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What will the CT 2013 Arctic SIA minimum be?

More than 3.5 million km2
0 (0%)
Between 3.25 and 3.5 million km2
0 (0%)
Between 3.0 and 3.25 million km2
2 (2.1%)
Between 2.75 and 3.0 million km2
2 (2.1%)
Between 2.5 and 2.75 million km2
5 (5.3%)
Between 2.25 and 2.5 million km2
11 (11.6%)
Between 2.0 and 2.25 million km2
12 (12.6%)
Between 1.75 and 2.0 million km2
28 (29.5%)
Between 1.5 and 1.75 million km2
13 (13.7%)
Between 1.25 and 1.5 million km2
11 (11.6%)
Between 1.0 and 1.25 million km2
1 (1.1%)
Less than 1.0 million km2
10 (10.5%)

Total Members Voted: 94

Voting closed: April 30, 2013, 06:13:01 AM

Author Topic: Cryosphere Today 2013 Arctic SIA daily minimum: April poll  (Read 40221 times)

Neven

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Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« on: April 02, 2013, 06:11:33 AM »
It should be 'fun' and interesting to hold a poll each month, to see how opinions change according to sea ice rhythm and pace. These monthly polls can then also function as a dedicated thread for everything concerning Cryosphere Today sea ice area. Daily updated data can be found here.

Again, this poll is for Cryosphere Today sea ice area daily minimum (unlike the other popular measure: NSIDC sea ice extent monthly minimum), so we're looking for the lowest total Arctic sea ice area number on any given day at the end of the 2013 melting season.

Here's how things are currently looking:



These are the daily minimums for the last 7 years (in millions km2):
  • 2005: 4.092
  • 2006: 4.030
  • 2007: 2.919
  • 2008: 3.004
  • 2009: 3.425
  • 2010: 3.072
  • 2011: 2.905
  • 2012: 2.234
Again, try to use this thread to discuss CT SIA mainly. There are other threads for the other topics, and if there isn't, feel free to open one.

Poll closes at the end of the month, and I will then open a new thread for the 2013 CT SIA minimum May poll. Let me know if you think there are enough options, or too little/many.
« Last Edit: April 02, 2013, 10:01:00 PM by Neven »
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Juan C. García

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #1 on: April 02, 2013, 08:09:34 AM »
Well, I thought to wait and see how Arctic sea ice will perform during April, but then, I prefer to start this poll. From my point of view, there should be more ranges between 1 and 2 million km2, if 2012 minimum was 2.234 million km2. So I invite Neven to make more ranges and I will vote again. Given the ranges that are right now, I chose from 1 to 2 km2 as the minimum.
I suggest making the following new ranges: from 1 to 1.3, from 1.3 to 1.6, from 1.6 to 1.8 and from 1.8 to 2 million km2. With the cracks that the ice had on February-March 2013, I expect to have a new record on September 2013. At this moment, I will bet for the 1.8 to 2 million km2, but I could change my mind during April.
« Last Edit: April 02, 2013, 09:48:00 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

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

slow wing

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #2 on: April 02, 2013, 09:54:59 AM »
This is a difficult poll! There could be some bounce back from last year. Or the more fractured ice could in one way or another lead to a record.

I agree with everything Juan said. 1-2 million km^2 being such a big bin makes it the most likely bin to contain the outcome imo. Even if the bins are split up like Juan suggests then I will still agree with his guess of 1.8-2.0 million  km^2.*

*EDIT: with the re-binning, I ended up picking 1.50-1.75 million km^2 as the sea ice had meanwhile continued to fracture.
« Last Edit: April 03, 2013, 09:07:03 PM by slow wing »

Richard Rathbone

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #3 on: April 02, 2013, 11:42:31 AM »
As already said, 1-2, because its the biggest bin. If I was trying to get within 0.1, I'd go for 1.9-2.1 as about right for weather that's neutral for melting, but its a complete guess at the moment, so largest bin gives best odds.

