t have happened.

    With regards winds, they could just as likely drive the low concentration ice apart, and increase extent.

    I agree the Siberian sector is a key area of current activity.

    #727 LG Norton,

    I’ve just seen that NSIDC have a new update of 1/8/08 which is also saying a new record looks less likely. That drop in extent looks like it’s due to Laptev/East Siberian Seas (from CT’s regional coverage).

    I’m still not holding my breath for last year being surpassed, I still think this year will be a new second lowest.

  31. 731

    Re: #730

    OK, I can’t believe no one ever discusses this, so I am going to:

    Last year, the atmospheric water vapor streams, and their attendant winds, pulled most of the potential hurricanes and typhoons straight up to the Arctic Circle.

    Additionally, sea surface temperature (SST) anomalies in the northern Pacific and Atlantic Oceans were higher for a longer period than they have been this year.

    The winds driving the water vapor streams were quite intense, and this situation persisted for several months in the latter half of 2007.

    As a consequence, warmer waters entered the Arctic Sea. At the same time, the gyres went faster, and the air above the ice was warmer. There were also extremely persistent 500-hPa, and above, height anomalies hanging just to the north of Alaska.

    None of that happened this year.

    Nevertheless, this year, the waters under the ice, and air temperatures this June, were still warm enough to melt a good bit of the sea ice until the much cooler weather of July.

    From what I understand, there is usually enough of an insulating layer of cold water between the bottom of the sea ice and the warmer water below it that the warmer sea water below doesn’t normally melt the ice that much from beneath.

    Obviously, that was not the case this year.

    But, this year, once enough of the sea ice melted from the bottom, by the end of June, a “protective” layer of cold, less-salty water might have been created (helped by the slowness of the gyres), and that, coupled with the cooler air temperatures in July, may have protected the sea ice somewhat throughout July.

    In any case, given the extra fragility of the single-year ice that remains, it may be very susceptible to the warming SSTs resulting from the changing albedo of the open ocean surface waters.

    Additionally, as I noted in #728 above, there is a rather persistent 500-hPa height anomaly stretching from Greenland to Norway. This is having an effect on the only area in the Arctic Sea where there are still some thicker remnants of sea ice (according to the images at the page linked to in #728).

    All of this just points to the extreme fragility of the ice — it is melting and decreasing regardless of the fact that there are no strong winds pushing it out into the north Atlantic this year.

    Temperatures in the high latitudes of the Northern Hemisphere do not seem to be as high as they were last year. But what goes around, comes around.

    Are y’all paying any attention to the +20 degrees C temperature anomalies hanging over Antarctica for the past 30 days? (I know — it’s just weather…)

    http://www.cdc.noaa.gov/map/images/fnl/sfctmpmer_01a_30frames.fnl.anim.html

    Isn’t about time for a post on “South Pole notes”?

  32. 732

    #730 Cobbly, Sea ice extent does not define melting entirely, if there is no compression like 2007, there will likely be less melting on account of more scattered open water, which in itself reduces sea temperatures from warming. However, if planetary waves behave slightly differently
    we may see the curtain of ice fold and reveal a wider body of water, Current melt is slowed by the winds, not by cooling.

  33. 733

    From New Scientist:

    “Christian Haas of the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, and his team estimated the thickness of late summer ice at the North Pole in 2001, 2004 and 2007. They found that the ice was on average 1.3 metres thick at the end of the summer in 2007. By contrast, its depth was 2.3 metres in 2001 and 2.6 metres in 2004.

    Records from 1991 show that the summer ice that year was 3.1 metres thick.”

    Geophysical Research Letters, DOI: 10.1029/2008GL034457

  34. 734
    CobblyWorlds says:

    Wayne,

    Yep, that’s why I prefer CT’s area as a metric, I figure it’s less prone to such effects. I leave Extent for long term comparison prior to the the satellite period, and for those with money riding on it.

