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Twemoran

Chris - I've been looking at the ASAR images for the last couple of days and it appears to be open, with a new, large crack near the top

I played around with modis in 2010 and could not find a precedent

Further south the fast ice is cracking up and may surpass 2010 levels after the today's spring tide

Neven

The spring tide is today? Thanks for reminding us, Twemoran!

Greg Wellman

I'm trying to figure out in what situation 1.8 km would take 25 minutes by car. (Ok, the opening scene from "Office Space" comes to mind...)

Philiponfire

I think we finally have transport in the NW passage.

Paul Klemencic

All the Europeans on the blog are asleep, so thought I would jump in and discuss the final Bremen map for August 15. The weak area I have been watching in the 105 E to 135E quadrangles has spread into the 135E to 150E quad. And the next two quads over, 150E to 180E, the weak area between 80N and 83N is also growing. These areas have significant areas with 50-70% concentration ice. The corner in the ice between the two area has moved 100-120 km west over the last four days.

If ice moves out from the North Pole area toward the Fram, these weak areas will be pushed down toward the pole. They also will likely melt out along the way, because the wind would be pushing warm water from the Laptev into the pack weak area. This is going to bring open seas very close to the pole: my guess is within 300 km. Every day the probability of this event gets stronger. If the current trends keep up, I will begin talking about the possibility of an "ice-free" North Pole, but not quite yet.

In the Beaufort and Chukchi regions, we saw some major ice melt. I was waiting for the IJIS figure, but not out yet ( 03:30 GMT), so I guess about 80k loss.

Chris Biscan

-40K prelim

Phil263

Extent down by only 40k on August 15th. Your earlier call (subdued losses in the coming days) was correct Paul!

Bob Wallace

I'm fascinated by the difference in concentration this year. If one compares ice from two days ago with ice a week earlier it looks like we could end the season with no areas holding concentrations greater than 60%.

http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=08&fd=06&fy=2011&sm=08&sd=13&sy=2011

The dark stuff is just plain going away.

That's a huge change from 2007 when while extent was very low what ice remained was tightly packed.

Kevin McKinney

FWIW, the -40K does get us below 5.6M. Wasn't that someone's guess for minimum, early on? Maybe the WUWT 'wizards?'

Anyway, another minor milestone passed.

Bob Wallace

The difference is 40,000 even.

I'm guessing the number is a place holder.

I think that the wizards revised downward to 5.3. Got to keep chasing the numbers if you want to celebrate your genius. Get out in front of that parade and wave your arms like you're the leader....

Neven

What is interesting of course, is that when SIA hits more than -40K for the same date, CAPIE will go down some more.

I believe Paul Klemencic or Chris Biscan have mentioned this already, but towards the end of the 10 day forecast ECMWF is showing a high trying to elbow its way into the Canadian Archipelago, with a low moving towards its favourite spot between the Kara and Laptev Seas. We all know what this could mean, but it's far off and the forecast will probably change.

Right now, I'm wondering how slow extent decrease can get. On the one hand the distribution of highs and lows is getting really unfavourable for extent decrease, on the other hand we have the sea of slush puppy.

Seke Rob

One other [Southern] European, awake. MASIE updated chart (data through 14th)... stalling overall and redistributing, with the Central Arctic handing over what it's got to it's satellite seas... it's spreading like [thicker] oil these latest days.

Espen

Healey is on her way to the ice again, she is now in the Barrow (Alaska) area, I wonder when they reach the remains of the Sea Ice, whether they will let people off on to the "Ice" for studies, or it is risky?

Regards Espen

Chris Biscan


http://www.iup.uni-bremen.de:8084/amsr/ice_ext_n.png

UB prelim out...early MODIS images show quite a bit of comapation/melt in the Siberian Sea and recede further South.

maltose

Found on the NPR website about Arctic ice:
http://www.npr.org/2011/08/15/139261223/the-arctics-diminishing-sea-ice

If you scroll the bar above the map, you can see the average September temperatures for the past 30 years. Interesting.

maltose

For those who don't know, NPR stands for National Public Radio, the semi-public broadcaster in the USA.

Chris Biscan

quite a bit of melt/compaction going on right now in the E. Siberian Sea from very warm 850s under sunny skies and a huge HP.

they have 2-3 more days of very warm days and clear skies.


Further south some pretty large Recede in the area of new low concentration. New Sat Images show a hole opening up. looks like it will be big enough to possibly effect extent by tomorrow with ice left in it under 15 percent. This may lower DMI 30% tonight as well.

in terms of extent drops the East and SE side by Greenland will be super crucial the next 5-7 days as it blow torches with very very warm SSTs being slammed into it.

the UB map shows concetration get crushed down there today.

idunno

Hi all,

Many comments I might have made have already been posted.

Waiting to see how significant the opening of the passages between the Canadian Archipelago islands will prove to be. The clearest sateliite images are from 14 August.

