Arctic Ice Discussion - 2010 Freeze Up

[Iceberg]

But Mr Pit look at the posts from myself and GW, particularly the conversation I had with Chapman around the cracked state of the ice.

The large cracks allow the ice to spread causing the extent to increase this time of year, the sea water between the cracks can then freeze giving a larger body of ice, however what this leads to is increased sensitivity to WAA and plumes during the melting period. What the ice needs to recover is either the current ice followed by a highly positive AO preventing WAA and high pressure radiative melting or a smaller polar ice cap in winter but more condensed and thicker thanks to a highly positive AO winter...atm the cycles with added warmth are literally killing it.

[4wd]

But Mr Pit look at the posts from myself and GW, particularly the conversation I had with Chapman around the cracked state of the ice.

The large cracks allow the ice to spread causing the extent to increase this time of year, the sea water between the cracks can then freeze giving a larger body of ice, however what this leads to is increased sensitivity to WAA and plumes during the melting period. What the ice needs to recover is either the current ice followed by a highly positive AO preventing WAA and high pressure radiative melting or a smaller polar ice cap in winter but more condensed and thicker thanks to a highly positive AO winter...atm the cycles with added warmth are literally killing it.

It usually starts retreating by now though.

Or does this explanation only apply this year?

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

Having said that 2010 had a similar late growth.

Surely the thinner seasonal ice around the edge would always be able to crack and spread - nothing 'new'.

[Iceberg]

I see your point

But back in the middle of march is wasn't the thinner ice that was cracking it was/still is the thick ice which is unusual, this happen last year but not to the degree of this year.

[BornFromTheVoid]

Using the modis images over the last few days, you can clearly see where the ice is fracturing and spreading towards Novaya Zemlya and leaving a increasingly large area south of the Franz Josef Islands completely ice free. This process has added over 100,000km2 to the overall extent recently.

Gaining ice for a few days into April isn't all that unusual though, happens in many years such as 1988 which gained roughly 120,000km2 between the 31st March and 3rd April. If it continues for more than just another few days or we even manage to reach a new maximum, then this will be exceptional.

Anywho, looks like the ice bridge in the Nares Strait is beginning to give way. Some large chunks broke off yesterday and several more cracks have formed near the edge.

[Gray-Wolf]

Beat me to it BFTV!

http://rapidfire.sci...204500.250m.jpg

The bridge was in place on the 10:30 shot but had given up the ghost by 17:30 (ish)

Makes me wonder if I've been bamboozled by snow cover blown off the glaciers to the East giving the 'appearance' of a solid ice 'plug'? I think I'll bring my 'clear Nares' forward by 1 week to April 8th!

As for the fragment and spread the MODIS Mosaic show this well. For extent to 'stall' yet so much open water/peripheral spread to be visible we must ask how much this reflects the 15% of more per pixel criteria. As in the four years previous I'll predict a rapid decline in ice levels (record losses?) in 4 weeks time. Enough time to have the ice outside the basin float beyond 15% per pixel and interior ice to start proper melt among the initial 'crumbling.

After seeing the paleocrystic ice succumb to the South Beaufort sea last July I have concerns about all the sub 2.5m 'young' ice?

With AO positive (and forecast to go more so) we will not see a lot of 'export' due to calm conditions (check PIPs for this) but a lot of sunshine across the basin. The size and type of ice melting 'in situ' before this year has me worried about the durability of the sub 2.5m ice even without export from the basin.

http://topaz.nersc.n...iable_name=hice

All in all ,don't worry Pit, by july you'll wonder why you ever questioned the scale of this years melt.....even with PDO-ve, feailing La Nina,low solar etc,etc

The Arctic has manouvred itself beyond some of the old 'checks and balances' (IMHO) so we'll continue to see massive summer losses even in synoptics that used to 'nurture' the ice.

Edited April 2, 2011 by Gray-Wolf

[Rob]

Using the modis images over the last few days, you can clearly see where the ice is fracturing and spreading towards Novaya Zemlya and leaving a increasingly large area south of the Franz Josef Islands completely ice free. This process has added over 100,000km2 to the overall extent recently.

