Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Neven on April 02, 2013, 06:11:33 AM

Title: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven 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 (http://arctic.atmos.uiuc.edu/cryosphere/) sea ice area. Daily updated data can be found here (http://arctic.atmos.uiuc.edu/cryosphere/timeseries.anom.1979-2008).

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:

(https://lh3.googleusercontent.com/-dWMgAqwBwkY/UVpXjGxEEDI/AAAAAAAAAc0/n_BXvoUwmNs/s800/CTSIA20130330.png)

These are the daily minimums for the last 7 years (in millions km2):
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.
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: Juan C. García 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.
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: slow wing 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.
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: Richard Rathbone 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.
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: ChrisReynolds 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/ (http://ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/)

2012 Week 13.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8383%2F8613292618_fa850e7499_o.gif&hash=f85a7babac3c58b2b3057044e66b3d5e)

2013 Week 13.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8263%2F8612185567_e53c312a4a_o.gif&hash=38ed66dbce03d222ee5fd9d5c90b27ab)

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:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8394%2F8612185569_ef24c35afa_o.gif&hash=804a37a98f90f7ea978e738a80fe3514)

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 (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.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8403%2F8613292624_056d566141_o.gif&hash=f777d5b15d6f27d305637dc718d0c9fb)

2012 Week 30.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8394%2F8612185569_ef24c35afa_o.gif&hash=804a37a98f90f7ea978e738a80fe3514)

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.
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: crandles 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?

Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: Jim Williams 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.
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: Pmt111500 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.
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: Peter Ellis 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)
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: Neven on April 02, 2013, 03:35:31 PM
Good tips about bins and monthly/daily! Will change those later in the day.
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: Juan C. García 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).
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: Nightvid Cole 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
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven 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?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: ChrisReynolds 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.
Title: Re: Cryosphere Today 2013 Arctic SIA minimum: April poll
Post by: Peter Ellis 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
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: AndrewP on April 03, 2013, 05:06:08 AM
I've guessed 2.7 already.. so went with the 2.5-2.75 category.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: DrTskoul 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
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Pettit 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.  :)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Espen on April 03, 2013, 12:06:51 PM
FYI: Between 2.25 and 2.5 million km2 8)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Pmt111500 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: sofouuk 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)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: TerryM 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
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: AndrewP on April 03, 2013, 07:30:29 PM
Almost every big drop is followed by a bounce.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Vergent 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Juan C. García 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.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1275.photobucket.com%2Falbums%2Fy449%2Fjuancgarcia22%2FNSIDC_DailyValuesAvg%2FPolynyas_april_2nd_2013_zps4a129149.jpg&hash=9acfcb6009bd61bae7fc225fb77d9fb5)
http://www.iup.uni-bremen.de:8084/amsr2/ (http://www.iup.uni-bremen.de:8084/amsr2/)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven 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

Quote
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 (http://www.arctic.io/observations/8/2013-04-03/8-N71.679995-W179.812954) at Wrangel Island as well.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: AndrewP 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Vergent 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:

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

Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: AndrewP 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: sydb 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: ChrisReynolds 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Vergent 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:

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

post #6204

V

Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: fred 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: FrankD 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Williams 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: SATire 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: frankendoodle 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. 
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: fishmahboi 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: crandles 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Williams 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?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: crandles 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Juan C. García 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.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1275.photobucket.com%2Falbums%2Fy449%2Fjuancgarcia22%2FNSIDC_DailyValuesAvg%2FPoll-ArcticSIAdailyminimumApril72013_zps9b34f162.jpg&hash=8a3d4ee85b415e3e6738aa16b75827f5)

It seems incredible that the perception of the status of the Arctic could change only 8+ days after this poll has started.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Wipneus 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Andre Koelewijn 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.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Artful Dodger on April 08, 2013, 10:50:18 AM
Hi folks,

Interesting pole results, a classic bimodal distribution:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.indiana.edu%2F%7Estatmath%2Fstat%2Fall%2Fttest%2Fstd_bimodal.gif&hash=f2cd3e16522f17b3a373aac60c3a481e)

How I interpret this is that there are two likely modes in which Arctic sea ice area will proceed in Summer 2013:
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?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Williams 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?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Artful Dodger 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?  ;)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: ChrisReynolds 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
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: DungeonMaster 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 ?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Artful Dodger on April 08, 2013, 10:19:17 PM
Looks like speed wobble, i'd say - or death wobble ?
Yeah, more like a 'death rattle'.  :o
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: NeilT on April 08, 2013, 11:33:31 PM
My analogy for what we are doing would be somewhat more different than the Snowmen.

