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Thanks, Neven! It will be interesting to see what the numbers are for 2010 and 2011 at the end of the month. That way we will know if we will have a record low volume for March. (That is looking pretty obvious right now.) The horse race begins!

Patrice Monroe Pustavrh

Hi Neven & co.,
first little OT, but your blog is really nice now (good it was before). And I have one small question, not about SIE or SIA, but about how solid ice looks viewing MODIS pictures (and particular area is Central basin), which are coming into play now.
Some nice shoots: Kara sea today (can we speak about polynya or about open sea - it looks that area of open water around Novaya Zemlja is connected)
I am very aware of the fact that this could be the effect of quite warm weather due to specific position of cyclones moving warm air along, but I would like to hear some more experienced people about it.
Also, in Beaufourt sea, there seem to be a lot of fractures in the ice:
I admit, I have no clue. But, on the other hand, can someone explain me, how good state of ice is this year comparing to some previous years ?

R. Gates


I've spent a lot of time on many blogs reading and writing about sea ice, and I've spent even more time studying the subject for many years. I'm not a professional scientist, though I have a strong science background, and I want to compliment you on one of the most thorough sea ice updates I've seen-- very nice job.


Patrice, I don't have enough experience yet to answer your good questions. I only started to seriously look at satellite images when I started the blog last year in June. Unfortunately the satellite images don't go back a long way, otherwise we could make some more meaningful comparisons.

But Patrick Lockerbie is the expert when it comes to satellite images, and as you probably have seen, he has just written his first blog post here, comparing satellite images of Baffin Bay. I have coincidentally brought up some of your points in my comment there.


R. Gates, that's a big compliment, especially coming from you. Thanks. I hope to keep it up during the melt season.

I also have to say that I think you're doing a great job on WUWT (I've been banned there multiple times for venting my frustration). I almost wrote a blog post about it last year, with an image of Mahatma Gandhi in it and stuff. ;-)


Hi Neven,

If you wish to vent some more frustration, Judith Curry has just started to blog on Arctic Sea Ice again.

I did pop up briefly while slightly under the affluence of incohol. Such fun!

Seriously, I suspect Dr Curry is becoming slightly semi-detached from the denialosphere. You might, or might not, like to invite her over here. I have left a comment on Patrick's blog suggesting that she seems to be looking for some information which logicman may be able to provide...


Thanks idunno, I had already seen your link over at Patrick's blog.

I'm not a fan of Judith Curry and her MO, but I'm pretty sure she know more about the Arctic than I do. She starts her post by saying she "spent the 1990’s conducting research on the climate dynamics of the Arctic Ocean, and then moved onto other things circa 2002". Too bad, she'd have much more exposure if she'd kept on focussing on the Arctic. Now Julienne Stroeve is queen of the pram, and JC has to 'build' bridges by patting pseudo-skeptics on the head. ;-)

Please no linking to this blog. I like our little, cozy tribal echo chamber just the way it is.


Hi Neven,

Yeah, I wouldn't want to invite her followers over. I think you're making a good call, and also incidentally agree that the GP ad idea from me on "new design" is probably best spiked, too. Just thought I'd mention the both as possibilities.

Have just checked the UniBremen change/month, and its now definitely entered the negative, at about the second earliest date of all those plotted.

Over at CT, the Barents, Kara and Central Basins appear to have caught fire. I know you have some archived images from CT, could you find one perhaps that looks like today from some date over the last few years? I'd suggest that it all looks a month or more ahead of schedule, and is fairly much in line with what TOPAZ was trending towards...

TOPAZ remains down. Maybe Bfraser broke it. Or they might be in a sulk because some clever monkeys got lots of interesting data out of it, so are now taking their ball home.

If anybody else is interested, Judith Curry's blog is called "Climate Etc," and the Arctic piece comments section contains, as well as some denialist claptrap, some interesting discussions. The extremely alarmist/alarmed comments from me have not been censored.


