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ChrisReynolds

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Re: Records and oddities
« Reply #50 on: March 02, 2013, 06:03:53 PM »
A4R,

I'm not going to do a PIOMAS overlay because the PIOMAS thickness fields are only a rough approximation and anyway I only have PIOMAS gridded data on a monthly basis up to December. Due to ice thickening and movement using December would be a bit pointless.

As it is we're lucky to have ASCAT to spot the MYI and as an observation it's far superior to either PIOMAS, HYCOM, or the DAM.

I should point out though that if you follow the middle line of crosses upwards to the third cross then go across along the large crack you'll see that that crack seems to deviate as it hits the MYI area, then follows the MYI area. Now the MYI area I've done in red is an approximation, and the overlay of the ASCAT image was only accurate to about <95%. However I do suspect that the deviation of this crack is due to the line of stress being deflected by MYI.

Dr Tskoul,

Yes I think you're correct. Within the MYI region there is ice of various ages, all of it is at least 17 months old, having at least survived the 2012 melt. I maintain that the behaviour of the arc stress fractures shows that this central remnant is substantially stronger than the FYI that composes most of the pack at present. However within this there will be areas with floes of older ice with younger ice frozen in around it.

PS - it's awkward but there is another parallel discussion taking place at The Sea Ice Blog.
http://neven1.typepad.com/blog/2013/03/the-cracks-of-dawn.html

Artful Dodger

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Re: Records and oddities
« Reply #51 on: March 03, 2013, 04:39:12 AM »
Quick question: Is MYI fragments of thick floes with slightly thinner ice in between?
Hi DrTskoul,

Dr. David Barber provides a good explanation of what's really happening with MYI in this Nov 2009 video:



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Re: Records and oddities
« Reply #52 on: March 03, 2013, 04:51:46 AM »
The Beaufort breakup of 2013 is not unprecedented. A similar event occurred in Jan 2008. I think this is significant because both events followed record low sea ice extent at the end of the previous melt season.

In both cases, Beaufort Winter sea ice was almost exclusively 100% first year sea ice, in fact just 4 months old or less. This new, salty sea ice does not have the mechanical shear strength to resist strong, persistent winds from the Polar vortex.

From the Canadian Broadcasting Corporation (CBC):
Huge fracture in Beaufort Sea ice pack worries scientists
Last Updated: Tuesday, January 15, 2008 | 12:21 PM ET CBC News

Caption: In December 2007, a massive fracture of the Beaufort ice pack was observed west of Banks Island. The image, from Jan. 9, clearly shows this fracture.
Image: (Environment Canada/NOAA)
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Re: Records and oddities
« Reply #53 on: March 03, 2013, 01:15:03 PM »
The Beaufort breakup of 2013 is not unprecedented. A similar event occurred in Jan 2008. I think this is significant because both events followed record low sea ice extent at the end of the previous melt season.

In both cases, Beaufort Winter sea ice was almost exclusively 100% first year sea ice, in fact just 4 months old or less. This new, salty sea ice does not have the mechanical shear strength to resist strong, persistent winds from the Polar vortex.

From the Canadian Broadcasting Corporation (CBC):
Huge fracture in Beaufort Sea ice pack worries scientists
Last Updated: Tuesday, January 15, 2008 | 12:21 PM ET CBC News

Caption: In December 2007, a massive fracture of the Beaufort ice pack was observed west of Banks Island. The image, from Jan. 9, clearly shows this fracture.
Image: (Environment Canada/NOAA)

I'm not sure if these two situations are directly comparable though.
In 2007, the Chukchi sea didn't really begin to freeze over until the second half of December, a nearly month later that in 2012. This allowed the sea ice in the region to be much more mobile than you would typically expect, and was only a few weeks old when the large break up occurred in January.
Environment Canada have this animation from December 8th 2007 to March 27th 2008

http://www.ec.gc.ca/glaces-ice/default.asp?lang=En&n=F4F1DC84-1

The ice in the region was continually on the move, but there was a temporary spread in the movement around January 9th to 20th, which may be comparable to now, though I we'd need more imagery to confirm it. 

