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The animation included in your post at 11:15 on Sep 17th intrigues me. What is the source? What is the color scale to surface temp metric?

What is your explanation behind saying “It is not the rate of cooling in the Chukchi that is critical; it is the total amount of warm salt water delivered from the Pacific that matters for onset of freeze-up...” I’m reading your “critical” as predominate, and I’d like to know what portions can reasonably be assigned to factors in the system and why. With other things held constant, what are the relative effects of cooling rate and inflow?

The Bearing inflow’s impact on “...end of winter ice thickness” seems quite reasonable in the sense that it should be ongoing.

I did monitor quite often the E. Siberian-Chukchi-Beaufort Sea’s Surface temp anomaly as the ice front advanced south in 07, and have sporadically done so since. Your pointing-out that northbound joules are “in the pipe” is something I hadn’t considered. Much thanks, and (to use both the current and previous motifs) we’ll see how it plays.

Nevin – Thanks, where concentration ~ fulsomeness.

For the many others, a tip of my dirty ball cap.

As I started with a request (and mostly kept in that vein), I’ll end with one. I’d be interested in what the posters (and lurkers) here are seeing “on the ground”, in their own daily circumstances, in terms of the overall climate change issue. I’m interested in observations of the people they contact, how the media “plays” things, etc. As far as I can tell, Neven’s managed to attract a group that, used as instruments, are likely well calibrated with good resolution.

Steve Bloom

Andrew, you're thinking of a statistical regression he did, which wasn't a projection or prediction. It's confusing since the results are similar to his model's, which are quite separate and are the basis of the 2016 +/- 3 projection.

As I understand it, he does have access to classified data, but can't publish based on them.

Re the encroaching warm water, he has stated that the reason he thinks his results are better than the GCMs is that the latter aren't sufficiently fine-grained to track the warm water.it may or may not have anything. His results are based on a regional model that is. He's also said that he expects the end, when it comes, to be fairly sudden, so I doubt he thinks the ice behavior of the last few years in any way contradicts his results, especially since PIOMAS has shown a continued reduction in volume.

Steve Bloom

Please disregard that sentence fragment.

Steve Bloom

WhiteBeard, FWIW Maslowski refers to sub-surface currents.

Guillaume Tell

"By "ice-free" Maslowki tells me he means more than an 80% drop from the 1979-2000 summer volume baseline of ~20000km^3. Some sea ice above Greenland and Canada may survive into the 2020's..." Joe Romm

Andrew Xnn: I agree with you that ALL sea ice predictions should be similarly qualified.



This girl at least checks in here every single day. Absolutely blown away by all the knowledgeable and dedicated people here. Keep it up guys.

And Neven, you've done a fantastic job. Good idea to keep things ticking over at a less hectic pace once it *is* over. But I'm sure there'll be good reason to do the occasional post with reports and analysis coming out from various bodies looking back over the data collected throughout the season.


SIE extent for Sep 17 (prelim ): 4,832,813, a drop of 58,125 sqkm!

Greg Wellman

"From Wieslaw Maslowski's presentation, he estimates that Arctic Sea Ice volume in the Fall of 2007 was about 9000 km3 and that about 1200 km3 has been lost every year for the past few years (since 1995). So, 9000/1200 = 7.5 years. 2007+7.5= 2014 or so."

Hmm, according to PIOMAS (which may not be perfect, but seems pretty good) Fall of 2007 got down to 7000 km3, and right now is probably about 5000 km3. (So we get about the same linear prediction - 2016 for 1000 km3, which is effectively ice free.) However, if we regress to the average 30 year PIOMAS decline, it would take a good bit longer (something like another 30 years). I think 6 is a little fast and 30 is kinda slow. I'm thinking 2020-2025 for an effectively ice free summer.

Of course if Maslowski really only meant an 80% decline from 20,000 km3, that's 4000 km3, and we could hit that in the next two years, but without necessarily setting a new extent minimum.

BTW, IJIS just updated and there's a (preliminary) drop of another 58k today(!) So whatever happens, the extent minimum is Sept 17 or later.