Hi All,

NSIDC has called the maximum and has an update up.

Rob Dekker

I've just accepted William's bet over at Stoat, regarding minimum extent dipping below 3 million km^2 by 2013 :


If not for physics and modeling and volume trends and excitement and concern, then at least I've taken this bet to express my belief of a sensitive Arctic climate.

L. Hamilton

So NSIDC and Uni Bremen call the same date, March 7, for the max. Although NSIDC sees a tie, the UB value is about 0.4% lower than 2006.

Artful Dodger

Barrow Sea Ice Mass Balance Site 2011

A Mass Balance Probe was deployed on landfast sea ice in the Chukchi Sea at Barrow, Alaska (71.3 °N 156.8 °W) on January 24, 2011. Scientists expect to recover the Probe in June.

Here is the current Vertical Temperature Profile plot (temps are accurate to approx. ±0.2 °C):

Measurements as of Mar 23, 2011, 2:00 PM AKDT:
Air temperature: -6 °C
Ice thickness: 1.32 m
Current ice growth rate: 1.3 cm/day

Current Temperature Profile - Barrow AK Sea ice


Rob, I won't allow you to bet that amount of money. Unless you're rich that is.

Remember, sensitivity cuts both ways. Nothing in the Arctic is a dead certainty.

Gas Glo

>"Rob, I won't allow you to bet that amount of money. Unless you're rich that is."

Yes I wouldn't recommend it either Rob (though I wouldn't presume to prohibit it either - it is your money). If William is allowing himself a large margin then so should you. You may well believe in further acceleration of the volume loss trend but there may be a lot more variability than we have seen in volume trend and even if volume does fall a lot might the ice be all spread out thinly to give a high extent?

I think I would also want to work in an exemption if there is a VEI6 or more volcanic explosive event before Aug 2013.


IJIS reports +40K today. Average for March is now 666, the number of the beast.

Rob Dekker

Neven, Gas Glo,
Thanks for your concern, but I'm not so worried about the money.
I'm more worried about the case that I win the bet.
I added this to William's blog:
In that regard, this (bet) is about recognizing the risk that we may be heavily underestimating the sensitivity of Arctic sea ice to warming trends. And recognizing the implications of being too conservative in our climate assessments. Remember that if I'm wrong, I will just loose some money. But if I'm right, Arctic sea ice is in state of imminent collapse, and we need to re-assess all projections and models not just for Arctic sea ice but also sensitivity of ice sheets and Northern Hemisphere climate. Not to mention figure out what to tell our kids about Santa's home..

Christoffer Ladstein

" Not to mention figure out what to tell our kids about Santa's home.."

I am glad my kids have such a devoted father already ruined their wiew upon this "fairytale"....

A brave and stout bet that is, but I figure this bet must be influenced by the "soon-to-become-father" kind of state your into these days!

I can't deny that an icefree North-Pole this very summer have crossed my mind as well, and the state of ice at several fronts (Kara, Bering, Laptev, Barents etc....), combined with a steady switch into purely positive AO-territory, AND perhaps caused by this a rather stubborn wind-system directing MUCH ice out into the North-Atlantic through the Fram-strait, makes me think "the worse" for this year minimum. Also an omen is the "heatwawe" in Oslo the last days, souring the temperatures above 15 C, the hottest since 2007, and we all know what took place that year....

Anybody able to estimate just how much ice is being pushed out through the Fram-strait at this time of the year? I suppose the thickness of the ice makes it a lot harder to push...

Artful Dodger

Rob: When you think about it, pursuit of MONEY is causing the loss of sea ice. So don't bet MONEY, bet something that actually bites into the lifestyle he is borrowing from future generations. How about "If Stoat loses, then he gives up his Car AND Jet travel until the Sea Ice returns"?