Artful Dodger

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Re: Records and oddities
« Reply #54 on: March 03, 2013, 02:07:54 PM »
In 2007, the Chukchi sea didn't really begin to freeze over until the second half of December, a nearly month later that in 2012. This allowed the sea ice in the region to be much more mobile than you would typically expect, and was only a few weeks old when the large break up occurred in January.
Hi BornFromTheVoid,

The satellite image from Jan 9, 2008 shows cracking emanating from Banks Island. This is over 1000 km away from the open water in the Chukchi sea 1 month previous (see attached AMSR-E sea ice concentration map from Dec 9, 2007). Freeze-up in the Banks Island region was similar in 2007 and 2012, in that there was zero sea ice concentration at the end of Summer.

If fact, freeze up in the Beaufort sea near Banks Island occurred later in the season during 2012 than in 2007, compared on Nov 1 (SIC maps provided below).

The key point is that 1st year sea ice has poor mechanical strength in shear. That's because, even if it reaches full thermodynamic equilibrium thickness of around 2 m, it is still full of air bubbles and liquid brine. Neither of those add strength, in fact they provide easy cleavage points to break the ice floe.

Only when sea ice has survived into it's 3rd year does the brine rejection process allow MYI to reach it's full strength. After that, slabbing is the only way for MYI to grow in thickness. And that takes LOTS of strong MYI, which is what we have now run out of. That's why they call it a 'death spiral'.  :(
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Re: Records and oddities
« Reply #55 on: March 03, 2013, 03:19:02 PM »
In 2007, the Chukchi sea didn't really begin to freeze over until the second half of December, a nearly month later that in 2012. This allowed the sea ice in the region to be much more mobile than you would typically expect, and was only a few weeks old when the large break up occurred in January.
Hi BornFromTheVoid,

The satellite image from Jan 9, 2008 shows cracking emanating from Banks Island. This is over 1000 km away from the open water in the Chukchi sea 1 month previous (see attached AMSR-E sea ice concentration map from Dec 9, 2007). Freeze-up in the Banks Island region was similar in 2007 and 2012, in that there was zero sea ice concentration at the end of Summer.

If fact, freeze up in the Beaufort sea near Banks Island occurred later in the season during 2012 than in 2007, compared on Nov 1 (SIC maps provided below).

The key point is that 1st year sea ice has poor mechanical strength in shear. That's because, even if it reaches full thermodynamic equilibrium thickness of around 2 m, it is still full of air bubbles and liquid brine. Neither of those add strength, in fact they provide easy cleavage points to break the ice floe.

Only when sea ice has survived into it's 3rd year does the brine rejection process allow MYI to reach it's full strength. After that, slabbing is the only way for MYI to grow in thickness. And that takes LOTS of strong MYI, which is what we have now run out of. That's why they call it a 'death spiral'.  :(

Afternoon Artful Dodger,

I agree that the Beaufort sea ice condition is comparable for both times, I still think the ice in the Chukchi plays an important role, if only to modify the potential movement of ice in that general region and increase the risk of wave and swell action on the Beaufort ice.

Seems that lately, the term "rare event" has been losing its meaning in the Arctic...

Dave C

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Re: Records and oddities
« Reply #56 on: March 04, 2013, 02:59:09 AM »
It's interesting that 2008 had a similar pattern to this year. 2008 had a record-breaking refreeze volume  and was the only year in the last decade that was a recovery year.

I am still skeptical that this ice cracking is an indicator of record melt. It could be that ice cracking is merely an indicator of thin ice from a big melt the previous year.

Also, the 2013 refreeze has been well above average so far. We will see, but it seems that 2013 is at least as likely to be a recovery year as a record breaking one.

Apocalypse4Real

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Re: Records and oddities
« Reply #57 on: March 04, 2013, 06:12:20 AM »
Two actions are still occurring relation to the Beaufort sea ice breakup.

One, some sections of the Beaufort ice continue to move and break down into smaller pieces in the main pack in the Beaufort Sea.

Second, the fracture lines that run toward the pole are lengthening and curving down to Ellesmere Island, especially the ones south of 80 N, which are snaking through MYI. These fractures are slowly showing more opening as the ice moves toward Alaska.



