SIE 2011 update 9: back and forth

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.

June 24th 2011

This year's melting season has so far been very similar to last year's, in size, if not so much in shape. In 2010 around this time sea ice extent was dropping spectacularly fast, leaving all other years in the dust. But at the end of June the decrease suddenly had a blowout, of which it only slightly recovered towards the very end of the melting season.

This year's rate of decrease has more or less matched 2010's free fall, even if there has been a bit of a slump since the last SIE update that saw two consecutive century breaks putting 2011 comfortably in the driver's seat. 2010 has jumped into the gap and regained the lead, as 2007 is about to start its impressive streak of century breaks (18 in 40 days).

Has 2011 bumped into the limit 2010 bumped into last year or will it fire up again, just in time to try and fend off 2007's offensive? Summer solstice has passed, but the coming weeks the Sun will shine almost incessantly. With abundant clear skies anything is possible.

Sea ice extent (SIE)

Here's the IJIS SIE graph:

2010 and 2011 are still intertwined, slightly apart from the rest, but this year's slump is clearly visible. Extent decrease has been picking up over the past few days (86K reported for the 24th), but we'll have to see if and for how long it can be sustained.

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

• 2005: -465K (-57,531)
• 2006: -230K (-59,609)
• 2007: -491K (-63,328)
• 2008: -663K (-57,526)
• 2009: -636K (-55,938)
• 2010: +110K (-74,120)

Between brackets is the average daily extent rate for the month of June. 2011's average daily extent rate for June is currently -66,348 square kilometers, still decent enough, but quite a bit less than last week (approximately 73K per day).

This year's rate on the Uni Bremen extent rate graph is also holding up well, but look at purple 2007 coming into play around this time:

Sea ice area (SIA)

For a while the trend line on the Cryosphere Today SIA anomaly graph went down hard and passed the - 1.5 million square km mark. But the slump is showing here too, and thus the anomaly has gone back up to -1.356 million square km.

It seems something of a Beaufort Gyre has started to turn (more below). Hesitantly perhaps, it's difficult to tell without the PIPS ice displacement map which has been off-line for way too long now. This means that the Beaufort Sea SIA has started to decline again, but as the ice then gets pushed into the Laptev Sea and East Siberian Sea the rapid decrease has slowed there. It seems that when there's action on one side of the Arctic, there is less of it on the other side. And things slow down when the action transitions from one part to the other. All in all a lot of back and forth lately.

Other Crysphere Today areas are showing a relatively steady decline, some of them starting to approach their minimum. We are now waiting for the Arctic Basin SIA to start dropping (like it did last year on June 28th).

Cryosphere Today area per IJIS extent (CAPIE)

The slowdown in decrease has been stronger in SIA than in SIE, meaning CAPIE rate has also slowed down considerably:

Sea Level Pressure

PIPS still hasn't updated their forecast maps (and three mails to three different addresses hasn't resulted in answers either). Luckily new friend Janne Tuukkanen has relieved me somewhat by re-introducing an old friend: the ice displacement forecasts from the Russian Arctic and Antarctic Research Institute (AARI). I don't how Janne did it, but he did, and it gives me something to hold on to. Much obliged, Janne!

Forecasts are updated every Thursday. Here's an animation of what AARI forecasts for the coming week (click for a larger version):

What these arrows point to is a continuation of what looks like the Beaufort Gyre spinning in the right way, pushing the ice in a clockwise motion from the Beaufort Sea towards the Siberian coast. A low pressure area between the Laptev and Kara Sea will then further churn and transport this ice towards Fram Strait. The ECMWF weather forecast maps confirm that this is likely going to happen, or at least the first few days (click for a larger version):

NOAA's Arctic Oscillation Index is still negative, meaning high pressure areas dominate the Arctic, but the forecasts aren't really clear on whether it's going to stay like this the coming two weeks:

Update conclusion

Clear skies, the Beaufort Gyre, compacting winds (and high SSTs) are the things that made 2007 into a record melting year, and also the reason that 2010 faltered in the curve before the final stretch. Around the start of July weather patterns altered drastically, reversing the Beaufort Gyre, spreading the ice pack and bringing clouds to the Arctic (meaning less solar energy reaching the sea water). Despite the long-term downward trend in total Arctic sea ice, these are the things that determine whether a melting season reaches a record minimum extent/area or not.

