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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GoreacleWarmites have changed their lexicon: the new phrase is:
“atmospheric warming”.
“There is little doubt that these changes are the result of atmospheric warming,” said David Vaughan of the British Antarctic Survey.”
…-
“Satellite shows Antarctic ice shelf breaking away”
urlm.in/chib
Philip B , My bad, the west side of the peninsular is ice free for 6 months the east side has quite a large ice sheet all year per climate4you sea ice. I agree that the ocean currents and prevailing winds are the primary cause of ice variations.
Watch the grass not grow – too cold
Watch the paint not dry – too humid
Watch the blue line reach for the grey line – too cool!
http://www.nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png
What a strange pasttime.
Peter Plail (11:43:07) :
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?
Yes, the images you refer to are dated last fall, the ones I linked to are current and show the complete destruction of the ice bridge.
http://www.esa.int/esaEO/SEMYBBSTGOF_index_0.html
Here’s link from a couple of days ago showing where the bridge used to be.
http://www.esa.int/images/asar20090427annotated_L.jpg
Way OT
In response to a headline on RC about the line in the NYT Rivken story about how oil industry knowingly buried conclusions confirming warming, I posted the following complete industry memo quote contradicting the story onto the thread:
(Line the NYT jumped on: ‘The potential for a human impact on climate is based on well-established scientific fact, and should not be denied.) While, in theory, human activities have the potential to result in net cooling, a concern about 25 years ago, the current balance between greenhouse gas emissions and the emissions of particulates and particulate-formers is such that essentially all of today’s concern is about net warming. However, as will be discussed below, it is still not possible to accurately predict the magnitude (if any), timing or impact of climate change as a result of the increase in greenhouse gas concentrations. Also, because of the complex, possibly chaotic, nature of the climate system, it may never be possible to accurately predict future climate or to estimate the impact of increased greenhouse gas concentrations.’
the response to the whole article is pretty interesting: http://www.climate-resistance.org/2009/04/know-your-times.
However, this in-context response to the Rivken cherry-picking never was allowed to make it onto the RC thread.
Seems like Stalinist etiquette reigns over at Real Climate. A real confidence builder as to RC’s objectivity.
Its like my cigarette, the ash doesn’t fall off because it is melting, it falls off because it is getting too large to hold its own weight, so, it grows, falls off, grows, falls off. The only difference in the Antarctic is that the snow/ice in the interior (and sea ice as well) continues to replenish this cycle. It has done so forever, and will continue to do so forever more. Nothing more to see here.
I just wanted to make a comment about the pictures (such as the very top one) and a YouTube video I watched of a fly through of a similar region. These are absolutely remarkable images! Until I watched that YouTube video, I had no idea of the magnitude of all of this. The shear size and scope of what the Antarctica is all about is absolutely amazing!
I can tell you this with absolute certainty, the general public has not one shred of a clue just how extensive, massively huge and majestic the Antarctic is. I am a fairly well educated individual and I had no clue (and probably still don’t).
I would suggest that if one really wants to get someones attention about the “real” state of Antarctica, simply put together a “real” image of what Antarctica is really all about, and then show them the insignificance of the various ice shelf breakages, and how these events obviously take place on a fairly regular occasion. You would enlighten people to the facts almost instantly I can assure you.
The whole reason the AGW propaganda machine is able to induce mass hysteria, is because there are too many people out there (like me) that have no clue what this all “really” means, and we need real and accurate imagery to grasp it.
IMHO…
Antarctica – 75 °C
SPO – 2.836 m -68,6 °C (31 marzo)
AW3 – 3.250m -72,4 °C (19 aprile)
CON – 3.233 m -73,9 °C (19 aprile) dati incompleti
AW1 – 4.084 m -75,3 °C (20 aprile)
VOS – 3.488 m -75,7 °C (20 aprile)
Regarding Vostok, last year we had to wait until May 15 (-75.8 ° C) to measure a value so low, at Dome Argus, however, even June 13 (-75.4 ° C). ( http://www.meteogiornale.it/news/read.php?id=19919 ). It should be remembered that this is not exceptional values: as already explained, in April on the Antarctic Plateau, temperatures can also break the barrier of -80 ° C
http://www.meteogiornale.it/news/read.php?id=20017
On the last picture on this post there is a spiral formed area of ice to the right of the highlighted ice sheet.
Winds or currents causing the ice to rotate in that area I guess. Maybe thats the reason why it got ripped off?
Phil. (12:40:11) :
Thanks for that Phil. I see that it has now collapsed, but the point I’m making is that there was a lot of fuss in the press about the collapse of the ice bridge then (start of April), so if it collapsed then has it regrown and collapsed again in the last few days, or were the reports of its demise exaggerated, as seems to be acceptable practice in AGW speak?
The text on the link I posted (http://earthobservatory.nasa.gov/IOTD/view.php?id=37806) clearly said “A narrow ice bridge connecting Charcot Island and Latady Island—the last remnant of the northern part of Antarctica’s Wilkins Ice Shelf—broke apart in early April 2009.” The picture above it was used to show the location of the ice bridge when it was in position.
Actually, anecdotal records from slightly higher up than Vostok Station purport to have measured -91C; but the official Vostok low was sbout -128.8 F, which is just short of -90C.
But -120 F is an every year occurrence.
