Previously on WUWT we discussed the media’s fascination with “melt” when it comes to ice shelves cracking off. Then there’s also this picture that keeps getting recycled.
http://www.ogleearth.com/wissm.jpg
It is clear from the photo above that we see a stress crack, not a melt. Now we have a time lapse satellite photo series of the Wilkins ice shelf that shows the process of currents and winds causing those stresses.
Mike McMillan writes:
Fox News is reporting that the Wilkins ice shelf bridge that’s been eroding has finally collapsed.
http://www.foxnews.com/story/0,2933,518374,00.html
I went back to the old ESA sat photos and noticed something interesting. I downloaded the gif animation and did some highlighting.
In the upper area, the shelf was previously fractured, then glued together by new ice. I highlighted a string of drift ice in green to show what the currents were doing during the previous collapse. The current runs down from the top, compressing the fractured shelf and likely busting up the new ice glue. The current then reverses, pulling the fractured shelf ice out to sea. The green drift ice looks almost like a fingertip crunching into the shelf, and clearly shows the compression.
A different process works on the lower side of the ice bridge. A gyre pulls
off chunks of unfractured ice. I’ve highlighted a chunk of non-edge ice in
pink, and we can watch it tumble out along with a companion berg. Note the
sea immediately refreezes in the open areas. One of the gif frames shows the
gyre swirling the new ice, and I’ve enlarged the frame.
http://i40.tinypic.com/erg287.jpg
UPDATE: I slowed down the original animation to 1 frame per second, with a 2 second pause at end, per requests in comments. -Anthony
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Przemysław Pawełczyk (P2O2) (09:45:25) :
“OT. BTW Russians made to the North Pole in trucks!
The news emerge a few days ago but I stumble oupon it today. See the truck images here: http://p2o2.blogspot.com/2009/04/driving-special-truck-to-north-pole.html”
Thanks for the link – that is very cool. I love the size of those tires – look like balloons.
A bit more efficient, and much less dangerous, than the Catlin adventure-thrill group excursion…
Anthony, you are correct about the current flowing north to south. Incidentally, it’s a warm current that results from freshwater runoff from the Peninsula. Which probably means its at the surface and seasonal (summer).
The gyre at the south of icesheet is probably due to the current after having flowed under the icesheet hiting a largish island on the southern boundary of your photograph.
This current was only discovered about 5 years ago and little is known about it. For example has it strengthened in recent years due to increased melt further north on the Peninsula? Anyway it is certainly a major factor in the Wilkins Icesheet melt.
I tried to find the link, but Google is swamped with numerous duplicate links to the Wilkins Icesheet ‘collapse’.
Antarctic ice shelf off the western peninsular is also surrounded by warmer than average water
There is no icesheet north of the Wilkins icesheet on the west side of the Peninsula.
The area of warmer water is adjacent to the land and supports the suggestion I just made about the current that flows south along the west side of the peninsula warming in recent years.
The UK Met Office have been so far off wrong predicting the climate in Britain the last several years I’d bet they’ll be off again this year. Don’t forget the eruption of Mt. Redoubt in Alaska will have an effect on the northern hemisphere’s weather and climate this year. I’m betting the weather and climate will be cooler consequently the UK Met Office will be wiping the egg off their faces again.
A notation on the Fox News Article referenced above: http://www.foxnews.com/story/0,2933,518374,00.html
If you look at the top left of it you will note that it is actually from the “Associated Press”. Many mainstream media (MSM) outlets do not write much of the news that they report, rather they rely upon News Services, such as the Associated Press (AP) and Reuters, as well as Press Releases that spoon feed them “the news”. As such, one of the root causes of the MSM reporting imbalance is that the Associated Press and Reuters are heavily biased towards AWG, and a second root cause is that the skeptic crowd hasn’t learned how to draft and distribute Press Releases that communicate the facts and will be picked up by the MSM.
There is not much that we can do about the bias at the Associated Press (AP) and Reuters just yet, but the drafting and distribution of Press Releases that communicate the facts and will be picked up by the MSM is something that we should get to work on…
alexandriu doru:
‘Somethig who is happening for the first time in 125000 years is not a “current event”.’
From what I can tell by your post I think you have misinterpreted the title (as I did when I initially opened this article), in context “current” refers to oceanic currents, and the idea that these are a substantial cause of the present state of the Wilkin’s Ice Shelf.
As a former resident of the UK just about every day could be forecasted the same; Cloudy with some sunshine and rain at times.
How do you know that it’s summer time in the UK ? The rain is warmer.
I thought that the Hadley Center doubled down on their hot year prediction for 2010 a few months back ? Was that before or after the sea ice forming in Poole Harbour ?
If you keep forecasting the same thing sooner or later you will be right. Even a stopped clock is perfectly accurate twice a day.
Seems they’re catching onto the recycled photos in Australia.
http://www.theaustralian.news.com.au/story/0,25197,25403129-12377,00.html
Sorry I mean 2009 not 2010 – currently working on budgets for next year so I have 2010 on the brain.
SORRY FOR THE HI SPEED !
It looked better in Photoshop.
Here’s slower –
http://i42.tinypic.com/14w7uyb.jpg
The BBC has an arctic story that isn’t about the Catlin survey
“Testing times for Arctic research”
http://news.bbc.co.uk/1/hi/technology/8021778.stm
“The BBC visits the most northerly human settlement on earth to see how scientists are measuring changes to our atmosphere. ”
“The day before our visit, the site measured CO2 levels of 394 parts per million. “
I bet that has not even put a dent in the global sea ice extent data. So what’s the big fuss???