    All I am saying is it’s late for such a lot of catching up. But we’ll see what happens in the coming weeks. :)

    Tenney Naumer,

    The changes in thickness are reflected in the change of designation by the National Ice Centre from thick perennial to thick first year ice that occurred in the High East Arctic over last year. Also in Nghiem’s findings of the massive drop in perennial ice. However I still maintain that we might not be at a stage where a seasonally ice-free state is stable. From all I’ve read it seems that last year’s crash was due to unusually clear weather allowing ice-albedo feedback to cause the melt out, the modelling studies I’ve seen support that. There was a storm in Beaufort that seemed to have an impact (QuickScat), and storms kept the Chucki/Beaufort Seas to Amundsen Gulf open well into the winter.

    On my doubts about whether we’re on the verge of a stable an persistent ice-free state: If I’m wrong, I’m wrong, no big deal. However I’d rather not wrong be given the signiicant dangers involved in a transition to a seasonally ice-free state.

    The North West Passage (NWP),

    I’ve had a good root through the last 48hrs of Terra/Aqua. The best I can find is poor, I need the coincidence of a direct sweep across, what I’ve found is at the periphery of the image (so is distorted), and there’s cloud over much of the interesting part of the image. Here it is, but I warn you, you really need to know your way around – I balk at giving directions. http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?T082170150

    For the time being Bremmen’s AMSRE are the best images for the NWP, and Terra/Aqua merely confirms what they show (espcially when viewed as a slideshow for those who collect such things). McClintock Channel has fairly compacted ice, but Viscount Melville Sound (major part of the Northern NWP route) is a fractured mess with significant open water.

    National Ice Service outlook from May (in the Arcus assesment) looks good. Northern NWP open after mid August.

  35. 735
    CobblyWorlds says:

    One for the “Trainspotters”.

    North West Passage ice state – visible.
    Terra 5 Aug 02:35
    http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?T082180235
    No cloud and minimal edge distortion.

    Directions.
    Top middle is a peninsular (green), from the water (dark) just below that follow along in a straight line (40 degrees down from horizontal) to the right, past a cluster of tiny islands there’s ice. Then about 1/5 of the image width from the edge turn vertically downwards. Cloud obscures as it goes into the Beaufort Sea past Banks Island (largely cloudy) on the right edge of the image. Hope that helps.

    Useful map page Wikipedia: Canadian Arctic Archipelago
    http://en.wikipedia.org/wiki/Canadian_Arctic_Archipelago

    PS Beautiful parallel strata on Melville and Bathurst Islands.

  36. 736

    #735 Cobbly, No chance in getting Peel Sound? If open the passage has been available for quite a while, I see contradictions between Cryosphere and Bremen and Danish ice maps, the very former appears to be clogged the Danish and German maps don’t agree.

  37. 737
    Greg Simpson says:

    I’m sure this must have come up somewhere, but I haven’t seen it and it is not something easy to search for.

    The large arctic sea ice melt in summer 2007 was presumably not primarily caused by a suddenly warmer Earth, but by a redistribution of the heat (or of the ice). So how much heat was absorbed by the extra ice melting? Was it enough to have been a significant cause of the following winter being unusually cool, or was it too small or too distant in time to matter?

  38. 738

    Well, its official in some ways, the “smaller” NW passage has been open for a while:

    http://www.theglobeandmail.com/servlet/story/RTGAM.20080806.wpassage06/BNStory/National/home?cid=al_gam_mostview

    But the story missed the point I raised, there is no cooling, just winds opposing Arctic Ocean sea current, causing the ice not to compress, hence making surface temperatures apparently cooler, and reducing the feedback process incurred by more open water. The atmosphere is quite warm, check out Kujjuaq extreme Northern Quebec: +27 C !

    http://www.weatheroffice.gc.ca/trends_table/pages/yvp_metric_e.html

    Even after a very cold La-Nina and unusaul quite cold late North American side Acrtic winter, the atmosphere is warm. It simply does not appear that way, unless you study it wholly, not at individual Upper heights, not only on the surface, the whole thing, which does not cool in one season after many years of warming. Recent scattered refraction sun shots from cloudy Montreal +18 C as I write, show no cooling at all! May be some institution will post a Density Weighted Temperature (DWT) map one day? You never know, it may be useful.