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Re: Records and oddities
« Reply #58 on: March 04, 2013, 02:14:35 PM »
Here is a highlighted example of the fracture lines that have appeared in the last couple of days. I anticipate more may develop as long as the high is in place and the ice continues to move.

Gray-Wolf

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Re: Records and oddities
« Reply #59 on: March 04, 2013, 04:26:52 PM »
Are we seeing fracturing now spreading into the NW Passage Deep channel? If the entrance to the passage is now allowing wave action under the ice I suppose we ought to expect as much?
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ChrisReynolds

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Re: Records and oddities
« Reply #60 on: March 04, 2013, 06:43:08 PM »
Dave C,

Don't be fooled by the extent/area metric. Go to ASCAT and download day 50 and the latest day 62.
http://manati.star.nesdis.noaa.gov/ascat_images/ice_image/

Day 50 was just before this cracking started, if you flick between the two while looking at the Atlantic sea ice edge you'll see how much ice has advanced into the Atlantic, this isn't new growth, it's ice being transported. That's what's making space for all the cracks, which are filling up with new ice.

The reason I think we're headed for a new record this year is simply the state of the ice pack.
http://dosbat.blogspot.co.uk/2013/02/ascat-piomas-and-dam.html
I think that is more important than this cracking, but the bulk movement into the Atlantic is moving ice out to be melted, and the new ice filling the gaps may play a role that's interesting from a technical point of view. I'm probably one of the few following the Arctic because I find it awesome and exciting.

A4R,

The bulk movement continues for yet another day, if you do a flick between today's and yesterday's IR images you'll see that along the most poleward crack in the MYI off the Canadian Arctic Archipelago (CAA) there's a new fissure opening extending that extends it further into the Arctic Ocean. This can be seen in the images you post above.

In a few days I'll post some more animated gifs, but I suspect there's more play in this event, to post now would be a waste of my time.

After blogging on the January status I'd been going to give February a miss. I now suspect it will be best to let this melt season carry my blogging as things happen.

Neven

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Re: Records and oddities
« Reply #61 on: March 04, 2013, 06:48:41 PM »
Just go with the floe, Chris.  8)
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ivica

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Re: Records and oddities
« Reply #62 on: March 04, 2013, 06:52:15 PM »
Watching those 2 images above posted by A4R:
What that large shadow along the crack going north (longitude 120W, above Prince Patrick Island) tell us?
« Last Edit: March 04, 2013, 07:11:23 PM by ivica »

ChrisReynolds

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Re: Records and oddities
« Reply #63 on: March 04, 2013, 07:38:32 PM »
Ivica,

The temperature scale is at the top of the image, the darker things are the warmer. So I suspect this is water vapour being vented from the fracture. This can also be seen on MODIS bands 367
http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r04c02.2013062.terra.367

Neven,

I think this is going to be a classic year!  ;D

Dave C

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Re: Records and oddities
« Reply #64 on: March 04, 2013, 07:40:29 PM »
ChrisR-

I was referring to volume in my post. I don't pay much attention to extent/area because I think volume is the more accurate indicator. A few more thoughts-

-If you look at the last few years, there does not seem to be much of a correlation between ice thickness and volume melt.
-Since 2007, melt volume seems to have plateaued somewhat.
-I might be misinterpreting it, but this graph seems to show that volume transport of ice through the fram has not been increasing.
https://sites.google.com/site/arctischepinguin/home/piomas/grf/fram.png
-I am not familiar with cracking in previous years, but as far as I know a firm correlation between cracking and melt has not been established.

I certainly can't rule out a record year due to all the uncertainty, but as of now I would predict an average to below average loss of volume this year. Maybe 2.8 km3 minimum if I had to pick a precise number.

John_The_Elder

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Re: Records and oddities
« Reply #65 on: March 04, 2013, 09:14:39 PM »
Dave C,
When I look at Piomass ice volume plot @ http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2_CY.png
I do not see a plateau from 2007 to present. I see less ice. If it melted in situ or was transported elsewhere it is no longer with us.