We will see in the coming week if these circumstances that are conducive to SIE/SIA decreases have an immediate impact on the ice pack, and by extension the numbers. And whether they will be prolonged into July, the month of mega-melt.

---

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

Mauro Pelti has put up a Glacier Index List, representing his first two years of posts, 115 total posts, 108 different glaciers. Impressive.

Tamino has been playing with PIOMAS volume data: Sea Ice 3-D

Comments

[Werther]

Neven, slightly off-topic...
Limit functions and buffer capacity. IMHO earth atmosphere passed a threshold somewhere around 1992. I thought effects would follow some geometrical or quadratic range. The Gompertz curve we’ve been discussing on SIV has a comparable appeal. How will the atmospheric buffer behave under growing (394 ppm CO2 may 2011) forcing?
Yesterday, Jeff Masters states he doesn’t believe that the extreme weather years 2010-11 will become the ‘new normal’ the coming decade (read his excellent compilation!).
I wonder how he concludes we're due for a few quiet years without a strong El Niño or La Niña.
OTOH Wayne Davidson today holds on to his vision that all signs call for the opposite coming months. And just look at NESDIS; isn’t that a serious pattern developing in the Pacific?
In Palaeological sense, today’s forcing happens in the blink of an eye. The biosphere buffer must have taken a formidable blow. It’s just a matter of time before feedback effects kick in full force (see ‘Awaken the Kraken...’).
Up to Masters FI, some remain conservative and predict spare time.
Others, like Davidson, are obviously very, very worried.

[Werther]

PS In the absence of PIPS: floes in 'my' study area steered south to Fram Strait some 21 km again. Very cloudy out there.

[Moregrumbinescience.blogspot.com]

You can get a sea ice drift model output at ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/omb/prod/sice.YYYYMMDD/global.YYYYMMDD
ASCII text of lat, lon, drift distance (in nautical miles, be forewarned) and direction. For the 'skiles points', the lat-lon may be omitted; their locations are given in ftp://polar.ncep.noaa.gov/pub/ice/support/forecast.points

It gives cumulative drift to day 16, as opposed, iirc, to the 6 days of the AARI model.

[Andrew Xnn]

Looking over the Cyrosphere comparison image for June 24 2007 and 2011:

Notice that both snow cover and sea ice extent is less for this 2011. Most noticeable in Kara Sea and areas on shore. Also, snow extent in Canada is less.

Of course, how the winds will blow this over the next month is anybody guess.

[R. Gates]

Excellent update. Another area of interest to watch is the mouth of the mighty Mackenzie river as it empties tons of sediment into the Arctic ocean and the ice retreats during the summer melt. This dynamic can be seen here:

http://www.arctic.io/observations/392/2011-06-25/8-N69.740194-W135.316584/Canada-Inuvik

It is also of interest to note that this region is full of methane hydrates and has already attracted commercial interest in their exploitation. By the way things are going, they'd better hurry as the natural long-term thaw in the area has been releasing these hydrates in increasing amounts over the past few years.

[Neven]

Will your prediction of a century break come about, Lord Soth? 115K before revision.

[Hans Verbeek]

bringing clouds to the Arctic (meaning less solar energy reaching the sea water)

Hmm, an increase in clouds can compensate for anthropogenic greenhousegaswarming. I wonder why I never hear about this negative feedback mechanism in the media.

[dorlomin]

Because most of the world does not have 24 hour sunlight....

[Hans Verbeek]

Are you suggesting that clouds don't play a significant role in weather and climate?

