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John Batteen

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Re: The 2016 melting season
« Reply #4550 on: September 03, 2016, 03:17:07 AM »
I've wondered if Eckmann pumping could maintain a warm, humid, (compared to the Arctic environment) ice free core to a persistent Arctic cyclone. E.g., a reversed flow polar cell with rising low pressure air driven by ocean circulation instead of a sinking high pressure cell driving by radiative heat loss.

Hi tp50, welcome to the Forum!

You ask a very astute question, one I've been working on for 5+years. We have no mechanism to explain our paleoclimate evidence of a perenially ice-free Arctic ocean: palms trees and crocodiles on Ellesmere Island, Lilly plants growing in the Central Arctic Basin, etc.

The ocean/atmophere system is a heat engine, and we need to understand the pump. Something kept things warm at the Pole, and we need to ask if that's were our future climate is headed.

I hope to have more to say on this question by October. So keep thinking, and asking "Hey what?"  8)

Cheers,
Lodger

https://www.fields.utoronto.ca/programs/scientific/10-11/biomathstat/Langford_W.pdf

Check out this pdf by Bill Langford at University of Guelph in Canada, entitled HADLEY CELL EXPANSION IN TODAY’S CLIMATE AND PALEOCLIMATES.

Basically, their mathematical model predicts that in Hothouse Earth paleoclimates there was a single Hadley cell going all the way from equator to pole, keeping temperatures relatively similar the whole way.  Interestingly, the model also predicts hysteresis bifurcation, "a nonlinear phenomenon in which there is co-existence of two different stable states (or modes), with abrupt jumps from either state to the other state."

The entire PDF is utterly fascinating and has some interesting implications.

DavidR

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Re: The 2016 melting season
« Reply #4551 on: September 03, 2016, 03:52:26 AM »
  As attached, 1 September is another one of the dates used for Neven's excellent side-by-side comparison of U. Bremen's Arctic sea ice concentration maps for the different years:

https://sites.google.com/site/arcticseaicegraphs/concentration-maps/sic0901

  By now, this year looks much more ragged than in any previous year, including the record-breaking 2012.

 The high-concentration band of ice off the Canadian Arctic coast in 2016 probably resembles most closely to that in 2010. However, compared to 2010 much less remains of the lower concentration ice on the Atlantic and Russian sides and what does remain is now mostly in or around the Barents Sea.

One thing these graphs do seem to be is a good predictor of the decline in extent from the 1st Sept to the minimum.

The years with big declines seem to coincide with the years with patchier extents in the graphs
2007,2008,2009, 2010 and 2014 had the biggest declines , all above 300K km^2.

I  agree that  this year looks most like 2010 and it had a 500K km^2 decline from Sept 1st. Best  guess for 2016 would be a minimum starting with 3.8 M.
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Artful Dodger

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Re: The 2016 melting season
« Reply #4552 on: September 03, 2016, 04:14:48 AM »
...The entire PDF is utterly fascinating and has some interesting implications.

Hi John,

Good powerpoint, very important topic. Nice find!

Indeed, you can stream the Author delivering this talk at the Banff Centre in Nov. 2012 (or download the entire 130 mb video) from this page:

http://www.birs.ca/events/2012/5-day-workshops/12w5073/videos/watch/201211061638-Langford.html

Cheers mate!
Lodger
Cheers!
Lodger

jai mitchell

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Re: The 2016 melting season
« Reply #4553 on: September 03, 2016, 04:48:56 AM »
https://www.fields.utoronto.ca/programs/scientific/10-11/biomathstat/Langford_W.pdf

Check out this pdf by Bill Langford at University of Guelph in Canada, entitled HADLEY CELL EXPANSION IN TODAY’S CLIMATE AND PALEOCLIMATES.

Basically, their mathematical model predicts that in Hothouse Earth paleoclimates there was a single Hadley cell going all the way from equator to pole, keeping temperatures relatively similar the whole way.  Interestingly, the model also predicts hysteresis bifurcation, "a nonlinear phenomenon in which there is co-existence of two different stable states (or modes), with abrupt jumps from either state to the other state."

The entire PDF is utterly fascinating and has some interesting implications.