John
John

ChrisReynolds

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Re: Records and oddities
« Reply #66 on: March 04, 2013, 09:58:10 PM »
Ahhh, sorry Dave mea culpa.

I don't know if you follow my blog, if you do then sorry, but in case you don't.

Yes the annual range increased after 2007.
http://farm9.staticflickr.com/8103/8481914926_1c34bd0f27_o.jpg

However this hides the massive change in PIOMAS seasonal cycle which is shown by the anomalies (difference from daily average)
http://farm9.staticflickr.com/8109/8453225199_b9b8d59ed6_o.jpg

And in terms of CT area, the anomalies are starting to behave more and more wildly.
http://farm9.staticflickr.com/8505/8454317998_9cbbd9da37_o.jpg

The relationship between volume and area/extent is critical. It is the volume loss that drives the reduction in area extent because of volume's implications for thickness, and the consequent implications for the ease with which open water is formed. The closer that April thickness (ann max) gets to the summer thinning the more open water is formed.

I agree that this cracking doesn't in itself mean an aggressive melt this year. I'll paraphrase my latest blog post - it's rather long. But basically the cracking does seem to be early and the structure of the initial arc cracking shows the thinness of the FYI in Beaufort. This is why I gave you a link to my post of PIOMAS DAM and ASCAT. If you look at that, and there are links there so you can go earlier, you'll see how there's an exceptionally large region of new ice from last year. This matters because this new ice is thinner and weaker. It also matters because younger ice absorbs more solar energy through the melt season (1/3 more). So the more younger ice the more rapid the melt. This is why the seasonal cycle has expanded.

ChrisReynolds

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Re: Records and oddities
« Reply #67 on: March 04, 2013, 09:59:54 PM »
PS - where have the first two pages of this thread gone?

Juan C. García

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Re: Records and oddities
« Reply #68 on: March 04, 2013, 10:13:46 PM »
Quote
ChrisReynolds
PS - where have the first two pages of this thread gone?
I understand that there were 25  posts/page before and now there are 50 posts/page, so the posts are the same but in less pages.
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.

Apocalypse4Real

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Re: Records and oddities
« Reply #69 on: March 05, 2013, 02:27:01 AM »
Anyone aware of where we can get AVHRR imagery of the Russian side of the CAB? Also, is there 1.7-1.9 km AVHRR imagery for the CAB area above Svalbard available?



Apocalypse4Real

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Re: Records and oddities
« Reply #70 on: March 05, 2013, 03:25:02 AM »
Here is a rough in of today's developments as of 030513 0031

danp

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Re: Records and oddities
« Reply #71 on: March 05, 2013, 09:48:48 AM »
Thanks A4R - this is riveting stuff and it's much easier to follow with graphical aids like yours.

Dave C

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Re: Records and oddities
« Reply #72 on: March 05, 2013, 10:22:24 AM »
JohntheElder- I'm not referring to total volume loss, but just the difference from max to min each year. The last 5 years have been 18.1, 18.2, 19.0, 17.9 and 18.7. I'll let you decide if that's a plateau or not.

ChrisReynolds- I suppose at any point something crazy could happen. But so far 19.0 has been the record, with 18.5 probably a reasonable average. I guess we'll see what happens. I would be pretty surprised if melt was much more than 19.

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Re: Records and oddities
« Reply #73 on: March 05, 2013, 11:53:51 AM »
Hi Dave C!

I'm not quite understanding what you hope to highlight by looking at this side of losses? Last year the beginning of melt saw a large extension of ice out into Bering which had no part to play in the melt season but still bolstered volume at the get go?

If we see a few years of such high start rates will it not mask the final finish point?

Prior to 2012 I'd use how much ice had melted that season, compared with 07's melt total, to rile Skeptics who were bust telling me we were in recovery.

I believe we are in a 'new' period of the Arctic sea ice and it involves the bulk of the ice being melted out earlier each year. This will lead to another 'step change' once we find a year that can remove the residual 'older ice' as ,the year following, the bulk of the ice will be gone as early and only weak ice will be left bringing the 'ice free' portion of the year instantly back a month.