I'd say it's more like this.  In the 1800's we loaded a pistol with one micro nuke.  Then everyone around the table (the whole planet), takes turns at pulling the trigger.  The chamber is not spun again.  In the first century we pulled the trigger once.  In the second century we pulled the trigger twice.  In the third century we will pull the trigger 3 more times, with the obvious result.

Clearly the only possible option is to stop pulling the trigger and then try to unload the gun.

We haven't stopped pulling the trigger yet!
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: ivica on April 09, 2013, 07:26:22 AM
Joined majority, no special insight on my side.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: werther on April 09, 2013, 10:23:37 AM
I still don't see new developments inclining me to change my 18 February take on this season.
A 'normal' summer 4 Mkm2 SIE/2,5 Mkm2 SIA. A 'dipole' summer resp. 2,6 / 1,7.
I vote 2,3 Mkm2, because I have a hunch this could be a consolidation year (though not necessarily on volume).
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: James Lovejoy on April 10, 2013, 03:24:56 AM
I'm waiting more information before posting my guess.  Right now though, I'm pessimistic.  Maybe someone could show me where I'm getting it wrong, but there's been almost a 700,000 km2 area loss since the high, and from what I've seen, in conditions that weren't that favorable for melting.  That makes me wonder what's going to happen when the conditions are favorable.


Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: werther on April 10, 2013, 10:11:13 AM
Morning James,

I have doubts about my poll prediction too.

When I count in what I (non-scientifically) call ‘winter-power’, based on NCEP/NCAR Reanalysis, this winter wasn’t what the sea ice needed to withstand further desintegration.
Secondly, the fragmentation during Feb-March, so well documented by A-Team a.o., produced some new FYI, albeit the structural weakness it created will enhance summer melt.
Third, an argument brought in FI by Chris Reynolds, the ice now consists mainly of FYI. My rough calc is that this counts for 95% of the 13.7 Mkm2 pack at 10042013.

Last year, based on that winter, I suggested the largest melt through spring in the satellite era, melt out of the Svalbard/Severnaya Zemlya sector and a record loss.

So why not again?

I’ve been closely following global weather patterns since last September. I’m influenced by several aspects.
One, the storage of heat in deeper ocean layers, accomodated through a flipflopping ENSO/THC. The sea level rise in line with that.
Two, the distribution of SST anomaly: positive in the central Atlantic, the Indian Ocean and the sub-Antarctic region. Also, the AO period has brought SST’s in the Barentsz Sea further down than we were used to in the last years.
Three, continued blocking events and a reversed AO (positive) could in the context help shifting the brunt of climate change consequences to other regions, affecting the Arctic less exclusive as last year (but still ravaging southern Greenland, I fear).

I hate to be a pessimist for such regions. But I hold my breath for the mid-latitudes, the Caribbean, Southern Asia this summer. On top of that, I wonder what winter Antarctica will experience (anomalously warm?).
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: werther on April 11, 2013, 10:27:46 AM
On the other hand….

When these are compared, my doubt over the next melting season grows…

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1036.photobucket.com%2Falbums%2Fa446%2Fhanver1%2FArctic%2520ice%25202013%2FComparisonday100100420122013small_zpsb12c9852.jpg&hash=5c39e9dcb139c6487f02e4f9859ffb75)

There’s more ice in the Frantsa Yosefa region….
But the quality overall seems a lot worse…

I reset my area prognose to 2.0 Mkm2, assuming that no matter what weather, 98% of the FYI will melt out.
That leaves weather to decide whether the remains of the more or less continuous “mesh-pattern”  pack from September ’12 will spread or hold together.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Artful Dodger on April 11, 2013, 11:55:03 AM
I’m influenced by several aspects.
One, the storage of heat in deeper ocean layers
Two, the distribution of SST anomaly
Three, continued blocking events and a reversed AO
Hi werther,

Thanks for that summary. To that, I would add +1 W M-2 for the 2013 solar maximum, and another 2 or 3 W M-2 for black carbon (ie: Siberian forest fires). Over the ~14 M km2 of the Central Arctic ocean, that's a lot of heat applied to the sea and ice.