Kevin McKinney

Provisional value for 9/17: 4,832,813 km2. Not much else to say!


This is the real graph to look at: Sea Ice Volume is what counts and its dire....!


See here for the full image as the blog here is not understanding scaling commands for IMG tags.


and here for the volume graph:


Daniel Bailey

Re: WhiteBeard September 18, 2010 at 02:08

" I’d be interested in what the posters (and lurkers) here are seeing “on the ground”, in their own daily circumstances, in terms of the overall climate change issue."
As some of you know, I live in the Upper Peninsula of Michigan, in a town called Marquette on the southern shore of Lake Superior. Our climate here has changed dramatically since the 1970's and continues to change to this day. Since I shared some of this w/ Lou Grinzo on his blog, I'll just link to them both.

Since I can't figure out how to resize the figure properly, I'll just link to it: Great Lakes Climate Map (soon to be outdated).

'Nuff for now.

The Yooper


I think Dr. Maslowski has the best intuition about Arctic sea ice summer melts - it's the ocean heat that's important, it's the volume trend that's important, and you need a high resolution regional model to better understand ocean eddies and currents getting heat under the sea ice.


Under-ice ablation by anomalously warm water advected from the Chukchi shelves and distributed at the subsurface layer in the western Arctic Ocean by mesoscale eddies has been found to explain at least 60% of the total variance of sea ice thickness. We have demonstrated that the excess oceanic heat that in recent years has been accumulating below the surface during summer and it might be a critical initial factor in reducing ice concentration and thickness in the western Arctic Ocean at the early melting season and onwards the following year.
In order to improve understanding of the role of mesoscale eddies on the regional ocean dynamics progress has been made toward the development of the fully eddyresolving model of the Arctic Ocean. The initial and forcing fields have been prepared and integrations started of the eddy-resolving model configured at 1/48-degree and 48 vertical levels.


The eddy-resolving model is computationally a very large problem requiring substantial computer resources. These two factors determine the actual rate of model integration, which is further slowed down by the actual turn out time (in contrast to run-time) of each model run. All the above translate into a delay of the planned completion of model multi-decadal simulations.

I look forward to the post-mortems of this strange summer melt season (when it's finally over...) I'm sure there was a lot more data being collected than we found on publicly available websites this summer.

Christoffer Ladstein

Prelim IJIS numbers: 4.832.813 km2. Another IMPRESSIVE decrease!

Timothy Chase

Kevin McKinney wrote:

Provisional value for 9/17: 4,832,813 km2. Not much else to say!
How about, "Two more days like that and we will be within striking distance of 2008..." No doubt in volume we left it far behind some time ago, though.

Lord Soth

I can use two words to describe this year.


In my childhood, I grew up in Southern Ontario, and I can remember the long hot humid summers. I moved to Nova Scotia in 1980, which has a cooler Maritime climate. Although the climiate difference is only slightly over 2 degree celsius, it was a real shock, to adjust to. Also the Mariitime climate brought fog that would not burn off for days. In Ontario, I never seen it last pass noon. I love the slower pace of Nova Scotia, however the climate really got to me.

Over the past 30 years, the Nova Scotia climate has gotten more like Southern Ontario. All day fog events are now more rare during the summer, and summer tempertures have probablly come close to what Southern Ontario was in the nineteen seventies. The shift has been gradual, but over the past 30 years, its has gone from weather I hated, to the weather I loved when I was a kid.

Summer is finally coming to a close in Nova Scotia, and it has been the longest hotest summer I can remember, and I loved it.

We normally get one day above 30 degrees every two years. This year we had 6 or 7 with another dozen just falling short of 30. We had 4 days above 32 in a row at the end of August and the start of September.

Every long weekend since the start of spring every day sunny and unseasonally warm, except for one day when we had hurricane Earl. But that does not count, as it was tropical.

When I first moved to Nova Scotia, I always joked that I wanted Global Warming to give a Florida like climate. We are half way there, and I will probablly live long enough to see this happen in my lifetime.