I also believe that transport will cause the biggest losses of the older ice and so to see a pack so mobile, this early in the season, raises concerns in me about ice being 'shunted' toward Fram (even if the correct synoptics are not present over Fram?)

 At present Conditions in the Beaufort sea are are translating to wholesale movement of ice toward Fram. Not good.
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crandles

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Re: Records and oddities
« Reply #74 on: March 05, 2013, 12:15:14 PM »
JohntheElder- I'm not referring to total volume loss, but just the difference from max to min each year. The last 5 years have been 18.1, 18.2, 19.0, 17.9 and 18.7. I'll let you decide if that's a plateau or not.


How do you decide if it is a plateau without seeing the earlier years?

try a graph
http://farm9.staticflickr.com/8224/8334481723_947248554a_b.jpg

I have for simplicity labeled the difference from max to min each year as 'Melt'.

To me that looks like it is curling upwards not changing from one plateau to a new plateau. At least so far.

I think it also make sense to consider what is physical. If the max volume is lower then the ice will be thinner allowing greater area to melt out earlier enabling albedo feedback to provide more energy into the arctic. Everyone agrees this is a major feedback.

At some point the melt volume will start to decline and I think it is conceivable that this could be before minimum volume reaches zero. There would be less melt in the outer seas because they are thinner and fully melt out and more melt in central areas because it is thinner and more energy is available. I think that so far extra melt in central areas is tending to be larger than declining melt in outer seas but I don't see why that couldn't change if sufficiently large areas by CAA keep getting up to thicknesses of 3m which is too much to melt in a season by transport of ice into the area causing mechanical thickening. So far the thickest ice seems to be getting thinner - very little over 3.75m per Piomas.

So a plateau after curling up does not seem impossible even physically plausible. However, I am not sure we have reached that yet.


Grey Wolf, I think you should see that I think it does make sense to look at 'this side of losses'.

Apocalypse4Real

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Re: Records and oddities
« Reply #75 on: March 05, 2013, 02:14:41 PM »
In addition to the wind and high pressure that has stressed the ice to date, here is the HYCOM CICE forecast for ice speed for March 4, 5, 8 and 10. It would seem to lead to additional fracturing.

The source is: http://www7320.nrlssc.navy.mil/hycomARC/navo/arc_list_arcticicespddrf.html

Apocalypse4Real

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Re: Records and oddities
« Reply #76 on: March 05, 2013, 02:25:41 PM »
Latest fracturing north of Ellesmere at 11:05.

Juan C. García

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Re: Records and oddities
« Reply #77 on: March 05, 2013, 03:23:45 PM »
A4R:
The cracks that you are showing and the forecast of the HYCOM CICE are very impressive.
I don’t believe that there will be a recovery before the start of the melting season, so this year the sea ice will be very weak and I would expect an early melt.
Do you agree?
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.

Shared Humanity

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Re: Records and oddities
« Reply #78 on: March 05, 2013, 05:33:46 PM »
A4R......Wow!

When I look at at the ice speed forecasts and the fracturing, I am drawn to the fracturing that is occurring over the pole. Does this suggest the Fram is set to pump a lot of ice into the Atlantic?

Dave C

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Re: Records and oddities
« Reply #79 on: March 05, 2013, 05:46:05 PM »
Gray-Wolf-
The forces that act on the ice during the melting and refreeze season are very different. It's an
assumption, but I think it's a pretty reasonable one to separate them.

I don't think "masking" is a useful distinction. Either ice melts or it doesn't. Whatever it ends up at is the "true rate". Higher ice gain in winter actually is a trend, which is partly why I separate the two seasons.

I posted the graph of fram ice transport in post 64. As far as I am aware, transport through the fram is not increasing. I guess this year will be a good test of that hypothesis.

Crandles-
I have seen the earlier years, I just make the assumption that the last 5 years is more important than the preceding. I think the change in 2007 was big enough to alter ice dynamics permanently. Of course there is too little data to state definitively either way, but it is testable. Does focusing on the last 30, 10 or 5 years give you better results? I'm going to predict 5 until I see evidence otherwise.