[Neven]

Are you suggesting that clouds don't play a significant role in weather and climate?

They do in the Arctic, particularly in July, which is what this blog is about.

[Kevin McKinney]

You hardly hear about ANY feedbacks in 'the media,' if by that you mean mainstream media. Too technical and boring.

OTOH, you often hear about cloud feedback on blogs concerned with the issue of AGW--faux skeptics arguing (a la Roy Spencer) that it will make everything OK, 'warmists' that it needs much further study as it's complex and tough to characterize adequately (but won't make it OK, else the paleo record can't be accounted for.)

[Hans Verbeek]

Suppose low level clouds (reflecting sunlight) have a significant effect on the temperature in the Arctic. Will highlevel contrail-induced cirrus clouds have a significant warming effect in the region?
And if so, could a ban on transarctic flying make much difference?

[Neven]

Intruiging question, Hans.

If this would have a marked effect, I'd think that transarctic flying would be stimulated during summer because insolation - and consequently albedo -> ocean temperature) - is a much bigger factor than air temperature. A ban in winter would make more sense, but I'm not sure how much air traffic there is over the Arctic in that season.

Again, if there is marked effect from contrails, in relation to the clouds already there.

[Neven]

No IJIS revision today? The century break (114,688 square km) still stands?

[maltose]

There is no IJIS update for today as well. It must be down.

[Gas Glo]

Now got the update for 26th - a small 6k increase to 3672k, but not a figure for 27th yet.

[Lord Soth]

With the 26th update, the century break stands at 109K.

Looks like we are entering the time frame of small updates, and maybe some negative morning (well morning for me) updates, as well.

I remember last year, someone kept track of all the updates. Did anybody ever graph the updates to see if there was a pattern?

Better yet, is there correlation/ or dependence between the size of the update and the resulting sea ice loss, or the predictive sea ice loss for the next day ?

[Account Deleted]

I know Neven loves his century breaks, so when will we have an update looking at that.
How many have there been so far this year?

Thanks again Neven for a good update - I've been a bit busy recently, so haven't had time to keep an eye on how things are progressing

[FrankD]

Colin,

Four so far, all in June - 5th (104), 15th (115), 16th (106) and the 26th (109). 2010 has been unusual in that there were no century breaks prior to June, but we got four this month. The average to the end of June is ~4.5 centuries, so we've caught up to about normal now. The only other year to have none before June and then a bunch was 2007 (five in June) - make of that what you will.

So far 2011 has been notable for the steady consistent daily loss - compared to other years, relatively less fluctuation day-to-day. Since these fluctuations are typically weather related, so I guess relatively stable weather has favoured steady loss. Either that or the melt is less weather-dependent than previously. (unlikely - just mentioning it...)

[Neven]

I know Neven loves his century breaks, so when will we have an update looking at that.

Today. :-)

[Gas Glo]

I also know that Neven loves his century breaks so I hope he doesn't hate me too much for posting the following:

I used Cryosphere today area numbers to get a longer data set in order to have some hope of determining whether the number of century breaks might have some useful meaning:

Year Centuries Min 8 year sum
1979 32 5.3067255
1980 18 5.5077119
1981 32 4.9564924
1982 32 5.13906
1983 44 5.386929
1984 26 4.6958923
1985 42 4.992847
1986 30 5.3818426 256
1987 33 5.2889948
1988 38 5.1448908
1989 46 4.8159156
1990 41 4.6289349
1991 42 4.4603844
1992 40 5.0267782
1993 43 4.4729533
1994 40 4.8160958 323
1995 44 4.4103012
1996 35 5.2381849
1997 45 4.8997059
1998 42 4.262403
1999 55 4.2044988
2000 39 4.1687655
2001 45 4.5336194
2002 38 4.0347104 343
2003 48 4.1416645
2004 33 4.2829733
2005 33 4.0917983
2006 33 4.0169191
2007 41 2.9194391
2008 44 3.0035558
2009 42 3.4245975
2010 46 3.0721295 320

39 Last 365 days

Correl year,centuries 0.455357601
Correl centuries,min -0.424719847

OK correlation coefficient seems on a similar scale to year so perhaps using number of centuries could be useful. So lets try it:

Using linear regression on year produces a RMSE of 0.3456.