What is probabbly scary, is my children will most likely see summers like they have in Afghanistan.

Enough typing, its time to go out and enjoy the last few days of the Endless Summer.

Lord Soth

With all the doom and gloom, about six degrees, and the fact we have past the tipping point, we need something a little lighter.

Shall we go from "It Aint over Baby" to "Don't Worry Baby" from the Album Endless Summer.



Lots of comments again, great stuff. :-)

why not try to learn some more about the South Pole,

Christoffer, Antarctica deserves a blog of its own. This one's for the Arctic, the bigger canary of the two.

A closer look upon the "Final Countdown" for year 2005, based upon the Ice Displacement Archive, will clarify clearly why the minimum was as late as the 23. Sep.

Indeed, lots of arrows, if I remember correctly. Unfortunately, the PIPS website is down again, so there's no telling what extent will do. Last time it also went down at the moment extent decreases were over, so perhaps this is a sign that we'll see the last extent decrease reported tomorrow, if at all.

I mentioned this to my wife and her reply was " You are all like little boys playing with your toys !!!" and My wife just proclaim "at least you're not addicted to football",

I'm addicted to Arctic sea ice AND football. Please sympathize with my poor wife. She rolls her eyes every time I mention the Arctic or Ajax (my club from Amsterdam). :-)

BTW, thanks for commenting, Clare and Adelady!

As far as I can tell, Neven’s managed to attract a group that, used as instruments, are likely well calibrated with good resolution.

That was the whole purpose of this blog. It's in the comment sections where all the real action is. QED.

How about, "Two more days like that and we will be within striking distance of 2008..."

I don't think we'll be having 2 more days like this. Weather forecast is not favourable to compaction action, but maybe the little ice pack in the E. Siberian Sea is melting out completely?

I have updated Lodger's animations of the areas in question.

Oh, and Phil., I think I'll use that image you linked to of the small Petermann ice island for a blog post, if that's okay with you.

Artful Dodger

Stop the presses! Arctic melt ain’t over ’til it’s over

A new post on Climate Progress begins "So the fat lady sang, but I guess she hit just the right note and shattered some more ice..."

r w Langford

The fat lady appears to be a witch. In the animation put up by Jack Taylor the witch is visible in the lower left corner of the sea ice in the Beaufort sea. It appears in late August and is visible in various forms up until yesterday when it blurs out. Hope you can find it.
http://www.polk-nc.com/agw/arcA15end.swf The image appears to be talking to someone probably this group of Arctic Addicts. Maybe her disappearance is the end of the melt, she has exited left stage.

Christoffer Ladstein

WhiteBeard, you take the price of the day, for inviting us all to report from our own backyard. But where to start....

Norway, the richest country in the world, is also among the dullest, when it comes to risk of nature disasters. We do have a couple rather nifty slides every decade


Apart from that, nature kill mostly due to people's own recklessness.

I've been a weather freak since 1987, in the start observing and taking notes very eagerly, later getting more "lazy" thanks to the www, "all is out there". Witnessing the incredebly green winters of 88/89 & 89/90, when we hardly had temperature below zero in the western part of Norway, trigging the first wawe of climate change believers.
Besides from these years, and some other "incidents", Norway have not so far been blessed with those very obvious changes. We might have a rise in average temperature of 0,5 C the last 100 years, and also 10% more precipitation, This is most easily observed in the mountains, moving the treeline to a higher altitude ASL, but is this more linked to higher CO2 feeding or less animals (sheep, cows, goats etc.) using the area?
Also the glaciers are shrinking, but I hardly think it takes more than half a degree (or two..) to make these changes come true?!
At Svalbard (in the Arctic!) on the other hand, the changes are taking place more rapidly, as predicted by scientists.

So guys, if you're getting flooded or scared by tornados or hurricanes, just move to remote Norway!

BTW, Neven, Ajax IS a GOOD team, we are fully aware of that, thanks to a norwegian player, born just 32 days before me, I guess you know who I'm hinting at...


Uhm, André Bergdølmo?