Now 2012 raises the chilling prospect ;) of another large source of heat: hot dry offshore winds from Continental heat waves crossing the Arctic coast, picking up moisture and turning into GAC2013.

Much of this is fundamentally unpredictable, except in the probabilistic sense. However like a coin, it must come down either heads or tails. I believe i will watch the Sunset, listen to some Stravinsky, and cross my finger tonight.

Igor Stravinsky conducts final of Firebird (http://www.youtube.com/watch?v=XTep91oqgVk#)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: werther on April 11, 2013, 12:07:18 PM
Hi Lodger,

I love The Firebird. It was written four years before the end of 'La belle époque' and people didn't have an idea of what was soon to come.
Seems very appropriate!
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Artful Dodger on April 11, 2013, 01:02:59 PM
I love The Firebird. It was written four years before the end of 'La belle époque' and people didn't have an idea of what was soon to come.
Seems very appropriate!

Oui, a propos Matthieu 24:42
Quote
Tenez-vous donc en éveil, puisque vous ignorez quel jour votre Seigneur viendra.
Par conséquent, l'esprit est éveillé et alerte.  ::)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: gfwellman on April 11, 2013, 08:07:33 PM
Isn't the "good thing" about black carbon and sea ice that there's effectively no accumulation?  Almost all soot from 2012 fires that fell during the 2012 melt season would have washed off with meltwater.  Yeah, some would have managed to "stick" to the surface of MYI.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Artful Dodger on April 12, 2013, 10:16:40 AM
Isn't the "good thing" about black carbon and sea ice that there's effectively no accumulation?
Hi gfwellman,

I don't know. But I do expect a repeat of Siberian forest fires during Summer 2013, so I don't think lack of accumulation of black carbon is an issue. BC is just treated as a short-lived pollutant in the Arctic. It is the instantaneous forcing that matters for the surface heat budget, comparable perhaps to the way water vapour is treated.

Here's a paper on the topic of short-lived pollutants, including black carbon (PDF available through the link):

Quinn et.al (2008), Short-lived pollutants in the Arctic: Their climate impact and possible mitigation strategies (http://www.atmos-chem-phys.net/8/1723/2008/acp-8-1723-2008.html), Atmos. Chem. Phys., 8, 1723-1735
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: gfwellman on April 12, 2013, 10:31:57 AM
Quote
I do expect a repeat of Siberian forest fires during Summer 2013
Definitely the forcing will be there if that happens.  Why do you expect it?  Just the general trend to warmer, drier conditions in Siberian summers?  That seems reasonable, but some experts considered the 2012 fires to be unusually extreme.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Artful Dodger on April 12, 2013, 11:21:25 AM
Why do you expect it?  Just the general trend to warmer, drier conditions in Siberian summers?  That seems reasonable, but some experts considered the 2012 fires to be unusually extreme.

Just the new normal, and the progressive warming/thawing of the permafrostmelt.

What I actually expect is for the fires to get worse and peat to get involved. Probably methane too.  :(
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Shared Humanity on April 12, 2013, 04:55:11 PM
Why do you expect it?  Just the general trend to warmer, drier conditions in Siberian summers?  That seems reasonable, but some experts considered the 2012 fires to be unusually extreme.

Just the new normal, and the progressive warming/thawing of the permafrostmelt.

What I actually expect is for the fires to get worse and peat to get involved. Probably methane too.  :(

Over the last couple of decades, Florida has had enormous peat fires due to drought, caused by lightning strikes. In some cases the smoke from these fires have nearly transected the central part of Florida, shutting down interstates. I'm not sure whether drought in Siberia is a near term risk from global warming but, if it is, I would expect fires to get worse.