Gaining ice for a few days into April isn't all that unusual though, happens in many years such as 1988 which gained roughly 120,000km2 between the 31st March and 3rd April. If it continues for more than just another few days or we even manage to reach a new maximum, then this will be exceptional.

Anywho, looks like the ice bridge in the Nares Strait is beginning to give way. Some large chunks broke off yesterday and several more cracks have formed near the edge.

That can't be good......

[Gray-Wolf]

That can't be good......

not good at all.

The 'Lincoln Sea' end of the straits is already broken and ready to drift. Once the back of the plug (which I think will just rotate off the West coast of Greenland and float into Baffin after todays ongoing collapse....MODIS available after 10:0pm ish?)

If you remember the 'clearing out ' of the Canadian Archipelago last summer you'll understand the ice there is the same as in Nares so we now need to keep an eye on this section through late April/Early May as we'll see just how this ice collapses. I believe that this area will now act as a drain on the Arctic basin 'thick ice' to the N of the C.A. and NW tip of Greenland (depending on drift/wind). This exit is up to 4 times the size of Nares (over 1/2 a fram?). Another 'Exit' for Basin ice is not what is needed right now!

[jethro]

There are losses and gains in different parts of the Arctic; what happens in one area cannot be extrapolated as an indication of what will happen everywhere else.

There's heavy, thick ice in the Gulf of Finland:

http://en.rian.ru/russia/20110328/163243727.html

[Gray-Wolf]

Rapid flow away of the collapse from April 1st. The crack across the bridge looks to be the next to fail

You can see from the ASAR image how little was left of the plug touching shore at the bottom of the image and this connection is within the next calve area.I feel the remainder of the plug will then rotate, clockwise, and disintegrate as it flows into Baffin. Something to watch over the next 5 days?

Jethro , is the 'thick ice' not a product of the Arctic Amplification? The flows out of Fram (and our Arctic plunges) shifted a lot of ice up against those shores. In the same way we are now planning for 1 in 3 winters to be blighted by Highly Positive AO values as the ocean sheds it's heat surely the coastal regions most likely to have accentuated drift ice amounts will have laid plans to deal with it?

I think you are mistaken about 'losses and gains' in the Basin ? There are losses and losses as the data clearly shows. The summer will show us where we are now we have a cleaned out Canadian Archipelago and Beaufort sea free of Paleocrystic. The impact of the Beaufort Gyre, not damped out by Paleocrystic ice and with exits now open into C.A. and out through Baffin makes for a 'novel' season ahead .......but one more indicative of the seasons to come than a reflection of ones past?

[stewfox]

EDIT: My punt for ice min? 3.5 million (extent) + or - 200,000

That would be such a fundemental shift no one could be left in any doubt.

[BornFromTheVoid]

Looks as though the ice has taken quite a hit over the last 2 days or so, with the pre-adjusted IJIS figures showing a drop of around 164,000km2.

With a reversal of the winds which was driving ice towards Novaya Zemlya now occurring and set to last for the foreseeable future, it will be interesting to see how the Barents sea ice extent copes over the next week.

We also have a rather large storm forecast to arrive around the Bering strait in about 4 days time which could do some early damage to the ice in the region.

The coldest upper air is being held in place mainly over the CA and North West Greenland for the next week, but no "mild" surface temperatures encroaching on the Arctic basin anytime soon.

Suppose I'll give my guess for the minimum extent this year, 4,300,000km2!

[cooling climate]

I see G.W. is as keen as ever to spread impending doom and gloom when there

is nothing of the kind on the horizon. Anyway putting that rubbish behind us my

WAG for the coming Arctic melt season minimum is 5.8 million km2,give or take

a couple of hundred thousand.

[Gray-Wolf]

I see G.W. is as keen as ever to spread impending doom and gloom when there

is nothing of the kind on the horizon. Anyway putting that rubbish behind us my

WAG for the coming Arctic melt season minimum is 5.8 million km2,give or take

a couple of hundred thousand.

