This fits right in to what I’ve been blogging about for two years. the 2007 record minimum ice extent was wind driven not melt driven. A significant portion of the ice did not melt in place. It was pushed south by the wind where it melted.
Here’s where the wind is a factor in pushing past the ice arches:
NASA Sees Arctic Ocean Circulation Do an About-Face
Arctic Sea ice loss – “it’s the wind” says NASA
Here’s where ice arches help: Update on Arctic sea ice melt – “Ice pockets choking Northern Passage”
Watch how ice flows in the Arctic: Arctic Sea Ice Time Lapse from 1978 to 2009 using NSIDC data
Today’s Press Release From JPL:
Missing ‘Ice Arches’ Contributed to 2007 Arctic Ice Loss
Animation: View animation (GIF 52 Mb) | View animation (GIF 13 Mb)
PASADENA, Calif. – In 2007, the Arctic lost a massive amount of thick, multiyear sea ice, contributing to that year’s record-low extent of Arctic sea ice. A new NASA-led study has found that the record loss that year was due in part to the absence of “ice arches,” naturally-forming, curved ice structures that span the openings between two land points. These arches block sea ice from being pushed by winds or currents through narrow passages and out of the Arctic basin.
Beginning each fall, sea ice spreads across the surface of the Arctic Ocean until it becomes confined by surrounding continents. Only a few passages — including the Fram Strait and Nares Strait — allow sea ice to escape.
“There are a couple of ways to lose Arctic ice: when it flows out and when it melts,” said lead study researcher Ron Kwok of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We are trying to quantify how much we’re losing by outflow versus melt.”
Kwok and colleagues found that ice arches were missing in 2007 from the Nares Strait, a relatively narrow 30- to 40-kilometer-wide (19- to 25-mile-wide) passage west of Greenland. Without the arches, ice exited freely from the Arctic. The Fram Strait, east of Greenland, is about 400 kilometers (249 miles) wide and is the passage through which most sea ice usually exits the Arctic.
Despite Nares’ narrow width, the team reports that in 2007, ice loss through Nares equaled more than 10 percent of the amount emptied on average each year through the wider Fram Strait.
“Until recently, we didn’t think the small straits were important for ice loss,” Kwok said. The findings were published this month in Geophysical Research Letters.
“One of our most important goals is developing predictive models of Arctic sea ice cover,” said Tom Wagner, cryosphere program manager at NASA Headquarters in Washington. “Such models are important not only to understanding changes in the Arctic, but also changes in global and North American climate. Figuring out how ice is lost through the Fram and Nares straits is critical to developing those models.”
To find out more about the ice motion in Nares Strait, the scientists examined a 13-year record of high-resolution radar images from the Canadian RADARSAT and European Envisat satellites. They found that 2007 was a unique year – the only one on record when arches failed to form, allowing ice to flow unobstructed through winter and spring.
The arches usually form at southern and northern points within Nares Strait when big blocks of sea ice try to flow through the strait’s restricted confines, become stuck and are compressed by other ice. This grinds the flow of sea ice to a halt.
“We don’t completely understand the conditions conducive to the formation of these arches,” Kwok said. “We do know that they are temperature-dependent because they only form in winter. So there’s concern that if climate warms, the arches could stop forming.”
To quantify the impact of ice arches on Arctic Ocean ice cover, the team tracked ice motion evident in the 13-year span of satellite radar images. They calculated the area of ice passing through an imaginary line, or “gate,” at the entrance to Nares Strait. Then they incorporated ice thickness data from NASA’s ICESat to estimate the volume lost through Nares.
They found that in 2007, Nares Strait drained the Arctic Ocean of 88,060 square kilometers (34,000 square miles) of sea ice, or a volume of 60 cubic miles. The amount was more than twice the average amount lost through Nares each year between 1997 and 2009.
The ice lost through Nares Strait was some of the thickest and oldest in the Arctic Ocean.
“If indeed these arches are less likely to form in the future, we have to account for the annual ice loss through this narrow passage. Potentially, this could lead to an even more rapid decline in the summer ice extent of the Arctic Ocean,” Kwok said.
For more information about NASA and agency programs, visit: http://www.nasa.gov .
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h/t to Dr. Leif Svalgaard
Doesn’t this call into question the whole sea ice extent melt trick?
I mean, unless you know how much sea ice blew away, what exactly do you know about sea ice melt.
Stephen Wilde 4:37:17
I agree with you and kadaka. Now make it about a hundred times more complicated and you’ll about have it.
I particularly liked your point that the Arctic melting was from the PDO in its warm phase, and the time between the onset of the cool phase and 2007 represents the lag time needed by the heat engine that is the earth to pump heat from the tropics poleward.
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“wayne (00:35:30) :
If you have an hour or so, this is well worth it:
Colloquium on The Peculiar Issue of Global Warming
Spreaker: Dr. Richard Lindzen”
Why is anybody using Real Player? What is this ten years ago? Haven’t they heard of Flash? Oh wait it is a university. When someone uploads this to one of the hundreds of flash based video sites let me know. This sort of technological stupidy kills content.
