Iceberg calving: the movie

ESA has a short movie of the calving – worth a look, Anthony

Petermann glacier

click to enlarge

From the European Space Agency: Greenland glacier gives birth to giant iceberg

Envisat has been observing a rare event in the Arctic since early August – a giant iceberg breaking off the Petermann glacier in North-West Greenland.

The Petermann glacier is one of the largest glaciers connecting the Greenland inland ice sheet with the Arctic Ocean. Upon reaching the sea, a number of these large outlet glaciers extend into the water with a floating ‘ice tongue’.

The ice tongue of the Petermann glacier was the largest in Greenland, with an extension of about 70 km until early August. This tide-water glacier regularly advances towards the ocean at about 1 km per year. During the previous months, satellite images revealed that several cracks had appeared on the glacier surface,suggesting to scientists that a break-up event was imminent.

In the Envisat radar image taken on 3 August, the ice tongue was still intact but, on 4 August, a large part of the floating ice tongue was separated from the glacier, giving birth to what is currently the largest iceberg in the northern hemisphere. Such a process of detachment, called ‘calving’, occurs regularly on the Petermann glacier, with smaller calving events in summer 2008 and 2009. However large calving events are rare, with the last such significant event being documented in 1991 by ESA’s ERS-1 satellite.

The animation [below] was created by combining three Advanced Synthetic Aperture Radar (ASAR) acquisitions (31 July, 4 August and 7 August 2010) taken over the same area. The breaking of the glacier tongue and the movement of the iceberg can be clearly seen in this sequence.

HI-RES GIF (Size: 1820 kb)

The detached iceberg is now about 30 km by 14 km in size with an area of about 245 sq km. It is floating away from Petermann glacier and will enter into the Nares Strait, which separates Greenland from the Ellesmere Island in Canada.

The Nares Strait connects the Lincoln Sea and Arctic Ocean with the Baffin Bay. The strait is usually navigable by icebreakers during August/September, when sea ice extent is at its minimum after the summer melt period. Envisat ASAR images will be used in the coming days to monitor the movement of the giant iceberg in support of icebreaker navigation.

The radar imaging system used by Envisat and other satellites is particularly suited to observe polar areas, as it can acquire images through cloud or fog, and night and day.

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60 thoughts on “Iceberg calving: the movie

  1. Cool movie!
    This is a nice radar that is not affected by weather, time of day etc. Is it part of the sea ice monitoring network?

  2. It seems to be common sense that the thicker the ice is, the more likely it is that a huge chunk is going to break off, rather than little pieces more often.

  3. I read somewhere that there was a 5.0 earthquake in the area of this calved ice island. Does anyone know if this is true, or was it a sceptical person making it up?
    If true, it could explain why it cracked and broke off.

  4. Tragically, I learned more about the Media than about the Science.
    From the first point you identified this story, the google links were insightful and became progressively dumb over time as the “Media” swarmed to own the “news”.
    One link, within minutes of your post, was already calculating the mass of “fresh water” in relation to the consumption of an average city. Sadly, the “News Media” isn’t able to do the numbers.
    The video and satellite “shots” capture a “moment in time”, yet display another poorly defined and improperly researched “teach”.

  5. Icebreakers will have a bit of a problem
    smashing up this thing (that is what icebreakers are
    appointed to do –smash up ice)–
    Ice breakers will not be zipping up and
    down the Fram (smashing ice)for the next few years–
    some may even have to travel the long way around the east coast of
    Greenland to just get home this year.
    Icebreakers smashing open up the Fram had unintended consequences–
    All that bunker fuel oil wasted trying to keep the Fram open–
    It’s not nice
    to fool with mother nature.

  6. Does this ice now become part of the sea ice volume? Or was it already included in that number?

  7. You can see a second crack forming generating the next “iceberg” about half the size of the previous one. Very nice shots.

  8. Ice tongues are extremely fast moving glaciers with speeds up to 1km per annum. If a 30km section has dropped off, then the glacier will have recovered in 30 years ready for the next calving. This is not unusual. I remember Scott (of the Antarctic fame) in one of his books complaining that a local glacier tongue had broken off since his last expedition and, if I recall correctly, commenting that this was highly unusual and might be expected every thousand years or so. Of course he was wrong in this regard. On a similar vein, I do find amusing the commentary on videos of glacier calving into the sea. These glaciers are moving several metres per day and so calve several metres per day into the sea.
    So, does anyone have velocity information for the Petermann glacier?