I agree that the thinner ice is a major feedback. But it's an empirical question whether the two major resistors to melt volume counterbalance it(less ice to melt, more difficult to melt what's left). Of course even if I am right that melt volume has stalled, it is still larger than winter ice gain. Overall ice volume will decline unless summer melt volume reverses or winter gain significantly increases.

crandles

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Re: Records and oddities
« Reply #80 on: March 05, 2013, 06:40:19 PM »
I have seen the earlier years, I just make the assumption that the last 5 years is more important than the preceding. I think the change in 2007 was big enough to alter ice dynamics permanently. Of course there is too little data to state definitively either way, but it is testable. Does focusing on the last 30, 10 or 5 years give you better results? I'm going to predict 5 until I see evidence otherwise.

I say use 34 years and try to use physical reasoning to arrive at a formula like
22.8 - 0.213 * max vol

That is still going up as max volume declines further. I suggest there is little to no evidence of the rate of melt volume increase is slowing down let alone that there is a plateau yet. Even so, average of last 5 years could work out to be a better predictor than such a formula which is not only increasing but also doing so at an increasing rate.

If there is a trend, 5 years is a bit short of a period to estimate that trend given the level of noise. So it seems use of 5 years would simply use persistence rather than the trend evolution that 34 years can suggest. So generally, I would prefer to use 34 years than 5 but it is possible that you are right in this case.

Dave C

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Re: Records and oddities
« Reply #81 on: March 05, 2013, 07:45:05 PM »
Don't know about exponential- wipneus is predicting volume down to 2.0, which would probably require a record melt. 10 year linear seems to predict 19.05, 5 year predicts 18.65.

It's possible that the variance could obscure the trend, but I think the difference is big enough that this year should give us an indicator if an exponential, linear or short-term linear trend is more accurate.

ChrisReynolds

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Re: Records and oddities
« Reply #82 on: March 05, 2013, 08:30:44 PM »
Last three days from Environment Canada, Northern Canada & Arctic Ocean, HRPT (Polar Orbiting) - animated gif.
https://docs.google.com/file/d/0B3pB-kdzoLU3V292VzJnVlROVzg/edit?usp=sharing

Day 50 to day 63 of ASCAT, showing bulk movement of the ice.
https://docs.google.com/file/d/0B3pB-kdzoLU3enpsVkZGZDdFZEk/edit?usp=sharing

 :P    Have at it ice nerds!     :o

SATire

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Re: Records and oddities
« Reply #83 on: March 05, 2013, 08:32:32 PM »
When I look at at the ice speed forecasts and the fracturing, I am drawn to the fracturing that is occurring over the pole. Does this suggest the Fram is set to pump a lot of ice into the Atlantic?

Indeed - if transport of ice-volume through Fram is going to keep constant while ice thickness in the arctic ocean is decreasing, it would have to go faster. Obviously it is trying to keep that flow rate constant, thus increasing velocity and tearing the thick ice appart by doing so. The fractured ice is surely more mobile allowing to keep that flow rate constant, but why? And it can not be like this for ever, because the old thick ice will be gone soon...

Gray-Wolf

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Re: Records and oddities
« Reply #84 on: March 05, 2013, 08:40:28 PM »
Again, let's not forget the findings from 07' which showed 'perfect storm' years come around every 10 to 20 yrs with the past two , prior to 07', having a 10yr period?

If changes to atmospheric circulation are all encompassing then we may have lost this old 'cycle' , if not? then we are drawing ever closer to a 'high export/high melt' year.

What chance does the current Arctic stand against such???

If we do not see such a collaboration of forces against the ice then we still must remember the last of the ice will go pretty fast? It will not be a slow fade over years but all within a single season (as the remaining ice reaches a critical thickness/thinness).
KOYAANISQATSI

ko.yaa.nis.katsi (from the Hopi language), n. 1. crazy life. 2. life in turmoil. 3. life disintegrating. 4. life out of balance. 5. a state of life that calls for another way of living.
 