^^^THIS^^^

we are already seeing the expansion of the Hadley and Ferrel Cells northward with a shrinking Arctic Cell. 

see here: http://forum.arctic-sea-ice.net/index.php/topic,784.msg27641.html#msg27641
« Last Edit: September 03, 2016, 06:54:46 AM by jai mitchell »
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Iain

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Re: The 2016 melting season
« Reply #4554 on: September 03, 2016, 07:14:23 AM »
China has ratified the Paris climate agreement.

In the nick of time too. Jaxa reports Arctic SIE of 4.09m km^2, a whisker above the 2007 minimum of 4.07 M km^2

Meanwhile there is still active weather causing CAA export, expected to continue for the next 24 hrs.  It can be seen on the Bremen map. On Worldview the area is mostly obscured by cloud, but I have seen movement southward there through the various sounds/channels during late August.
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Rob Dekker

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Re: The 2016 melting season
« Reply #4555 on: September 03, 2016, 08:07:54 AM »
It's interesting looking back at Jim Pettit's projections graph from a month ago.  On 1 August the extent was around 6.7M km2 and it's now a touch over 4M km2.  The interesting thing is that the lower projections from a month ago follow trajectories from the 80's and 90's (from 1 August).  Now that we know what occurred from 1 August to 1 September, we can see that this year followed a trajectory from the 80's (a blue line).

You are showing Jim Pettit's VOLUME (km^3) graph, but quoting ice EXTENT (km^2) numbers.

Now, it is interesting that the volume graph suggests a slow-down in melt over August, and that certainly is worthwhile exploring.

But for the record, could you also post Jim Pettit's EXTENT graph from a month ago ?
That one (if my memory serves me right) shows the opposite from the volume graph : that extent drops in August were larger recently than they were in the 80's.

The two graphs combined may very well teach us what is going on exactly on this multi-decadal scale in the PIOMAS model.
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jdallen

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Re: The 2016 melting season
« Reply #4556 on: September 03, 2016, 09:00:42 AM »
EDIT: very interesting, Artful Dodger! The procession of powerful cyclones through the Arctic Basin has certainly been a striking feature of this melt season. The trend looks set to continue over the rest of this melt season, as follows.

 There's a strong low pressure system sitting currently about halfway between Svalbard and the North Pole, with a minimum pressure of 981 hPa according to the GFS run at tropicaltidbits.com
http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=nhem&pkg=z500_mslp&runtime=2016090218&fh=6&xpos=0&ypos=155.

 As appended, Nullschool shows it generating winds reaching 50 km/h in the Atlantic-side rubble sea ice.

 There's another low in the Arctic Basin, much weaker and further over towards Alaska, as well as a high pressure system just inside the Bering Strait and near Wrangel Island.

 What's notable in the GFS forecast - extending over 17 days, and more-or-less confirmed by the ECMWF forecast over the first 11 days - is the forecast dominance of low pressure in the Arctic Basin over the foreseeable future. Of those 17 days, the lowest forecast pressure in the Arctic Basin is in the:
990s hPa for 5 of 17 days
980s hPa for 11 of 17 days
970s hPa for 1 of 17 days (973 hPa way out on 18 September).

 That low pressure dominance is underpinned by the Arctic Basin showing a persistent pressure minimum at the 500 hPa height - displayed as deep blues and purples in the tropicaltidbits.com weather charts.

 So perhaps the Arctic Basin is going to remain windy and dominated by low pressure over the final weeks and days of the melt season?
I suspect the supernormal heat in the Barents is playing a very big role in this.  A huge stretch of that sea, along with the Kara are 4+C above normal.  Along with the moisture being carried in from further south, this cyclonic activity may not stop until after most of the region has refrozen, if then.
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Crocodile23

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Re: The 2016 melting season
« Reply #4557 on: September 03, 2016, 10:36:00 AM »
I have one question about the different values of sea ice extent the IJIS(JAXA) and NSIDC give.
 I see that they give similar values(not identical but similar) generally, but for 2016 they give completely different.
For example for 1 september IJIS gives 4 170 000 km^2 while NSDIC give 4 478 000 km^2. A not that small difference of course. Since for example in IJIS, 2016 is already on the point of reaching 2007 minimum, while on NSIDC it has a long way to go for that.
Why this happens?