And I draw little comfort by the fact that "some experts considered the 2012 fires to be unusually extreme." After all, some experts consider the loss of sea ice in 2010 to be unusually extreme. Oh, and some experts consider the drought in the plains states to be unusually extreme. Isn't "unusually extreme" what we are expecting from AGW?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Shared Humanity on April 25, 2013, 07:13:00 PM
Pacific side SIA, Bering and Okhotsk (OK...Hot...SKedaddle) Seas, is shrinking fast.....

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.14.html (http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.14.html)

What's driving this?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Vergent on April 25, 2013, 07:39:28 PM
Pacific side SIA, Bering and Okhotsk (OK...Hot...SKedaddle) Seas, is shrinking fast.....

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.14.html (http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.14.html)

What's driving this?
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Farctic.atmos.uiuc.edu%2Fcryosphere%2FIMAGES%2Frecent365.anom.region.14.jpg&hash=718354e05d8f6593557d843128062128)The anomaly is not significantly increasing, so this is normal loss rate.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: SteveMDFP on April 25, 2013, 09:25:50 PM

 But I do expect a repeat of Siberian forest fires during Summer 2013, so I don't think lack of accumulation of black carbon is an issue. 

I'm with Lodger-Dodger on this.  For a slightly different reason.  I followed the fires pretty closely last summer, and the area that seemed most devastated seems to correspond with low snow cover now.  One of the darkest land areas on the MODIS Arctic mosaic, thus with least snow cover, is near Yakutsk and the Lena river.  I really can't proclaim that this is necessarily unusual, I"m not that much of an expert, but I'd think most of Siberia should look pretty white over winter, and this area never got whiter than it is now on the mosaic:
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Peter Ellis on April 25, 2013, 11:08:27 PM
What's driving this?
Spring :-)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Agres on April 26, 2013, 03:26:31 AM
For more than a year, I have expected the 2013 Arctic sea ice curves to fall off the charts. This summer we start saline intrusions and storm mixing. Come next fall, all that we will have for seed is some "bergy bits". 

Last year, the Barents barely froze, and next season, I expect the Kara to join that barely frozen category.  Thus, in 2014, I expect significant melt by 21 June.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Pettit on April 28, 2013, 04:09:28 AM
Very late, CT SIA has been updated; area decreased by 100,000 km2 yesterday.

--That's the third century drop in as many days. The last time that happened was August 1-3 of last year.

--Area is currently 401k less than it was on this same date last year. If area were to behave this year exactly as it did last year after this date, SIA would bottom out at about 1.83 million km2.

Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: wanderer on April 28, 2013, 11:51:25 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Farcticicespddrfnowcast.gif&hash=0cda48db52e205f5a15acbce8f6e0387)

Action!
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: crandles on April 28, 2013, 03:03:41 PM
Very late, CT SIA has been updated; area decreased by 100,000 km2 yesterday.

--That's the third century drop in as many days. The last time that happened was August 1-3 of last year.


Now 4 centuries in 4 days

2013.3069  -0.2430956  12.7934523  13.0365477
 2013.3096  -0.3252518  12.6753159  13.0005674
 2013.3124  -0.3962290  12.5647573  12.9609861
 2013.3151  -0.4486383  12.4647274  12.9133654
 2013.3177  -0.5220118  12.3415442  12.8635559

Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven on April 28, 2013, 03:15:27 PM
I think this is mostly coming from Bering and Barentsz. I was expecting more of Baffin and Beaufort, but not much going on there as of yet, area-wise.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Vergent on April 28, 2013, 04:10:40 PM
Now 4 centuries in 4 days

2013.3069  -0.2430956  12.7934523  13.0365477
 2013.3096  -0.3252518  12.6753159  13.0005674
 2013.3124  -0.3962290  12.5647573  12.9609861
 2013.3151  -0.4486383  12.4647274  12.9133654
 2013.3177  -0.5220118  12.3415442  12.8635559
We are losing 322 acres per second.