  9. Only 1km / year?
    Either the scale on the map in the previous thread was wrong, or the glacier moves much faster than that.

  10. What happens when it get stuck in the pack ice at the opening to the Nares Strait?
    What will be the news when this winters freeze re-connects the iceberg to the glacier as the gap between the iceberg and the glacier freezes over?
    What will be the news if the frozen over gap does not thaw next year?
    Will we have news of a 30 Km growth in the size of the glacier in one year?
    Will we have news of 2,000 year old Arctic sea ice?
    Can they still call it an iceberg if it becomes re-connected to the glacier for a year?
    A small bit of 2,000 year old Arctic sea ice would skew the graphs.
    A 30 km one year growth in the glacier would likewise skew the graphs.

  11. This seems to be moving quite fast. in 4 days, moved about 4-5 miles.
    at that rate, it could be a hundred miles, before it freezes all around it, stopping it from going anywhere. anyone knows if this high a speed is typical?

  12. What must calving of icebergs in Greenland have been like before satellites? :o)
    “Calving rates are controlled primarily by water depth, but, for any given depth, are an order of magnitude greater in tidewater than in freshwater. Calving dynamics are poorly understood, but differ between temperate and cold glaciers, and between grounded and floating termini. Nonclimatic behaviour of calving glaciers has been documented in a large number of locations, both in historical time and during the Late Glacial and Holocene. Interactions between calving dynamics, sedimentation and topographic geometry can partially decouple calving glaciers and marine ice sheets from climate, initiating independent advance/retreat cycles; it is therefore rarely possible to make reliable inferences about climate from their oscillations. ”
    http://ppg.sagepub.com/content/16/3/253.abstract
    [Iceberg calving and the glacioclimatic record,
    Charles R. Warren
    Department of Geography, University of Edinburgh]

  13. This seems to be moving quite fast. in 4 days, moved about 4-5 miles.
    at that rate, it could be a hundred miles, if it progesses unimpeded, before it freezes all around it, stopping it from going anywhere. anyone knows if this high a speed is typical?
    there is also a peanut shaped white image to the west of the iceberg. it is a large peanut on july 30th, then it is much smaller on aug 4th. and back to big peanut on aug 7th. what is it? is it fresh snow, without any melt water on it?

  14. Message to the MSM,
    Glaciers have been calving like this for millenia. We have just not had the technology to observe it in such detail before. Because we now have that technology does not necessarily mean it is something new or mindboggling.

  15. nandheeswaran jothi:
    The movement is probably mostly wind-driven. A large ice-cap like Greenland acts as a permanent high-pressure area, so on average wind blows away from it more often than towards it. You can see on the radar that the sea ice is drifting even faster.

  16. Points not mentioned in the MSM hype about this event:
    This tide-water glacier regularly advances towards the ocean at about 1 km per year. We usually only hear of receding glaciers.
    Such a process of detachment, called ‘calving’, occurs regularly on the Petermann glacier, with smaller calving events in summer 2008 and 2009. However large calving events are rare, with the last such significant event being documented in 1991 by ESA’s ERS-1 satellite.
    And how many such large calvings occurred in the early 1900’s, the 1800’s, etc? I would not expect there to have been too many visits to this area over recorded history to know what the life-cycle of this glacier has been (but then I am not a ‘climate scientist’.

  17. I don’t get the relevance or the significance – or is it just that it’s an interesting, unusual phenomenon and nothing more than that?

  18. With all of the smaller chunks of ice already in the Nares straits it seems that an equivalent volume of ice falls off these glacier(s) in smaller pieces without all of the fanfare.
    I’m no expert, but it would seem that glacier calving is about as natural a process as there could be. Otherwise the extent of these glaciers would rival those of the ice-age.

  19. Well that thing was just an accident waiting to happen. What the heck did they think it was going to do; advance all the way down that fijord; and then meekly turn the corner and remain intact. They’re darn lucky it held up that long.
    I thought that Greenland’s glaciers were supposed to be retreating; not advancing.
    I still think they should tow it to LA and dump it in the LA river.