 A guess from me is that because i've read somewhere here that IJIS has a resolution of 10 km, while NSDIC of 25 km(is that true?) and because this year's ice is very much scattered, disperced into small pieces with water in between, the better resolution of IJIS calculates ice extent better.
Or there is a different reason?



georged

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Re: The 2016 melting season
« Reply #4558 on: September 03, 2016, 10:44:58 AM »
EDIT: very interesting, Artful Dodger! The procession of powerful cyclones through the Arctic Basin has certainly been a striking feature of this melt season. The trend looks set to continue over the rest of this melt season, as follows.

 There's a strong low pressure system sitting currently about halfway between Svalbard and the North Pole, with a minimum pressure of 981 hPa according to the GFS run at tropicaltidbits.com
http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=nhem&pkg=z500_mslp&runtime=2016090218&fh=6&xpos=0&ypos=155.

 As appended, Nullschool shows it generating winds reaching 50 km/h in the Atlantic-side rubble sea ice.

 There's another low in the Arctic Basin, much weaker and further over towards Alaska, as well as a high pressure system just inside the Bering Strait and near Wrangel Island.

 What's notable in the GFS forecast - extending over 17 days, and more-or-less confirmed by the ECMWF forecast over the first 11 days - is the forecast dominance of low pressure in the Arctic Basin over the foreseeable future. Of those 17 days, the lowest forecast pressure in the Arctic Basin is in the:
990s hPa for 5 of 17 days
980s hPa for 11 of 17 days
970s hPa for 1 of 17 days (973 hPa way out on 18 September).

 That low pressure dominance is underpinned by the Arctic Basin showing a persistent pressure minimum at the 500 hPa height - displayed as deep blues and purples in the tropicaltidbits.com weather charts.

 So perhaps the Arctic Basin is going to remain windy and dominated by low pressure over the final weeks and days of the melt season?
I suspect the supernormal heat in the Barents is playing a very big role in this.  A huge stretch of that sea, along with the Kara are 4+C above normal.  Along with the moisture being carried in from further south, this cyclonic activity may not stop until after most of the region has refrozen, if then.

When does the 'season' of ice-loss and prevention of freezing end? Is there reason to think that it might extend beyond mid-September in these exceptional conditions?

Watching_from_Canberra

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Re: The 2016 melting season
« Reply #4559 on: September 03, 2016, 10:52:42 AM »
You are showing Jim Pettit's VOLUME (km^3) graph, but quoting ice EXTENT (km^2) numbers.

Oops!  So i did... apologies for any confusion.

The extent graph is attached, but it's now from 1 September.  The extent graph doesn't show anything counter-intuitive though it doesn't seem to include data from the 80's/90's.

Juan C. García

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Re: The 2016 melting season
« Reply #4560 on: September 03, 2016, 10:53:40 AM »
I have one question about the different values of sea ice extent the IJIS(JAXA) and NSIDC give.
 I see that they give similar values(not identical but similar) generally, but for 2016 they give completely different.

NSIDC has 2 values: the daily value and the 5-day average daily value. On the public information, like the Chartic graph, it uses the last one. When there are big drops, the 5-day average has an important lag.

Date                 Daily        5-day avg.
28-ago-16        4.707   
29-ago-16        4.547   
30-ago-16        4.469   
31-ago-16        4.388   
01-sep-16        4.278         4.4778

Data on the daily value (2016):
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/NH_seaice_extent_nrt_v2.csv

IJIS has a 2-day average. I believe that they only make public the average, not the original values. The different satellite and resolution also make a difference.
« Last Edit: September 03, 2016, 11:04:26 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

oren

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Re: The 2016 melting season
« Reply #4561 on: September 03, 2016, 11:22:16 AM »
When does the 'season' of ice-loss and prevention of freezing end? Is there reason to think that it might extend beyond mid-September in these exceptional conditions?