ChrisReynolds

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #4 on: April 02, 2013, 12:15:59 PM »
Wow, finally I seem to be in with the peak of the distribution.

I've voted between 1 and 2 M km^2, this is what I see as most likely, if I had a second vote it would be 2.234 to 2 M km^2. But I now rate the probabilities as around 75% and 25% respectively, with a probability distribution peaking between 1.75 and 2, and a slim tail extending down towards 1M km^2.

I've voted for that because of the prevalence of FYI. Nightvid Cole has been good enough to let me know that DAM (drift age model) plots are now available up to this year week 13.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/

2012 Week 13.



2013 Week 13.



The above images show that this year's pack is far more dominated by FYI than was last year at the same time. This is significant in terms of the melt pattern last year, where as with 2010, the effect of the older ice in the Siberian sector could be seen in the overall melt pattern. As seen in DAM for 2012 week 30:



And Bremen satellite images of the same period.
http://www.iup.uni-bremen.de:8084/ssmisdata/asi_daygrid_swath/n6250/2012/aug/asi-SSMIS-n6250-20120801-v5_visual.png

The area of persistent low concentration sea ice was, in my opinion, due to the scattered presence of MYI within that region.

This year there will be no such retarding of ice melt due to MYI, the central pack of MYI will not spread, as shown by 2012's spread:

2012 Week 1.


2012 Week 30.


Basically sea ice doesn't move fast enough for such a spread this year, looking at other years supports this contention, in my opinion. Therefore the melt will proceed aggressively in the Siberian sector without impedance due to older ice, which will largely remain an issue in Beaufort.

But I still maintain that under 1M km^2 extent is impossible, and think that under 1M km^2 CT area is very unlikely.

crandles

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #5 on: April 02, 2013, 12:45:17 PM »
I think Neven should say more prominently that this is daily minimum not a monthly average.

Agree that the bin sizes changing from .2 to 1, a factor of 5, seems a large sudden change.

What would I set? Perhaps:
0-1
1-1.5
1.5-1.75
1.75-2
2-2.25
2.25-2.5
2.5-2.75
2.75-3
3-3.5
3.5+

so have to go below 1.5 or above 3 to get larger bins. Bins then double the size and continue to do that or more with each bin as they move further from most peoples expected range. Just 50% larger bins has been suggested which also looks sensible; perhaps should also apply at high end?


Jim Williams

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #6 on: April 02, 2013, 01:49:26 PM »
I'm sticking with melt-out this year at least until mid Summer.  I'm convinced that whenever it happens it will be much more sudden than most people expect, and it's as likely to be this year as any.

After Spring melt it will be much more obvious one way or the other.

Pmt111500

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #7 on: April 02, 2013, 01:51:08 PM »
I'm still in the belief that the restructurization of the jet stream is a winter phenomenon only, so I put in my guess higher than many, believing the low pressures travelling along Siberian coasts will pile up the ice so fast it clogs the northern channels for long enough in  the CAA, so the ice can't escape that route... Still, it's a hazard guess when the sun's active phase continues.
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Peter Ellis

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #8 on: April 02, 2013, 03:32:06 PM »
Around 2.6 is my guess, so I've picked the upper bound from that to be conservative.  It would be utterly unprecedented to have two records in a row, so some bounce back from last year's low seems inevitable to me. Also, although the long term trend is accelerating downwards, 2012 was still noticeably below it, so some upward reversion to the mean seems likely. This mustn't be mistaken for "recovery" though. I think 2007 is a likely upper ceiling, so I've gone about half way in between the 2012 and 2007.

I just do not buy all the arguments about "first year ice = inevitable melt".  We heard them made in 2008 and again in 2009, and in each year there was substantial bounce back from the record low.  Tietsche et al showed that there is no more than a year or so's "memory" of record lows, and that ice levels are set by overall climatology and not by irreversible tipping points.  So, back to trend it is. 