V
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim on April 28, 2013, 05:19:12 PM
Just a cautionary guys, the ice usually melts quickly at this time of year! The ice area decline is about the same as last year, and 2011, and 2010 - 2008 saw an even greater drop! Heck, even 1990 saw a similar drop AND the absolute area was smaller in 1990!  ???
Let's not get too carried away  ;)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Pettit on April 28, 2013, 06:46:10 PM
Just a cautionary guys, the ice usually melts quickly at this time of year! The ice area decline is about the same as last year, and 2011, and 2010 - 2008 saw an even greater drop! Heck, even 1990 saw a similar drop AND the absolute area was smaller in 1990!  ???
Let's not get too carried away  ;)

Well, I don't think anyone's getting "too carried away" (whatever that means). We're just talking statistics, that's all. Yes, there have been previous years with lesser or greater SIA loss by this date. But there's something to be said for the fact that since this year's maximum, half-a-million more square kilometers of area have been lost than had been lost by this same day last year--and last year was, as you'll remember, a really bad one for ice. (In fact, if the rest of this year behaves exactly as it did last year, this year's minimum would bottom out at less than 1.8 million km2.) Too, it's unusual to see four consecutive century breaks at this time of year; that didn't happen during last year until peak melt in mid-June. So, again, no one is getting "carried away"; we're just talking about something of obvious interest.  :)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven on April 28, 2013, 06:57:06 PM
I think this is mostly coming from Bering and Barentsz. I was expecting more of Baffin and Beaufort, but not much going on there as of yet, area-wise.

Sorry, caught carried away there!  :D
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: OldLeatherneck on April 28, 2013, 07:03:11 PM
While the losses in the past few days have been significant and I certainly expect records to be set in all three categories (Extent/Area/Volume), I am waiting to see what both SIE & SIA are doing toward the end of May.  Those measurements, as well as a view of how badly the fracturing has broken the ice floes, will determine whether it's time to get excited.  If we are weeks ahead of previous years when the sun starts shining 24/7 in the Arctic, we will be in for a rough ride towards the bottom.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim on April 28, 2013, 07:28:47 PM
As OLN says, the time to get excited will be later - if the cracks and leads result in rapid melting in May/June.
At the moment, though, the reduction in ice area is reasonably normal for this time of year. Indeed, in 1990 the loss from area-maximum to day 116 was 1.76 times greater than this year, so we have seen much greater falls in the historic record.
I'm just concerned that some folks may be 'over egging the pudding', so to speak, when in fact nothing out of the ordinary is actually occurring (for now - time will tell).
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven on April 28, 2013, 07:51:25 PM
No need to be concerned as of yet, Jim. Or have I missed someone putting to much eggs in this pudding thread?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: SteveMDFP on April 28, 2013, 08:03:46 PM
No need to be concerned as of yet, Jim. Or have I missed someone putting to much eggs in this pudding thread?

The proof of this pudding will be in August.  Of this, I am eggsactly cock-sure.  No yolk.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: OldLeatherneck on April 28, 2013, 08:12:37 PM
................have I missed someone putting to much eggs in this pudding thread?

Neven, there are so many cooks in this kitchen that some days you get Chateaubriand and some days you get Hash!  That's why dining here, on a daily basis, is such a culinary delight.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim on April 28, 2013, 11:31:07 PM
SteveMDFP - eggsactly! LOL  ;D
But you are right, along with OLN, the result of this year's 'cooking' will be manifest later. This time of year is always a bit frustrating (as is the autumn) as there is little going on. This time next month, perhaps, we might have a better idea as to whether another record-breaking melt is on the cards (or plate, to continue with our culinary metaphor  ::) ).
Cheers!
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Pettit on April 29, 2013, 10:43:27 AM
SteveMDFP - eggsactly! LOL  ;D
But you are right, along with OLN, the result of this year's 'cooking' will be manifest later. This time of year is always a bit frustrating (as is the autumn) as there is little going on. This time next month, perhaps, we might have a better idea as to whether another record-breaking melt is on the cards (or plate, to continue with our culinary metaphor  ::) ).
Cheers!


But even 1990 with its big early drop (and subsequent slow down) didn't manage to put together a string of four consecutive century breaks until the first week of June. In fact, it didn't even see three straight century breaks until then. This year, on the other hand, has just finished doing so, right here in April. (I haven't performed an analysis on every year in the dataset, so I don't know whether or how rare it is. I only know that it didn't happen in either 2007, 2012, or--thanks to your prompting--1990.)