On the new PIPs pages, there is a Surface Sea Salinity map. This seems to me to show an increasingly large stream of saline water entering the Arctic between Svarlsbard and Severnaya. Or I may be imagining that it has changed. I cannot find any archive images to compare.

DMI's average temperature chart has just hit 0 degrees Centigrade, right on cue.

Espen

Another +/- 2000km2 ice piece is off from the pack at Jøkulsbugt (North East Greenland), more to come soon!

Regards Espen

Seke Rob

Dramatic. Just looked up Ward Hunt on Google Earth. There was reporting of a widening crack.

Jøkulsbugt, 'bugt' in Dutch would be 'bocht' meaning 'corner'. Google was worked and did not reveal but a Jokuls Fjord, way somewhere else.

Espen

Bugt in Scandinavian means bay!

Phil263

CT just posted CIA for Day 226 ( August 14th). It went UP by 63k !

Seke Rob

[ot]

Bugt in Scandinavian means bay!

Ah, I was looking for the right word... a 'bocht' can be inward or outward, the inward, shielded from full force of weather. Yes, you wrote you could follow that Danish interview :D A Dane once told me that they could understand Norwegian, but the Norwegians not the Danes... something in the linguistic evolution of the spoken word.

Google remains reticent.

Espen

Seke
Try Joekelbugt, yes danish is almost like dutch, like somone with a sore troath!
Regards Espen

Seke Rob

Had changed the ø to oe before, but dropping the s did it: COI gave it, with a quadrant map to go: http://ocean.dmi.dk/arctic/joekelbugt.php

Espen

But you will not see on today's image, since it happened earlier today.
Espen

Russell McKane

There is a great clear view of the melt out in the Laptev on Lance modis (15 Aug) at the moment

Kevin McKinney

OT: "Bugt"--I believe the English cognate would be "Bight", becoming archaic but surviving mostly in the nautical sense of "bay." (In knot-tying parlance, it's synonymous with "bend"--but I think it's a dying usage there, too.)

Kevin McKinney

The IJIS revision is in; today's drop is ca. 36K now.

idunno

Hi all,

Opening soon - the fast lane of the Northern Sea route, to the North of all of the Arctic islands.

Setting off from the Siberian coast, it would perhaps be possible to reach 85 degrees N in open water.

Both of these are unprecedented as far as I know...

Around here, "bugt" means "very tired" or "broken".

Christoffer Ladstein

Very OT: The Norwegian writer Knut Hamsun, winner of the Nobel Litterature prize, once wrote: "An old saying says that women's list is endless. I believe now that women's list, both the BAY and both ends." (Et gammelt ord sier at kvinnelist er uten ende. Jeg mener nu at kvinnelist har både bukten og begge endene.)

So this word bugt/ bukt is like many other words, very flexible!

For a Scandinavian it's rather fascinating to see all these Names for bays, islands, fjords etc. named after Norwegian/ Danish explorers or kings (& queens ?, just try to imagine the extreme efforts they had to go through at those days, enduring the harsh climate not only for 1 winter, no perhaps 2 or 3 until they were able to get back to more civilized territory. Not many today would have dared this, with no ability to being picked up by a Sea King or a Atomic driven Ice breaker!

BTW: Paul, where art thou with todays discussion of the prelim Bremen map?
I figure many of us have come to enjoy those analyzes!

Peterman seem to be cracking/calving or do my eyes do me unjustice!?


http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r03c03.2011228.terra.250m

Last but not least: Norwegians DO understand danish just as easily as opposite, but don't make me elaborate this issue on Nevens blog!

Paul Klemencic

Well OK, Christoffer Ladstein. I was busy this morning, and its approaching midnight in Europe, but here are a few thoughts:

First, the movement on the eastern edge of the pack was relatively minor. On the Bremen map, I normally ignore shade changes between purple and lavender, even red and yellow areas; they shift back an forth and its usually hard to draw conclusions from changes in these colors (areas above 70% concentration). But when the green areas (less than 70%) show up, sit up and take notice. Today, some of the pack north of Franz Josef Land turned green. Ice pack weakness showing up here, should help eat the pack away in the area from 45E to 75E and create open sea for the ice from 75E to 150E to move into. The open water and weak ice pack area from 105E to 150E continues to weaken and expand, even though the edge of the pack didn't recede much in this area.

Out in the Chukchi region, the quadrant from 150W to 165W between 75N and 80N had a big area of water open up in today's map. Given the weakness there, and the weakness I discussed above, we could see a significant amount of ice pack remain in the E. Siberian region, eventually only connected to the main pack by a thin isthmus of ice. The final Bremen map today should show more info in this area.

I don't think there was a big daily drop in extent, maybe 40-50k, depending on the final revision.

dorlomin
Peterman seem to be cracking/calving or do my eyes do me unjustice!?
I have been thinking that his eavening as well, the ArcticIO graphic for the 16th certainly seems to show a growing crack.
crandles

Re "Setting off from the Siberian coast, it would perhaps be possible to reach 85 degrees N in open water.