  20. “”” tty says:
    August 9, 2010 at 1:11 pm
    nandheeswaran jothi:
    The movement is probably mostly wind-driven. A large ice-cap like Greenland acts as a permanent high-pressure area, so on average wind blows away from it more often than towards it. You can see on the radar that the sea ice is drifting even faster. “””
    “”””” so on average wind blows away from it more often than towards it. “””””
    So “on average”, what is it that happens when ALL of the air has blown away from Greenland; on average of course ?
    Do Kirchoff’s laws (circuit theory) not apply to Greenland ? Next time I need to defrost my Freezer; I’ll just blow on it; on average of course !

  21. Judging by Google Earth, it looks like a disaster movie writer would have quite a tough job coming up with a scenario where this giant ice-berg collides with a monster hurricane in New York Harbor.

  22. George, step back and think a moment. A high pressure area is caused by air descending from higher in the atmosphere, so of course air will move in to replace it at the top of the column. A high pressure area creates winds away from itself at the base of this high-pressure column of air.
    Now I understand the process would work something like this: the ice-cap cools air over it, causing it to shrink, which brings more air in to the column; that creates a high-pressure zone. The air will move outwards from this high-pressure zone, at the base, on avarege, most of the time. In layman’s terms, at ground level, at levels that matter to our perception of events around this glacier, the air moves away from greenland on average most of the time.
    In your haste to snark you’re not actually understanding what you read.

  23. <blockquote cite="Fred says:
    August 9, 2010 at 12:14 pm
    We are watching a Fiord being created . . "
    A “Fjord”? Well, when the next big chunk comes off in perhaps ten years, perhaps it will be a “Chevy” (if Government Motors is still in business by then :^)
    Impressive Synthetic Aperture Radar images and a lot more impressive than the normal calving of glaciers that drop a building-sized chunk every half-hour or so. http://tvpclub.blogspot.com/2010/08/three-times-size-of-manhattan-and-it.html

  24. Maybe the ice huggers should fly their flags at half mast and get their loony left wing majority in congress to declare a national day of mourning.

  25. That’s quite an optimistic use of ‘movie’ – three frames that don’t link through persistence of vision. 🙂

  26. “”” Archonix says:
    August 9, 2010 at 2:27 pm
    George, step back and think a moment. A high pressure area is caused by air descending from higher in the atmosphere, so of course air will move in to replace it at the top of the column. A high pressure area creates winds away from itself at the base of this high-pressure column of air.
    Now I understand the process would work something like this: the ice-cap cools air over it, causing it to shrink, which brings more air in to the column; that creates a high-pressure zone. The air will move outwards from this high-pressure zone, at the base, on avarege, most of the time. In layman’s terms, at ground level, at levels that matter to our perception of events around this glacier, the air moves away from greenland on average most of the time.
    In your haste to snark you’re not actually understanding what you read. “””
    What is your evidence that I snarked in haste ? Actually I snarked quite leisurely; and only after understanding fully what I had read; namely that the winds blow towards Greenland, on average more often than they blow away from Greenland; and now you have introduced a set of winds that is blowing mostly on average towards Greenland; rather than away.
    So which is it; is there an assymmetry or do the winds blow towards Greenland just as much as they blow away from Grteenland; in order that the place not run out of air.
    And if in fact the winds do blow mostly away from Greenland (I’m always willing to learn) how the heck does all that ice and snow end up on Greenland; with the wind always or mostly blowing away from the island ?

  27. George, what he’s trying to explain to you is called the katabatic wind system
    Here’s a link to a picture of it:
    http://explorersweb.com/sitemedia/TSthumbs/20090630katabaticemirates.jpg
    “Katabatic winds exist thanks to the huge piece of ice on top of Greenland. That ice cap is at places more than 3000 meter thick, which forms a vast plateau 3000 meter above the main sea level. The air mass on top of this plateau becomes extremely cold, and cold air is very dense, which means it is much heavier than the relatively warm air along the coasts of Greenland. Due to gravity the colder air starts rolling down from the high plateau towards the coast. This movement of cold air, which happens only in the lowest hundred meters of the atmosphere, is called ‘katabatic’ wind.”
    ”The wind direction of the katabatic wind is, at one point, nearly always the same: it blows from the interior of Greenland to the coast and almost perpendicular on the elevation contours. The speed depends mainly on the angle of the slope, the steeper the slope the stronger the katabatic wind. At some places it is not exceptional that this wind blows with a speed of 40-60kt and this for several days in row.”