Actually we are doing it by posting here. Fox news ran a segment on the German overflight of the ice yesterday and its “surprising thickness”. I have noticed recently that certain Fox news programs may be watching this blog as on several occasions items that get mentioned here get mentioned very soon after on some of their shows.
Like any news service they look for story leads where they can find them, and the combined culling of the worlds news that finds its way to this blog is in effect a free research service for the news organizations that are willing to use it for picking up interesting information quickly.
Larry
If it was melting, it would be receding, not pushing into the sea, correct?
Maybe the Antarctic ice factory is making more cubes than blocks, but there sure is a lot of it these days: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.365.south.jpg
Late Wed evening I sent the following to the Fox News web site:
I have three questions about the ice breaking away from Antarctica: ONE: Has this ever happened before, and when? TWO: If the ice is already floating in the sea, how can it hold back a glacier that has its bottom on land? THREE: If the ice shelf is in the sea would it not be buffeted by storm waves and tides so as it grows and extents farther into the sea it might be more inclined to fracture. If so, would this not be a sign that the ice has been growing, and like a floating dock pushed around more the farther out it is extended? But unlike a dock, it is not hinged, and so doesn’t it have to break at some point? As you might guess from these questions, I’m not convinced this activity is related to global warming. I think these scientists are seeing a cause they expect to find and not looking for other, more direct, causes. To be “Fair & Balanced” I think you need to have another go at this story.
Alex (08:32:01) :
. . .I see in the centre of the images a hair-thin peninsula of ice… Has this broken yet? Is it ice or a land bridge? If it is ice, and has not broken yet, why not?
It was part of the shelf, floating, and it’s gone. The majority of the Wilkins shelf is still there, more sheltered than the bridge out to the island.
hotrod (10:58:05) : “Actually we are doing it by posting here.”
True to an extent, but this site only reaches the MSM outlets that visit it, whereas a Press Release issued using a service such as PR Newswire http://www.prnewswire.com/ has the potential to reach thousands of MSM outlets and to be picked up by hundreds of them.
Stop the presses! President Obama just released his Arctic ice forecast in remarks he made in Missouri yesterday!
“So this is no joke. And the science shows that the planet is getting warmer faster than people expected. Even the most dire warnings, it’s gotten—it’s moved forward faster than anybody expected. They’re talking about, just in a few years, during the summer, there won’t be any ice in the Arctic, something we have never seen before. So we have to do something about it.”
(See ICECAP for more details…http://www.icecap.us/)
I propose a massive ice cube donation drive! Everyone in America can donate one tray of ice cubes from their freezer. These will be trucked to the Arctic in those Russian-made trucks that recently made it to the North Pole (or optionally to be hand carried by the Catlin Expedition). Save the Arctic!!
John Galt (10:58:58) :
When ice becomes thick enough the crystals compress and flatten much like a deck of playing cards. Increasing mass causes the ice to slide down slope or outward from the highest/thickest place. Warm temperatures can cause ablation (melting, evaporation, iceberg calving and sublimation)
http://en.wikipedia.org/wiki/Ablation_zone
but it is possible for the snout of the ice to be moving forward more rapidly than it is ablating – so it is not receding. [I think the extreme flattening of the crystals also contribute the blue color one sees when looking at old glacial ice. Perhaps someone with an optics background might comment on that.]
The following article Rapid climate change in the ocean west of the Antarctic Peninsula during the second half of the 20th century contains an interesting graphic of “Decadal surface temperature anomalies in the vicinity of the Antarctic Peninsula.”
Fifty years ago, the area experienced a cold anomaly, now it is experiencing a warm anomaly.
When the media cites “increases in temperature over the last 50 years”, isn’t that a lot like attributing the change in temperature between January and July to “a warming trend”?
Re: wattsupwiththat (10:04:16) :
You must have already refreshed to read the above post 🙂
I’m confused – on April 6th the ice bridge to Charcot island was reported to have collapsed (http://earthobservatory.nasa.gov/IOTD/view.php?id=37806) but on the pictures above there still seems to be a connection. Am I missing something?
Whilst this work was specific to ice bergs it would not seem too great a leap to think it would also apply to ice shelves.
Alaska Science Forum May 12, 1983 – Polar Ice: Problems with a Potential Natural Resource, http://www.gi.alaska.edu/ScienceForum/ASF6/606.html
Squire and his colleagues mounted “strainmeters” on a number of icebergs in the Antarctic and monitored the small distortions resulting from the “surf” around the bergs’ margins. It was found that each iceberg has a unique resonant frequency of vibration, depending on its size and shape.
Although it would seem that ordinary ocean waves should have little effect on such a massive body, if the wave frequency matches that of the iceberg (or of one of its harmonics), the expansion and contraction induced could build to the point where the iceberg shatters. A good analogy, says Squire, would be that of a singer’s voice shattering a wine glass.
The process is then repeated with the smaller pieces, each of which has a higher resonant frequency, until the bulk has been reduced to the point that only waves of unattainable frequency could damage it further.
GregS, send those expert following chart:
http://www.junkscience.com/MSU_Temps/UAHMSUSPol.html