Both of these are unprecedented as far as I know..."

85N looks easy on 24 Sept 2007 but I don't think there has been any other occasion recently.

http://iup.physik.uni-bremen.de:8084/amsredata/asi_daygrid_swath/l1a/n6250/_2007/sep/asi180-n6250-20070924_visual.png

michael sweet

NSIDC updated today.

Kevin McKinney

Thanks, michael!

39K prelim, more or less.

Phil263

Where are our meteorologists?
Wasn't the weather going to be favourable to melting this week? I can't make any sense of these maps....

Neven

Phil, I would have expected two more days of decent extent decrease, but the switch seems to have started right after that big melting day. ECMWF shows something which might turn into a Dipole Anomaly, but that's 8 days from now. So 1) it's hardly sure whether it will come about, and 2) it means more than a week of slow extent decrease (unless the slush puppy sea disintegrates, regardless of weather patterns).

I'm waiting until the 20th, but I'm pretty sure we can rule out a new record minimum extent by then.

Phil263

I am a bit surprised because the AO index is strongly negative and i thought that meant fair weather over the Arctic Basin...
I can see a High over Svalbard,another one just north of Wrangel Island and a Low North of Ellesmere. How does this affect the melting/ ice flow?

Neven

Phil, the AO Index doesn't tell us much about the distribution of highs and lows.

Remember that highs have winds circulating in a clockwise fashion, lows in an anti-clockwise fashion. If you look at where the isobars are, you have an idea of the general direction of ice transport.

Melting is influenced by other things as well, like SSTs, and whether sea level pressure systems are pulling in warm air or not, clear skies vs clouds, etc.

Christoffer Ladstein

Thanks Paul, you'r the true Oracle!

BTW, today proves that "never give up summer", 16 C they woke up to at Longyearbyen, Svalbard this morning, so I figure the local Icebears are sweating out!

http://retro.met.no/observasjoner/svalbard/SvalbardLufthavn/index.html

Anyway, by far the hottest day up there this season. Considering how hot the Canadian Archipelago have been the last weeks, maybe now it's Svalbards time...

crandles

Re: "ECMWF shows something which might turn into a Dipole Anomaly, but that's 8 days from now. So 1) it's hardly sure whether it will come about, and 2) it means more than a week of slow extent decrease"

Did you forget to add 3) By that time more air is below 0C and the sun lower in the sky so these don't cause much melting and it is better for the ice if the ocean loses heat to atmosphere and space than to the ice.

Or is dipole anomaly still bad for the ice? It surely cannot be as bad as in July can it?

Neven

I think it's the best way to compact the ice and send it out of Fram Strait. It's the only thing that can counter the onset of freezing temperatures.

Russell McKane

Christoffer
Peterman seem to be cracking/calving or do my eyes do me unjustice!?
I think your eyes are right. Lance modis for 16th appears to confirm that the crack has now spread right accross the width of the glacier. This seems to be confirmed by Polar view
http://www.seaice.dk/test.N/ envisat.n.WSMForbits.23:22
it does not look like it has separated yet but too early to tell. The same image castes doubt on Ward hunt crack but unable so far to cross check with Lance due to cloud.

Russell McKane

Going by our earlier discussions on An Observers Predictions. Using Polar View Ti2 (Ice temperature) graphic - the refreeze has stated but only along the coast of North Greenland. The central arctic appears to still be very wet ( snow melt / ponds) These conditions are holding out a bit longer than previous years. This change will be worth watching as it will give a good graphic of the end of the melt process. It could also make a good animation. I will see what I can do.

Seke Rob

Re: michael sweet | August 17, 2011 at 02:40

The mid month report, buoys bottom / top melt is very interesting. From combined 80cm to just 30cm. Don't know how this compares to prior years and how typical August ratios of top/bottom would compare. From recent discussion here the dominance would be from bottom, dictated by solar angle. OBuoys5 webcam on yesterdays visit suggests fresh snow up top which will have it's breaking effect.

MASIE/CT data for the day before yesterday not yet available... see, I'm infected :D

Seke Rob

Corr on what I wrote "From recent discussion here the dominance would be from bottom, dictated by solar angle", the August reference fell off the typewriter :O

Seke Rob

Re: Russell McKane | August 17, 2011 at 14:27

Tracking Polarstern, aiming right for the heart of the pole i.e. excellent on-site observational feedback is on it's way. More data for Cryosat-2 validation.

crandles

Area is up again to 3.453, a further 62k increase!

Neven

It's amazing. 2011 was leading 2007 by 272K, and within 5 days this has been turned around into a 211K lead for 2007.

So where I was thinking extent would catch up, it is area that has stopped in its tracks. As has CAPIE, of course.

Strangely (or maybe I'm not looking right), SIA number for yesterday was released as well: -15,617K

crandles

As the yearfrac is the same I would guess it is a revision to 15th not 16th data. But I could easily be wrong.