That's THE question. Either it ends late because the storms prevent freezing and because of the abnormal heat all around, or it ends early because lots of open water is in the CAB and near the Pole and therefore vulnerable to early refreeze. Or the center refreezes early while the periphery continues losing ice. We'll know quite soon though.
I personally lean towards an earlier minimum, but it's a coin toss.

greatdying2

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Re: The 2016 melting season
« Reply #4562 on: September 03, 2016, 11:39:12 AM »
Lodger and John, Thank you. Fascinating and illuminating.
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

iceman

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Re: The 2016 melting season
« Reply #4563 on: September 03, 2016, 12:39:57 PM »
   ....
I use the term hybrid to describe these Arctic cyclones because they mix the features of the two other types: a cold-core at low levels (including fronts) like a mid-lattitude cyclone, and a warm core at upper levels (200-300 hPa).
   ....
Cheers,
Lodger

Thanks, this is something I've been puzzling over.
Seems to merit a blog post and/or separate topic.

Jim Hunt

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Re: The 2016 melting season
« Reply #4564 on: September 03, 2016, 02:23:24 PM »
A brief extract from:

"Could Northabout Sail to the North Pole?"

Quote
Here's a (somewhat foggy) NASA image of the North Pole right now:
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Phil.

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Re: The 2016 melting season
« Reply #4565 on: September 03, 2016, 02:51:04 PM »
I have one question about the different values of sea ice extent the IJIS(JAXA) and NSIDC give.
 I see that they give similar values(not identical but similar) generally, but for 2016 they give completely different.

NSIDC has 2 values: the daily value and the 5-day average daily value. On the public information, like the Chartic graph, it uses the last one. When there are big drops, the 5-day average has an important lag.

Date                 Daily        5-day avg.
28-ago-16        4.707   
29-ago-16        4.547   
30-ago-16        4.469   
31-ago-16        4.388   
01-sep-16        4.278         4.4778

Data on the daily value (2016):
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/NH_seaice_extent_nrt_v2.csv

Which means that strictly the 5 day average represents 2.5 days earlier, so the 1 Sept average should be quoted for 30 Aug. When you do that you'll see a good correspondence between the daily and the 5-day when you do that (except when you have large fluctuations).

seaicesailor

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Re: The 2016 melting season
« Reply #4566 on: September 03, 2016, 03:18:04 PM »
Time for an update on the Chukchi melt front. I have added the September 2 ADS NIPR melt extent image to the previous gif (July 30 and August 19). Same as before, little or no ice has survived east of the front after so much dispersion - lateral drift - compaction.
The September 2 DMI SST anomaly map permits now to see the SSTs along the east of the front as the ice pack mask has gradually shrunk. Three spots of warmer water along the front have been there very clearly for a week. In contrast to other warm areas, these do not vary in response to warm airs, and they just stay put. I doubt they have been caused (directly) by insolation since these waters were ice-covered until early August.
Another thing is the elongated extension of ice that survives towards the North of Alaska and that shows colder water in the DMI map. This elongation is seen in the animations as a product of ice transport by a steady current (see arrow in the map) that corresponds to one of the bifurcations of the Chukchi sea currents as described in papers/books. The underlying current is probably not very warm, but not that cold either. I think it is the ice that is being constantly fed which keeps the water surface at melting temperature.
In the next days the very southernmost part of the Wrangel arm is going to be pushed toward the north and only slightly toward the front. It has good chances of completely detaching and surviving; the winds will be cold and it still has pretty solid ice core. Unless a storm such as LMV mentions passes by and makes a mess of it.
« Last Edit: September 03, 2016, 03:23:43 PM by seaicesailor »

DavidR

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Re: The 2016 melting season
« Reply #4567 on: September 03, 2016, 03:26:50 PM »
This is a bit off topic but interesting to consider. When this was written in 'The Guardian'?

"Depending on how the weather plays out over the next few weeks, that minimum is likely to fall somewhere between second and fifth place, they estimate — still a remarkably low level that shows how precipitously sea ice has declined in recent decades".
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Juan C. García

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Re: The 2016 melting season
« Reply #4568 on: September 03, 2016, 03:27:48 PM »
Which means that strictly the 5 day average represents 2.5 days earlier, so the 1 Sept average should be quoted for 30 Aug. When you do that you'll see a good correspondence between the daily and the 5-day when you do that (except when you have large fluctuations).