Using linear regression on number of centuries is 0.627 (and we don't know the number of centuries until late in the season).

Using multiple linear regression using both year and number of centuries reduces the RMSE to 0.3448. This is only marginally better than just using year, but it has to be better by the definition of the process. I tried using ten different sets of random numbers and in 7 out of those 10 attempts a set of random numbers outperformed the number of century breaks.

The conclusion would seem to be that the number of century breaks do not appear to have much predictive power in the way used here as they appear worse than an average set of random numbers. There could of course be other ways of usefully using such information.

[dorlomin]

Not today
06,26,2011,9372188
06,27,2011,9281250

[Neven]

Ooh, Gas Glo, how I hate you now. ;-)

As there doesn't seem to be a trend in century breaks, it could perhaps be interesting to see the yearly average of century breaks? Because CT area century breaks can be pretty wild.

[Gas Glo]

Sorry, probably being thick but I am not sure what you are asking given that I have posted number of century breaks for each year above.

Actually, it appears there could be a small trend of increasing by .35 century breaks per year. However, there have been fewer century breaks (320) in last 8 years than the previous 8 years (343). The trend is, by definition, as useful for predicting the minimum as the trend in years. I am saying that the wiggles don't appear useful to predicting the minimum.

The average for 1979 to 2010 is 38.8 century breaks per year. If not that, are you asking about the decrease in km^2 of all the century break days in a year or something else?

Decrease in km^2 of all the century break days sounds like desperation to find some useful numbers.

Length of strings of consecutive century breaks or correlating number of century breaks to difference from Gompertz smoothed trend, or century breaks during certain periods sound more likely to find some usefulness to me.

[Neven]

Sorry, Gas Glo, I wasn't clear enough.

I meant: what if you take all CT area century breaks in one year and divide them by the amount of century breaks, could the average of 40 century breaks from a recent year (for example) be higher than the average of 40 century breaks from a year in the 80's or 90's?

When I look at my CT area spreadsheet for the period 2005-2011 I see quite a few century breaks that are over 200K and sometimes even over 300K.

And maybe there is a trend in 200K+ century breaks?

I don't have the time to check this, so I won't ask you to do so. Unless you have some fancy way of doing it quick (I would do it more or less manually, or ocularly to be more precise, if that's a word).

[Patrice Pustavrh]

Well, my not so humble opinion: Century breaks are fun, but, actual extent is more important (and area and volume even more so). If I can remember from my school days (about 20 years ago), the derivative of given variable is really unstable variable ( change of variable per time, for example ) and it really does not says much about that variable (number of century breaks for example). Think about it this way: If we have two breaks of 101.000 km2 and three breaks of merely 40.000 km2, we have lost significant less extent than in case, where we have 5 98.000 km2 breaks each day. So number of century breaks is really poor measure.
P.S. Lecture has been given to me on numerical calculation of derivative of given function from data points. We were specially instructed that error can be large. On the other hand, calculation of integral, the opposite of derivative is more stable, since small variations cancel out.

[Lord Soth]

Here is an interesting article from CBC, on how fresh melt water is pushing warmer sea water to the surface and accelerating the melt.

http://www.cbc.ca/news/canada/story/2011/06/28/arctic-ice-melting.html

On another subject, whoever was collecting the daily IJIS corrections for the past year, did you do anything with the data?

[Christoffer Ladstein]

Nonetheless the actual scientific value of century breaks, it's quite an intriguing algebra, 100 K EVERY day from now till 1. september will bring extent down below 3.0 mill. km2... Possible?! A few might say yes, but the rest would claim lunacy to the entire thought! At least we won't need to hang around until 2015 to find out! (A hint to the "Famous" Ice Extent bet....)