If you want people to watch something provide it in a content format that they easily can (no I do not want to install 20 MB of crappy Real Player). I haven’t had to use that in years.
The current AMSR-E plot shows Arctic sea-ice extent plot value is now about mid-range for all data values recorded this time of year since 2003. This would seem to indicate that we need not worry about all this ice melting away any time soon.
Those ice-bridges would seem to be formed by huge icefloes that were propelled by the wind, tides and coriolis into the strait, and then are grounded.
So the whole icebridge phenomenon must be to do with the clearance between the bottom of icefloes and the seabed. A small reduction in clearance will result in an early grounding, and an increase in clearance would result in no grounding at all, and so no ice-bridge!
Factors controlling the clearance would include water density, ice thickness, seabed slop, and so on. As this phenomenon is ripe with possibilities for speculation/hypotheses etcetera, perhaps it is a suitable subject for a great collaborative piece of ‘blogsphere-science’ ?
Robert (19:09:51) :
“Watch the goal posts move before your eyes. ”
I hate to burst anyone’s bubble, but I know of no climate scientist who has claimed that all or even most ice loss is the result of melting in situ. It melts enough to break apart, then it drifts out to sea where it melts completely. Nobody thinks the Wilkins ice shelf melted away in place.
Much like the fantasy in which Al Gore claims it will never snow again, this is a distortion of the past in order to try and construct a “win.”
It really is funny to see the mental contortions that warmists will subject themselves to when they come across facts that do not support their preconceived beliefs.
Now, young Robert, I wouldn’t want to burst your bubble … but, exactly where did you see anyone claim the opposite of what you stated?
Me too – that is why I installed Real Player Alternative to watch it although it would only work in IE8 not Firefox
Ola Tedin, you have a very cool name. Ya.
@Poptech
I’m glad I’m not the only one who was disappointed to find that Dr. Lindzen’s latest presentation is encoded in Real Player format. Ugh, what a stupid decision. The only thing I can figure is that they wanted to use the interactive slide feature of Real Player so that when Dr. Lindzen is speaking and clicks on the next slide it pops up in a new browser window. It’s actually sort of annoying because it opens up dozens of browser windows!
Anyway, if you don’t like Real Player (and what’s to like?), remember that you can also download “Real Alternative” and thus avoid all the Junk and Adware that Real Player normally installs:
http://www.codecguide.com/about_real.htm
I would be looking at how the arches form. It is a natural phenomenon, thus the structure will be naturally different each and every time. Weak here, strong there, in a rather chaotic way from year to year. Add warmer currents underneath that naturally show up from time to time. Add a steady wind during formation that naturally shows up from time to time. And what you get is the wonderful infinite variety of nature’s structure building. Nature does not care, if this year, it builds something that isn’t quake proof. It has not and will not read the building codes or fork out money for a building permit. If we don’t like fickle mother nature thumbing it’s nose at how to build something that will last, I suggest we find another planet that has far less variety and live there.
Something I have not seen mentioned before. I don’t know if it has been posted here. From:
http://www.openthemagazine.com/article/international/the-hottest-hoax-in-the-world
“Another total lie has been that the Sunderbans in Bangladesh are sinking on account of the rise in sea level. The IPCC claimed that one-fifth of Bangladesh will be under water by 2050. Well, it turns out this is an absurd, unscientific and outrageous claim. According to scientists at the Centre for Environmental and Geographical Information Services (Cegis) in Dhaka, its surface area appears to be growing by 20 sq km annually. Cegis has based its results on more than 30 years of satellite imagery. IPCC has not retracted this claim. As far as they are concerned, Bangladesh is a goner by 2050, submerged forever in the Bay of Bengal.”
The Albedo-feedback from the sea ice melting or not melting in the Arctic is very, very small. This has been way over-blown because people haven’t worked through the numbers.
First, the area we are talking about here is that above 75N. The ice already more-or-less melts out in the summer melt season up to 75N. This area above 75N is only 1.7% of the Earth’s surface.
Second, the Albedo above 75N is already pretty low in the summer melt season. Melt ponds and melted snow put the Albedo down to about 0.5 in the summer. It is only the freshly-snow-covered sea ice that has the high Albedos of 0.7 to 0.9.
Even if this ice melts, the Albedo is still going to be 0.3 or so just because of the cloudiness, some remaining ice etc. So the change is only 0.2.
Third, we are only talking about a month or two extra when the ice above 75N will melt. It is still going to be frozen solid well into August and then re-frozen again by early October even in a warmer world.
So overall, if the ice melted out above 75N in mid-August and then refroze in early October, the Earth’s Albedo would only decline by 0.0004 and the solar forcing would only increase by 0.03 watts/metre^2 – much less than that which occurs during a solar cycle. Throw in the ice melting out earlier in the season in the areas below 75N and you could double those numbers – still very little impact.
rbateman (22:57:31) :
Robert (22:32:54) :
I can think of something really bad happening if the sea level were to drop:
Panama and Suez canals idled for starters.