White Beard:
Happy to answer what’s got me triggered in my personal habitat. I like geography, experiencing an artistic sense of space since I was young. Became a landscaper/gardener. First signs; early flowering shrubs in the seventies. Maybe weather, but phenology (i.e. the yearly return of natural phenomena) is an interesting study. So, being able to use plants in Holland which were sixty years ago described as solely surviving Cornwall winters, something must have changed lately. Now there are some interesting physical aspects to plant life that wont be as easy explained as this supposes. But the bird scene delivers some parallel stories out here. The return of large white heron to these parts is probably just regaining lost natural territory. But the small white was always confined in its breeding by 45 degrees north. A lot of damage was done last winter (birds and plants), but after cutting back hard my damaged Oleander shrub, it reappeared out of its roots… A plant formerly surviving south of the European Alps and Normandy. All together, interesting enough, not much harm done…out here. But the fringe isn’t here, out here we’re lucky since 1953 (night of the North Sea Flood). The worse goes to other places, like Pakistan this summer, or Russia. The game is evolving in time and space like a diffuse net-structure and that may be exactly why our beloved scientific method doesn’t get to grips with it. It is a matter of feel, a moral matter, there won’t be a calculation or a single phenomena convincing the majority of us.

Christoffer Ladstein

Neven: Right!

Werther: Extreme weather, both ways, will be more normal, and that is more worse to handle for us humans, than just a steady increase/decrease of several vectors, wether we're speaking of earlier spring, rising sealevel etc.
BTW, you and me are having almost the exact same study background, and much of the plants I'm selling are grown in your beloved "lower than sea-level" country, read: Booskop, an amazing canal-district so scenic, you for sure have to go to Switzerland to get more aroused.

Lord Soth: Most wonderful description you gave us there, alomst feel for visiting your "outpost" in Nova Scotia. We had no heatwawe in Norway this year, which is kind of rare, but on the other hand I and my family of 5 met it "bang in the face" further south in Europe, while going Inter Rail for a couple weeks. 40 C in the shadow (Berlin/Prague) is NOT a dream come true on a TRAIN!
And the glaciers in the Alps had another great step backwards, according to the papers i came across...

Neven, how are we going to interpret the further temperature dive from DMI?
And the decline in extent for September ALONE so far is stupendous, maybe you would be nice enough to post monthly decline for 2010, should prove some interest?!

L. Hamilton

Personal/climate story:

When I first moved to New Hampshire (Northeastern US) with my family several decades ago, I discovered that in winter I could often ski from home to my office. This distance is less than 10 km, mostly through forest and open fields. But I had to cross one river, and it had to be well frozen. Over the years, it seemed that more and more often I could not get across that river. Finally I gave up the idea.

Much later, when I started hearing about climate change, I wondered whether that could possibly have anything to do with my river crossing. So I looked up local climate records and found, with some surprise, that New Hampshire winters have indeed been warming since the 1970s, around 0.5 C per decade. This discovery led to further research, and writing several articles.

While Washington DC newspapers cried "Snowpocalypse" last winter, our normally snowy state had a relatively un-white winter, followed by early spring. Lake Winnipesaukee, the state's largest lake, experienced the earliest ice-out date since records began in 1887.

Steve Bloom

IJIS upward revision of ~10K for the 17th, but still an impressive drop. We await the number for the 18th.

L. Hamilton

Unofficially, it just broke 4.8.

Greg Wellman

Heh, I would have beaten you to posting that (4,798,750 preliminary) if Google hadn't delayed my ID verification for 5 minutes (something was down). Anyway, I doubt that sub 4.8 will stand revision, but it could be broken for real tomorrow.

Lord Soth

NSIDC has updated, and their five day average has finally recorded a new minimun also.


L. Hamilton

I know it's an ignoble reason, but part of my keen attention to the numbers comes from having sent in a SEARCH forecast.


I still have plenty of popcorn - hope the Show lasts a few more days.

I didn't think we'd be seeing a late-season challenge to 2008.

p.s. I recommend freshly grated Parmigiano-Reggiano on the still hot popcorn.