[Gas Glo]

OK 'Average km^2 reduction in century break days' is probably better than total km^2 in century break days.

Year Centuries Total km^2 Avg km^2 Min
1979 32 -4.6170642 -0.144283256 5.3067255
1980 18 -2.3684177 -0.131578761 5.5077119
1981 32 -4.4653372 -0.139541788 4.9564924
1982 32 -4.3404537 -0.135639178 5.13906
1983 44 -5.5245612 -0.125558209 5.386929
1984 26 -4.3045169 -0.165558342 4.6958923
1985 42 -5.7870403 -0.137786674 4.992847
1986 30 -4.0629231 -0.13543077 5.3818426
1987 33 -4.8633007 -0.147372748 5.2889948
1988 38 -5.6880888 -0.149686547 5.1448908
1989 46 -6.4194954 -0.139554248 4.8159156
1990 41 -5.8903435 -0.143666915 4.6289349
1991 42 -6.3517074 -0.151231129 4.4603844
1992 40 -5.8922116 -0.14730529 5.0267782
1993 43 -6.2021023 -0.144234937 4.4729533
1994 40 -5.8805938 -0.147014845 4.8160958
1995 44 -6.0084145 -0.136554875 4.4103012
1996 35 -4.7555421 -0.135872631 5.2381849
1997 45 -5.9793433 -0.132874296 4.8997059
1998 42 -6.0610489 -0.144310688 4.262403
1999 55 -8.1776087 -0.148683795 4.2044988
2000 39 -5.9563771 -0.152727618 4.1687655
2001 45 -6.6941426 -0.148758724 4.5336194
2002 38 -5.7568805 -0.151496855 4.0347104
2003 48 -7.0111419 -0.146065456 4.1416645
2004 33 -4.4579023 -0.135087948 4.2829733
2005 33 -4.7205853 -0.143048039 4.0917983
2006 33 -4.7038803 -0.142541827 4.0169191
2007 41 -6.135042 -0.149635171 2.9194391
2008 44 -6.9659804 -0.158317736 3.0035558
2009 42 -6.4141986 -0.152719014 3.4245975
2010 46 -6.477607 -0.140817543 3.0721295

There is no trend in the average numbers (-0.00027). Using this 'average km^2 reduction in century break days' only for linear regression results in RMSE of 0.61 only marginally better than number of century breaks 0.627 and a lot worse than just using year, 0.3456.

However, despite not looking much better on above measures, when used in multiple linear regression with year, it fairs better. The RMSE is reduced from 0.3456 for using year only down to 0.312. This is better than any of my 10 sets of random numbers though one set got close, 0.314.

For comparison using area at end of June and year in multiple linear regression reduces RMSE to 0.303.

So as Patrice would have expected, area at end of June appears a better predictor than average km^2 decrease in century break days.

[Janne Tuukkanen]

Peek to the other side.

Looks like Southern Hemisphere is heading towards quite low winter SIE this year. So even if NH wouldn't break the 2007, we still could see record low global SIE.

[Gas Glo]

Doing a multiple linear regression using 3 predictors: year, end June Area and average km^2 reduction in century break days reduces the RMSE to 0.261.

So adding end June to year reduced the RMSE from 0.3456 to 0.303 a reduction of 0.0426.

Adding average reduction in century breaks as a third predictor seems to be capturing something else not in year or end Jun Area as the reduction from .303 to .261 a drop of 0.042 is very nearly as large as the drop from adding the end Jun area as my second best predictor.

Of course, there is still the problem that we don't know the average area reduction in century breaks very well until near the end of the melt season. Could always try the average reduction in April-June century break days.....

[Gas Glo]

>" but the rest would claim lunacy"

Well the idea of doing that through August 2011, I think, should be dismissed as lunacy even though I do think August could show a noticably larger drop than previous years' Augusts due to thinner ice.