Christoffer Ladstein

THAT would be a hard bet:-)

Are you all aware that last year we had to wait for sunny May to find an Arctic situation similar to this years March!!
Makes me almost seasick....
Artie: I also like that Barrow site and am curious to see for how long time till the icethickness start to decline...

Artful Dodger

Christoffer: ( please, call me "Lodger" ;^)

I'll be watching the Pt Barrow Ice mooring closely for the daily melt rate. After Barrow breakup (~June) the data should be predictive for points North as the season continues... Just have to match SST's and Insolation.

Artful Dodger

Christoffer: (please call me :^)

Indeed, today's Barrow, AK ice growth rate is down to 0.8 cm/day, so down 0.5cm/day/day vs Mar 23.

Thickness is now up to 1.33 m vs 1.32 m yesterday.

Artful Dodger

Bah, duplicate comment. Please ignore my 00:32 comment :^)

L. Hamilton

Here's a September graph I've been meaning to do for a while.


It's just curve-fitting, but with a slight difference. Others tend to use linear, quadratic, exponential or logistic curves. Quadratics actually rise in the early years, then later crash below zero. Logistics have the more plausible property of approaching zero at a slowing rate, but the deceleration and acceleration phases must have the same rate.

What this graph shows is a Gompertz curve, still relatively simple but yielding an assymetrical S. It looks similar to a quadratic but the differences are improvements: no rise in the early years, no crash below zero.

The Gompertz predicts a slightly lower value than the quadratic for 2011: 4.4 instead of 4.6. It crosses the 1.0 line a few years sooner, but after that approaches 0 asymptotically.

NOT that such curve fitting is more than a what-if exercise!


Thanks for that, Larry. I might use that graph for a short blog post on first predictions after the weekend, if that's okay.

Artful Dodger

Interesting curve, Larry. Let's talk about some likely boundaries for this year's Sep SIE. The greatest year-over-year drop in the Satellite record is 2006<>07 at -1.62 M km^2. The highest y-y Increase is 1995<>96 at +1.75 M km^2.

Then, assuming the Gompertz curve best fits the underlying trend, the 2011 Sep SIE could lie anywhere in the range 2.78 to 6.15 M km^2, and still be within the range of observed climate variability.

Arjen Costerus

I'm a long time lurker with who has a comment this time.

I do not see the Gompertz curve working. If my logic and knowledge doesn't fail me, the fewer ice there is, the faster it will melt. There is more heat available to melt the ice, there is less ice, so instead seeing a slower rate of decline in sea ice area extent in the end game, I expect a crash whenever we get to a certain minimum where the remainder of the sea ice extent will dissapear very fast.


Very interesting Larry. This is exactly the sort of thing I was looking for in appealing for better curves that a quadratic when I originally posted on this during Neven's hibernation (Open Thread 3). In particular, I note that right now, the Gompertz curve is steeper than the quadratic, something that seems to be borne out by the measurements we are getting. (And no less interesting for being a what-if. Just so long as we all remember that).

I've tried messing around with this curve with the volume data I've previously posted, but its all trial and error on Excel, rather than getting a maths engine to optimise the fit.

I assume you used an app to do this. Could I beg a favour, then? Could I ask if you would fit this sort of curve to the September volume data I posted here: http://snipt.org/wkuj ?

I'd be very interested to see the results.

Arjen - Welcome! My thinking was that the last areas of sea ice (maybe 100 - 200,000 km^2) would be in sheltered areas, near icecaps, and be topped up by calving from glaciers. It would not mean the rate of change has slowed on the large scale, but a few little pockets here and there would last for a few years longer than a quadratic trend would suggest.

Kevin McKinney

". . .My thinking was that the last areas of sea ice (maybe 100 - 200,000 km^2) would be in sheltered areas, near icecaps, and be topped up by calving from glaciers. It would not mean the rate of change has slowed on the large scale, but a few little pockets here and there would last for a few years longer than a quadratic trend would suggest."