  39. 739
    CobblyWorlds says:

    #737 Greg Simpson,

    Bearing in mind that I’m an amateur, not a real scientist…

    The large arctic sea ice melt in summer 2007 was presumably not primarily caused by a suddenly warmer Earth, but by a redistribution of the heat (or of the ice).

    Yes, the heat of any area (like the Arctic) in any one year is not really related strongly to global temperature changes, weather has more of an impact.

    From what I’ve read, what happened last year was that the ice cap was pre-conditioned from the previous years. This allowed an unusually clear sky due to an area of high pressure to melt much more ice than usual. The heating of the sea was because of sunlight (google – ice albedo feedback). That warming actually delayed the winter melt as that heat was lost from sea to atmosphere.

    So how much heat was absorbed by the extra ice melting? Was it enough to have been a significant cause of the following winter being unusually cool, or was it too small or too distant in time to matter?

    With regards what caused a cold winter in some parts of the Arctic Ocean, it’s weather. I’m not sure what factors contributed towards that weather.

    Ignoring atmospheric heat fluxes from outside the Arctic (a gross simplification). In summer you have sunlight coming in, and infra-red going out up into space. In winter you only have the infra-red going out into space, no sunlight. Over months of “night” at the pole the heat loss can be massive, much more than any imbalance between any 2 years. So the heat doesn’t really carry over from year to year.

    What can carry over from year to year is the amount of ice. Not really the area(the change within a year is much bigger than the difference between years), but mainly the thickness/volume. There has been some increase in thickness from 2007 to 2008 in some areas, but a massive amount of thick ice was lost in 2007.

    A big factor in the areas where ice thickness has increased more than expected has been a lack of snow, because the snow insulates the ice surface it can reduce the heat lost to the atmosphere (or space). So it can reduce the amount of ice forming on the underside ot the ice.

    However from all I’ve read the ice loss of last year far outweighed the small gains in thickness this winter.

    Wayne,

    Re Peel Sound and the Southern NWP:

    For me the NWP is the northern route (Lancaster/Visc’t Melville/McClure) that’s the best bet commercially. So I must confess I haven’t paid any attention to the Southern Route. I’ve just had a look and it’s too cloudy on all possibly relevant Aqua/Terra for the last 3 days, as far as I can see. I’ll let you know to save your bandwidth.

    The way I use AMSRE type images is wih slideshows because I find it’s only by “visually averaging” that I can get a feel for what’s really there, as opposed to being swayed by weather. For me the still images are not enough, the time-domain is a crucial dimension. So I have never looked at the sort of tiny detail you point out in Franklin Strait/Peel Sound area.

    But looking at Bremmen AMSRE in Windows Photo Gallery, and squinting at Cryosphere Today’s 30 day animation. It is as near as damn-it clear.

    27degC – WHOA THERE! You guys have stolen our (UK) summer weather! ;)

    Here http://weather.noaa.gov/weather/current/EGNH.html we had 93% relative humidity earlier today, 88% as I type. Our Summer has been eaten up by latent heat… :(

  40. 740

    The northernmost point of Quebec, is Povungnituq, near by Salluit is + 26 C, right by Hudson Strait. There is a High Pressure again trying to settle North of Alaska , if it stays, a great deal longer than it has recently, there will be some serious catching up with 2007 melting in the works.

    Cobbly lets we forget, Franklin and his 125 sailors all dead, after horrible last days of living, totally stuck for 2 years in a place NW of King William Island, beset in impossibly thick ice, now today 2 years running with no ice during summer.