Lower reductions in August could be accomodated with larger reductions in July. However, with area 260k higher (320k yesterday) than in 2007 that has got to give 2007 an albedo advantage that could wipe out any thinner ice advantage we have this year even if the weather is as melt causing as 2007. I could be talking rubbish here if the thinner ice is greyer but I suspect thin grey ice is still fairly reflective?

[Paul Van Egmond]

It would seem to me that the number of century breaks is less important than the area where the ice loss is occuring. Ice loss that opens up straits and passages has a larger influence on the overall picture in September than, say, a century break due to lots of melt in Hudson bay as it will melt out sooner or later anyway.

[Rob Dekker]

Beautiful pictures on Modis today, with much of the Arctic having clear skies. Especially spectacular is the crumbing ice in Baffin Bay :
http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r03c02.2011179.terra

And check out the Beaufort Sea : Little (<1km size) openings/crack all over the ice pack.

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c03.2011179.terra

Is that normal this time of year ?

[dorlomin]

Another near miss but this must mean some big average losses atm.

Hudson is near the end and the north Alskan coast seems to be experiancing a great deal of ice loss with detatchment between the main body of ice and the land within days current circumstances prevailing.

The winds have not favoured export this year, so its mostly down to thinner ice and warmer world.

[Neven]

Thanks a lot for your thorough analysis, Gas Glo. I have referred to it towards the end of the new Century Breaks post.

[Gas Glo]

I was wondering whether you might transfer my posts to the century break thread.

I am not so sure about about "thorough". I don't really like the linear of multiple linear regression when we all (even inc W Connolley) agree there is downward acceleration.

To effectively get than sort of multiple non-linear regression where the non linear is only for one variable, time, then 'all' I need to do is change the predictand from the minimum to the anomaly of the minimum from the smooth non linear function. I am thinking of Larry Hamiltons' Gompertz fit as the smooth non linear function.

I wonder if Larry is planning to submit an update to his prediction to the June SEARCH report. Whether he is or not, what factors would you want to throw at this muliple (sort of non) linear regression?

Obvious ones occuring to me include:
Area at end of June for albedo effect,
Volume near end of June for less ice disappears faster,
Arctic oscilation for some of ice export effect,
Area reductions over 100k km^2 per day in April to June,

What else, suggestions welcome?

I am suggesting changing from average km^2 reduction on century break days to the reductions over 100k km^2 per day because small difference between above and below the 100k threshold can affect the average noticably whereas the effect on total reductions in excess of 100k is going to be small.

Seems like there is lots more to do rather than having been thorough.....

[dorlomin]

Looks very dramatic today, although things change quickly and it can go back to looking a lot more boring quite quickly
http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/arctic.seaice.color.000.png

[Neven]

It could be that the high over the Beaufort is pushed away (AO Index is also going towards neutral/positive, meaning more lows in the Arctic) and extent decrease slows down again.

[Lord Soth]

Something dosen't look right a the north pole.

http://www.arctic.noaa.gov/npole/2011/images/noaa2-2011-0629-004435.jpg

It may be just the angle, but it appears that the ice is buckling around the ice cam, creating a bit of a valley on the left of the cam and heading into the distance.

Also it appears that a new crack is appearing next to the buoy (marker on the left)

[Kevin Adams]

Good eye. Looks like there's a bit of meltwater forming right in front of the camera. (I'm going to have to check this every ten minutes now because I want to see whether or not we get underwater shots off this camera.)

[Twemoran]

Does anyone know if the ice shelf in front of Independence Fjord is a permanent fixture?

On the 26th I believe I saw cracks forming - too many clouds since, but today there may be some water showing just west of the more southerly of the two islands.

If the shelf is permanent, and if it breaks up, the three glaciers emptying into the area may accelerate big time

[Neven]

Twemoran, I remember we discussed this last year, but I can't remember if it was here or over at Patrick Lockerby's blog. I'll let you know if I remember.