VIRESCIT VULNERE VIRTUS

ChrisReynolds

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Re: Records and oddities
« Reply #85 on: March 05, 2013, 10:12:16 PM »
Dave C,

Currently we have January volume - Ok let's work with that. If I take the volume for 31/1/XX I can work out the difference between 31 Jan and the following minimum I can work out the range from January. Indeed as expected this shows the plateau behaviour you are talking about. So I take the post 2007 years and subtract from these the current volume on 31/1/2013.

Jan Vol/Jan to Min/Projection
19.584,   13.126,   3.717
20.21,   13.138,   3.705
20.389,   13.496,   3.347
18.861,   14.433,   2.41
17.565,   13.548,   3.295
17.594,   14.333,   2.51

Note the years in order are 2007 down to 2012.

These naïve projections support what you're saying. Last year's record was 3.261k km^3, only two out of six projections give a new record, the other 4 are rebounds. Therefore the probability of a new record this year is 1/3 right? No, wrong.

I said this is a naïve method, that's not meant in an insulting manner, it's the common term used in the literature for a simple unphysical method. Essentially the problem with the above method is that it is unphysical.

You'll note from the above sequence of projections that the lowest are from 2010 onwards. Why is this? Further up thread I provided you with a graph of anomalies for PIOMAS volume, this shows that since 2010 there has been a pronounced and massive spring melt within the model. This will happen again this year. It's initiation coincides with a massive loss of volume in 2010, mainly a loss of thick multi year ice (off the CAA). I'll be posting another blog post about this spring volume loss in the next few weeks - I think I'm closer to understanding exactly what's going on.

This year we have something similar. I've linked to a blog post showing PIOMAS DAM and ASCAT with links to longer term data. The state of the ice now is the thinnest it has been in the satellite record, this will have physical effects during the melt season. Because there is now more first year ice than at any other time, the albedo of the ice will be lower and therefore the energy gain higher. This isn't a matter of conjecture - it is physics, both theoretical and empirical.

ivica

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Re: Records and oddities
« Reply #86 on: March 06, 2013, 11:01:25 AM »
Beaufort Sea uncovered by daylight: http://www.arctic.io/observations/
All credits to arcticio.

(Maybe not obvious to newcomers, moving mouse over Date box opens Calendar.)
« Last Edit: March 06, 2013, 12:46:13 PM by ivica »

ChrisReynolds

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Re: Records and oddities
« Reply #87 on: March 06, 2013, 04:50:20 PM »
Net ice movement between 19 Feb and 5 Mar.



Arrows connect features that move between these dates, dotted areas do not move.

werther

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Re: Records and oddities
« Reply #88 on: March 07, 2013, 10:13:09 AM »

Thought I'd post a larger version of the ECMWF prognosis for 14 March here.
In seems to illustrate effects of a new SSW event in progress now.
Meanwhile, the cold spell in the Arctic has suppressed the built-up 'winter-power' I posted on above. The Bering side and the Barentsz hotspots have weakened, a large 'zero anomaly' has showed op over the remaining stronger pack north of Nares Strait.

Apocalypse4Real

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Re: Records and oddities
« Reply #89 on: March 07, 2013, 02:29:17 PM »
What a difference a month makes! I thought I'd compare February 5 and March 7 to reveal how much change has happened in the last four weeks. It is clear that we have seen changes that will likely have real impact later in the melt seadson.

Here are a few I observe:

1) The fracturing is obvious!
2) The change in direction of the fracturing.
3) The movement of ice towards the Atlantic/Fram
4) The further breakdown of ice moving towards the Fram along the Greenland coast.


Shared Humanity

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Re: Records and oddities
« Reply #90 on: March 07, 2013, 06:26:07 PM »
A4R.....From your images

With major fractures having migrated east to the coast of Prince Patrick and some evidence of emerging(?) arc fractures further east and north and the sorry state of ice north of Ellsmere, could we be looking at the nearly complete desintegration of ice north of the CA?

Shared Humanity

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Re: Records and oddities
« Reply #91 on: March 07, 2013, 06:29:21 PM »
By disintegration, I don't mean a complete melt out but that the remaining MYI will no longer be a cohesive pack. :-\

Apocalypse4Real

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Re: Records and oddities
« Reply #92 on: March 08, 2013, 02:23:17 PM »
Shared Humanity,

The ice dynamics are such that the fracturing will likely be slower. The changes in wind patterns, temperature, and the coming sun are all in play.