I agree. The right place will be to put on day 3, with two days behind and two days afterwards. But that is not the way they do it. So, on the daily information (Charctic), there is normally less ice on the melting season and normally more ice on the freezing season.

Quote
Processing Steps
...
2. Reduce erroneous artifacts.
On daily scales, these extent values can have fairly large variations, both due to real changes in ice extent from growth, melt, or from motion of the ice edge, and due to ephemeral weather and surface effects. To reduce erroneous variations, a 5-day trailing mean is used in the plot. This is calculated by averaging the extent value from a given day with the extent value from the previous four days to produce a 5-day average, so the value plotted for a day is the average of that day and the four previous days.
http://nsidc.org/data/docs/noaa/g02135_seaice_index/

(Back to topic  ;) )
« Last Edit: September 03, 2016, 03:34:51 PM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

FishOutofWater

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Re: The 2016 melting season
« Reply #4569 on: September 03, 2016, 04:31:02 PM »
I don't think it means what you guys think it means.

   ....
I use the term hybrid to describe these Arctic cyclones because they mix the features of the two other types: a cold-core at low levels (including fronts) like a mid-lattitude cyclone, and a warm core at upper levels (200-300 hPa).
   ....
Cheers,
Lodger

Thanks, this is something I've been puzzling over.
Seems to merit a blog post and/or separate topic.

A warm core storm is typically thermodynamic, driven by oceanic heat, so the warm core is seen at the lowest levels. Over the Arctic 200mb is probably in the stratosphere. The warmth you are seeing on the weather map over the low pressure area is the result of the lowering of the stratosphere over the cold Arctic atmosphere. Hybrid storms have both frontal and thermodynamic characteristics. At this moment Hermine is such a storm.

Check out the web pages information on hybrid storms http://moe.met.fsu.edu/ when it comes back up.

Nightvid Cole

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Re: The 2016 melting season
« Reply #4570 on: September 03, 2016, 05:22:46 PM »
The area of low concentration ice now extends very near the north pole. Does anyone here think that it might be possible to make it to 88-89N in a small boat?

jai mitchell

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Re: The 2016 melting season
« Reply #4571 on: September 03, 2016, 06:00:33 PM »
NSIDC SIE has a 100,000 KM^2 drop today.  last time we had a drop that large this late in the melt season???  never.

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epiphyte

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Re: The 2016 melting season
« Reply #4572 on: September 03, 2016, 06:37:01 PM »
The area of low concentration ice now extends very near the north pole. Does anyone here think that it might be possible to make it to 88-89N in a small boat?

With the wind behind you... perhaps. I wouldn't care to give odds on your chances of getting back out again alive though!

BornFromTheVoid

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Re: The 2016 melting season
« Reply #4573 on: September 03, 2016, 07:19:22 PM »
NSIDC SIE has a 100,000 KM^2 drop today.  last time we had a drop that large this late in the melt season???  never.

Just under 100k, but yep, largest September drop on record.

https://forum.arctic-sea-ice.net/index.php/topic,1457.msg88797.html#msg88797

12Patrick

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Re: The 2016 melting season
« Reply #4574 on: September 03, 2016, 07:26:37 PM »
Expect more of the same as the ice grows thinner and thinner :(..
NSIDC SIE has a 100,000 KM^2 drop today.  last time we had a drop that large this late in the melt season???  never.

Jim Hunt

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Re: The 2016 melting season
« Reply #4575 on: September 03, 2016, 08:21:47 PM »
Does anyone here think that it might be possible to make it to 88-89N in a small boat?

Realistically? No! It makes an interesting thought experiment though:

http://GreatWhiteCon.info/2016/09/could-northabout-sail-to-the-north-pole/
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Tigertown

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Re: The 2016 melting season
« Reply #4576 on: September 03, 2016, 10:02:50 PM »
And so, the observation leaves the forecast behind!

http://cires1.colorado.edu/~aslater/SEAICE/fcst_apr_oct.gif

Juan C. García

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Re: The 2016 melting season
« Reply #4577 on: September 03, 2016, 11:16:52 PM »
The interesting part about the 5-day average, is that we can anticipate what it is going to happen tomorrow. The 2011 minimum ice extent is 4.34 million km2 (with 5-day avg.). so, even if tomorrow the original NSIDC daily increases by 100k km2, the 5-day average will decrease to be a little lower than the 2011 minimum ice extent.
Maybe it will be possible to anticipate when 2016 will get lower to 2007, become 2016 the second lowest on record.