[Artful Dodger]

Twemoran: no need to wait for a clear day, ASAR penetrates the clouds.

http://ocean.dmi.dk/arctic/nord.uk.php

[Twemoran]

Thanks Dodger - I'd stumbled on to that page a few weeks ago, didn't bookmark it, then couldn't find it again - I DID bookmark it this time.

[Artful Dodger]

Cheers mate, and please... call me "Lodger"

[Neven]

It could be that the high over the Beaufort is pushed away (AO Index is also going towards neutral/positive, meaning more lows in the Arctic) and extent decrease slows down again.

Et voilà: 39K reported.

[Artful Dodger]

It's a warm, sunny day cruising the Chukchi Sea in our favorite webcam platform, en-route to Arctic West Summer 2011.

[Neven]

That's funny. Coincidentally I had a look yesterday and the Healy was still docked. Maybe that was an old image.

[Neven]

Does anyone know if the ice shelf in front of Independence Fjord is a permanent fixture?

Twemoran, I did some more thinking (until it hurt) and then remembered I did a short blog post (+ animation) on this last year in August.

[Artful Dodger]

Well, our favorite Cutter sailed from Dutch Harbor on Jun 25 just before 16Z...

http://mgds.ldeo.columbia.edu/healy/reports/aloftcon/2011/20110625-1601.jpeg

[Neven]

Silly me, the link I clicked on the United States Coast Guard web page sent me to the 2010 images.

[Artful Dodger]

oh, then u missed shore leave in Hawaii...

http://mgds.ldeo.columbia.edu/healy/reports/aloftcon/2011/20110609-2001.jpeg

[Artful Dodger]

View of the Aloha Tower departing the US Coast Guard Base at Sand Island, Oahu, HI:

http://mgds.ldeo.columbia.edu/healy/reports/aloftcon/2011/20110612-2001.jpeg

[Gas Glo]

IJIS extent falls by a mere 39k but CT area falls by 231k. How inconsistant is that?

It takes the area is back below 2007.

[Lord Soth]

Ironic, 2011 finally has a chance to make some headway against 2010, and it falls flat also.

AMSE area also shows a good drop, AO is still negative, and arctic temps are high, so we have a totally differnt scenario than 2010.

This pause is totally due to spreading of the thin pack, which may in the short term give a false impression that the melt is slowing.

[Lord Soth]

Here is a good exmaple of how fracture and spreading impacts extent.

This is the last clear image of a section of Siberian Laptev Sea, 9 days ago.

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r05c05.2011172.terra.1km

and then again today.

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r05c05.2011181.terra.1km

Look at the lower left hand corner.

Using extent, it is obvious that extent has increased, but the ice is in much worse shape.

Now if you repeat this for every bay and fjord that has fractured, and you be surprized why extent has not actually gone up.

In another week or two, we are going to have a big surprize as most of this fractured ice melts.

[Neven]

Another very low extent decrease reported. I think it has everything to do with this:

The high has been pushed too far out, meaning there is no gyre, no compaction. According to ECMWF that high could be pushing back, starting tomorrow. We'll see if extent decrease will then pick up again. Expect another low one tomorrow.

[Peter Ellis]

I agree - from a compaction perspective, the high and low are the wrong way round, with a low on the Canadian side and a high on the Siberian side. That's the exact opposite of the Arctic dipole. The winds spiralling anticlockwise round the low will oppose the normal clockwise Beaufort gyre, and the trans-polar winds between the high and the low will oppose the normal Bering-to-Fram transpolar drift.

[Gas Glo]

>"Another very low extent decrease reported."

But another large area decrease 7.102 from 7.280 a 178k drop.

I would suggest that it is area not extent that matters because it is area that drives the albedo feedback effect.

Area is well above 2010 but is below 2007.

[Neven]

CAPIE is dropping like a rock as well. So we have divergence of the ice pack.

Or does this have to do with melt ponds as well?

[Artful Dodger]

Melt ponds change sea ice albedo as well. CAPIE compares the same factors year over year. What we are missing is a Cloudiness Index.