Hmmm, nothing to see eh? I think we'll re-visit this in sept for both the punt and the assurance

I noted the drop off BFTV. I don't know whether this is a mixture of compaction of spread ice and a bit of 'float off' beyond 15% on the Bering side of the basin. I'm surprised we have not seen the next chunk fall of Nares ice bridge considering the speed with which the debris from the initial collapse has cleared off into Baffin??

[songster]

Since we're now past the minimum and seeing the likely onset of the melt season, is it time for a new thread? We should probably also make a list of the various predictions, prognostications and hasruspications so we can laugh at each other appropriately when we're all proven wrong to varying degrees :-)

My overall feeling is that the overall tale is written in the volume loss - current projections from that have the Arctic ice-free within a few years. However, that won't show up in the extent figures until right at the end when it all goes away very suddenly. The reason for that is simple geometry. Any given piece of ice melts from the outside in, more or less equally in all directions. So, you're starting with ice floes a few metres thick and hundreds of kilometres wide. Shave off a few cm from each dimension at a time, and what happens? The volume goes down but the area stays almost exactly the same until you get to the last few cm, when it vanishes all at once.

In practice, there's a spread of ice thicknesses from <1 m to 3m+, so it won't be quite simultaneous. In addition, once the ice gets really thin, it shatters into slush, which will start to reveal the water below. That leads to a staged collapse, where volume loss shows up first, then area loss, then finally extent loss. Volume is on the way out according to PIOMAS, but area and extent are just about holding up. We saw the harbingers of area collapse at the end of last season, with ice melting through across the entire basin, and open water areas near the Pole that had completely melted out (and it was genuine melt, not opening up of leads)

For extent rather than volume, my prediction is for "a new record, but not startlingly so yet" - let's say 4 million +/- a couple of hundred. Area-wise, I think the collapse may well start in earnest this year - average concentration at the end of the melt season will be either the lowest on record or nearly so.

Summarising extent predictions to date, we have:

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

Any more?

Edited April 5, 2011 by songster

[BornFromTheVoid]

Hmmm, nothing to see eh? I think we'll re-visit this in sept for both the punt and the assurance

I noted the drop off BFTV. I don't know whether this is a mixture of compaction of spread ice and a bit of 'float off' beyond 15% on the Bering side of the basin. I'm surprised we have not seen the next chunk fall of Nares ice bridge considering the speed with which the debris from the initial collapse has cleared off into Baffin??

The drop off continues today, with what appears to be out first >100,000km2 drop of the year. On the IJIS concentration map, it would appear to be mostly coming from the Barents sea.

As for the Nares bridge, with slack winds and the coldest air in the entire Arctic sitting directly on it and looking set to remain for the next week at least, I think it may last quite a bit longer than first suspected.

[Thundery wintry showers]

Summarising extent predictions to date, we have:

stewfox: 6.125 million

cooling climate: 5.8 million

BornFromTheVoid: 4.3 million

songster: 4 million

Graywolf: 3.5 million

Any more?

I'm going for 4.5 million. I think the ice extent might be "saved" to some extent this year by relatively favourable synoptics, especially during the spring, but nonetheless get quite close to the 2007 value. However I think Gray-Wolf's prediction of 3.5 million is a matter of "when" rather than "if" unfortunately, and I'll be surprised if we don't get a minimum that low by 2014.

On a lighter note, I'm hoping that the Arctic sea ice starts missing some blacks off the spot and losing confidence:

http://neven1.typepad.com/blog/2010/06/century-breaks.html

Edited April 5, 2011 by Thundery wintry showers

[songster]

No century break today - saved by the afternoon upward revision (much like yesterday). Suspect we're definitely seeing the start of the melt season though - latest ever winter maximum was 2010 on March 31st, so to go up again now would be unprecedented. They were definitely a bit premature in calling the winter maximum for March 7th at NSIDC though as it bounced up on all measures subsequently. It didn't quite get to a second maximum peak, at least the IJIS figures didn't, but it was certainly a flatter peak than the historical average, and a later onset to the true melt season.

