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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: 92

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

Author Topic: Cryosphere Today 2013 Arctic SIA daily minimum: April poll  (Read 66841 times)

Artful Dodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #50 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
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Lodger

NeilT

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #51 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!
Being right too soon is socially unacceptable.

Robert A. Heinlein

ivica

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #52 on: April 09, 2013, 07:26:22 AM »
Joined majority, no special insight on my side.

werther

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #53 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).

James Lovejoy

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #54 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.



werther

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #55 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?).

werther

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #56 on: April 11, 2013, 10:27:46 AM »
On the other hand….

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



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.

Artful Dodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #57 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.

Cheers!
Lodger

werther

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #58 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!

Artful Dodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #59 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.  ::)
Cheers!
Lodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #60 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.

Artful Dodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #61 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, Atmos. Chem. Phys., 8, 1723-1735
Cheers!
Lodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #62 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.

Artful Dodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #63 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.  :(
Cheers!
Lodger

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #64 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?

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #65 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

What's driving this?

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #66 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

What's driving this?
The anomaly is not significantly increasing, so this is normal loss rate.

SteveMDFP

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #67 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:

Peter Ellis

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #68 on: April 25, 2013, 11:08:27 PM »

Agres

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #69 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.

Jim Pettit

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #70 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.


wanderer

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #71 on: April 28, 2013, 11:51:25 AM »


Action!

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #72 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


Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #73 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.
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Vergent

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #74 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

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #75 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  ;)

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #76 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.  :)

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #77 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
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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #78 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.
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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #79 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).

Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #80 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?
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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #81 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.

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #82 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.
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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #83 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!

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #84 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. ;)

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #85 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.
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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #86 on: April 29, 2013, 11:14:28 AM »
And another one. Five in a row...
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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #87 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...

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #88 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.

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #89 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?
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crandles

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #90 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.

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #91 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.







Anne

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #92 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?

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #93 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.

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #94 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.

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #95 on: April 30, 2013, 10:48:42 AM »
Thanks, ICK and SATire. Makes sense!

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #96 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.

« Last Edit: April 30, 2013, 12:39:41 PM by Ice Cool Kim »

Jim Pettit

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #97 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.  :)

Ice Cool Kim

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #98 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

Sigmetnow

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: April poll
« Reply #99 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.
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