Date       Original      Original       5-day avg.  5-day avg.
                daily            drop            daily            drop
             (M km2)        (k km2)       (M km2)       (k km2)
Aug-24      4.939         
Aug-25      4.850         89.0      
Aug-26      4.710       140.0      
Aug-27      4.537       173.0      
Aug-28      4.707      -170.0          4.749   
Aug-29      4.547       160.0          4.670           78.4
Aug-30      4.469         78.0          4.594           76.2
Aug-31      4.388         81.0          4.530           64.4
Sep-01      4.278       110.0          4.478           51.8
Sep-02      4.211         67.0          4.379           99.2
Anticipating increase of 100k km2:
Sep-03      4.311      -100.0          4.331           47.2  (a little lower than 2011)



Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

jdallen

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Re: The 2016 melting season
« Reply #4578 on: September 04, 2016, 12:41:57 AM »

<snippage>


I suspect the supernormal heat in the Barents is playing a very big role in this.  A huge stretch of that sea, along with the Kara are 4+C above normal.  Along with the moisture being carried in from further south, this cyclonic activity may not stop until after most of the region has refrozen, if then.

When does the 'season' of ice-loss and prevention of freezing end? Is there reason to think that it might extend beyond mid-September in these exceptional conditions?

Indeed it may - we may have a late minimum, and even if not, loss on the periphery may keep up with refreeze taking place at high latitude.  There is a lot of sea surface there to recover currently.

The effect on the metrics may be to keep the extent fairly flat right straight through October all the way to early November.  If the "cyclone cannons" fire up along the eastern seaboards of Asia and North America again as they did last fall, we may not see serious extent/area increases until December.  If that happens, we may see 2016's "MinMax" record broken, with commensurate negative implications for next year's melt season.

While this year has been bad, as a number of other posters have indicated, the real show may be next seasons.
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Watching_from_Canberra

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Re: The 2016 melting season
« Reply #4579 on: September 04, 2016, 06:07:04 AM »
So, according to JAXA's graph, this year's extent is now (3 Sept) the second lowest on record:
https://ads.nipr.ac.jp/vishop/#/extent

Looking at what previous years have done from this date (3 Sept), extent has mostly stayed flat or started to rise.  Just from looking at the graph, it seems there were 4 years with notable drops after today's date: 1984, 2007, 2010 and 2012.  The data for 1984 seems incomplete, so it may not be useful for comparison.  Of the others:

- 2007 dropped a further 310,000 km2
- 2010 dropped a further 410,000 km2
- 2012 dropped a further 270,000 km2

So, if 2016 equalled the previous largest post 3 September drop, it would drop to 3.64M km2.

Iain

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Re: The 2016 melting season
« Reply #4580 on: September 04, 2016, 07:31:33 AM »
Jaxa reports 2016 at 4.05 M km^2 in 2nd place below the 2007 extent of 4.07 M km^2
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Iain

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Re: The 2016 melting season
« Reply #4581 on: September 04, 2016, 07:42:45 AM »
A bit wobbly for my 1st animated GIF but movement can be clearly seen.
Larger floes can be seen breaking up during transit.
North of the CAA the ice is fragmented with a small enough grain size to fit through.
26 Aug to 3 Sept:
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Iain

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Re: The 2016 melting season
« Reply #4582 on: September 04, 2016, 07:47:41 AM »
North of CAA 27 Aug:
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Iain

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Re: The 2016 melting season
« Reply #4583 on: September 04, 2016, 08:25:29 AM »
I note there is no option to attach a sound file to posts, but I think Siegfried's funeral march may be an appropriate accompaniment for this one.
Bremen does not display North of 89deg. Taking the grey areas as cloud, it looks like <50% ice to me between 120 and 150E:
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Andreas T

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Re: The 2016 melting season
« Reply #4584 on: September 04, 2016, 09:20:46 AM »
North of CAA 27 Aug:

the type of lines (leads) in the right of this image can also be seen in McClure strait now. They are a sign of the deformation under compression of the ice pack I think when the floes are not slipping past each other as freely as they were earlier. I have noticed this at the end of previous melting seasons and coincides with snowfall which can be seen on Banks and other islands.