I saw somewhere recently that the all time Antarctica High Temperature was +17 deg F. I’m a bit surprised it is always below freezing, but if I run across the table of continental record lows again I wll mention it.
George
What happened to “Ice Area” plots at NSIDC? I can only find “Ice Extent”.
Ice shelves may or may not be “grounded”, more or less buried or resting on the sea floor. If they are grounded, wave action would probably not have much effect on them except maybe at the edges. Contrary to popular AGW opinion, ice shelves are not static entities. They are constantly being fed by glaciers (at least five for the Wilkins), which tend to push the ice shelf out to sea. In the case of the Wilkins Ice Shelf, more than likely the bulk of the ice shelf is not grounded. There are also a number of ice rises (essentially, islands over which the ice sheet flows) within the Wilkins Ice Shelf. Two of them, Burgess and Vere (http://www.uni-muenster.de/Physik.GP/Polargeophysik/Wilkins-Schelfeis.html see top photo) are very close to where this year’s and last year’s break-ups originated (http://www.uni-muenster.de/imperia/md/content/geophysik/polargeophysik2/bilderfotos/map_feb2july.jpg). Just the pressure of the multitude of glaciers feeding it from Alexander Island would induce stress fractures, as the ice sheet flowed over these rises. The ice shelf would tend to bulge/buckle inducing tension along the crest of the bulge. This tension could result in fractures in the ice similar to what is seen in the photos. Once fractured, these fractures (even if they refreeze) become weak areas in the ice sheet. At this point, the ice sheet is at the mercy of the wind, ocean currents, and waves.
Looks to me that the breakup is totally natural.
Barry Foster (08:44:57) :
So the Met Office has issued yet another ‘forecast’ of a hot summer. Hmm. ‘Hanging on in quiet desperation is the English way’.
Barry, there’s a lot of us shaking our heads ‘in quiet desperation’ at how our once respected institutions have been reduced to following the money. That really wasn’t the English way, but Blair and Brown have been swinging their wrecking ball for 12 years now, and the place is indeed beginning to resemble the dark side of the moon.
Further research reveals this website, confirming my suspicions:
http://www.zfl.uni-bonn.de/
However, the authors have not forgotten who fills their rice bowls by inserting the following text “The here observed effect, which is likely to be amplified by the high temperatures and in particular due to the dynamic effect of the break-up events, however, acts destabilising.”. This, in spite of no evidence of any “high” temperatures over the past 30 years (http://mclean.ch/climate/docs/Wilkins_Ice_Shelf_con.pdf Figure 2).
Here is a thout for an expedition… what if they used a submarine to go take pictures of under (obviously) unbroken ice shelves and look if there are fractures?
Peter Plail (14:10:57) :
Phil. (12:40:11) :
Thanks for that Phil. I see that it has now collapsed, but the point I’m making is that there was a lot of fuss in the press about the collapse of the ice bridge then (start of April), so if it collapsed then has it regrown and collapsed again in the last few days, or were the reports of its demise exaggerated, as seems to be acceptable practice in AGW speak?
The bridge did collapse in early April as had been anticipated for a few years because each year the bridge had become narrower and more precarious.
The reports of its demise were not exaggerated, indeed the predictions of rapid further collapse following the loss of the bridge (the pinning point for the ice sheet), prove to be correct as the animation of the breakup of the main body of the sheet over the last few weeks has shown.
“…totally natural”.
But I think the whole point here is that the 10 ice bridges that have been disintegrating had been in place for THOUSANDS OF YEARS, thus indicating an overall trend towards less ice. And it requires energy(i.e. heat) to melt ice.
Is it “natural” for earth to have this much melting? Yes if you look back more than 10,000 years. However mankind didn’t exist so we didn’t care. This time we care… a lot.
Pete
Greg S says:
I think the answer to this question is likely the same as the answer to why the Steig et al. paper’s study used data starting about 50 years ago, namely that 1957-1958 was designated The International Geophysical Year (see e.g. http://www.geosc.psu.edu/~sak/IGY/ ) and was accompanied by a major effort to coordinate globe-wide measurements, with Antarctica being a particular area of focus (since it was at that time a very neglected area). As a result, most of the data for Antarctica is only available starting then. I believe before that time the data for Antarctica is much less extensive.
I love looking at this stuff. It’s like the car crash on the side of the highway or something
It’s sick but true. The picture looks so peacefull, the first one that is. Shame we are doing our part in destroying it.
j
mastercontrolcast.wordpress.com
Pete W (16:47:53) :
Pete – please remember, as weather is NOT climate, the Wilkins ice shelf is also NOT climate…
Also, have a look at this before concluding that antarctica is “indicating an overall trend towards less ice. ”
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.south.jpg
lurkerbelow (18:36:39) :
“Shame we are doing our part in destroying it. ”
Please prove this…
I am curious to know how high above the water is the sheet edge that starts in the bottom-right of the color photo and extends to the middle of the photo. Also, about how long are the sheets in the picture. I am clueless as to their scale. Can anyone help me on that? Thanks!
Pete W.,
You’re missing the point. There hasn’t been any heat or energy (other than kinetic) to melt the ice (and the kinetic energy is not melting the ice, but is fracturing the ice). Do you see any evidence of melting in any of the photos above? The breakup is doing the fracturing. Did you even bother reading any of the links I provided?
Are there any images of Antarctica showing absolute temperatures? Such a picture might show in red, only the areas known to have ever risen above the melting point.