Yes, that's what you see in natural analogues, like snow cover in irregular terrain. Most places melt faster as the cover fragments, but the statistical outliers--places with relatively large accumulations and which are also relatively well-protected from solar irradiation or other warming mechanisms--linger for a surprisingly long time.

I have no idea about the mathematical basis of the Gompertz curve; how well-constrained is the shape of the 'tail?' (I'm wondering if there's any mathematical guidance there as to where the terminal knee of the curve falls, and hence how much 'lingering' ice is suggested by this model.)

L. Hamilton

Neven, you're welcome to use that graph or any that I post here. Note that I just now uploaded a slightly newer version (dated 3/25) in which I changed the title to specify NSIDC. Because it looks like I might be drawing a few others.

Lodger, I've been thinking about ways to show the uncertainty. One thing I'll try today is calculate standard errors, and see how it looks with a +/-2SE gray band.

Arjen, my intuition, similar to FrankD's, has been that ice could fall quickly lower levels, but reaching zero extent would be harder than because there will always be freeze-up in winter, some piling up along the Archipelago and N Greenland, etc.

FrankD, it was your comment elsewhere about short-tailed ogives that inspired me to finally fit this model. (Decades ago I did some work with Gompertz models, but yesterday had to remind myself how.) I'm using an iterative least-squares algorithm that fits nonlinear models. Given the positive response here, I'll try applying it to some other series including your PIOMAS data, and post results soon.

Gas Glo

Frank, you can use Excel:


with AG4=17210

produced rmse of 1017.5
for volume numbers at http://snipt.org/wkyg

Gets under 2000 km^3 by 2015 and under 1000 by 2017.

You can do better with solver installed I am sure. I must do that.

L. Hamilton

There's one other motivation for this model choice that I haven't mentioned. I recently had a look at unpublished (and not final) Uni Bremen extent data, which go back to 1972. I was very interested to see what context the 1972-1978 trend might suggest for modeling 1979-present.

Well, the earlier data show only a weak negative trend, but a quadratic's positive slope in early years looks even wrong-er. And fitting a quadratic to the whole series also gives a worse-looking match in recent years, where of course the main interest lies.

A Gompertz curve, on the other hand, looks equally (and has similar parameters) for both NSIDC 1979-2010 and UB 1972-2010.

So, coming next: a confidence-bands version of NSIDC; PIOMASS; possibly CT area.

I've also updated last fall's cycle plots, which are developing an even stronger year-round pattern.

Gas Glo

Larry, I like it a lot. I particularly like the way both extent fits and volume fits come down to negligable values at similar dates. It has always worried me a bit that straight line and quadratic fits give different dates for ice free depending whether you do extent or volume. That this gives similar dates seems very encouraging to not have this discrepancy and seems to me to support this model choice.

L. Hamilton

As promised, here is another version showing only the NSIDC/Gompertz model, but with 95% confidence bands. The 2011 prediction equals 4.44 (3.75 to 5.12).


The bands are simply statistical extimates for my black-box model. As usual with regression, the uncertainty is narrowest at mid-range X values (middle years, here), and widens as we predict out of sample (2011 and beyond).

Gas Glo

Larry, I surely shouldn't be able to count 14 points outside the 95% ci, should I? Is that a 1 SD band?

L. Hamilton

And based on the PIOMAS data that FrankD and Gas Glo linked, here is a similarly-designed graphic for PIOMAS September volume:


Is there a convention for when volume becomes "negligible"? I showed a 1-million line in the extent chart, but don't know of a consensus level for volume. It appears headed pretty quickly below 2,000 km^3, if the projections are believed.


Larry and others, I've just written a post on First forecasts. If you could, please continue the discussion there. :-)

Artful Dodger

Larry, nice. You *may* wish to tweak your Chart Title, which begins "NSICD Extent ="

Now that you've teased us, will we see a snapshot of a UniBremen Gompertz?

