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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FoxNews says, “Average temperatures in the Antarctic Peninsula have risen by 3.8 degrees Fahrenheit (2.5 Celsius) over the past 50 years — higher than the average global rise, according to studies.”
Okay…….
But why does the press chose the 50 comparison? Why not a 25, 75 or 100 year endpoint?
Could it be because the West Antarctic Peninsula was colder than average 50 years ago and choosing the half-century endpoint serves to amplify the temperature differential and heat up the rhetoric.
OT:
UK Met Office came out today with its forecast for a Hotter than Average and Dry UK Summer
http://news.bbc.co.uk/2/hi/uk_news/8026668.stm
Does anybody study the wave effect on this event beside the current and wind
Good work.
Please slow down the animation or provide a second one that is much slower.
It is difficult to view at that speed, when you are first trying to get a handle on what is happening.
Thank you
Fox news, I’m shocked! I thought their stories were all biased to the right-wing, evangelical, denialist point of view.
I would also appreciate a slightly slower animation. 🙂
There’s a more recent animation showing what’s happened in the last week:
http://www.esa.int/esaEO/SEMWZS5DHNF_index_0.html
Notice the development of the large gap over the last few days,
most recent image:
http://esamultimedia.esa.int/images/wilkinsarctic/pub/images/ASA_IMM_1PNPDE20090428_045952_000002122078_00305_37433_3737_100m_img.jpg
Very interesting indeed!
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?
Ben (08:11:07) :
Good work.
Please slow down the animation or provide a second one that is much slower.
It is difficult to view at that speed, when you are first trying to get a handle on what is happening.
If you go to the ESA site you can see the individual images from which the animation has been created to view at your leisure:
http://www.esa.int/esaEO/SEMYBBSTGOF_index_0.html
JaneHM That sounds very reasonable when you look at http://earth.rice.edu/mtpe/hydro/hydrosphere/latest/avhrr_sst/avhrr_ssta.html
this is a daily update by NOAA of the global sea surface temperature which as most knowledgable people are aware controls our land temperatures and climate. The SST changes very slowly and the UK is surrounded by warmer than average water. You will notice two very warm patches in the Arctic which is the cause of the Loss of Arctic ice together with prevailing winds. The Antarctic ice shelf off the western peninsular is also surrounded by warmer than average water unlike the rest of the antarctic which is colder than normal thus the antarctic has over a million sq km more sea ice than the 1979 – 2000 average the arctic has 200 000 sq km less. The reason the average starts at 1979 is that is when the satellites fist started to measure the sea ice extent. One can cherry pick isolated weather events in time and location on both sides of the argument but they have absolutely nothing to do with climate. In a similar fashion to try and debate the issue using global averages is equally futile one should look at the long term history of regions of the world, one of the best records is the oldest continuous thermometer record from central england which dates back to 1659 and can be found on climate4you.com I would challenge anyone to show any global warming in this record.
Again and again we see this statement that the sea ice is “holding back” glaciers. This demonstrates a complete misconception of how glaciers move. If a glacier’s rate of melting (ablation) exceeds it’s rate of accumulation it RETREATS (i.e. it would move back from the shoreline, not towards it). If the sea ice is in fact holding the glaciers back (how does something that brittle hold back something with far greater mass?) then the glaciers must be ADVANCING. So we shouldn’t have to worry about sea level rise. Aaahh, the frustration!!
Yes, can I endorse a slower video for us old ‘uns?
So the Met Office has issued yet another ‘forecast’ of a hot summer. Hmm. ‘Hanging on in quiet desperation is the English way’.
JaneHM, the UK Met Office could be right this time… might rain, might not, who knows? LOL
Or, perhaps provide a link with the still photos you’ve highlighted?
You appear to be making a good point. Would like to see it more clearly.
Again – Good work.
Here’s an interesting description of the Wilkins collapse:
http://www.the-cryosphere-discuss.net/2/341/2008/tcd-2-341-2008.pdf
The study suggests that the collapse of the Wilkins ice shelf (WIS) is due to a superposition of slow mechanical destabilization and rapid breakup events. Their main conclusions is that the warming Wilkins ice is prone to fracturing more than others, which explains its quite rapid disintegration. .
What about the tidal effects and does anybody know what the normal levels are for this latitude? As shown on this site before the tides up in Alaska can reach 40+ feet. Don’t think even a large ice sheet could withstand this kind of shear.
Here is a basic question: If Antarctica is cooling (which I believe) and the ice is growing (which I believe) won’t this growth always create areas that will “calve off” or break off at some point? I mean, sure, if the Oceans got really cold then the ice could grow all the way to Australia and eventually beyond, but when you see large chuncks breaking off – doesn’t this show it was pushed out there where the environment is not stable by the ice behind it where cooling is occurring? I’ve seen posts here that show this Wilkins area breaks off every so often and it seems like its happening more often – doesn’t that suggest it’s growing faster, leading to more numerous break off?
I’m all for slower as well, and thanks, Mike McMillan and Anthony. Yes, Greg S., it seems that all corporate-owned news stations have been taken over by global-AGW-cap-and-trade corporatism. Don’t “we” have any group that can put forward fair-and-balanced mainstream news? Anthony, have you or any of your crew thought of a mainstream outlet in addition to WUWT?
[snip ]
JaneHM: Based on the Met Office statement of September last year ‘The Met Office forecast for the coming winter suggests it is, once again, likely to be milder than average’, I should be prepared for a cool, wet summer. No apologies were forthcoming from the Met Office after we were totally unprepared for the cold and snow, and that it cost a lot of extra money to cope with not being prepared.
[snip – don’t ever post a reference to Nazi death trains here again, poetic or not, first and final warning- instant banishment awaits. – Anthony]
Confirmation bias in action. They’ve got to report on something and that darn Arctic ice isn’t playing by the script.
And when, over time, as ice flows and the ice shelf reforms, what are the odds this will be reported by the media? Selective perception.
This is not a” current event ”
In 1990, area of the ice shelf was 17000km^2
in 2008- area=13000 km^2
Now, some 4000 km^2 are disapearing.
(The animation is not updated.There is another, from April-2009 on esa.int{europeean space agency)).
Probably ,in February next year, Wilkins ice shelf will be only 8000 km ^2.
The Larsen B was 10000 y old, as it resulted from drilling under the collapsed area(in 2002}
Wilkins ice shelf is 3 deg.south then Larsen.
When drilling will be performed, they will probably show that it was in place during all the last ice age.
Somethig who is happening for the first time in 125000 years is not a “current event”.
Hi,
I once published a post titled “Wilkins Ice Shelf Paranoia”
http://p2o2.blogspot.com/2008/07/wilkins-ice-shelf-paranoia.html
The part called “Disintegration. Antarctic Warming Claims Another Ice Shelf.” which hyperlinks to Earth Observatory has no images. They can be found now here:
http://earthobservatory.nasa.gov/Features/WilkinsIceSheet/
The Earth Observatory simply removed “Study” category and moved the text to “Feature Articles” directory.
Regards
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
Regards
A slower animation has been posted, please refresh. – Anthony