Now, I'm not saying that this recent four-day string can be extrapolated to mean that we'll definitely see a massive loss from here on out, nor do I think anyone else is saying that, either. Hell, area could increase by half a million km2 over the next week for all we know. We're just talking about a decrease of interest during a time of year in which, as you yourself stated, there's not much going on. No hyping, no unhinged excitement, no "over-egging".  Just talk, that's all. ;)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven on April 29, 2013, 11:00:56 AM
Jim, according to my spreadsheet 2010 also saw 4 consecutive breaks from April 11th to 14th, and then another one on the 16th. 2007 had 6 century breaks in a 9-day period in April as well.

At this point last year 2012 had the highest total area, but in the next 4-5 weeks dropped precipitously. This year is currently half a million km2 lower than that, so it'll be interesting to see if that pace can be repeated. I don't see why not, with Baffin and Beaufort being held up due to low temps. As soon as temps go up and insolation comes more into play, I'm expecting big losses there.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven on April 29, 2013, 11:14:28 AM
And another one. Five in a row...
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Pettit on April 29, 2013, 12:41:49 PM
Jim, according to my spreadsheet 2010 also saw 4 consecutive breaks from April 11th to 14th, and then another one on the 16th. 2007 had 6 century breaks in a 9-day period in April as well.

At this point last year 2012 had the highest total area, but in the next 4-5 weeks dropped precipitously. This year is currently half a million km2 lower than that, so it'll be interesting to see if that pace can be repeated. I don't see why not, with Baffin and Beaufort being held up due to low temps. As soon as temps go up and insolation comes more into play, I'm expecting big losses there.

I agree with everything else you said, but I just checked--and double-checked--and see that 2007 had but a single century drop in April. However, 2008 did indeed see six century breaks, all of them during a nine-day period--and then failed to produce a stretch with four (not to mention five) consecutive century breaks after that. Though I could be wrong--which wouldn't be the first mistake I ever made. ;)

Now I'm going to have to comb through my spreadsheets and look at all the years to see how many five-day century drops there have been outside the month of June. I'm willing to bet they aren't all that common...
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Pettit on April 29, 2013, 02:37:56 PM
Okay, I have gone back through the dataset, and it looks as though four consecutive SIA century breaks have happened in April just three times before this year: in 1986, 1999, and (as Neven noted earlier) 2010. 2013 is the first time there have been five consecutive century breaks not just before May, but before June. And that's never happened before in any month outside of June or July.

Again--and now I feel I have to use a disclaimer less I be accused of "egging"  :) --I'm not saying this is necessarily indicative of future performance. I'm simply pointing out an interesting statistical anomaly.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven on April 29, 2013, 02:43:32 PM
Thanks for checking, Jim P! Basing myself on IJIS I don't think we'll see another CT SIA century break tomorrow, but who knows?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: crandles on April 29, 2013, 07:27:57 PM
Don't forget to get your votes in if you haven't already done so. Not much time left - Less than 12 hours.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Ice Cool Kim on April 29, 2013, 10:55:38 PM
I'm going to invoke annual alternations to suggest this year's (smoothed) melting period will be longer than last years ( which was already the shortest since 1985 according to my graph). Though one would expect shorter melting season to be good, I don't see a direct effect on area.

https://forum.arctic-sea-ice.net/index.php/topic,174.msg2793.html#msg2793
I'll guess that method will produce about 0.495 this year.

Then I have rate of change of ISST small  but positive looking like it's bottomed out on latest swing. So small melting push from that end.
https://forum.arctic-sea-ice.net/index.php/topic,234.msg4250.html#msg4250

Ice area acceleration should be back up near the next max by sept 2013.
https://forum.arctic-sea-ice.net/index.php/topic,266.msg4786.html#msg4786

Max +ve accel happens at a minimum (trough) in area. So this year will be lower that last year but should bottom out, leading to a (weaker) 2008 style recovery next year.


That's my reading of the tea leaves but I'm not going to 'vote' since I think a daily minimum is a worthless metric of the general trend which ultimately is what everyone is interested in.