There are however two differences between 2012 and 2007:

a) 2012 was not such a large excursion below the trend line, so the "bounce back" will be less pronounced and likely won't continue into 2014 (unlike 2007 -> '08 -> '09)

b) The trend itself is accelerating downwards and within the next couple of years will be dropping fast enough that new records every year will be inevitable until we bottom out a bit above zero.

If you want "broad brush" forecasts for the next few years, here they are:

2013:  2.6 +/- 0.2  (no new record)
2014:  2.0 +/- 0.3  (likely new record)
2015:  1.4 + / 0.4  (very likely new record)
2016:  0.9 +/- 0.6  (likely new record)
« Last Edit: April 02, 2013, 03:37:09 PM by Peter Ellis »

Neven

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #9 on: April 02, 2013, 03:35:31 PM »
Good tips about bins and monthly/daily! Will change those later in the day.
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Juan C. García

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #10 on: April 02, 2013, 07:26:18 PM »
I think Neven should say more prominently that this is daily minimum not a monthly average.

Agree that the bin sizes changing from .2 to 1, a factor of 5, seems a large sudden change.

What would I set? Perhaps:
0-1
1-1.5
1.5-1.75
1.75-2
2-2.25
2.25-2.5
2.5-2.75
2.75-3
3-3.5
3.5+

so have to go below 1.5 or above 3 to get larger bins. Bins then double the size and continue to do that or more with each bin as they move further from most peoples expected range. Just 50% larger bins has been suggested which also looks sensible; perhaps should also apply at high end?
I believe that Crandles made a good recomendation (so forget mine, too many options).
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

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

Nightvid Cole

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #11 on: April 02, 2013, 09:33:40 PM »
Around 2.6 is my guess, so I've picked the upper bound from that to be conservative.  It would be utterly unprecedented to have two records in a row, so some bounce back from last year's low seems inevitable to me. [....]
Unprecedented? What about 2011 and 2012? We're talking about one-day CT area here.

Of course, you can just argue that it's unprecedented to have three records in a row, and thus we expect a bounce back, but this would borderline on moving the goal-posts :P

Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #12 on: April 02, 2013, 09:56:11 PM »
Okay, I've made the changes, but had to reset the vote results because the bins changed. Sorry about that, but it's the first time and I want to get it right for subsequent polls in coming months.

So please vote again and let me know if it's not okay like this.
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Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #13 on: April 02, 2013, 10:02:10 PM »
Oh, and BTW, this is a real headache for me every year. What is best: sea ice area daily minimum, or daily minimum sea ice area?
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ChrisReynolds

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #14 on: April 02, 2013, 10:11:57 PM »
Neven,

Because 'sea ice area' is effectively a noun, either way is OK as far as I can see.

Peter Ellis

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Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
« Reply #15 on: April 03, 2013, 12:46:57 AM »
Unprecedented? What about 2011 and 2012? We're talking about one-day CT area here.
I don't really count 2011 as a break seeing as it's a statistical tie with 2007, but  I take your point.  Still expecting a bounce back though :-p

AndrewP

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #16 on: April 03, 2013, 05:06:08 AM »
I've guessed 2.7 already.. so went with the 2.5-2.75 category.

DrTskoul

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #17 on: April 03, 2013, 05:49:11 AM »
2 - 2.25

Best guess, but really this year might be one of the most difficult to pin down. Will keep surprising us
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Jim Pettit

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #18 on: April 03, 2013, 11:58:40 AM »
Oh, and BTW, this is a real headache for me every year. What is best: sea ice area daily minimum, or daily minimum sea ice area?
As Chris already wrote, either is fine and clear enough. However, if you wish to be truly pedantic about it, you might want to abide by the rules of adjectival order, which are generally as follows:

(Article); Opinion; Size; Age; Shape; Color; Origin; Material; Purpose; [Noun/Noun Phrase]

So to be "perfect", you would want to say: minimum (size) daily (age) sea ice area (noun phrase).