All that cheap Global Seafaring stuff would take a hit.
Sea levels dropping would mean ports in difficulties, and northern sea lanes interdicted with treacherous icebergs.
You don’t know how good you got it until it’s gone.
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Reply:
Consider the impact the next Ice Age will have on all the above when the sea level drops as much as120 meters like it has in the past!
I’d much rather have open oceans due to a bit of warming than have a significant portion of the ocean’s mass depressing the continents with up to two miles (~3km) of ice!
There is no comparison. Warm is good; cold is bad!
Ref – wayne (04:08:23)
“Robert, you are exaggerating again.
“Not going to do your math for you but, for one, you forgot your geometry.
“We don’t want to mislead here on WUWT if we can help it, do we?
“And don’t feel alone, your fellow AGWers do it all the time.”
__________________
Wayne? Why do you like playing with matches and gasoline?
Robert 21:51:38
Here is an excellent site showing the arctic as likely being ice free 6,000 to 7,000 years ago, think 4,000 BC.
http://www.ngu.no/en-gb/Aktuelt/2008/Less-ice-in-the-Arctic-Ocean-6000-7000-years-ago/
Extract
Open sea
”The beach ridges which we have had dated to about 6000-7000 years ago were shaped by wave activity,” says Astrid Lyså. They are located at the mouth of Independence Fjord in North Greenland, on an open, flat plain facing directly onto the Arctic Ocean. Today, drift ice forms a continuous cover from the land here.
Astrid Lyså says that such old beach formations require that the sea all the way to the North Pole was periodically ice free for a long time.
”This stands in sharp contrast to the present-day situation where only ridges piled up by pack ice are being formed,” she says.
Lloyd Graves
@RockyRoad
I just read through Burt Rutan’s Intro for a future report on Global Warming Data Presentation Fraud:
http://rps3.com/Pages/Burt_Rutan_on_Climate_Change.htm
The thing I get is, looking at longer periods, it is really hard to see how global warming could be bad — the system has always exerted a very definite strong downward correction. And even if we were somehow exceed limits, we’re still due for an ice age.
Whether the temperatures go up or down, something somewhere changes.
The irony is the AGW environmentalists and politicians are trying really hard to force changes upon us.
re- crosspatch (23:48:19) :
Speaking of sea level, anyone have any idea of how often ucolorado updates this:
http://sealevel.colorado.edu/results.php
It hasn’t been updated since some time in 2009.
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Last year, I asked about update frequency because there had not been an update between about March to September 2009.
And received this reply from one of the site contacts, Dr Nerem, in September 2009: “We have never updated the site more than 3-4 times a year. A new update should be available by the end of the week.”
(that being in Sept 2009 time reference)
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I subsequently checked their web site, and indeed the #version_2009_rel4 data was posted not long after the email.
Comparing the 2009 rel4 data with earlier data from their site, I was surprised to find that, not only were there new appended values in 2009, but also there had been changes made going back through at least the 2008 data. The changes were both – and +, with the largest adjustments ( about + 3 mm) made to already published “barometer not applied” 2009 values. That +3 mm is significant, relative to their published trend line of 3.2 +/- 0.4 mm/year. I do not recall seeing discussion at the web site as to the nature or reasons for those adjustments.
sorry Charles. I am content to share it only with you.
“The IPPC report, of course, is not a PhD thesis – it is supposed to the “gold standard”. Yet what would be unacceptable of a college graduate is deemed by the “climate scientists” of Real Climate to be perfectly acceptable for the IPCC.”
http://eureferendum.blogspot.com/2010/02/self-deception-writ-large.html
If I’ve understood it correctly, this article is talking about 44k km2 “more than normal”. . . isn’t that fairly small beer?
crosspatch (23:48:19) : I pulled up this at their site, it has 2010_rel1 on it.
http://sealevel.colorado.edu/current/sl_ib_ns_global.jpg
You’re right, though, it looks truncated about Nov/Dec 2009
Robert:
“One swallow does not” a summer make. By the way, what is the temperature record at Nares Strait?
That’s not a bridge, it’s a bugger. Nares Strait….get it? Omigod, kim, go away.
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Don Shaw (04:54:27) :
“…It seems to me that the DMI temperatures that jog above and below the 42 year daily mean plot predict the jogs in the slope slope of the extent curve. This might make sense especially in the winter when wind and currents may have less impact…”
Good attempt, Don, but that little blue line near the top of the DMI chart represents the freezing point of water. The Jigs, Jags and jogs you currently see are at least 30 degrees Kelvin below that. At this time of year wind, currents and water temperature are the only explanations for sea ice extent. Air temperature, I’m afraid, has nothing to add.
Hah, Cicerone criticizes the IPCC but not the National Academy of Science. Someone hold a mirror up to him.
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