Guillaume Tell

4842031 (Sep 17, 2010) - 4798750 (Sep 18, 2010) = 43281 preliminary

4798750 (Sep 18, 2010) - 4707813 (Sep 09, 2008) = 90937

And global temp uah 14000ft AQUA channel 5 is up there with the record high, today.

And I recommend lots of bulk grated parmesan with expensive olive oil, on the popcorn.


Well just when it was getting boring, another side of the change in the arctic shows itself. I agree with Anu, we have a challenger. I hope none of the bookies already paid out!


"Unofficially, it just broke 4.8" L. Hamilton | September 19, 2010 at 05:07

Larry, the "Cycle Plot" you did for Neven to post in
and my latest find/update at
of 8/5/2010
is there an update within the past 30 days?

I am curious if you will have to expand the "bottom" of the plot (below 4) to accommodate the area line?

It's a GREAT Plot, better than Opera.


I know it's an ignoble reason, but part of my keen attention to the numbers comes from having sent in a SEARCH forecast.

Larry, just a question. Did you know beforehand that the SEARCH prediction is based on NSIDC September mean value?

And global temp uah 14000ft AQUA channel 5 is up there with the record high, today.

Thanks, Guillaume, I hadn't looked at that one for a few days. La Niña is not yet having much of an effect, is it?

Neven, how are we going to interpret the further temperature dive from DMI?
And the decline in extent for September ALONE so far is stupendous, maybe you would be nice enough to post monthly decline for 2010, should prove some interest?!

Christopher, I'm doing a (pen-ultimate) SIE update later today, after IJIS revision.

PIPS is back up, but the ice displacement forecast map is stuck at the forecast for the 18th. Hopefully they will show the forecast for the 20th in a few hours.


PIPS is back up - - - Hopefully they will show the forecast for the 20th in a few hours.

Neven, I'm getting the 20th at
the "Archive" is still stuck on 18th for me

the arrows have shrunk to very small as you've previously predicted.


Thanks, Jack. Here's the image:



About the SEARCH "minimum ice" definition : you're right, they don't display the correct definition on their front page. However you'll find on the "Background" page: "An integrated monthly report is produced that summarizes the evolution and expected state of arctic sea ice for the September mean arctic sea ice extent, based on the observations and analyses submitted by the science community.". On NSIDC 2009 Minimum page, http://nsidc.org/news/press/20091005_minimumpr.html , one also finds that "The average ice extent over the month of September, a reference comparison for climate studies, was 5.36 million square kilometers". On http://www.arcus.org/search/seaiceoutlook/2008_outlook/summary_report.php , you'll also find that "The projections of the Sea Ice Outlook groups for the September 2008 mean minimum ice extent, based on May data, had a median value of 4.2 million square kilometers. This value is roughly the same as that observed in 2007 (monthly average of 4.3 million square kilometers) and somewhat lower than the monthly averaged value of 4.7 million square kilometers observed in 2008 (as provided by W. Meier, NSIDC)."

Well, I agree with you that it's far from being obvious. I just learnt about this the painful way when I debunked a denialist's graph last year - this crap-producer wasn't happy at all when I posted on his blog about 3 bigs errors he had made, including this one...

It's also why I posted here some days ago, about the future significance of this September Average: as the minimum extent date gently drifts to october, computing the September Mean Extent might prove meaningless. Computing the average from the 30 days before/after the Minimum's date would probably be more significant statistically (see 2005 curve for instance: September mean value is probably quite different from this 15 days before & after method).

Artful Dodger

Fred: You're almost there. Now, how do you determine the true Date of the minimum SIE, correcting for all the 'slosh'? (Hint: I've commented about this with my 31 day moving average chart).

The IJIS revision for Sep 18 was +14,844 km^2, for a final SIE of 4,813,594 km^2. The daily change from Sep 17 was -28,437 km^2 and the 5-day moving average change in SIE is now -39,031.

L. Hamilton

Jack, I did update my cycle plot when the NSIDC August means came out,

I'll do one more version when September is final, probably in the first half of November.