But, again, what you have is clear enough. And besides, nobody likes a pedant.  :)

Espen

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #19 on: April 03, 2013, 12:06:51 PM »
FYI: Between 2.25 and 2.5 million km2 8)
Have a ice day!

Pmt111500

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #20 on: April 03, 2013, 01:54:24 PM »
Jim Pettit:" (Article); Opinion; Size; Age; Shape; Color; Origin; Material; Purpose;

[Noun/Noun Phrase]"

Wonderful!
so I guess it would be almost correct to say:
"the royally fucked-up minimum daily meshed greenish-white central arctic slushy un-comedical sea ice area of leftover isothermal smallish multiyear fragmental brownish-white smokestacky icelike reversally miocenic-pleistocenic boundary remnants of the H2O freezing/melting -process? :-)

On numbers, I'm with Espen here.
« Last Edit: April 03, 2013, 02:00:10 PM by Pmt111500 »
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sofouuk

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #21 on: April 03, 2013, 02:10:20 PM »
@ Peter Ellis - about the likelihood of a bounce back. 2007 was a weather driven event, so a recovery the next year was only to be expected unless a similar set of freak weather reoccurred. nothing special about the weather in 2011 and 2012 (except the storm, but a new record was in the pipeline by then anyway) so why wouldn't a similar melt occur again? people might be overegging the significance of the ice cracking up so early a bit, but it can't be good.

well, im with ChrisReynolds (and nice pics, btw)

TerryM

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #22 on: April 03, 2013, 06:50:05 PM »
I opted for the 2 to 2.25 bin - but without much confidence.


I think it all depends on how the CAA reacts and whether Nares Strait chokes trying to swallow the ice island.


Terry

AndrewP

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #23 on: April 03, 2013, 07:30:29 PM »
Almost every big drop is followed by a bounce.

Vergent

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #24 on: April 03, 2013, 09:10:57 PM »
Oh, and BTW, this is a real headache for me every year. What is best: sea ice area daily minimum, or daily minimum sea ice area?
Neven,

Great poll! Thank you.

Wouldn't "daily minimum" be the minimum in a 24 hr period? Whereas "minimum daily" would be the least among daily measurements. My vote is for "minimum daily SIA".

V

My vote is for <1.0. My actual opinion is for a hard zero, not counting bergs and shelves. This break up gives the insolation more than a months head start over last year, on low albedo lead ice. This is going to give us several extra weeks of high insolation on millions extra of km^2 open water up there.

I sincerely hope I am wrong. Last year I predicted 2.06 Mkm^2, I missed by 174kkm^2.

Juan C. García

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #25 on: April 04, 2013, 01:01:50 AM »
I want to use the occasion of Neven’s question to ask if it is ok to write: “Arctic sea ice free” or would be better an expression like: “Arctic free of sea ice”?
On the other hand, I already voted for 1.75-2.00 million km2. I agree with Reynolds about the concern of FYI, but from my point of view, it is more important to highlight the actual weakness of the ASI. I  believe that the cracks are the evidence of this weakness. Also, there are starting to appear polynyas that are another evidence of weakness and show the possibility of an early melt during April-May. So FYI is the cause, but cracks and polynyas are two consequences that we can see right now.
I concern that could be a strong melt at 2013, but for now, I will keep my vote on the 1.75-2.00.

http://www.iup.uni-bremen.de:8084/amsr2/
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

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

Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #26 on: April 04, 2013, 01:10:17 AM »
Wouldn't "daily minimum" be the minimum in a 24 hr period? Whereas "minimum daily" would be the least among daily measurements. My vote is for "minimum daily SIA".


Thanks, my headache had just subsided.  :D

I want to use the occasion of Neven’s question to ask if it is ok to write: “Arctic sea ice free” or would be better an expression like: “Arctic free of sea ice”?