Philiponfire

A burning question in my mind is how thick is all that slush? my speculation is that it cannot be very thick at all with ice in such small pieces lubricated by water it would have a desire to spread out rather than stack up . would it not? So if that is correct then not only is all the blue low ice concentration area the volume logically is very small also.
So the thinner/smaller crushed ice gets the greater the area it will want to occupy relative to its volume. so that would cause an increase in area shortly before final melt would it not?

Seke Rob

The CT SIA file for the Arctic has 2 entries for year fraction .6219 (15th). The second one is 46k up from the 14th. MASIE has no entry for the 15th, and shows a change down of 88kkmsq from the 14th to the 16th.

Bob Wallace

Do we know anything about water temperatures in 2007 vs. 2011? How about strong incoming wind patterns in 2007?

Right now the extra 2011 ice is still in the East Siberian and Greenland Seas. In all other regions 2011 is in the lead or the total amount of ice left is insignificant.

The surface temperature values adjacent to the ice edges of both still-iced regions is high. The ESib is getting pinched in on both sides. The ice in both areas shows lower concentration.

By this time in 2007 water temperatures were having to work on thicker, more concentrated ice in a more compact area (less overall heat to be tapped).

Unless current water-stored heat is significantly lower or some large import of warm air which might have happened in 2007 isn't repeated in 2011, I don't think the tale is told.

Philiponfire

So if that logic holds then there could well be some immanent mind boggling area losses in the Beaufort, Chukchi and East Siberian seas unless we get some serious cold coming from somewhere.

Neven

Bob, JAXA has a website where you can compare SSTs from previous years in the 2002-2011 period. I use that for the monthly blog posts on temps, like last July.

Philiponfire, you are correct. This is the big question.

Chris Biscan

UB Prelim is out and there is quite a bit more compaction/melt than in previous days. Probably going to see a large decrease.

Bob Wallace

Flipping back and forth between Aug 2007 and 2011 on the JAXA site the open water temperatures look similar for the Greenland, less so for the ESib. My question would be how the water temperatures under the ice compare.

If there's heat under the ice, if currents have spread summer heat around down below, then the remaining less concentrated ice is sitting in a large warm bowl while 2007 ice was piled up higher in a smaller bowl. 2011 has a lot more bottom surface while volume is less.

I'm looking at the study which found that melting ice water sinks and causes warmer water to be transported up to the remaining ice. The larger the ice area, the more heat movement possible.

It all might be moot if the remaining ice is too thick. It would just mean going into 2012 with a thinner ice sheet.

So interesting watching history happen. Too bad it's a historical event that we don't really want.

Bob Wallace

Phillip - currently 2011 is only 200k sqkm higher than the 2010 record in the Beaufort and up only 100k sqkm in the Chukchi (2007 record low). Both of those areas melted to zero last year.

My guess is that those regions are coasting out of the final total.

Will we have 'mind boggling' losses in the other two areas? I don't know, but I see a possible mechanism. I'll bet someone has under ice temps, average ice thicknesses, and is calculating the probability.

The folks in the labs have so much better data than what we get our hands on....

Kevin McKinney

Well, speaking of OTHER things that are about to happen, it looks as if Matt "Solo the Americas" is about to clear the NWP--he's headed West at 6 knots in the Rae Strait, with one more (slight) chokepoint to go, and lots of clear water.

http://www.solotheamericas.org/

Chris Biscan

12z GFS says what cold?

completely different in moving the low H5 heights towards the bearing allowing warm air off North America to fly into the Beaufort then the Arctic Basin instead of a prolonged cold period.

Paul Klemencic

Looking at the preliminary Bremen map, there are some interesting changes to talk about, but OTOH we need to get realistic about all that vulnerable ice in the E. Siberian, Chukchi and Beauforts regions (notice I use the word 'regions' , not 'seas') melting out this year. Given the weather has been favorable to preserving ice in those regions the last four days, and the significant amount of ice that remains, its apparent much of this ice will survive. These regions melted out further in 2007, so we will end up with ice extent added to 2011 from these three regions. Up until the last several days, I thought we would lose 80-90% of the this low latitude ice.

We are in the bottom melt season, where the surface begins to refreeze, and the sole surviving pole cam (tilted, but still working) shows the leads and melt ponds are refreezing. There seems to be two mechanisms that really accelerate bottom melt: either the wind drives warm seas into the pack, or the winds push the pack over warm seas. For either to happen this year, we need a wind out of central Siberia pushing the Laptev water into the pack, or a wind cycling around a high pressure system to push the pack back toward Svalbard and Franz Josef Land and over warm seas in or adjoining the Laptev and Kara regions.

For either event to happen, we must see a HP system set up in the Canadian Archipelago. Yesterday, and so far today, the HP ridge stretching from the Kara and Barents seas all the way over to the Bering strait, coupled with a LP system in the CA, has one of the worst configurations for melt.