  28. Fred and Ira,
    The Fjord would have been created during some previous glacial period when the water level was lower and the ice was scraping and gouging the sides and bottom of its valley. In our present time the valley is flooded and the tip of the glacier would be floating. Otherwise it could not “sail away” as an ice island after it fractures from the ice up-valley (or up-Fjord).

  29. Cool!
    Hey, now that this “chuck of ice as big as Manhatten” has broken away from its glacier ice roots and is moving towards the sea ice trapped near the fjord’s outlet, can we get it added to the AMSRE sea ice extent list and move up the mid-September sea extent margin a bit?

  30. I don’t see the ice melting. I see it breaking. And that is not unprecedented. It’s called calving; you can even find it in the dictionary. Calving of ice is normal. What would be unprecedented is if ice didn’t calve.
    I wonder what it sounded like?

  31. Something quite interesting is happening at the NOAA pole cam I think?
    The pictures are showing the melt ponds fully frozen over, its been snowing and the snow is not melting now. NOAA is not showing external temperatures on its pictures only the internal temp which as we know has internal heating powered by solar cells, is the external sensor broken or has NOAA disabled it?
    The melt ponds should not be freezing over this early if past years are anything to go by and it may be that the melt season is winding down earlier than past years. Of course the melt may resume and its open season on the probability but it would help if we knew what the actual temperatures are through the day and night.
    The disappearance of the melt ponds may signify nothing but then again…interesting times ahead for watchers of the NOAA pole cam eh?

  32. I can imagine a writer imaginatively describing this event, “With a sound like 100,000 screaming new-born cattle and the growls of 10,000 polar bears, the huge glacier began slowly to break apart from one side to the other …”

  33. Envisat has been observing a rare event in the Arctic since early August – a giant iceberg breaking off the Petermann glacier in North-West Greenland.

    I bet if you had a satellite video showing calving events over the past 500 years compacted into 30 seconds you would not see anything unusual or ‘rare’. Human time V nature time. Arctic ice extent comes to mind. :o)

  34. George E. Smith writes:
    “So “on average”, what is it that happens when ALL of the air has blown away from Greenland; on average of course ?
    Do Kirchoff’s laws (circuit theory) not apply to Greenland ? Next time I need to defrost my Freezer; I’ll just blow on it; on average of course !”
    It does, but a high pressure area is a high pressure area because the air is sinking, so the air over the icecap is replenished from above, and blows away to the sides. Conversely in a low pressure area the air is rising. That is why it rains a lot more from low pressure areas than high pressure areas.
    Incidentally the many storms off the icecap were already known back in the Middle Ages. They are mentioned in the 13th century Norwegian böok “Kónungs skuggsja”.

  35. Just a thought ~ With regards to the idea of an earthquake causing this calving; wouldnt the calving itself (the sudden freeing of an island of ice) create the release of enough energy to cause a fair sized earthquake?

  36. The U.K. Daily Mail, which has been reasonably sceptic seems to have fallen for this big time. Their Science editor Michael Hanlon reports from “The crack in the roof of the world”, and says “Yes, global warming is real – and deeply worrying”.
    Unfortunately he’s rather inconsistent, first we get emotive stuff like: “This river runs deep, possibly 13ft. Not a speck of dust, mud, weed or debris pollutes its flawless, azure depths. ” Then further down we suddenly find: “Minute specks of black airborne dust – a mixture of desert sand blown thousands of kilometres from the south, soot particles from power stations and microscopic algae and bacteria – settle on the ice and, being dark, absorb the sun’s rays, magnifying their heat like a spyglass onto the ice. ”
    http://www.dailymail.co.uk/sciencetech/article-1301713/The-crack-roof-world-Yes-global-warming-real–deeply-worrying.html

  37. Ken Hall says:
    August 9, 2010 at 12:11 pm
    I read somewhere that there was a 5.0 earthquake in the area of this calved ice island. Does anyone know if this is true, or was it a sceptical person making it up?
    If true, it could explain why it cracked and broke off.
    …and…
    Smokey says:
    August 9, 2010 at 7:38 pm
    Paul Hildebrandt,
    From your source: Greenland area quake. August 5th.
    The quake was a 4.4 and was over 650 miles from Petermann Glacier. I doubt very much if it had an effect.