I think everyone agrees it's "ice-free Arctic".

There's a nice polynya at Wrangel Island as well.
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AndrewP

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #27 on: April 04, 2013, 02:10:28 AM »
Vergent.. you guessed 2.06 (also I think you guessed 2.0 at some point) in July and/or August at which point it was pretty close to the minimum already. Not quite the same as guessing in April.

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #28 on: April 04, 2013, 08:02:42 AM »
Vergent.. you guessed 2.06 (also I think you guessed 2.0 at some point) in July and/or August at which point it was pretty close to the minimum already. Not quite the same as guessing in April.

On topic "arctic sea ice extent" page 173 post #6052 I said:

The normal loss from this point on is -1.0 mil. However there is nothing normal about this ice cap. How can you expect a normal loss when you factor in the thin ice and albedo feedback. My expectation is closer to 2.0 mil. than 2.5. I would not be surprised with a value below 2.0 mil.


http://www.americanwx.com/bb/index.php/topic/156-arctic-sea-ice-extent/page-173

"closer to 2.0 than to 2.5" translates to 2.0 to 2.25.  That was the +/- of my 2.06 that was on 174 #6087. This predictions were for SIA. The extent at the time of this prediction was 6.2.

In the April AmWx SIE poll, I chose the correct answer <4.25, you I believe chose 4.51 - 4.75. But your name was different. I am not ashamed of my handle in spite of being banned for impiety at AmWx. Are you ashamed of your AmWx identity?

http://www.americanwx.com/bb/index.php/topic/33746-predict-summer-2012-minimum-arctic-sea-ice-extent-millions-sq-km/


AndrewP

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #29 on: April 04, 2013, 10:15:47 AM »
Vergent,

Area was at 3.6 at the time you made the prediction and the date was August 4th. Decent prediction, not amazing. And the weather in September certainly helped.

My name is different because skiing in VT didn't seem very relevant to a sea ice forum.

sydb

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #30 on: April 04, 2013, 02:55:14 PM »
This is a difficult one to call as last year was below trend and a big drop, which might be expected to be followed by a bounce back towards the long-term trend. In 2008, this happened and the unusually favourable melt conditions of 2007 were not repeated in 2008. However, the surface conditions in 2012 were not so favourable for a large melt, but it happened anyway. If 2012 was driven mainly by the advection of heat into the Arctic, then this could continue its inexorable melt and preclude a bounce. Given the poor state of the ice, I expect an early melt so I'd guess at 1.75-2M square kilometers.

ChrisReynolds

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #31 on: April 04, 2013, 07:05:33 PM »
Almost every big drop is followed by a bounce.

The past may no longer be a guide to the future.

Vergent

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #32 on: April 04, 2013, 07:42:44 PM »
Vergent,

Area was at 3.6 at the time you made the prediction and the date was August 4th. Decent prediction, not amazing. And the weather in September certainly helped.

My name is different because skiing in VT didn't seem very relevant to a sea ice forum.


Andrew(skier),

On 8/7/12 skierinvermont(AKA AndrewP) said:

Vergent's prediction of close to 2 million in area is going to fail horribly. I'd guess around 2.8 or 2.9.


http://www.americanwx.com/bb/index.php/topic/156-arctic-sea-ice-extent/page-178

post #6204

V


fred

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #33 on: April 05, 2013, 12:02:33 PM »
I'm going for  -700000.

The negative represents the amount of ice that would be melted if we were not already at zero.

This works better for volume, because then heat content could be used. But given the subject is area, this is what I would guess.

Sorry if I am pessimistic but eyeballing the charts, then adding the fracturing and loss of heat into Europe and the US this winter, I think we are effed.

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #34 on: April 05, 2013, 02:26:18 PM »
I'm with Vergent on the grammar and Peter on the sea ice area.