I have marked recognizable floes to get a better view of the deformation as the ice is pushed against the southern side of the strait at the same time as it funnels eastward

world view linkhttp://go.nasa.gov/2cbjzDw

BornFromTheVoid

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Re: The 2016 melting season
« Reply #4585 on: September 04, 2016, 10:25:10 AM »
Looks like we'll be seeing something of a reverse dipole taking shape during the next week, with winds blowing the remains of the pack out toward the Pacific side of the Arctic.







And with it, some pretty cold air too.






In general, a reverse dipole is associated with an earlier minimum and more extent gains in September.
Of course, this isn't the same Arctic as before, but the reverse dipole will certainly begin to spread out the remaining ice and carry with it some cooler air (well, closer to average at least). So the question for me is: Will the continued melting of the Wrangel Arm and the warmth of the upper ocean be enough to prevent extent from increasing during the week, or, is there a chance we record an early minimum in 2016?

Adam Ash

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Re: The 2016 melting season
« Reply #4586 on: September 04, 2016, 11:42:35 AM »
The same weather will continue to push ice against/into the CAA.  As AndreasT points out, there are signs of some compaction starting, which could lead to a bit of thickening.  So there may be a chance of some thicker ice forming again in the ice-haven against the CAA for the coming winter.

The thickness maps tho show remarkably little MYI there now.  Its mostly tucked against Greenland which for now is somewhat less porous.  But for ice there, Nareas and Fram beckon with their warm embrace,and the other side of this dipole will encourage that movement too.  Another no-win/no-win situation for the ice pack overall.

Thomas Barlow

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Re: The 2016 melting season
« Reply #4587 on: September 04, 2016, 03:26:59 PM »
North Pole is trashed.

Jim Hunt

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Re: The 2016 melting season
« Reply #4588 on: September 04, 2016, 04:44:01 PM »
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Juan C. García

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Re: The 2016 melting season
« Reply #4589 on: September 04, 2016, 08:53:51 PM »
The interesting part about the 5-day average, is that we can anticipate what it is going to happen tomorrow. The 2011 minimum ice extent is 4.34 million km2 (with 5-day avg.). so, even if tomorrow the original NSIDC daily increases by 100k km2, the 5-day average will decrease to be a little lower than the 2011 minimum ice extent.

Yesterday I forecasted that 2016 NSIDC 5-day average would be lower than the 2011 minimum, even if the original daily value (that is, without 5-day average) increases 100k km2. Interestingly, the original daily value increased 52k km2, but as I forecasted, that was not enough to overcome the inertia that the 5-day average has. So, 2016 is today below the 2011 minimum, become third lowest on record (after 2012 and 2007).

The other part of the story is that, with the 52k increase, 2016 is losing inertia to beat the 2007 minimum. Let's wait to see what it happens.  8)

Date       Original      Original       5-day avg.  5-day avg.
                daily            drop            daily            drop
             (M km2)        (k km2)       (M km2)       (k km2)
Aug-24      4.939         
Aug-25      4.850         89.0      
Aug-26      4.710       140.0      
Aug-27      4.537       173.0      
Aug-28      4.707      -170.0          4.749   
Aug-29      4.547       160.0          4.670           78.4
Aug-30      4.469         78.0          4.594           76.2
Aug-31      4.388         81.0          4.530           64.4
Sep-01      4.278       110.0          4.478           51.8
Sep-02      4.211         67.0          4.379           99.2
Sep-03      4.263        -52.0          4.322           56.8
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Jim Hunt

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Re: The 2016 melting season
« Reply #4590 on: September 04, 2016, 09:56:25 PM »
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

jdallen

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Re: The 2016 melting season
« Reply #4591 on: September 05, 2016, 12:13:42 AM »
Some large holes at around 87N:


I was just peering at that myself.  What I find even more striking than the open water is the fact we have brash ice at 87N.
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jdallen

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Re: The 2016 melting season
« Reply #4592 on: September 05, 2016, 12:16:14 AM »
Looks like we'll be seeing something of a reverse dipole taking shape during the next week, with winds blowing the remains of the pack out toward the Pacific side of the Arctic.
And here is what that reverse dipole will be driving into in the Laptev - my best guess is about 250,000KM2 of rather vulnerable ice and brash.