Other than bottom melt, the other thing that could drive late season extent loss is export of ice through the Fram strait. Right now the pack is almost perfectly situated for heavy losses into the Fram, except that the weather pattern is all wrong. Again, a HP system must set up over Greenland or the CA. Eventually this will happen, but the later it does, the less impact it will have.

Any chance of 2011 catching 2007 extent, depends on a high pressure system 'camping out' in the CA for at least 4-5 day period soon.

HenkL

Polarstern, August 17, 18Z:
air temperature -1.9°C (freezing drizzle)
water temperature +1.6°C

position: 86°54'N 58°48'E

Paul Klemencic

Back to the preliminary Bremen map... Chris Biscan, I don't see much extent loss today. Ice receded somewhat in the Greenland Sea, but ice seemed to spread out in the Beaufort. I guess another small decline.

But the weak area of ice in the quadrangles between 90E and 165E continued to grow. This increases chances of seeing open seas significantly above 85N, and even closing within 300km of the pole.

The emerging weak area at the edge of the pack near Franz Josef Land closed back in. Sometimes we see this on the map one day, and then the next day the weak spot reappears. I will keep my eye on this spot.

Other comments can wait for the final map.

crandles

Re: "There seems to be two mechanisms that really accelerate bottom melt: either the wind drives warm seas into the pack, or the winds push the pack over warm seas."

How about a third, wind direction opposite to water current causing much more turbulent mixing bringing warmer water up from below? I cannot remember where but I saw a suggestion of an order of magnitude more mixing.

Chris Biscan

Paul,

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?mosaic=Arctic.2011229.aqua.4km


you can verify the UB maps with this.


also as far as your comment on warm water/air hitting the ice.


http://ocean.dmi.dk/arctic/weather/temp_latest.big.png


As well as warm SSTS and warm 850s.

that air is getting pumped by strong winds the next 4 days around that HP.

Christoffer Ladstein

Just some written proof and photos documenting the "heatwawe" that today struck Svalbard!

http://translate.google.com/translate?js=n&prev=_t&hl=no&ie=UTF-8&layout=2&eotf=1&sl=no&tl=en&u=http%3A%2F%2Fwww.nrk.no%2Fnyheter%2Fdistrikt%2Ftroms_og_finnmark%2F1.7753350&act=url

Patrice Pustavrh

Neven, I hope I am not too nasty, but I think you can do good analysis and prediction of the end season comparing to your data in 2010 End Zone posts. The reasons are, that ice distribution in 2010 and 2011 is quite similar (at least regarding East Siberian Sea). And even in 2010, after checking the articles you've provided, I personally do not find much difference (except that area and extent this year a somewhat smaller). Well, my eyeballing (as the most inaccurate form of prediction) tells me we will be somewhat just below 2010 minimums (and likely below 2008 too), with quite quick rebound in late september. But, it is just my eyeballing and please, do not take it seriously. But (giving some ideas to Chris Randles), if the weather, rounding SST are similar, we could probably get same extent/area ratio loss at the end of season.

Paul Klemencic

crandles: The mechanism you suggest would work well where a current exists, along with the correct conditions. But remember we are looking for a 200k-300k impact in ice extent.

In 2007, the Chukchi and E. Siberian melted out early, and then the warm waters was driven into the pack by a classic Arctic dipole, with a HP over the CA. This melt was augmented by the export of ice into the Fram strait. This year we could see a similar mechanism if the Laptev region water was driven into the pack by wind coming up from central Siberia. We could be hitting 1000 km of ice edge pretty hard.

But consider my hypothesis: If the ice pack simply reversed the 4-5 day sprint of 100-120 km toward Alaska about 5-10 days ago, this would move 120 km of ice edge over a 3000 km 'front' over warm seas, and quickly put 360k sq km of ice into the 'melt zone'.

This is why I focused on the buttress at Severnaya Zemlya earlier. This back and forth movement of the pack only happens really quickly when the pack isn't anchored against land on the ends. So this mechanism really doesn't become really significant until the individual seas have all melted, and the pack is free to move back and forth. And of course, a big flush into the Fram becomes possible and augments this mechanism.

Paul Klemencic

Chris Biscan: Wow! What a spectacular image!

I don't spend much time on viewing the Modis visuals as you guys do, because it takes me too much time to tease out what I am interested in from below the clouds; but I don't recall seeing anything this clear and all encompassing before.

Espen

And what I find so interesting comparing Modis with the Bremen map is how reliable the Bremen map is.

Espen

Neven

Patrice, during the melting season 2011 has started to resemble 2010 more and more, although there still remain a few differences. Hopefully I'll have time next week to do something like last year's End Zone series.

Artful Dodger

HenkL: Water temp measured by the Icebreaker Polarstern Aug 17, 18Z hrs was -1.6 C

Here's the ship tracker history:
http://www.sailwx.info/shiptrack/shipposition.phtml?call=DBLK

Phil263

As I did about a week ago, I have prepared a simulation of SIE changes this year based previous yesrs changes from August 16th until SIE reached its minimum.

