SIE 2011 update 6: unperturbed

During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graph webpage for daily updated graphs, maps and live webcam images.

May 15th 2011

First, let me apologize for not doing an update last week, even though I promised I would do one every week from now on. There's only so much time, and the pieces on sea ice thickness took precedence. And although as fascinating as always, nothing really spectacular has been happening with the Arctic sea ice in the past few weeks. But this depends on your perspective of course, as there's always more to the eye in the Arctic.

What could be labeled as a lack of spectacle is the fact that the sea ice extent decrease has been incredibly steady. Except for a very short blip upwards when an extent increase of 26,094 square km was reported for May 6th, the trend line for 2011 is dropping very gradually (as can be seen on the IJIS graph below). The curve has been remarkably steady all year.

However, and this in a way is quite spectacular, the actual circumstances on the ground haven't been steady at all. The Arctic Oscillation turned negative at the start of the month and as we saw in the previous SIE update this meant that the anomalously warm air in Siberia was moving slowly towards North America. But instead of getting more negative the AO index has remained stuck just below neutral.

High and low pressure areas are continuously trading places, resulting in ice displacement arrows pointing every which way from one day to the next. One other effect is that in the past week temperatures have shown a negative anomaly practically all over the Arctic (more on that below). Moreover, our CAPIE index has dipped several percentage points below other years, which could be a sign that there is a slight divergence of ice (more on that below as well).

Both these factors, especially combined, ought to have slowed down the rate of extent decrease. But extent is plodding downwards unperturbed, and showing a very decent average daily decrease for the month so far. So the fact that extent decrease isn't spectacular, is pretty spectacular, si vous catchez mon drift.

Sea ice extent (SIE)

Here's the IJIS SIE graph with its smooth curve for 2011. It has just passed the 12 million mark:

The current difference between 2011 and the other years is as follows:

• 2005: -135(-44,778)
• 2006: +209K (-43,432)
• 2007: +9K (-41,991)
• 2008: -291K (-45,373)
• 2009: -478K (-53,952)
• 2010: -179K (-67,661)

Between brackets is the average daily extent rate for the month of May. 2011's average daily extent rate for May is -51,049 square km, which is quite a bit more than most other years, very close to 2009, but of course out of 2010's league. 2010 has been catching up very fast - the difference with this year was 474K two weeks ago - and is now in 5th spot. It will take the lead quite soon and hold it until the end of June, with the incredible streak we witnessed last year. 2011 is currently in third position, more or less tied with 2007.

The slowly, but steadily increasing rate of decrease for this year is also reflected in this graph from the university of Bremen that shows the change per month of Arctic SIE:

If things continue in this manner, 2011 will soon have the fastest rate of SIE decrease after 2010.

Sea ice area (SIA) and CryosphereToday area per IJIS extent (CAPIE)

The trend line on the Cryosphere Today SIA anomaly graph has been hovering again around the minus 1 million square km mark in the past two weeks:

SIE has just passed the 12 million mark. SIA will probably do the same with the 11 million mark tomorrow.

Because of a combination of ice pushing back towards the Siberian coast and even some refreezing due to anomalously temperatures, the SIA decrease was halted in the East Siberian Sea, Kara Sea and Laptev Sea. The SIA in the Barentsz Sea hasn't stopped from going down though, and things in the Bering Sea are still progressing very fast, as noted in this blog post. It will have melted out before the end of the month, which means the Chukchi Sea will come into play. The Beaufort Sea SIA number is bound to go down any day now. Hudson Bay and Baffin/Newfoundland Bay have continued to go down as well, and my expectation is that they will melt out very fast.

All in all SIA numbers have been going down a bit faster than SIE numbers, and this means that the percentage on our CAPIE index has gone down a tad as well. Because of the freeze-up during winter and the uniform shape of the ice pack (meaning no holes), area and extent are very similar, despite the fact that they are calculated differently. This is why the CAPIE percentage hovers around 95% until the second half of May, when percentages start to drop, because of the ice breaking up at the fringes.