And here's a different cycle plot, this one showing seasonality and trends in the mean ice edge latitude by month.

The latitude data come from a 2010 GRL paper by Eisenman, discussed by Tamino

L. Hamilton

Neven, I did know that SEARCH's criteria is NSIDC mean extent, which is what I use for many of my graphics as well. Statistically, it's more predictable than daily extent although the latter is more fun to watch.

Here's a graphic showing the model for my SEARCH offering, which coincidentally led to the same prediction as Tamino's simpler quadratic model, but from a different direction:

For the SEARCH process you also send in your rationale. Mine is naively statistical. Its elements are ideas I tried out earlier on this blog.


Well, Lodger... I don't know how exactly it should be computed. Probably taking the "lowest moving average on 30 days" would do (and yes, I saw your previous graph). I'd love to see if such a redefinition would change years ranks - but as we don't have (yet) the NSDIC numbers to crunch... Heraclitus' note was quite similar than mine.

Of course, we would have to wait for 15 days to get the official minimum... which is more or less the same as today's press release, as it usually occurs in the 10 first days of september. Luckily NSIDC were careful in their statement, "Sept. 10 appears to have been the lowest extent of the year;" - otherwise the deniers crowd would have fun...

OT (or not ?) : http://www.climate.gov/ is out - its ranking on Alexa should be interesting to follow.

L. Hamilton

Fred, from a quick glance it seems to me that using a 30-day moving average instead of actual daily IJIS values produces a very similar-looking plot, slightly smoother and with minimums less sharp. It doesn't shift the yearly rankings, however.


99.7 percent accuracy CONGRATULATIONS for Larry Hamilton prediction
considering I view it as 4,800,000 / 4,813,594

Some 10K to 15K decrease and it's 99.999999% to 100%

"dat's close enough for guvamint work"


Well, I agree with you that it's far from being obvious.

Exactly. It should be obvious on the front page and in the opening paragraph of every monthly SIO report. I sent a mail to someone from ARCUS today to repeat how important it is they communicate clearly. Or else I won't be participating next year with a prediction! ;-)

If I'm interpreting Jack Taylor's last comment correctly, he also is under the impression that Larry Hamilton's SIO prediction is based on IJIS absolute minimum. Just another example of the confusion.

Jack, Larry's prediction is based on September mean value as reported by NSIDC, so we have to wait a few weeks more. But he will probably be close nonetheless.

Artful Dodger

Several comments have noted how close 2010 IJIS SIE is getting to 2008. So how is the comparison with NSIDC, now that 8 days have passed since the NSIDC faux-minimum?
NSIDC Sep Minimum
Will 2010 take 2nd place? Remember, NSIDC compares Monthly average SIE, so 2010's got to get below the purple line, then hold fast til the end of the month..

Does anyone have a Wind Forecast? Animation?

Charles Wilson

... This gives Highs & Lows, so a High on Greenland/Canada & a Low in Europe/Russia give a Fast Flow out into the Atlantic (Optimum is when they are next to each other).
Looks like moving to a Single Low in the middle, one of the Worst possible for Melt. Lows are Counterclockwise, Highs not.

+74,531.8 = Cryosphere Area Gain.
> DMI just melted off most of the last 2 days' Gain.
> Bremen new Min: beat 2008 (had tied before) !
> Fram Export may Reverse soon ... Yet the Arctic Central Basin did lose 250 K Area in 2009 Spt 20-Oct 8. What Next ??? ==>>
>> Clear Skies ? <<
Are you seeing what I am seeing?
...Winning Cloud Duration Equation: 34 Days times Nino rating +33%
(+33% if longer-lasting Modoki Nino = more heat = more Clouds).
At LAST, the Clouds break.
2 whole days before Polar Sunset.
God loves his Jokes.

Charles Wilson

Now the Beaufort Sea has a HUGE storm = Clouds but you can see the Pattern has returned to Lows = Clouds ... High = not. As Opposed to the last 11 weeks:
Low = Clouds
High = More Clouds
...JAXA & Bremen Up, Cryo down.

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