646 replies to this topic

[pottyprof]

Well, it doesn't seem like two minutes since the start of the freeze up. How low will we go this year? Is there any sign of a recovery or a more worrying scenario, where the record low of 2007 will be broken?

Continue your discussions here...

[Gray-Wolf]

Thanks Jethro and P.P.!

Surely doesn't seem a long time since we turned the corner into 're-freeze'....but then we had the longest winter in history!!!



We seem to definitely have turned the corner and even with a few 'wiggles' we look to be on the way down now.

Why 3.5 million? Well we will be doing 4 million+ as a min from here on in I guess so it's all a question of the weather conditions across the basin. I'm thinking that last years melt has left the pack more susceptible to melt this year with a lot of 2nd year ice still not braking the 2.5m thickness barrier. All of this ice will melt out (plus the two passages) leaving a lot of warm water at the end of the season to finish off the eroded 2nd year blobs stranded in it.

The inclusion of the NW Passage in the 'outlets' will have it's own impact (by late June this year?) leaving the perennial nursery nearly ice free.

Anyhoo's , 3.5 million it is (give or take 200k).

[songster]

Predictions thus far:

stewfox: 6.125 million
cooling climate: 5.8 million
4wd: 5.75 million
oldsnowywizard: 5 million
NorthNorfolkWeather: 4.8 million
Thundery wintry showers: 4.5 million
BornFromTheVoid: 4.3 million
Iceberg: 4.1 million
songster: 4 million
Graywolf: 3.5 million

Edited by songster, 06 April 2011 - 19:04 .

[oldsnowywizard]

Thicker ice to start with and first year ice which survived last years more open water, warmer world, warmer ssts etc etc my guess 5 million

[NorthNorfolkWeather]

songster, on 06 April 2011 - 08:03 , said:

Predictions thus far:


When I get a moment I'll edit this to have links back to the posts where each prediction was made.

stewfox: 6.125 million
cooling climate: 5.8 million
Thundery wintry showers: 4.5 million
BornFromTheVoid: 4.3 million
songster: 4 million
Graywolf: 3.5 million

4.8 million

[Iceberg]

WRT this years ice extent minimum I would have to go at between 3.8 and 4.8 million ( A wide shout I admit but it all depends on synoptic set ups, a negative AO set up would encourage the lower figure and a positive AO set up the higher).
Allow for this band I would actually go with a mid -AO set up and 4.1 million.

Anything sub 4m is pretty terrible.
So a few extra predictions as well.

40% chance that the geo north pole will be ice free at some point this melt season.
40% chance that 4m will be broken.
20% chance that 3.5m will be broken.
30% chance that minimum ice extent will be inexcess of 5m.

[songster]

NorthNorfolkWeather, on 06 April 2011 - 11:24 , said:

4.8 million

That's Numberwang! :-)

(In all seriousness, it'd be nice to have some discussion on why people pick one number or another, even if it's just "I'm staking out territory nobody's claimed yet")

[stewfox]

Gray-Wolf, on 06 April 2011 - 07:47 , said:

Thanks Jethro and P.P.!

Surely doesn't seem a long time since we turned the corner into 're-freeze'....but then we had the longest winter in history!!!

AMSRE melt.png

We seem to definitely have turned the corner and even with a few 'wiggles' we look to be on the way down now.

Why 3.5 million? Well we will be doing 4 million+ as a min from here on in I guess so it's all a question of the weather conditions across the basin. I'm thinking that last years melt has left the pack more susceptible to melt this year with a lot of 2nd year ice still not braking the 2.5m thickness barrier. All of this ice will melt out (plus the two passages) leaving a lot of warm water at the end of the season to finish off the eroded 2nd year blobs stranded in it.

The inclusion of the NW Passage in the 'outlets' will have it's own impact (by late June this year?) leaving the perennial nursery nearly ice free.

Anyhoo's , 3.5 million it is (give or take 200k).

Glad to see you will using IJIS data

Where will the volume data be coming from ?

My post 6m was a bit tonugue in cheek , I don't expect a post 6m but happy to stick by it.

[Iceberg]

We can put our money where our mouths are here if anybody's interested.

http://www.intrade.c...ntractId=744206

Latest NSIDC view from the 5th of April is available here.

http://nsidc.org/arcticseaicenews/

[BornFromTheVoid]

Latest graph with last 6 years highlighted

[4wd]

I don't see any reason to assume there'll be more melt than last year, nevermind some sort of catastrophic melt.
So my guess would be just under 6,000,000, maybe 5.75
Interesting the three years which had less ice at this point varied hugely at the minimum by September.
What happens is mostly just random weather really, and not predictable by any sensible methodology.

It's very cold in the right places at the moment and the cold is coralled up nicely.
So even if the margins are melting here and there the Arctic Ocean will likely be pretty solid until June.

[songster]

Eh, there's a bit of a gulf between not assuming more melt than last year and what you've done, which is to forecast almost a full million increase over last year. That would be completely unprecedented in the satellite record! Still, I'll put you down for 5.75 - gives us a good spread!