In this respect 2011 is a bit early when compared to other years in the 2006-2011 period:

If I remember correctly, this metric is useful because it can indicate two things:

1) melt ponds on the ice fooling the satellite sensors into reporting more open water than is actually there (which has a greater effect on calculations of sea ice area, and thus a dropping percentage).

2) convergence or divergence of the ice floes. If they converge, the percentage goes up, because there is less open water between them and the ice pack becomes more compact (making the difference between SIA and SIE smaller). Conversely, if they diverge, the CAPIE ratio goes down.

Well, 1) can't be in play right now, because the air is way too cold for melt ponds to form. And thus it has to be 2), in other words, an early divergence of the ice pack, which nevertheless didn't have much of an effect on the steadily declining SIA and SIE numbers, as noted in the introduction.

Air temperatures

For over a week now much of the Arctic is anomalously cold, as can be seen on this NOAA/ESRL temperature anomaly map:

All the world's heat seems to be in the Antarctic, and except for a mildly warm Beaufort Sea and a neutral Greenland (which had been extremely cold the past 1-2 months) all of the Arctic is between 5 to 10 degrees below normal.

I have managed to remind myself to save most of the images from the DMI temperature map (updated twice a day) and can now give an impression of what has happened in the past two weeks:

We can see how the greens have slowly taken over the very cold Canadian Archipelago and how the yellows and oranges are pushing in from the south on both the Atlantic and Pacific side of the Arctic. But apparently this is slower than normal, and a light bluish hue continues to pop up here and there.

The relative cold is expressed more clearly in the DMI temperature above 80N graph:

Update conclusion

It's difficult to forecast what is going to happen next. The AO is forecasted to remain slightly negative, which could mean much of the same, or perhaps even a slowdown in SIE and SIA decrease. A shift in weather conditions could mean the opposite, especially if they remain more constant than they are now.

But recent developments are evidence that the ice on the fringes is very weak. Air temperatures are down all over the place and ice displacement is geared more towards divergence than convergence. This can only be compensated by the fact that ice floes on the fringes (especially on the Siberian side of the Arctic) is relatively thin.

We'll just have to wait and see what happens. The 12 million mark has been passed, moving to 11 million now.

 

TIPS - Other blog posts and news articles concerning the Arctic and its ice:

Patrick Lockerby has released his first update for Arctic Ice May 2011.

Very early fires in eastern Russia (h/t noiv from the Wetterzentrale forum)

The Montreal Gazette: 'Unprecedented' 1999 Arctic storm called portent of future

 

Comments

[Artful Dodger]

Yes, Peter is quite right. Here are IJIS summaries, sorted by Avg SIE:

Year:	May Avg:	May Decr:
2,006	11,659,975	-1,346,406
2,004	11,744,138	-1,141,250
2,011	11,876,396	-1,581,250
2,007	11,941,527	-1,301,719
2,010	11,995,882	-2,097,500
2,005	12,049,909	-1,388,125
2,008	12,123,690	-1,400,313
2,003	12,182,359	-1,220,157
2,009	12,327,515	-1,672,500

[Artful Dodger]

Christopher: Temperature is not Heat.

[L. Hamilton]

Peter, you're right, not sure what I was looking at in the IJIS data, 2004 and 2006 means are both higher. Not so with UB, CT, or (as best I can see) DMI since 2005.

[Christoffer Ladstein]

Right, Lodger, perhaps that error is to be blamed upon a stay in a Hot sauna too close to the Heater, after a stay in the municipal swimmingpool together with 2 of my kids. The Oslofjord doesn't tempt any such desires yet, ought to move to Arkhangelsk where they're experiencing close to 30 degrees C these days, must bring the Bay of Kola to the "boiling" point. I expect the seatemps around Novaja Zemlja to rise to around 5 C in a day or 2...
Most of Norway had temps slightly above normal in May, the most positive anomaly came "as usual" at Svalbard, +2,5 above normal (+ 4,1 last May...). I might just in the same breath of air mention that the trend up there is much warmer than normal winters, but not so extreme summers. But....2007 compared to the chilly summer of 2010 show that Jun-Aug. was 4,4 C warmer in 2007. This fact have been pointed out earlier, I know, but last years extent fell sharply but landed too early, all due to a not too good summer!?

