Cloudy interlude

Have you ever been to the French island of Corsica? Imagine you're there and all of a sudden the whole 8,680 square km island starts moving, moving away from the Côte d'Azur and gradually falling apart...

The Arctic has been very cloudy lately, so I haven't had the chance to update any animations. Luckily I saw a huge chunk of landfast ice - approximately the size of Corsica - breaking off the eastern coast of Greenland today. I hope to update the image the coming few days. That should buy me some time.

There's no need to zoom in on any satellite images, you can easily see it on today's Arctic Mosaic (day 195). Check Greenland's northeastern coastline.

Update July 15th: I've added day 196, despite a bit of cloudiness. The floe is already falling apart (they're not making the ice like they used to) and is drifting northwards for the time being.

Update July 21st: Added some more images (days 197, 201 and 202). Breaking apart some more.

Update July 25th: Added the last images (days 204 and 205). The story of this ice floe is over.

Update August 1st: I have made a second animation (from day 205 to day 213), not just to show how the ice floes has completely disintegrated, but also that it has hardly moved during the whole process of disintegration. This implies there isn't much ice transport out of Fram Strait.

Comments

[Kevin McKinney]

Definitely cool animation. . . and catch.

Today, the mainstream media was catching up to yesterday's news from "Neven1"--the Jakobshavn calving:

http://www.cbc.ca/technology/story/2010/07/14/greenland-glacier-iceberg.html

(I don't think CBC is generally too bad with their science reporting, but this one got mangled some.)

[Lord Soth]

Well the russians have updated the projected ice drift chart for the next week.

http://www.aari.nw.ru/clgmi/forecast/show_drift.asp?fign=0&lang=0

The Beaufort Gyre is expected to breakdown by the weekend. I assume it will then start turning in the proper direction.

If this does happen, prepare for shock and awe!

For what will be the past three weeks, the true ice loss in the arctic has been masked by the spreading of the ice field. Besides near the north pole, the Canadian side is showing large areas of loose ice, within the pack.

http://rapidfire.sci.gsfc.nasa.gov/subsets/?mosaic=Arctic.2010195.terra.2km

When, the gyre reverses, we will be in compression mode again, and the pack will decrease in size. Instead of reported melts of 40-50K a day, we will see a string of century melts, with the possibility of double century melts.

[Neven]

Well the russians have updated the projected ice drift chart for the next week.

Yes, I've noticed this too. I thought they update on Thursday, but this update was out yesterday (and perhaps even sooner). Let's see what PIPS' ice displacement map will look like today.

Looking at meteorological maps I see that there's a big low over Siberia. Perhaps when a high forms over the Canadian Archipelago the Arctic Dipole Anomaly will turn positive again.

If this happens I think there's a good chance the Northwest Passage and the Northern Sea Route will both be open again this year.

[Neven]

PIPS has updated, still looks a bit erratic, but there are some big arrows pointing to the right.

[Anu]

When, the gyre reverses, we will be in compression mode again, and the pack will decrease in size. Posted by: Lord Soth | July 15, 2010 at 13:09

I don't believe much in the "wind compression" story - what will wind do for this ?
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2010193.aqua

How much more compressed will these ice floes get ?
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r03c02.2010193.aqua

But more cloud-free days would warm up the exposed water and melt these ice floes from the bottom and from the top:
http://www.livescience.com/environment/071212-arctic-clouds.html

http://www.arctic.noaa.gov/detect/climate-clouds.shtml
84% cloud fraction over Arctic seas in Spring ? How much cloud cover is normal for summer ?

Maybe the Arctic Dipole and Arctic Oscillation affect the cloudcover, but I don't think the winds are that important besides blowing some thick ice out of the straits...

[Artful Dodger]

The gyre is a unique feature of the Beaufort sea / Arctic Basin (not the Baffin sea or Cdn Archipelago) and is caused by the rotation of the earth (as are winds). Something extraordinary is occurring there right now.

Patrick Lockerby has written extensively about the physics of the Arctic Basin pack ice. Thickening of the pack ice occurs when sea ice is driven against a resistive object (either land or more sea ice). The pack ice used to act as if it were a single mass (think "inelastic collisions")

Now that the pack ice has thinned and fragmented, it has lost it's strength in both sheer and compression. The process which used to cause sea ice to pile up and thicken now instead causes it to break up into ever smaller pieces.

Imagine a rock tumbling machine. The pack ice is the rock, and the Beaufort gyre is the tumbler. Folks, the 'stone age' is rapidly coming to an end...

[Lord Soth]

I was showing my six year old daughter the MODIS maps this morning, and I was explaining to her, that when she grows up, the North Pole will be open water in the Summer.

She burst into tears, saying that Santa and all the elves were going to drown. With quick thinking, I told her that Santa has a emergency contingency plan, and Santa will move his workshop to the middle of Greenland, and showed her all that thick ice in Greenland. It worked, and I saved the day.