For me the heirarchy of concepts is
1. minimum/maximum
2. daily/monthly
3. sea ice area/extent
so the order should be minimum daily sea ice area. "Daily" in this construct is not age - of the options listed, its probably closest to "purpose".

As Vergent says, daily minimum implies the minimum in a specific 24 hour period, not the minimum 24 hour period in a longer timespan. YMMV.

Oh, yeah, SIA  :D
I'm thinking 2.6 to 2.7.

Jim Williams

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #35 on: April 05, 2013, 06:02:11 PM »
so the order should be minimum daily sea ice area. "Daily" in this construct is not age - of the options listed, its probably closest to "purpose".

I think what you want is instantaneous, with Daily being about as good as you'll ever get.  A technology which could determine the actual minimum would be a technology which could get us out of this jam.

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #36 on: April 05, 2013, 07:29:55 PM »
Since I believe in the exponential decribing the volume due to albedo-feedback, I would guess 2 Mio km2 (of about 1m thick ice) as most probable value. Since the standard deviation is quite large (also about 2 Mio km2) I voted for the largest bin closest to that value: 0-1 Mio km2.

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #37 on: April 06, 2013, 12:38:39 AM »
Almost every big drop is followed by a bounce.

The past may no longer be a guide to the future.

Agreed Chris. I also guessed 1.75-2 mkm2 because there is so much ice out there less than a year old. I will be surprised if we don't get a new record SIA. I will not be as surprised if the SIE record holds. 

fishmahboi

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #38 on: April 06, 2013, 01:21:08 AM »
I vote less than 1.0 million km because of the recent steep decline in the Arctic Ice which makes me fear that the Arctic, should the losses continue, will melt out as early as June or with horrific luck, May.

crandles

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #39 on: April 06, 2013, 03:27:12 AM »
I vote less than 1.0 million km because of the recent steep decline in the Arctic Ice which makes me fear that the Arctic, should the losses continue, will melt out as early as June or with horrific luck, May.

31 March 2012 piomas volume 21.665
31 March 2013 piomas volume 21.612

31 May 2012 Piomas volume 18.186

So a decline in volume of 3.5 K Km^3 last year with horrific luck is going to become 21 K Km^3; six times more volume loss. What horrific luck is that? Perhaps lots of meteorite impacts vapourising ice and causing lots of open water for albedo feedback?

30June 2012  was 11.882 so "only" a little more than double last year's volume loss.

Jim Williams

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #40 on: April 06, 2013, 12:45:49 PM »
\31 March 2012 piomas volume 21.665
31 March 2013 piomas volume 21.612

....

30 June 2012  was 11.882 so "only" a little more than double last year's volume loss.

How much of that volume is north of 80 degrees?

crandles

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #41 on: April 06, 2013, 04:25:17 PM »
\31 March 2012 piomas volume 21.665
31 March 2013 piomas volume 21.612

How much of that volume is north of 80 degrees?

While I have the data and could calculate this for each month in 2012, for 2013 I only have the total figure so it would be circa mid Jan 2014 before this can be fully answered. Slight shame but I think it is only fair that the PIOMAS team should have the right to publish first what they discover.

Juan C. García

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #42 on: April 07, 2013, 08:03:35 AM »
After seeing how the sea ice concentration is changing at Bering Sea, Okhotsk Sea, Barents Sea and the exit of Hudson Bay, I want to keep record of the status of the poll at this moment, because I bet that the percentages are going to change in the following days (to ranges with less value). Let’s wait and see.



It seems incredible that the perception of the status of the Arctic could change only 8+ days after this poll has started.
« Last Edit: April 07, 2013, 08:18:30 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

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

Wipneus

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #43 on: April 07, 2013, 09:14:27 AM »
I know it is not going to help, but we are in Terra Incognita: somewhere between 1.0 and 2.5 Mm2

So the choice is made for the 1.75-2.0 range.