  38. There are ‘Good’ Witches at East Anglia and there are ‘Bad’ Witches there too. This was done by one coven or the other, though it’s hard to tell at this time which. If the shelf ice had melted and shrunk, I’d have thought it was the Bad Witches. If the shelf ice had continued to grow and didn’t break, I’d have thought the ‘Good’ Witches did it. But since the shelf did grow and break, there must have been a great competition between the two sides, on brooms of course since they left no prints in the snow. I know some think Harry Potter and all that stuff was just a fairy tale but it wasn’t. EAU is actually called Hogwarts Academy by many who have been there.

  39. And one would expect an advancing glacier to be calving ice, while a retreating glacier would be …. not calving? (not that either have anything/much to do temperature).

  40. Why is it that everybody wants to explain to me how it is in their mind that winds can always blow away from Greenland; without running our of air; but in their explanation they are forced to introduce some other source of air from some other place that is blowing IN towards Greenland. That’s WHY Greenland doesn’t run out of air; because there is just as much air flowing into it as is flowing out of it (on average of course).
    This isn’t Rocket science; it’s common sense; and giving the wind out some fancy name doesn’t alter the simple 8th grade science fact that air must be flowing in as well as out or else it either runs out of air; or gathers up all the available air to sit on top of Greenland.
    Did you suddenly tap into another population of WUWT readers Anthony; this is getting totally weird !

  41. I can sympathize with George; I’ve had two-dimensional episodes, too. You just need to catch a few z’s and the x and y fall into place.
    On another note, stuff falls off the end of glaciers regardless of whether they’re advancing or retreating.

  42. “”” Oliver Ramsay says:
    August 10, 2010 at 4:44 pm
    I can sympathize with George; I’ve had two-dimensional episodes, too. You just need to catch a few z’s and the x and y fall into place.
    On another note, stuff falls off the end of glaciers regardless of whether they’re advancing or retreating. “””
    So we have some endless source of air that is directly above Greenland, that can keep supplying a downdraft to spill out over the edges.. I don’t remember restricting the altitude of winds to just the surface; we don’t restrict ocean current to just the surface, so the gulf stream can continue to our into the arctic ocean, without it all piling up there.

  43. George,
    Well, yes, there is an endless supply of air to all locations in the atmosphere. After all, if there were an end, there’d be a vacuum and we don’t think that happens.
    If air is arriving from Iceland, horizontally at 20,000 feet, we would call that air movement ‘upper level wind’ or ‘winds aloft.’ When this air moves down towards the surface of Greenland it is not typically known as a descending wind. In the context of propulsion of ice chunks floating in surface water, the winds at 20,000 feet probably exert very little direct influence.

  44. Well I guess I’ll have to be happy with all the air rushing outwards from Greenland to go somewhere else. Evidently it is getting replaced by snow and ice that must come straight down from heaven; since there aren’t any inward blowing winds to bring moisture in from over the oceans or other lands.
    By the way Anthony; the IceCapage is pretty cool; which is a good way for ice to be. Pretty soon WUWT is going to become the most cited data reference in future Climate science Peer Reviewed Papers.
    I’ve even noticed that some of the more famous yet incognito AGW denizons from “Real Climate” seem to be coming over here to comment now and then.
    That’s good because while they remain at RC they can hardly change their views, and continue to get printed.
    And finally; at least some of that Icecapage data seems to be trying its darnedest to back up what Steve Goddard has been risking his neck for. Sept 2010 looks like it is going to be another teaching moment.

  45. This morning I came across a very interesting graph (below) from one Richard Alley, a Penn State colleague of Michael Mann. Richard Alley has just testified to Congress with the outrageous testimony that Greenland could melt in decades.
    What’s amazing is that this graph I mention is also by Richard Alley from 10 years prior and appears to undermine his own scaremongering! The graph shows that warmer temps bring more snowfall in Greenland, hence presumably offsetting any ice loss due to warming:
    http://www.ncdc.noaa.gov/paleo/pubs/alley2000/alley2000.gif
    from webpage:
    http://www.ncdc.noaa.gov/paleo/pubs/alley2000/alley2000.html
    My own blog post on it here.

  46. Does anybody know if this is big enough or will be sitting deep enough in the water to get jammed in the Nares Strait?

  47. HR;
    Yes, that’s a point, isn’t it? Only 10% or so is visible, above the surface. That’s one humongous underwater mass moving along there …

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