[Kevin McKinney]

Dodger, your idea makes sense to me, especially after watching a few of these animations.

But I'm very curious about the reversal of the gyre; clearly the Earth's rotation doesn't cause that! Do I recall correctly that this reversal was forecast? That would imply that someone understands this matter reasonably well!

Also, I seem to recall mention here that this is something that happens occasionally. Any information on how often, what conditions are associated with it, etc.?

[Neven]

Kevin, here's a quote from the Asplin et al. 2008 paper:

The circulation of the BG is strongly driven by synoptic-scale
atmospheric circulation patterns. The prevailing atmospheric
circulation pattern is anticyclonic, thus the usual rotational
direction for the BG is anticyclonic (clockwise). This promotes
sea ice convergence, higher ice concentrations, and
increased ice ridging via Ekman convergence [Proshutinsky
et al., 2002]. During the summer, the BG can occasionally
reverse to a cyclonic (counterclockwise) circulation pattern.
Reversals of the BG are attributed to lower sea level pressure
(SLP) throughout the Arctic basin, and persistent low-pressure
systems occurring over the southern Beaufort Sea

[Gas Glo]

Not sure if I am allowed to post this as a matter of interest rather than any encouragement to join in but intrade is running a market on the ice extent being more than 2009. I think I remember Lord Soth saying he was certain extent would be in lowest 3 years which suggests certainty of the outcome being no. Someone has placed a large order at a price of 35 suggesting they think the probability is at least 35%.

[Neven]

I mentioned that Intrade thing somewhere on the blog, but didn't understand how it works. I think it could be a good time to step in and bet on this year being lower than last one, but I've already bet 70 euros (50 for 2010 being lower than 5 million square km, and 20 for 2010 being lower than 4.73 million square km) and I'm not so sure anymore about winning those bets.

[Kevin McKinney]

Neven, thanks for the link to Asplin et al. It's a rich paper, and not easy going for me. (Just keeping the positive/negative phase AO terminology straight seems like a constant effort!) It was certainly right on target for the questions I asked.

I was struck by this bit:

We expect. . . a more mobile sea ice regime in the southern Beaufort Sea, and likely increase[d] variability in the response of the BG to seasonal atmospheric circulation conditions. The sea ice gyre vorticity will likely increase in magnitude and reversals
will most likely increase concomitantly.

Using Dodger's simile, this makes sense, since the smaller ice "fragments" will respond more quickly to winds than very floes. And it certainly seems like an apt characterization of what we observe this summer; we have fragmented ice, and we have the BG reversal.

[Gas Glo]

If you want to know how it works:

For each bet quantity of 1, US $10 is the amount received by winner (possibly) less 10c in fees making a net $9.90. The person offering to buy at 35.0 has had $3.50 of their funds frozen for each quantity of 1. So for the buy order quantity of 50 that makes $175. If taken up by someone and if extent is higher than 2009, they get back $500 less settlement fees of $5 for a profit of 500-5-175 = $320.

Someone taking up the book order would have to provide funds of 50*$6.50 + 50*.03 fees = $326.50.
If they won their profit is 500 - 5 - 326.5 = $168.50.

This is close to the 2:1 traditional odds as you would expect for a probability of 35%. (Without the fees for 35% probability you should expect stakes to be $175 and $325; fees possibly increase stake and reduce winnings slightly.)

You can of course trade for example sell at 35 than buy back out of the contract at 25 for a smaller profit.

Hope this helps if you wanted to know how it works. I agree, I'm not so sure anymore about winning these bets - I have sold at higher prices averaging ~44.

[Kevin McKinney]

Poking around a bit WRT "Ekman Convergence," I found these undergrad lecture notes rather helpful; perhaps some others here will as well:

http://eesc.columbia.edu/courses/ees/climate/lectures/o_circ.html

[Lord Soth]

Depsite my confidence that 2010 will beat 2009 and 2008, i would never bet real money on Sea Ice. Because with my luck, the extent would be 6 millions sq km of slush puppie (but without the syrup).

I will stick with betting quatloos.

[Nick Barnes]

I have bet real money with Stoat again this year. I regard it as a hedge: if the sea ice is that low, at least I'll have some money as compensation....

[Neven]

Thanks for that, Kevin. Very helpful.

Well, at least the 70 euros I bet are going to a good cause, whether I win or lose (except the 20 euros for Stoat, which I'm sure he'll use to expand his world empire through Wikipedia).

[FrankD]

Another couple of chunks have broken away just south of here. Much smaller than Corsica (the larger is "only" the size of Mallorca, if we're doing Mediterranean islands), but not a trivial amount. This landfast ice has some other cracks in it, so some more (smaller) bits will probably break away soon.