No matter, summer returned here today, so cheers and happy holiday tomorrow!

[Daniel Bailey]

Neven, you have a tröllstalker.

[Kevin McKinney]

"Mac's update late?"

Maybe, Christoffer--or maybe the computers talk slower in Georgia, too.

[Lord Soth]

We are now in first place for IJIS with a near century loss last night. Currently at 11030625 for June 1.

Currently 21K below 2010, so I give it a 50/50 chance of surviving the update in a few hours.

[Gas Glo]

Yes, but what is happening with CT area? 3 consecutive rises so now 129k above 3 days ago.

[Christoffer Ladstein]

What a laugh! The update brought it 625 km2 ABOVE 2010, that's fairly much the same as a small farm in the midwest, or half of New York City area!!! Tomorrow then will bring it below the 11 million mark, 1 day earlier than 2010..... Then we set a new goal, 10 million! June 14'th perhaps?!

[Bfraser]

I noticed that upswing, too, Gas Glo.

But whatever it is, the most recent prediction from Topaz (published Jun 1)doesn't include it.

I've posted the Topaz data by CT region for both Topaz3 and Topaz4, in case anyone's interested (remember the last 10 days are subject to revision):

snipt.org/xQnl
snipt.org/xQnm

(Remember that the Bering Sea is not included. That's why we crossed 11M on 5/30.)

[idunno]

Hi Bfraser,

Really good to see you back here.

Any chance of an update on your TOPAZ by CT area post? I really appreiated the original, and would be very interested in any update...

[Lord Soth]

I suspect the Cryosphere today is having calibration issue. The biggest change is in the high arctic. Could be a melt pond issue, but probably to early for that.

Whatever it is; its an artifact and is not real.

As far as IJIS, I would call call 2010 and 2011 a statistical tie. Like how may pixels can 625 Km be. If they are using 25 sq km grids, it would be 1 pixel.

[Bfraser]

@idonno, actually, I have updated some of the graphs from last time with the new information, but I haven't figured out how to post them. Can anyone recommend a site (like snipt, but for pictures)? Or does anyone want to perform some new analysis based on the raw data that I just posted?

@Lord Soth. 625 km2 is 4 pixels. I agree that it is a statistical tie.

[Wayne Kernochan]

My apologies for being a bit off-topic for this post, but PIOMAS seems to have quieted. Included in http://thinkprogress.org/romm/2011/06/02/234291/royal-society-7f-4c-world/ is a just-published Met-Office projection. It is for the 2090s but also for a more conservative scenario that we are presently on. Joe Romm appears to believe that for our present scenario (A1F1), this graphic applies to the 2060s, not the 2090s. My interpretation is that by the 2060s, temps in the Arctic will have warmed by 17 degrees C.

[Gas Glo]

Can anyone recommend a site (like snipt, but for pictures)?

I use flikr

[Anu]

Can anyone recommend a site (like snipt, but for pictures)?
Posted by: Bfraser | June 02, 2011 at 17:45
===========================

You can use http://imageshack.us/ to post images and graphs that you can link to here, like this:
http://img703.imageshack.us/img703/6530/tooleetalfigure2.jpg
http://img525.imageshack.us/img525/6569/sigmoidfunctionssmall.png

Or you can make them small enough, and put them directly into your comments:

[Artful Dodger]

LS: IJIS uses 6.25 km square 'cells' to compute extent. Therefore SIE changes in discrete quanta of 39.0625 km^2 (SIE is always rounded to the nearest whole number).

This was discussed last year. Search this blog for "least common divisor".

Cheers!