Year Minimum Date Decrease 2011 predic
2005 5,315,156 (22/9) -785,000 4,763,906
2006 5,781,719 (14/9) -557,500 4,991,406
2007 4,254,531 (24/9) -986,875 4,562,031
2008 4,707,813 (9/9) -1201,875 4,347,031
2009 5,249,144 (13/9) -910,781 4,638,125
2010 4,813,594 (18/9) -883,972 4,453,594

As you can see all simulations give a minimum above the one reached in 2007. The lowest extent (4,347,000) would require the ice to behave as it did in 2008. This is very unlikely considering the weather patterns and forecast described by Paul and Neven. 2008 had a loss of 120K on Aug 25th.
OTOH if the ice behaved like it did in 2006, the minimum would be close to 5 million. If the small losses seen in the last few days persist until the end of the month, we cannot rule out a minimum around that figure.
If we agree with Patrice that the ice this year looks pretty similar to last year, then we would be looking at a minimum around the 4.5 million mark.
In summary, based on statistical analysis( not on observations), we can almost rule out a new extent record. There is only a remote chance that the minimum would be around or above 5 million mark. Bearing in mind the recent behaviour of SIA as reported by CT, I would agree that there is strong likelihood of a minimum being within 4.6- 4.8 million bracket.

L. Hamilton

Uni Bremen extent paints a bit different picture than IJIS these days. As of 8/15 UB sees only a 10k gap between 2007 and 2011 extent, both around 5.2m.

maltose

I know about the UB extent graph, but where are the raw numbers?

Chris Biscan

UB has amazing resolution. Jaxa must not have the same. UB detects the holes in the more so than Jaxa so it is more accurate.

Artful Dodger

Yes, the Aug 16 Sea Ice News report from NSIDC says that Uni-Bremen uses the AMSR-E 6.5 km product. We have determined here at Neven's hangout that IJIS is using the 12.5 km AMSR-E product (thanks crandles!).

BTW, IJIS SIE Aug 17, 2011 (prelim):
5,488,906 km^2 for a change of -60,000 km^2

That's exactly 384 fewer cells than yesterday's IJIS final, for those discreet variable lovers ;^)

Oh, and due to IJIS 2-day averaging, today's drop in SIE is closer to -80K. But, the other 20K will be averaged in tomorrow...

FrankD

@Phil263: The lowest extent (4,347,000) would require the ice to behave as it did in 2008. This is very unlikely considering the weather patterns and forecast described by Paul and Neven. 2008 had a loss of 120K on Aug 25th.

While I agree that a record minimum seems out of reach, I would point out that over the last two weeks, 2011 is tracking more like 2008 than any other year (which is not to say that will continue).

That loss of 120K was part of a big week, but a week later we were seeing -15K, -25K, +3K...when 2008 stopped at stopped dead. Steady but less spectacular loss can achieve the same total.

2008 was highly variable day to day, but averaging a bit over 70K per day at this time, was still plugging away in the high 60's into September and then stopped. For comparison, across 2002-2010, average loss for mid-August is around 50K, slowing to just over 30K per day at then end of the month.

2011 is more consistent and averaging a bit under 70K per day, but over the last few days it's "relative speed"(K/day) has built up again, and its now melting at a rate second only to 2008 (which was fastest in the IJIS dataset at this point in time).

The melting might stop dead like in 2008, but that's not what most years have done. Steady melting and a later-than-average minimum could still produce a 2008-sized loss between Aug 16 and minimum. I wouldn't bet on it, given the weather forecasts we're seeing, but I wouldn't be too quick to rule it out either, especially given the qualitative state of the pack, something completely missing from these numbers.

We'll see...

Phil263

FrankD
Totally agree with you that statistical analysis is missing the actual "field" variables such as weather, ice quality etc... which means that ice can behave very differently this year from the way it did in previous year... There is yet to be a model that would give extent predictions based on observations and short term weather simulations!

Rob Dekker

Neven, I said it before and I say it again : you have enabled an amazing group of knowledgable people here.

I have a few thoughts on the increase in ice area from the past few days.

As I mentioned before, the radiative balance of the atmosphere is turning around this time. This means that top freeze starts to set in across the pack. Since melting ponds are relatively 'fresh' water, they freeze a degree or so before anything else and are thus the first thing to go.

This is especially visible in the Obouy5 movie (frames 1 per hour) in the Beaufort Sea (78 N 140 W) :
http://obuoy.datatransport.org/data/obuoy/var/plots/buoy5/camera/buoy5-movie.mp4

For the AMSR satellite observations, freezing melting ponds will show up as an increase in ice 'concentration'. Since the 'slush' ice in the Beaufort and other areas shows so many melting ponds this year, and this freezing happens relatively fast (in a few days) it actually shows up as an increase in ice area.

Freezing small melting ponds (and cover them with snow) takes only a few days, so I predict SIA will return to it's normal decline soon (probably by today or tomorrow).