  41. 741
    Nigel Williams says:

    One is reminded of Goldblum in Jurassic Park II
    “Ooh, aah, that’s how it always starts, and then later the running and screaming”

  42. 742
    Phil. Felton says:

    Re #740

    Yes Wayne, looking at the weather forecast for Gjoa Haven which is for ~12ºC and sunny later this week it’s hard to believe that it was ever thus for Franklin and his men! Even more recently Amundsen was iced in there for 2 years I think around 1903 (hence the name).

  43. 743
    Nick Barnes says:

    I’m wondering what’s going to happen around the Queen Elizabeth Islands, north of the northern NWP (75-80N, 80-120W). The main channels are Ballantyne Strait, Hazen Strait, Prince Gustav Adolf Sea, Peary Channel, Maclean Strait, Belcher Channel, Norwegian Bay, Massey Sound. Temperatures there are now persistently high (10C, 13C, see http://www.weatheroffice.gc.ca/data/analysis/jac18_100.gif). Bremen shows melt. Modis shows breakup, the same sort of crushed-ice-margarita look that we’re seeing elsewhere. I don’t think that area melted out last year.

    Good PDF topo maps of Canadian archipelago: http://atlas.nrcan.gc.ca/site/english/maps/archives/imw

  44. 744

    #742 Phil, there wont have been any stigma or fear attached to the NW passage if it was always like this, Most good sea Captains the world over must know how scary it is to sail in this passage.
    That is history, but the scary part lags, fear is a hard thing to break. Its a question of time before a serious shipping company will take up this opportunity to save a fortune, and hire Captain daring, to open this passage as once dreamed about, a nightmare once, a day dream now.

    #743 Nick, Ya that is a good point,

    http://seaice.bplaced.net/gfs.html

    Ice thickness is key, there are huge areas of ice barely thicker than 20 cm, all gone come September I would say, including in the Archipelago, Which incidently continues to be pummeled by winds, which may in this case accelerate the melting given the thin ice.

  45. 745
    LG Norton says:

    According to the IJIS site (See #727 for link) we lost over 140,00 sq. km. of ice yesterday, and we are now at the second lowest ice extent for this date.

    The ice lost is now accelerating, when it should be slowing down. This has been one strange summer in the arctic.

  46. 746

    #745, LG, right you are! Look at this site:

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

    stop it at the end, and observe how fast ice is disappearing in the last few days, by advancing each frame manually. Incredible daily surface water gains indeed. I still think this year is helpful in understanding how mega melts work,
    two things are needed: wide open water coupled with very thin ice, Notice, thin ice not surrounded by wide open water does not disappear as fast. There may be something else at play, winds, being excessively important , but these three factors seem to be dominant.

  47. 747
    Nick Barnes says:

    wayne@746: I hypothesize from your observation that wave action is important. The wide open water provides a reach for waves to build up.

  48. 748
    Peter Ellis says:

    Surely all it tells us is that extent (or area) is a poor indicator of the actual amount of ice present? In all likelihood the melt (and total ice loss) is slowing down by now – but the ice that’s remaining is so thin that even a small loss (by volume) equates to a large change in area. Coupled with that is the fact that the winds/currents can disperse or compress the remaining slurry and produce apparent changes in ice area without altering ice volume at all.

    [Response: Unfortunately, all we have are the things we can observe - and the focus is likely to stay on those until such time as the observations become more extensive. - gavin]

  49. 749
    Hank Roberts says:

    I guess there’s nobody actually at the North Pole these days? of the webcams, number 1 over a period of days has slowly rotated so most of the image is blocked by part of its mount, number 2 got wet a while back and hasn’t returned images lately; number 3 is still working (straight up, fisheye).

    http://www.arctic.noaa.gov/latest/noaa1.jpg

  50. 750
    Nick Barnes says:

    Hank, you do know that the North Pole station is actually at about 83N now, don’t you? Just north of the Fram Strait. One of the pages on that site has a drift map.


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