Andre Koelewijn

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #44 on: April 07, 2013, 06:41:27 PM »
Just voted 'between 1.25 and 1.5 M', before I read all replies, which I've done by now.
Based on an eye-balled guess from the figures since, roughly, 2005.
Yet, I hope it will turn out to be higher, which would then be a result of good weather (i.e. bad for melting).
I believe the amount of ice mid-September is determined by both area and volume, and the downward trend of PIOMAS doesn't promise a rebound - and note that the declining PIOMAS-average has been clearly too high in the past years.

Artful Dodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #45 on: April 08, 2013, 10:50:18 AM »
Hi folks,

Interesting pole results, a classic bimodal distribution:



How I interpret this is that there are two likely modes in which Arctic sea ice area will proceed in Summer 2013:
  • No recurrence of a Great Arctic Cyclone like 2012
  • a GAC occurs with sufficient strength to mix the surface layer
In case 1, we have a regular incremental melt season. Peripheral sea melt first, melting toward the Pole in an 'outward-in' fashion. Linear predictions apply, which is why I estimate 1.9 M km2 being about 10% below 2012. As Peter suggests, there could easily be regression to the mean, with some noise for weather.

In case 2, the sea ice melts out completely. There is more than enough heat below 50 meters depth right now to melt all the sea ice, but the fresh water lens (salinity gradient make fresh water float) preserves the ice cover.

Break the lens, melt the sea ice. Yes, completely.  :o

So my outlook for Summer 2013 is bimodal. But note the failure mode for the sea ice. This is the way I expect it to end, with a mighty whoosh of wind and a sudden total melt.

The only real question is, which year?
« Last Edit: April 08, 2013, 01:16:13 PM by Artful Dodger »
Cheers!
Lodger

Jim Williams

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #46 on: April 08, 2013, 12:56:25 PM »
Break the lens, melt the sea ice. Yes, completely.  :o

So my outlook for Summer 2013 is bi-modal. But note the failure mode for the sea ice. This is the way I expect it to end, with a mighty whoosh of wind and a sudden complete melt.

The only real question is, which year?

I think enough open water for a good fetch with moderate wind will be enough, but otherwise I agree with you.  As soon as there's almost no ice there's none at all.  Which year?

Artful Dodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #47 on: April 08, 2013, 01:40:41 PM »
I think enough open water for a good fetch with moderate wind will be enough, but otherwise I agree with you.  As soon as there's almost no ice there's none at all.  Which year?

Hi Jim,

Well, it didn't happen last year. GAC2012 encountered too much MYI beginning at around 83 N to kick the can. The surface layer either remained stratified or quickly recovered by horizontal flow down the halocline.

Einstein famously said "God doesn't play dice with the Universe." But then he wasn't talking about the weather either ;)

It happens when it happens. There is a random component which is real, and fundamentally unpredictable. Just like dice and weather.

It's enough to say "Soon" followed by "You were warned". Perhaps a better analogy is snowmen playing Russian Roulette with a hair dryer?  ;)
« Last Edit: April 09, 2013, 12:26:30 AM by Artful Dodger »
Cheers!
Lodger

ChrisReynolds

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #48 on: April 08, 2013, 07:55:02 PM »
Whoo Hooo,

I actually managed to vote in one of the more popular categories, and it still is.  ;D

Doesn't mean I'm going to stop being spikey and contrary though.  :P

DungeonMaster

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #49 on: April 08, 2013, 09:19:45 PM »
Voted between 1,5 and 1,75.

Recently I was looking at recent graphs about variations between minimum / maximum (probably on Tamino's blog), and managed to put a name on my feeling about the system looking like going out of control.

Looks like speed wobble, i'd say - or death wobble ?
This forum helps me to feel less uncomfortable about "doing something" about the melting Arctic and the warming world.
Read again  Maslowski paper : why Arctic could melt in 2016 +/- 3Y !