Edit:  A further concern about this dipole; it is effectively a suction pump pulling weather out of the Barents and NE Atlantic - areas which shortly will be hosting remnants of the latest hurricane and its payload of moisture.  If it persists, we will have an accelerator for the Atlantic "cyclone cannon".
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slow wing

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Re: The 2016 melting season
« Reply #4593 on: September 05, 2016, 04:06:26 AM »
A reasonably dramatic Arctic sea ice concentration map today from University of Bremen: the purple-coloured 'ice sanctuary' of closely packed ice off the Canadian Arctic coast can no longer be said to extend to the North Pole.

  That's only going to get more stark over the coming days as the winds generated by the 'reverse dipole' atmospheric setup (low pressure at the Canadian Arctic coast combined with high pressure on the Russian side of the Arctic Basin) shove the edge of the high concentration 'sanctuary ice pack' further away from the North Pole and in the direction of Alaska.

wili

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Re: The 2016 melting season
« Reply #4594 on: September 05, 2016, 04:19:44 AM »
Is anyone else noticing this? (Apologies if this was already posted, and thanks to Cid at POForums for pointing it out):

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Juan C. García

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Re: The 2016 melting season
« Reply #4595 on: September 05, 2016, 04:33:54 AM »
Is anyone else noticing this? (Apologies if this was already posted, and thanks to Cid at POForums for pointing it out):

Yes. Seems that Bremen fixed yesterday's problem, but the change that the Arctic sea ice had in these couple of days is huge. Maybe will be better to wait another day before drawing any conclusion, because the drop is enormous!

Let's see IJIS in  more or less an hour.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Adam Ash

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Re: The 2016 melting season
« Reply #4596 on: September 05, 2016, 05:12:35 AM »
Thanks Slow Wing.  Isn't that an unusually large wedge of ice heading south via Fram Straight?  What chance does that have?

Juan C. García

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Re: The 2016 melting season
« Reply #4597 on: September 05, 2016, 05:35:23 AM »
IJIS:

4,056,306 km2(September 4, 2016)up 2,127 km2 from previous.

There is not an important change on IJIS.  ???
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Artful Dodger

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Re: The 2016 melting season
« Reply #4598 on: September 05, 2016, 05:47:35 AM »
A reasonably dramatic Arctic sea ice concentration map today from University of Bremen: the purple-coloured 'ice sanctuary' of closely packed ice off the Canadian Arctic coast can no longer be said to extend to the North Pole.

Hi Slow Wing,

The worst part about those yellows and oranges on the SIE map is that wind causes the maximum affect on sea ice drift at around 80% concentration.

The damage is still being done, with effects reaching beyond Summer 2016. Let wait to see what the transpolar drift does this Fall/Winter. We could lose a lot of hard-won MYI (ie: drift thru Fram, Nares, CAA channels) even after the Summer SIE minimum is well past.

Regards,
Lodger
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georged

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Re: The 2016 melting season
« Reply #4599 on: September 05, 2016, 06:42:09 AM »
A reasonably dramatic Arctic sea ice concentration map today from University of Bremen: the purple-coloured 'ice sanctuary' of closely packed ice off the Canadian Arctic coast can no longer be said to extend to the North Pole.

Hi Slow Wing,

The worst part about those yellows and oranges on the SIE map is that wind causes the maximum affect on sea ice drift at around 80% concentration.

The damage is still being done, with effects reaching beyond Summer 2016. Let wait to see what the transpolar drift does this Fall/Winter. We could lose a lot of hard-won MYI (ie: drift thru Fram, Nares, CAA channels) even after the Summer SIE minimum is well past.

Regards,
Lodger

You make an important point. If MYI is being transported, then it would be possible for there to be conditions in which you are losing volume at the same time as you are gaining in both extent and area. I have no idea how likely this is.