[michael sweet]

On the North Pole web cam picture number two it appears that the ice flow the camera is on has cracked in half only a short distance away from the camera. Some of the instruments are on the other side of the crack. Presumably they used the thickest ice they could find. What does this mean about the stability of the ice at the pole???

[Peter Ellis]

Is that a crack, or is it a pressure ridge forming? Not sure we can tell until we get a clearer picture.

[Kevin McKinney]

If I had to guess right now, I'd say pressure ridge.

[Daniel Bailey]

Agreed, Kevin. Pressure ridge. The left half of the field shows clear uplift along the line. The right half is less distinct.

There's evidence of larger pressure ridges and stacks/slabbing in the background as well. Granularity gets bad when zoomed in too far.

If one were to venture a guess, I'd say the foreground ridge is about 1 meter, +/- 0.5 meters in places.

I know budgets are tight, but the new HD cameras aren't all THAT expensive...

[Bfraser]

I don't ordinarily like to disagree with Lodger, but I'm pretty sure that the pixel size is 12.5km (or at least it was at the start of 2011).

Also, here are two updated graphs (one for thickness and one for extent/area/volume).

http://img101.imageshack.us/img101/9445/centralandtotalice.gif
http://img64.imageshack.us/img64/1495/centralandtotalicethick.gif

[Artful Dodger]

I too am glad you're back, Bill :^)

On August 30, 2010 at 18:30, Phil wrote:

"the data is compiled from the signal using 6.5x6.5 areas ('pixels'), so the greatest common divisor is 156.25 sq km..."

So not quite right yet, as 12.5 x 12.5 is 156.25 km^2

Phil?

[Paolo]

@Michael, Petre, Kevin and Daniel
I think it is a crack :
http://www.arctic.noaa.gov/npole/2011/images/noaa2-2011-0603-233142.jpg
http://www.arctic.noaa.gov/npole/2011/images/noaa2-2011-0604-073143.jpg
http://www.arctic.noaa.gov/npole/2011/images/noaa2-2011-0604-153243.jpg
and I think that the block across the crack as moved left to right

[michael sweet]

Paolo:
Nice series of pictures. It looks to me like the other side has moved also. The middle picture looks like the far side is undercut, perhaps the two sides rubbed together for a while.

[Daniel Bailey]

@ Paolo

Nice. I agree with Michael the second of your 3 pix is the most significant, showing what appears to be open water in a lead.

Now that the floe is fractured, it will open and close repeatedly. Each time the rupture edge will either be forced above or below the colliding edge from the far side of the rift.

Eventually the slabbing could endanger the webcams themselves (they must be close to have enough elevation to see open water in the lead).

Ice looks wafer-thin. Quite unlike that of 50-60 years ago...

[Patrice Pustavrh]

Well, it is both pressure ridge and crack, nice description here:
http://en.wikipedia.org/wiki/Pressure_ridge_(ice)

[Paolo]

It change very fast
http://www.arctic.noaa.gov/npole/2011/images/noaa2-2011-0604-233346.jpg
24 hours between the first image and this one

[Paolo]

@Patrice
1) The opening and closing are very fast
2) The other side has moved
3) The opening is not caused by “extreme cold” and not any “freeze again” and “temperatures rises”
No, I don’t see any link between what we see and the description from Wikipedia
(Sorry for my English)

[Paolo]

We can see “pressure ridge” with the other webcam:
http://www.arctic.noaa.gov/npole/2011/images/noaa1-2011-0530-082612.jpg
http://www.arctic.noaa.gov/npole/2011/images/noaa1-2011-0605-004119.jpg

[michael sweet]

The cameras cannot survive the melt season when the ice edge is so close at the start of June. Should we guess when they will stop transmitting? Does anyone know how fast the edge of a flow erodes during the melt season? It looks to me like less than 100 meters to the edge now from both cameras.

[Peter Ellis]

Seems tailor-made for an animation of the images from camera 2 - maybe when our gracious host gets back?