The next few months will let us know the conclusion.

ChrisReynolds

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Re: Records and oddities
« Reply #93 on: March 10, 2013, 09:24:48 AM »
ASCAT 9/3/13, shows that the general clockwise movement of the entire Arctic ice pack continues (except for the regions noted in my post of 5/3/13 4:50).

gfwellman

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Re: Records and oddities
« Reply #94 on: March 10, 2013, 10:08:22 AM »
It's going to be an interesting melt season.  Comparing the visible spectrum (e.g. http://www.arctic.io/observations/ ) for the same time last year, there was less ice in the Barents, but the main pack showed almost no fracturing.  The ice on the east coast of Greenland was much more solid as well.  There's no guarantee that this spells doom for the ice pack but if there is a strong transpolar drift this melt season, we could see another record minimum.

Apocalypse4Real

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Re: Records and oddities
« Reply #95 on: March 10, 2013, 04:43:14 PM »
Here are the before, during and after AVHRR images from:

8 March 2342, when there is no major MYI fracturing and prior to the wind event,
9 March 1850, when the warm wind is streaming over the ice, and you can see some new fracturing beginng, and
10 March 1333, when the full fracturing of the MYI is fully apparent.

I am not aware of any comparison in the records with this event. Any others aware of a similar event at this time of year - or ever?

Shared Humanity

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Re: Records and oddities
« Reply #96 on: March 10, 2013, 05:57:53 PM »
A4R...

I also see what appear like many more arc fractures forming with the sharpest points of each arc moving progressively closer to the pole. As these arcs turn south and move towards Ellsmere they appear to terminate in the MYI. Could a renewed Beaufort Geyer cause these to push through the last remaining pack of MYI?

SATire

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Re: Records and oddities
« Reply #97 on: March 10, 2013, 06:48:16 PM »
A4R - it seams like cracking has reached "mission accomplished"-state as there is no save haven left for multi-year-ice. Every part of multi-year-ice left has now a good chance to leave either via Fram-Express or to visit the sunny coast of Alaska for a short summer holiday to get extinct.

I am not sure, if the 2 oberservations discussed above "ice-volume transport through Fram stays constant" and "volume-melt has reached constant/maximum value" are linked - but I think so. Both are signs for record years to come until arctis is seasonaly ice-free, since after that date both values must decrease anyway. If the multi-years ice is gone, the only thing to export or to melt is then the ice grown in the winter just before. Therefore - to observe the 2 plateaus now is a sign that we will reach ice-free arctis soon, e.g. this year or in 5 years.
« Last Edit: March 10, 2013, 06:56:29 PM by SATire »

Artful Dodger

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Re: Records and oddities
« Reply #98 on: March 10, 2013, 08:01:20 PM »
A4R - it seams like cracking has reached "mission accomplished"-state as there is no save haven left for multi-year-ice. Every part of multi-year-ice left has now a good chance to leave either via Fram-Express or to visit the sunny coast of Alaska for a short summer holiday to get extinct.
Hi SATire,

Indeed, it's Bedtime for Bonzo in the Canadian Arctic Archipelago: (h/t to A4R for linking the pictures above)

Here's a cropped, grey-scaled, resized, auto-colour-adjusted image of the sea ice graveyard: (Image avhrr IR Ch 4 (10.8mu or -5C peak emissivity) taken @ 2013-03-10 15:39:55 GMT)
Cheers!
Lodger

Apocalypse4Real

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Re: Records and oddities
« Reply #99 on: March 10, 2013, 08:05:16 PM »
SATire

Here are two images that I think help establish that fact:

The first is the AVHRR Ellesmere Island at 1839 GMT.

The other is the last HYCOM/CICE thickness model.

Whatever was modeled as over 3 meters seems to be as vulnerable as everything else that has fractured, and north of Banks, Borden, and Brock Islands - has already done so.

I anticipate more fracturing to come.