Stronger winds explain puzzling growth of sea ice in Antarctica
From University of Washington press room by Hannah Hickey
Much attention is paid to melting sea ice in the Arctic. But less clear is the situation on the other side of the planet. Despite warmer air and oceans, there’s more sea ice in Antarctica now than in the 1970s – a fact often pounced on by global warming skeptics. The latest numbers suggest the Antarctic sea ice may be heading toward a record high this year.
While changes in weather may play a big role in short-term changes in sea ice seen in the past couple of months, changes in winds have apparently led to the more general upward sea ice trend during the past few decades, according to University of Washington research. A new modeling study to be published in the Journal of Climate shows that stronger polar winds lead to an increase in Antarctic sea ice, even in a warming climate.
“The overwhelming evidence is that the Southern Ocean is warming,” said author Jinlun Zhang, an oceanographer at the UW Applied Physics Laboratory. “Why would sea ice be increasing? Although the rate of increase is small, it is a puzzle to scientists.”
This mixture of different types of Antarctic sea ice was photographed Oct. 13, 2012, by a NASA aircraft flying over the Bellingshausen Sea.
His new study shows that stronger westerly winds swirling around the South Pole can explain 80 percent of the increase in Antarctic sea ice volume in the past three decades.
The polar vortex that swirls around the South Pole is not just stronger than it was when satellite records began in the 1970s, it has more convergence, meaning it shoves the sea ice together to cause ridging. Stronger winds also drive ice faster, which leads to still more deformation and ridging. This creates thicker, longer-lasting ice, while exposing surrounding water and thin ice to the blistering cold winds that cause more ice growth.
In a computer simulation that includes detailed interactions between wind and sea, thick ice — more than 6 feet deep — increased by about 1 percent per year from 1979 to 2010, while the amount of thin ice stayed fairly constant. The end result is a thicker, slightly larger ice pack that lasts longer into the summer.
“You’ve got more thick ice, more ridged ice, and at the same time you will get more ice extent because the ice just survives longer,” Zhang said.
When the model held the polar winds at a constant level, the sea ice increased only 20 percent as much. A previous study by Zhang showed that changes in water density could explain the remaining increase.
“People have been talking about the possible link between winds and Antarctic sea ice expansion before, but I think this is the first study that confirms this link through a model experiment,” commented Axel Schweiger, a polar scientist at the UW Applied Physics Lab. “This is another process by which dynamic changes in the atmosphere can make changes in sea ice that are not necessarily expected.”
The research was funded by the National Science Foundation.
Still unknown is why the southern winds have been getting stronger. Some scientists have theorized that it could be related to global warming, or to the ozone depletion in the Southern Hemisphere, or just to natural cycles of variability.
Differences between the two poles could explain why they are not behaving in the same way. Surface air warming in the Arctic appears to be greater and more uniform, Zhang said. Another difference is that northern water is in a fairly protected basin, while the Antarctic sea ice floats in open oceans where it expands freely in winter and melts almost completely in summer.
The sea ice uptick in Antarctica is small compared with the amount being lost in the Arctic, meaning there is an overall decrease in sea ice worldwide.
Many of the global climate models have been unable to explain the observed increase in Antarctic sea ice. Researchers have been working to improve models to better reproduce the observed increase in sea ice there and predict what the future may bring.
Eventually, Zhang anticipates that if warmer temperatures come to dominate they will resolve the apparent contradiction.
“If the warming continues, at some point the trend will reverse,” Zhang said.
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The polar vortex that swirls around the South Pole is not just stronger than it was when satellite records began in the 1970s, it has more convergence, meaning it shoves the sea ice together to cause ridging.
This makes me wonder if this isn’t one of the reasons that the “ozone hole” continues, despite CFC reduction schemes. Of course the study is all model based, so it may not represent reality.
Meanwhile, the NSIDC appear to be blaming this years record Antarctic sea-ice extent on LIGHTER winds….:
http://nsidc.org/arcticseaicenews/
First, the oceans around Antarctica are not warming. All the datasets show no warming going back more than 100 years and there is clearly recent cooling given the sea ice conditions.
Secondly, the Antarctic sea ice extent reached a record high level on September 14th, 2013 according to NSIDC.
http://s17.postimg.org/wb91x69b3/Antarctic_SIE_NSIDC_Sept15_2013.png
(although I have some data showing it was higher in the early 1970s and the Cryosphere Today sea ice “area” is not showing a record).
The inconvenient truth is the Antarctic sea ice at (close to) record levels has to be explained by the warmers and there is no physically-logical reason why more wind would make the sea ice grow to a record.
Only “cold” water can make water freeze.
Dang, in all the online discussions I am repeatedly assured by warmists that the increased Antarctic sea ice is caused by the melting Antarctic ice cap. They are always very, very sure that is a fact, even though I explain it is simply one hypothesis, and that we can’t even be that sure the ice cap is losing mass, and there is little proof of acceleration.
Now they have a new
theoryfactidea.“model experiment” is an oxymoron. Why do they think their model comes anywhere near to reality? How does one calibrate such a model before doing an “experiment” with it. Totally bogus “science”.