Currently, under-ice water temperature is at it's peak and some 1 C higher than ocean water freezing point. Consequently, bottom melt in the ice margin is still in the range of 50-100 W/m^2, as shown clearly in, for example, this flux bouy in the Beaufort :
http://www.oc.nps.edu/~stanton/fluxbuoy/deploy/buoy21_deltaT.html

This under-ice heat flux will knock out 1-2 cm/day of ice, and also, since it has a giant 'buffer' (100 meter of water) this heat flux and bottom melting will continue until deep into October. It is this bottom melt that drives SIE/SIA reduction, until ocean temps cooled down enough so that top freeze will overtake bottom melt (at the minimum) halfway September.

This suggests that ice thinner than 30-60cm will still melt out completely before the minimum, by ocean heat flux alone. Ice patches thicker than that will still melt out if they will be drifting around in nearly open water halfway September.

Because of the widely dispersed pack this year, it may be that we will see a few very interesting surprises, and a late minimum this year.

Rob Dekker

Russel said : Going by our earlier discussions on An Observers Predictions. Using Polar View Ti2 (Ice temperature) graphic - the refreeze has stated but only along the coast of North Greenland. The central arctic appears to still be very wet ( snow melt / ponds)

Thanks for that observation Russel !
Ti2 temps indicate wet-ness of the top layer, and I agree that this is a very interesting data point to observe. Since observations are in the 9 GHz (3 cm wavelenght) range, you may need to wait until snow pack is at least 3 cm before the 'temperature' starts to resemble true 'frozen' conditions. This may take a couple of weeks.

Chris Biscan

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r03c04.2011229.aqua.1km


Now today: Try and line up the images on the screen. fit then to be full view and make sure the land is in the exact spot. Then go back and forth and you can see a major wind shift that took place. As well as the ice making a 15-20KM march West North West and melting taking place. Also note the clear skies for sun to help exploit the strong winds and a weak area of SLP has formed in the Greenland Sea that models were under forming a few days back.

Winds will be a constant 15-20kts from the ice pack to the coast and stream mostly south to north all the way to the other side of the arctic, but not to strong.


http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r03c04.2011230.aqua.1km

Seke Rob

There's a nice add-on for Firefox called Fox Splitter, which allows to have content of multiple tabs in one view, though that might not give the blinker effect to reveal the movement.

Chris Biscan

http://lance-modis.eosdis.nasa.gov/imagery/subsets/Arctic_r05c04/2011227/Arctic_r05c04.2011227.aqua.2km.jpg

http://lance-modis.eosdis.nasa.gov/imagery/subsets/Arctic_r05c04/2011230/Arctic_r05c04.2011230.aqua.2km.jpg

Chris Biscan

It is not the DA but it's many different little areas being compacted causing the extent to keep dropping.

Ned Ward

Back in early July I described a statistical model for projecting the daily minimum, based on past years' decrease in extent from any given date. (A lot of other people are using similar projection methods, I see.)

That model now gives a projected low for this year of 4.7M km2, essentially identical to 2008. The 95% confidence interval is (-4.2, 5.15).

Thus, there's a very small chance of a new record. It's likely that this year will rank 2nd (after 2007) or third (after 2007 and 2008), but it could easily come in behind 2010 as well.

Comparing this to the ARCUS predictions is a bit dicey, since they're based on the NSIDC monthly mean extent, not the IJIS daily minimum.

I've modified my model to predict the NSIDC monthly mean for September. One complication here is that the NSIDC monthly data don't match up very well with the average of IJIS daily data for September. The NSIDC data can be anywhere from 0.1 M km2 above the IJIS number, to 0.2 M km2 below it. There also seems to be a trend in the difference -- from 2002-2005, this difference averages +0.06, while from 2008-2010 it's -0.13.

So ... my model first predicts the IJIS monthly mean for September; then I adjust that based on the mean NSIDC-IJIS difference for the past three years. Using this adjustment, by a weird coincidence, the predicted NSIDC monthly mean is actually very close to the predicted IJIS daily minimum.

So the monthly model I would use to make an ARCUS-type prediction gives a mean of 4.68 M km2, with a confidence interval of (4.26, 5.09).

The actual August ARCUS predictions have a large cluster around 4.6-4.7, close to my model's mean. The WUWT prediction (5.0) is about as far off on the high side as Randles & Hamilton are on the low side of my model. But WUWT, Randles, and Hamilton are all within my 95% confidence interval.

Disclaimer: Yes, this is just playing with statistics, not actual science.

Ned Ward

For comparison, here's what I posted a month ago:

"14 July my model now predicts a mean of 4.33 and a confidence interval of (3.45, 5.17)."

So over the past month the model projection went up by about 0.3 M km2, the lower bound of the 95% CI went up by 0.7 M km2, and the upper bound stayed approximately the same.

maltose

It seems that updates are not happening today...IJIS, Bremen, and CT area have yet to give us the daily numbers.