That's hardly unexpected as the melt at the start of the season is usually dominated by lower latitude regions such as the Gulf of St Lawrence, and the ice just never formed there this year, so there's nothing much to melt out.

I'm going for 4.5 million. I think the ice extent might be "saved" to some extent this year by relatively favourable synoptics, especially during the spring

Possibly. I'm expecting record melt through late May and early June though, driven largely by Hudson Bay. It was so late to freeze over that the ice there has to be much thinner and more fragile even than last year.

Edit: Added your prediction to the list.

Edited April 5, 2011 by songster

[Gray-Wolf]

I'm with you on the 'new thread' Songster, I think we are now within the melt/fragmentation season. I'd like to hold onto folks suggestions for ice min though? I've had a lot of confirmations brought to me over these past 4 years by the 'guesses' some of my harsher critics have put forward and a lot of comfort from some of my valued fellows with their 'punts'!

EDIT: http://nsidc.org/arcticseaicenews/2011/040511.html ,just in!

Edited April 5, 2011 by Gray-Wolf

[songster]

I'm with you on the 'new thread' Songster, I think we are now within the melt/fragmentation season. I'd like to hold onto folks suggestions for ice min though? I've had a lot of confirmations brought to me over these past 4 years by the 'guesses' some of my harsher critics have put forward and a lot of comfort from some of my valued fellows with their 'punts'!

How do you mean "hold on to"? The moderator posting the thread doesn't need to do anything - all I'm doing is editing my post as new guesses come in. If it gets buried too far back upthread, I'll make a fresh post if needed. I can keep doing that in this thread if people want, or when someone creates a new thread I can just copy and paste it over. I don't think it's a good idea to ask the moderator who creates the thread to post up the list, since that's also implicitly asking them to continually edit it to keep it up to date, and that's not a fair ask.

Or do you mean you want to be the one to keep track of things? Be my guest if so.

[Gray-Wolf]

How do you mean "hold on to"? The moderator posting the thread doesn't need to do anything - all I'm doing is editing my post as new guesses come in. If it gets buried too far back upthread, I'll make a fresh post if needed. I can keep doing that in this thread if people want, or when someone creates a new thread I can just copy and paste it over. I don't think it's a good idea to ask the moderator who creates the thread to post up the list, since that's also implicitly asking them to continually edit it to keep it up to date, and that's not a fair ask.

Or do you mean you want to be the one to keep track of things? Be my guest if so.

No Songster, It'd just be nice to have a record , if we swap threads, of our first thoughts on the season? There was a time when it'd been much of a muchness with not a lot of years falling below 6 million whereas today?

Instead of looking at 'synoptics' ,for both oceans warmth and air temp, as the control for melt we now have a basin bereft of the old 'backbone' of paleocrystic ice that made up the majority of ice left at summers end. We seem to have a basin full of ice younger than 4 years old and of a thickness that will melt out in an average season?

Some folk are still living in the world of the 'old Arctic' and their punt's betray (to me?) that fact. Come summers end it will be educational , for us all, to see why we put our guesses where we did?

I think we need wait until late June until we'll have any idea as to whose 'understanding' of the impacts of climate shift are most pertinent?

Edited April 5, 2011 by Gray-Wolf

[jethro]

If either of you, or indeed anyone else wants to go through and see what posts you want transferred to a new thread, I'll happily do it. Make a list, send me a PM and I'll do my best to not mess it up.

You're on your own if you want a regularly updated thing going on though....attention span of a gate post with the memory of a fish, it just wouldn't happen...

[songster]

Don't think there's any point copying posts over, I'll just make sure I post up the list and keep it up to date as and when we get a new thread.

[pottyprof]

We did start a new thread for the freeze up so it does seem logical to keep the seasonal stuff in its place.

Melt season 2011 is here.

Will leave this one open for a short while so we can keep this for any further comments regarding the freeze up.