The Antarctic is decoupled from the rest of the planet by the Coriolis currents, which are broken up and scattered by land in the Northern Hemisphere. If there was no land the planet would be separated into bands like Jupiter’s atmosphere (and probably wouldn’t have an ocean or be liquid anyway).
This is the reason it was difficult to even GET to Antarctica for earlier sailors. There is a boundary that is not easy to cross, either for ships or moisture or warm or cold.
This makes it difficult to draw any conclusions that have anything to do with climate from observing the Antarctic. Although, as usual, that doesn’t stop people from trying.
So here’s my question: what kind of mind set does it take to conclude that just because something is different than before, that:
a) it will continue being different
b) the difference will be harmful or hazardous or otherwise undesirable,
c) something “we” did must be causing it
?
“Why would sea ice be increasing? Although the rate of increase is small, it is a puzzle to scientists.”
That’s what you get when you are trying to make the data fit the theory-model instead of the other way around.
Zzzzzz
Using real world data instead of a model, other scientists come up with a much more plausible answer:
Study Finds Antarctic Sea Ice Increases When It Gets Colder
http://notalotofpeopleknowthat.wordpress.com/2013/08/17/study-finds-antarctic-sea-ice-increases-when-it-gets-colder/
So:
Air is warmer. Sea is warmer.
But:
while exposing surrounding water and thin ice to the blistering cold winds that cause more ice growth.
I sense an oxy-moron. And I’m not talking about the words. (specifically)
These folks are getting desperate; even hysterical.
Wait till they get a load of the bad winter that is coming for the Norther Hemisphere.
And with the ice build up in the Beaufort Gyre they are going to be really disappointed next year.
Every other climate related chart that I’ve seen shows reds for warmer and blues for colder. I wonder why this one uses the opposite. It wouldn’t be to make it look more “scary” would it?
‘small’ rate? Reduced, slow, even, what does it matter: it confirms a guess.
Thank you, Surfer Dave
“… the first study that confirms this link through a model experiment,” commented Axel Schweiger, …” A posited ‘link,’ confirmed by a ‘model experiment!’
When a theory blows more hot air than the winds do, is it still a theory?
To paraphrase two statements attributed to President Harry Truman (though I do have some doubts if he actually said the originals about economists) “If you lined up all the Climate Scientists in the world, they would still point in every direction.” and “If you lined up all the Climate Scientists in the world, they still would not reach a conclusion.” Good Ol’ Harry was a Democrat before the lefties made “Democrat” a dirty word.
Modeling study? Are the current batch of climate scientists incapable of studying data?
Oh, for the good old days before fatally flawed climate models.
So there we have it – wind pushes ice away from the Arctic however pushes it toward the Antarctic.
And a modelling study just released indicates that warm tropical winds are responsible for the melting of sea ice in the Arctic since 1970 despite much cooler temperatures in the region. According to Professor Able Zarkoff of the Arctic Modelling Research Facility “dis is sumthink vee nefer expeckted”.
So then why the big flap about 2007 which was subject to intense winds pushing ice out of the Arctic. Winds make ice lessor and greater, just like the rest of the CAGW proof, add wind to the warmer/colder/rain/drought/sea rising etc.
Hmmmmm. I’ve been talking about this on another thread. There are lots of longish term oscillations that are part and parcel of the Antarctic. One of them could be wind. Wind moves, shoves, and builds ice boundary extent closer to or further out from the continent and into the ocean and if thick enough (6 ft is thick!), can possibly shove oceanic surface currents out of their normal path boundaries.
And so I speculate: If the wind is creating a different boundary position near Drake’s passage, could it be that more of the circumpolar current gets diverted into the Pacific than usual? Is this a self-correcting somewhat irregular oscillation leading to a colder Pacific?
It snowed in Santiago, Chile yesterday. Same latitude as San Diego, CA, but inland & a 1700 feet above sea level. Unusual but may become more common in September.
OK.
So, the south polar winds are higher, so the ice is packed together MORE tightly, so the AREA is less unless the volume becomes larger (right?), so the final AREA is greater because the ice is thicker. However, the southern ice MELTS AWAY over their summer period (down to a slowly rising but miniscule 10% fraction of the winter extent peak of now 19,500,000 km’s. So, the ice remaining over the summer melt period cannot affect the extents of the following winter. But the winds DO carry from season to season?
OK. Yeah. Right. Sure. Whatever. (If two lefts make a right, and two negatives multiply to make a positive, don’t four rights make a climate model more correct?)
Zhang was wrong up north. He is now trying to be even more wrong down south. Now, winds spreading OUT the ice mass might explain a larger area, but then he’d have to explain why the ice exposed between the newly spread regions is freezing, when (up north) exposed ocean water is supposed to be melting faster!
They cannot let the increase in ice stand. They have to come up with some cock and bull study to make us believe that it is still worse than we thought. Will the insanity ever end..
I love climate models. !!!
Isn’t “climate” the Elvish word for “lingerie” ?
Looks like a thermostat to me, to dump the heat coming in from the temperate zone oceans that was pumped in by the last few rampant solar cycles.
Antarctic ice may also be a proxy for the extent of the fabrication of the climate record by the climate liars.
I guess he didn’t get the memo – the climate is not warming.