HenkL

Latest from Polarstern research vessel (Aug 18, 18Z):
air temperature -0.2°C
water temperature +1.4°C
position: 87°30'N 61°00'E

Kevin McKinney

+1.4 C at 87:30?

Hmmmm. . .

Paul Klemencic

Preliminary Bremen map (August 18) is out. The weak area in quadrangles 105E to 135E has now spread into the adjoining quad 135E-150E, with some open water showing up; and a significant expanse of 'green' area, indicating less than 70% concentration ice has spread into the 90E-105E quadrangle. The center of these four quads of weak ice has a hole forming which likely has over 50k sq km of low concentration ice averaging below 30%. This hole should melt out prior to the end of August, leaving a huge gap of open seas right up to, and likely over, the 85N parallel.

Although 2007 had open seas extend up to the 85N parallel, this happened right at the end of the melt season. Given that "the hole" is already weakening ice over 85N adjacent to it, the likelihood of open water above 85N within several weeks is quite high.

the ice edge receded significantly above the Svalbard archipelago, and the edge of the pack there seems to be weakening. The E. Siberian and Beaufort regions showed some significant melt, but this could change (and often does change) with the final revision.

With some carryover extent decline from yesterday, already in today's estimate, I think we will beat yesterday's reported decline.

Chris Biscan

the 12z GFS is light years from the single SLP sitting over Alaska then sliding into the Beauforrt then over to the E. Siberian Seas with very cold air in place and not much movement.

Now. it has slowly changed to a compacting and warmer pattern the next 7 days.

The Torch in the Greenland sea ,Barrents, Kara. Continues and expands to the arctic circle before it recedes day 5-6. This comes iwth strong south winds transporting this air into these areas. It is also pushing the ice back as Paul talked about. The Fram is cut off and is taking a beating. Much of that ice will melt out the next 4-5 days before more gets pushed back in, which may take a while. We will see significant melt here and receding here. The E. Siberian sea was supposed to see it's south/easterly wind stop and cool. IT will still cool a lot but the winds will stay that way for a bit longer forecasting compaction/melt. This area has torched as well which has helped much warmer waters push into the Kara and help melt the ice pack there as we can see it falling apart and that hole getting bigger. You can see on the SST maps the warm water moving into the pack. this will cool but at the cost of ice melting more so than it should otherwise. Winds here will become southerly on the Arctic basin side and Northerly on the Kara side. causing a bit of compaction.

The major player coming is the massive SLP that is going push the cold out of the Beaufort and CA and bring in warmer not torching but warm air with the strongest south winds this summer to his the arctic. which will cause major compaction in the Beaufort, these winds slowly move East along the CA stopping about half way through.

Models current forecast 30-40Kts over a couple hundred mile area at the peak.

interesting week ahead.

the cold air wont be cold enough to cause any significant freezing with the water so warm. And it won't stay over any one area to long.

Peter Ellis

Polarstern is in -1.4 degree water
http://www.sailwx.info/shiptrack/shipposition.phtml?call=DBLK

Account Deleted

Rift largest glacier shelves of Canada?
http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r03c03.2011230.aqua.250m

Comparison with last year's photograph shows a lot of new cracks.
http://earthobservatory.nasa.gov/IOTD/view.php?id=45463

Artful Dodger

HenkL: Since you are posting wx data for Polarstern, perhaps you could include a link to the source of your data? Thanks.

Paul Klemencic

Stupid question time and help needed: Some of you who spend more time studying the Modis imagery than I do, I need an image interpreted.

Here is an image of the ice edge near the hole that I have discussed the last several days.

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r04c04.2011230.aqua.1km

Notice that the cloud cover is moving roughly parallel to the ice pack edge, and that a nice "swath of blue" at the 'edge of the ice' extends toward the upper left corner. Well, this feature seems to penetrate well into the ice pack, cutting off much of the E. Siberian region ice pack (ice floes). And if I click back over the previous several days, I see it yesterday, but not as well defined, and only traces of this feature two days ago.

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r04c04.2011229.aqua.1km

Am I seeing an image that is real, or is this some kind of trick of the atmosphere or clouds? This almost appears that the ice pack sheared along this boundary edge, caused by the wind, as though a channel extended through the ice pack. This seems unusual, particularly for such a large feature. OTOH, it seems far more likely that this could just be the edge of the cloud shadow, allowing the blue color of ice to show up, and appear as an "open blue water" mirage.

I don't see this feature in the Bremen map, or the CT map, and the more I look at this image, it doesn't seem to be real. Any explanation appreciated.

r w Langford

Paul; It could be a dark shadow on the ice from the edge of the cloud if the sun is on the far side of the cloud.

Twemoran

Paul; This site helps me with weather patterns and interpreting some of the other graphic sites

http://www.weatheroffice.gc.ca/satellite/animateweb_e.html?imagetype=satellite&imagename=hrpt_dfo_nir_m_..................jpg&nbimages=1&clf=1

Phil263

SIA down by about 87k for Day 228 (16th).

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