[Patrice Pustavrh]

Lodger, could not agree more. And as I've checked ECMWF forecast, it is quite possible that we will have clear skies over the Arctic Basin and if I remember it right, it is just excatly the opposite to 2010. We'll see, but I do expect that next month will reveal much about state of the ice in central basin.

[Janne Tuukkanen]

Maybe these satellite maps could be somewhat useful:

http://stratus.ssec.wisc.edu/products/rtcaspr/

Got little carried away with The Hunt of Things With Arrows, and found these atmospheric wind observations interesting. No mosaic :(

http://stratus.ssec.wisc.edu/products/rtpolarwinds/

[Patrice Pustavrh]

Hmm, maybe, just maybe, but I think that there can be some correlation with sea surface temps (difference between two days) and decrease in area for a given day. I mean, when sea area is not decreasing sharply, temps in surrounding areas rise more and when area decreases more sharply, temps tend to decrease. If we would up the cloudiness in that area, the pattern may be exposed.

[Janne Tuukkanen]

In the latest Bremen map. East Siberia has gone totally rotten. It seems like the whole Arctic had received some serious shotgun shots.

[Neven]

In the latest Bremen map. East Siberia has gone totally rotten.

This can actually be observed on today's LANCE-MODIS image as well. Check it out, the ice in the East Siberian Sea is brown-gray. Amazing...

[Twemoran]

Janne - Maps are very good! One more piece of the puzzle.

[Neven]

I second that, Janne. I'll have to get into wind one of these days...

[Wayne Kernochan]

Not sure whether this is off-topic. It occurred to me that with PIOMAS' figures on monthly volume, and the AMSR-E (or whatever) figures for daily area, it would be possible to get figures for Arctic sea ice average monthly thickness (i.e.,depth). This would provide an excellent complement to both the volume and "% of more than 1 year of ice" figures already collected. For example, if at minimum 50% of ice was remaining but it was an average of 1 meter thick, and that thickness had decreased by 1/2 m since the same time last year (my guess at the state of affairs this Sept.), we could, in the words of the old TV show Get Smart, "prepare to panic!"

[Gas Glo]

This would provide an excellent complement to both the volume and "% of more than 1 year of ice" figures already collected.

Minimum thicknesses of recent years
2004 1.546714961 317
2005 1.427439172 315
2006 1.459023708 308
2007 1.232745313 310
2008 1.303704143 315
2009 1.330650417 315
2010 1.104540845 310

Day 265 thicknesses
2004 2.24608419
2005 2.131858687
2006 2.185062579
2007 2.104383479
2008 2.212321682
2009 1.809586749
2010 1.414008132

Or if you wish look (& copy to your favourite spreadsheet) at data at
https://spreadsheets.google.com/spreadsheet/ccc?key=0AjpGniYbi4andFpmUzNMa1c0R1hLd1lIUno1OXJWcXc&hl=en_US#gid=0

[FrankD]

Preliminary IJIS numbers for June (preliminary because I haven't double checked my sums, and may have a facepalm in there):

Average extent: 10,091,386 sq km. Second lowest behind 2010 (10,030,484) and ahead of 2006 (10,303,927) - no great surprise there. Average June Average Extent for 2003 - 2011 = 10,472,579 sq km.

Loss of Extent: 1,980,312 sq km. Second greatest behind 2010 (2,223,594) and ahead of 2007 (1,899,843). Average June loss for 2003 - 2011 = 1,768,559 sq km.

[Gas Glo]

NSIDC monthly average numbers - second lowest for extent and area behind 2010, but only just second for both:

2006 6 Goddard N 11.06 8.34
2007 6 Goddard N 11.49 8.15
2008 6 PRELIM N 11.46 8.47
2009 6 NRTSI-G N 11.49 8.86
2010 6 NRTSI-G N 10.87 7.98
2011 6 NRTSI-G N 11.01 8.14