[Kevin McKinney]

Yes, Peter, that would be a good animation project!

On the pressure ridge/lead question, I don't much care for this particular Wikipedia article (much though I love Wikipedia as a convenient source in general): I'm not a expert, but clearly there are multiple possible causes for pressure ridges to form--not just thermal stress. (In fact, I bet it's not even 'normally' thermal stress.)

But it's equally clear that the ridge *does* also imply cracking, and that divergence can turn a 'ridge' into a lead very, very rapidly. Seems like this sequence of images illustrates that nicely.

[Paolo]

I see two crack, the first very near right after a stick (the little dark mark in the centre of the picture), and the other more far.
The ice continues to move (and I think always left to right).
Michael, I think too that this camera not survives the melt season.
I not find analogous in the previous years and the animation project is a very good idea!!
http://www.arctic.noaa.gov/npole/2011/images/noaa2-2011-0604-233346.jpg
http://www.arctic.noaa.gov/npole/2011/images/noaa2-2011-0601-152533.jpg

[Paolo]

Sorry the second link is bad (06/01!)
http://www.arctic.noaa.gov/npole/2011/images/noaa2-2011-0604-233346.jpg
http://www.arctic.noaa.gov/npole/2011/images/noaa2-2011-0605-073545.jpg

[Anu]

http://esciencenews.com/articles/2011/05/16/research.aircraft.polar.5.returned.spring.measurements.high.arctic
Research aircraft Polar 5 returned from spring measurements in the high Arctic
Published: Monday, May 16, 2011

One of the key aspects of the expedition were large-scale sea ice thickness measurements in the inner Arctic, in which researchers of the Alfred Wegener Institute and the University of Alberta cooperated closely. For this purpose they used a four metre long electromagnetic ice thickness sensor, called EM Bird. The Polar 5 towed the sensor on an 80 metre long rope at a height of 15 metres above the ice surface for the surveys. A preliminary evaluation of the measurement results shows that one-year-old sea ice in the Beaufort Sea (north of Canada/Alaska) is about 20-30 centimetres thinner this year than in the two previous years. In 2009 the ice thickness was 1.7 metres on average, in 2010 1.6 metres and in 2011 around 1.4 metres.

The research aircraft Polar 5 of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association returned to Bremerhaven from a six-week expedition in the high Arctic on May 6. Joint flights with aircraft of the European and American space agencies (ESA and NASA) were a novelty in sea ice research: Simultaneous measurements with a large number of sensors on three planes underneath the CryoSat-2 satellite led to unique data records.

[Lord Soth]

2011 IJIS is now back in third place, but not by much, two days after is made first place for ice lost.

From June 5, 2010 it took a steep dive with many century drops. Much of this was driven by the rapid ice loss in Hudson Bay.

Envirnonment Canada is predicting that the breakup and clearing events in Hudson Bay is going to be near normal, despite the fact that Hudson Bay froze over much latter, its been warmer this winter, and the ice is much thiner than last year.

When it comes to the Canadian Ice Service, they are a ultra conservative bunch, when it comes to predictions, but I guess they don't want ships plying ice infested waters, so I see where they are coming from.

I think they are wrong, and the 2011 will start taking a nose dive, driven by Hudson Bay ice lost, like in 2010, but it could be delayed by a few days to a week, due to weather related events.

[dorlomin]

IJIS
06,04,2011,10922500
06,05,2011,10798750

124 000 drop. Pre revision.

[Lord Soth]

Update in revision.

Its official, first century lost of the season of 104,219 sq km

[Christoffer Ladstein]

Finally!!! I must say I agree much with your point of wiew upon Hudson Bay, and also the weatherprognosis along the Sibirian and Greenland coast, "just have to" lead henceforth to a lot of century-losses in the next 2 weeks. I am more curious about what Nevens headline for what's taking place at the very North Pole point.... The North Pole Divided, The North Pole "continental shelves" slip apart.....The Russian Submarine Tourist-season started early this year....
We better wait and see, exciting anyway!