Monthly averages are also clumsy crude attempts at filtering out short term weather. What we should be doing to examine progression of minimum of the annual cycle is using something like the 14 day HWHM gaussian filter I used in deriving the melting season here:

https://forum.arctic-sea-ice.net/index.php/topic,174.msg2660.html#msg2660

That produces a nice smooth annual cycle with a relatively 'weather' free minimum area and more objective turning point data.






Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Anne on April 29, 2013, 11:48:03 PM
It's interesting that people tend to avoid "Between 1.0 and 1.25 million km2". What's that about?
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Ice Cool Kim on April 30, 2013, 12:03:24 AM
I don't think it's a case of avoiding.

There is a statistically 'normal' spread of opinion around 1.75-2.00  plus the OMG vote that would probably have gone for 0.00 if it was in the list.

DM described this as "classic bimodal" but the lower category lacks the spread. It seems more like a spike.  Maybe if there were values all the way down to zero he would have got spread around some lower value.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: SATire on April 30, 2013, 09:44:13 AM
Hi Anne,
the 0-1 million km2 bin is prefered over the 1-1.25 million bin, because the larger bin is more likely. It is not out of distribution if you consider them as a "4 bins at the price for one".

Instead the peak at 1.75-2 million mk2 is very large and statistically significant out of any distribution. Maybe some poeple got psychologoly trapped by the disclosure of the histogram on 7th April - maybe poeple just went with the majority since then... Such things are called systematic bias.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Anne on April 30, 2013, 10:48:42 AM
Thanks, ICK and SATire. Makes sense!
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Ice Cool Kim on April 30, 2013, 12:34:28 PM
Quote
Maybe some poeple got psychologoly trapped by the disclosure of the histogram on 7th April - maybe poeple just went with the majority since then... Such things are called systematic bias.

Yes, that was a bit unfortunate (and unhelpful).

However, I think going for 'like last year but a bit less' is a fairly obvious play and it's not surprising that's the centre of the distribution. I suspect if there was another that tried to guess summer max for N. Atlantic SST the results would be very similar.

Rendez-vous early October to see who needs to adjust their perceptions of what is happening to arctic ice.

Though I doubt anyone suggesting the imminent collapse of arctic ice will not be deterred, they will just predict it will happen next year instead.
 

Looking at the actual numbers outside the 5 central intervals, there are 11 votes below and 9 above. So accepting SATire's point about 4-in-1 it is a pretty symmetrical single mode distribution.

Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Jim Pettit on April 30, 2013, 01:50:12 PM
I doubt anyone suggesting the imminent collapse of arctic ice will not be deterred, they will just predict it will happen next year instead.

I'm sure. Just as I doubt anyone denying the imminent collapse of arctic ice will be deterred when the ice finally does disappear; they will just call it a fluke, then produce a handful of wonky charts and graphs showing that the ice isn't really gone, and will at any rate most likely be back very soon...

Rendez-vous early October to see who needs to adjust their perceptions of what is happening to arctic ice.

Yes, let's do that.  :)
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Ice Cool Kim on April 30, 2013, 02:41:26 PM
Quote
they will just call it a fluke, then produce a handful of wonky charts and graphs showing that the ice isn't really gone, and will at any rate most likely be back very soon...

LOL, I'm sure there will be some folks that would say that too.

If your 'wonky graphs' comment was supposed to refer to my posts here, you may take the time to note that I used my wonky graphs to suggest further loss this year.

If some of those working on this stuff could get beyond fitting arbitrary straight lines to 'chaotic' systems we would probably have a much better understanding already.

Here's another wonky graph showing that much of the inter-annual variation is due to an internal 2 year oscillation modulated by an external 12.8 year driver, possibly N. Atl SST.
https://forum.arctic-sea-ice.net/index.php/topic,266.msg4869.html#msg4869
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Sigmetnow on May 02, 2013, 01:48:10 AM
2013 is the first time there have been five consecutive century breaks not just before May, but before June.

I noticed significant changes in Barents Sea ice (thickness) during this time.
Title: Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
Post by: Neven on May 02, 2013, 12:18:27 PM
May poll is up (http://forum.arctic-sea-ice.net/index.php/topic,272.0.html).