ESA has a short movie of the calving – worth a look, Anthony
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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the sky is falling … it has too much CO2 to stay up …
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?
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.
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.
We are watching a Fiord being created . . .
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”.
Looks like there will be another big one following…
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.
Does this ice now become part of the sea ice volume? Or was it already included in that number?
You can see a second crack forming generating the next “iceberg” about half the size of the previous one. Very nice shots.
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?
Only 1km / year?
Either the scale on the map in the previous thread was wrong, or the glacier moves much faster than that.
So GW is resulting in bigger icebergs? I would have expected the opposite.
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.
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?
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]
Same story, different hemisphere
http://wattsupwiththat.com/2009/04/26/media-addicted-to-melt-when-it-it-should-be-crack/
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?
Would that be considered an ice island?
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.
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.
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’.
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?
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.
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.