Prediction list updated, now with clickylinks!

Edited by songster, 06 April 2011 - 19:05 .

[oldsnowywizard]

Now now songster that's how issues start by trying to make light of someone's estimate . Let's leave that until the end of sep... 2007 to 2009 had more than a million increase which would be totally unprecedented wouldnt it in todays new ice era ?...ok so yes that's two years but still after 2007 we were supposed to be ice free and in a death spiral were we not ?

[Gray-Wolf]

oldsnowywizard, on 07 April 2011 - 08:37 , said:

Now now songster that's how issues start by trying to make light of someone's estimate . Let's leave that until the end of sep... 2007 to 2009 had more than a million increase which would be totally unprecedented wouldn't it in todays new ice era ?...ok so yes that's two years but still after 2007 we were supposed to be ice free and in a death spiral were we not ?

Lest we forget. In 07' the final 'spine' of Paleocrystic ice was broken (I remember commenting on the 'drift' we saw of the last 'ribbon' of Paleocrystic ice from the north shore of Greenland). Check out the C.T. movie of the 07' melt and you'll see what I mean. Much of the 'excess' ice in 08' came from the 'collapse and spread' (as witnessed by Prof Barber the year after) of this ice (all gone now).

As such we will not see the 'million gain' scenario as we did then as we do not have the ice to 'collapse and spread' anymore?

Edited by Gray-Wolf, 07 April 2011 - 08:52 .

[songster]

Oh, I'm quite prepared for people to giggle at my estimate on similar grounds - the prediction's scarcely the most serious part of the discussion :-)

[songster]

Gray-Wolf, on 07 April 2011 - 08:43 , said:

Lest we forget. In 07' the final 'spine' of Paleocrystic ice was broken (I remember commenting on the 'drift' we saw of the last 'ribbon' of Paleocrystic ice from the north shore of Greenland). Check out the C.T. movie of the 07' melt and you'll see what I mean. Much of the 'excess' ice in 08' came from the 'collapse and spread' (as witnessed by Prof Barber the year after) of this ice (all gone now).

I've never been convinced by your "collapse and spread" argument. As I understand it, your contention is that old ice (10m thick) has spread out into rubble 2m thick, thus covering 5x the area. Although an enticing phrase, it is not what Prof. Barber saw. What he said was, ""As I watched, over the course of five minutes, the entire multi-year ice floe broke up into pieces. This floe was 10 miles across. Something that's twice the size of Winnipeg, it just broke up right in front of our eyes."

"Broke up" does not imply an increase in area or extent: when you fracture your windscreen or dismantle a jigsaw, the sum of the area of the pieces is still the same as the whole. Moreover, to even double the area of that 10-mile floe (let alone 5x "spread" as you've implied before) over the course of a few minutes, that implies an increase of 41% (= sqrt(2)) in linear dimensions in the same time period. The fragments at the edge of the floe would have to be moving outwards from each other at around 60 miles per hour. That's fundamentally unphysical. And, in the context of the "spine" of ice stretching across the basin after '07, completely impossible - where would the collapsing ice expand into, with first- and second-year ice wedged fast all around it over the winter?

The point of Barber's observations is not that 10m slabs of ice are breaking into 2m rubble and thereby covering a wider area, it's that stuff that looks from a distance like it should be 10m thick is in fact only a skim of rotten ice: i.e. the volume has already disappeared.

In summary: collapse yes, spread no.

[stewfox]

Prince Harry came across far more open wated then expected and some cracks apparently , which has delayed his return from the high Artic.

http://www.metro.co....e-runway-cracks

There are of course better references then the metro

[DeepSnow]

Ok its a bit off topic but i didn't want to start a new thread for it!

http://www.bbc.co.uk...onment-13002706

Is this likely or is it more hype? it would be a shame to see it go so soon...

[Gray-Wolf]

A big drop off today (IJIS) before the second update. I wonder where this came from?

[songster]

DeepSnow, on 08 April 2011 - 07:26 , said:

Ok its a bit off topic but i didn't want to start a new thread for it!

http://www.bbc.co.uk...onment-13002706

Is this likely or is it more hype? it would be a shame to see it go so soon...

*shrug* Maslowski's been predicting this since 2008. He's now updated his models and is sticking to the existing forecast of 2016 +/- 3 years. He's (I believe) the only guy running fully coupled water/ice/air models, so in my view it's the best prediction out there.

The BBC reporting is painting it as a retraction of his supposed previous prediction of 2013. All that proves is that they misunderstand error bars. At least he's been more careful this time to control the narrative and not let the reporters run fast and loose with only the lower bound. If you go and read the 2008 prediction it's quite clear it's the same as today's.


Here’s the 2008 link, see page 12: http://soa.arcus.org...ski-wieslaw.pdf

Edited by songster, 08 April 2011 - 10:20 .