L. Hamilton

Lodger, where's the misplaced "NSIDC"? In the versions I see, both the NSIDC and PIOMAS seem properly labeled. There might be an earlier draft floating around somewhere though, I draw these things in a bunch of steps.

I was asked not to publish the UB data, so all I'm doing for now is making these vague general statements. Sorry!

The UB data track NSIDC pretty closely but there is often a small offset, which the PIs are studying. They hold their work to high standards, of course!

Also quite interesting is their southern extent time series, which so far as I know has no published counterpart.

L. Hamilton

Wait, I see what you mean, Lodger. D'oh!

A de-typoed version should be up in a few minutes.

Kevin McKinney

Ooh, that Gompertz volume curve is a kick in the stomach!

Right back into the warmist's dilemma again--not that hoping for one result or the other is going to affect anything.

Artful Dodger

Barrow Sea Ice Mass Balance Site 2011

The latest measurements available are
Mar 25, 2011, 10:15 PM AKDT:
Air temperature: -14 °C
Ice thickness: 1.34 m
Current ice growth rate: 0.6 cm/day

Gas Glo

Heat Transport to Greenland Glaciers 29/03/2011
New research by scientists at Woods Hole Oceanographic Institution (WHOI) highlights the role ocean circulation plays in transporting heat to glaciers. A research team led by WHOI physical oceanographer Fiamma Straneo discovered warm, subtropical waters deep inside Sermilik Fjord at the base of Helheim Glacier in 2009.



Looks like we might get a strongly positive AO over the next few days. I seem to remember that the late ice buildup of March 2010 was due to a strongly negative AO. Could this year's value mean increased melt in early April? I am still a newbie at understanding this.


That's a good question to which I unfortunately don't know the answer (perhaps others do). I suggest we watch and learn together. :-)


I've updated the Daily Graphs page with a link to an archive that contains radar images (ASCAT) of the entire Arctic. On the OSI-SAF Quicklooks page there's a very nice tool that shows large images of ice displacement.

With regards to a potential new maximum that Phil263 mentions in another comment section: IJIS notes another decrease. It is still possible for the maximum to go a tad higher and later (in some data sets), but it needs some pretty weird weather, and fast.

Artful Dodger

How to Measure Ice Thickness at ICEX
There are several different ways of measuring or estimating ice thickness, none of which is perfect...
For this experiment, we are using all of these methods to measure the same stretch of ice so that all of the methods can be compared.

Christoffer Ladstein

While it takes a good amount of patience to get this "snowball" downhill, or watching the wallpaper dry as Neven, so nicely put it, it might help having some "evidence" that the world actually do care what's going on up there in the Arctic:
1) Nature is out with a new magazine concerning climate change http://www.nature.com/nclimate/index.html
2) The relatives of Knut always make the way to the press, this time the "real stuff-bears" - http://www.theage.com.au/environment/conservation/bears-face-shrinking-future-20110331-1cn9d.html
3) Greenland is an very important issue regarding worldwide sealevel, and now new scince show alarming effects taking place in the sea and fjords below the ice...http://www.redorbit.com/news/science/2020173/how_heat_is_transported_to_greenland_glaciers/index.html
4) And finally the rest of the world also have noticed the new ways of measuring the ice extent and volume, from the sky above...

So lets enjoy these articles while (restlessly!)waiting for spring to enter the arctic, the REAL spring:-).


Christoffer, thanks a lot for those links! I'll be using them tomorrow for the TIPS at the end of the newest SIE update.


Neven I like to use the Cersat data to follow the ice movement:

Ftp link at bpttom of page: ftp://ftp.ifremer.fr/ifremer/cersat/products/gridded/psi-drift/

Then I go to Quicklooks, then arctic then asmre-merged.

The 6day map for the 24th to 30th is quite impressive.



Wow, Phil. That's just awesome. I'll link to this one on the Daily Graphs page. Thanks.

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