1611 replies to this topic

[Thundery wintry showers]

Another thread for insights into, and discussions of, issues relating to sea ice, including the monthly/daily Arctic sea ice extent as we head into the main period of melt.

[Gray-Wolf]

Just to keep us updated. We are just about to sink below the 10 million sq km mark and the 'melt proper' is yet to begin!!!

We heard a lot in March/April of 'how well' the ice was doing but this only went to serve as a warning that ice is a 3 dimensional (not two) thing and that without depth it melts very quickly come summer.

We now have IceBridge and CryoSat2 ,taking real time thickness measures, and so by summer's end we'll have a much better idea as to how well the ice is fairing this year.

Recent acceleration in mass loss across the Arctic has some worried that we are beyond the point that ice can rebuild to past levels without the intervention of an ice age (which could be 2 processional circuits away!!!) and Dr Barbers discoveries of the 'chameleon ice' may prove key as if we find a percentage of what we took to be 'good ice' as rotton ice then we are much further down the road to 'ice free' than we knew.

[kold weather]

I feel we are going to have a big melt this season, there is huge amounts of warmth in the Atlantic right now, esp south of 30N and whilst some think the La Nina developing may put a cap on how low things will go I think the lag effect will be too long to make much of a difference this summer on the ice cap, and instead it'll be the tropical season and the huge warm Atlantic anomalies which will tell the tale this summer up there.

[Thundery wintry showers]

High pressure over the pole at the moment- bad news for ice retention, the same synoptic setup was common during the summer of 2007:
http://www.netweathe.../00/npsh500.png

However, synoptics out to about T+120 suggest the high becoming displaced to the west with cold pooling bottled up over the ice mass, therefore turning much more favourable for ice retention:
http://www.netweathe...132/npsh500.png

[masheeuk]

I have been looking at a site for PIOMAS and they are predicting things to be worse that 2008 but not down to 2007 levels. I think everyone is right to be concerned this year.

[Gray-Wolf]

Well looking a JAXA's slow wind into melt season proper I'd not be so convinced that we''l not see a sub 4 million end to the season!!!

It hinges on weather and 'rotten ice'. If Dr B's discoveries are true across the Basin (and not just southern Beaufort) then there will be a lot of ice that used to form part of the 'final figure' that is going to melt out this year. If we also use a bit of nous and figure the way this collapsing ice used to spread out (over 8 times it's area prior to collapse) then we can see that there is a sizable chunk of the 'old extent' that is now not going to occur this autumn.

Do we see the NW Passage ,deep channel, open this year?

[Gray-Wolf]

A fellow 'concerned' chap posted this over on another site. It shows Nares from june 3rd to 15th. If you track the 'big chunk' of ice you'll see it didn't log jam the straight but rather just collapsed???? Is this thin ice or rotten ice?

[4wd]

The rotten ice term currently in vogue to use at every opportunity is rather amusing.
It seems to stem from a certain 'stance'.
There's nothing new or unusual about this type of ice being widespread, and breaking up quite rapidly in the spring thaw.

[Solar Cycles]

4wd, on 21 June 2010 - 18:53 , said:

The rotten ice term currently in vogue to use at every opportunity is rather amusing.
It seems to stem from a certain 'stance'.
There's nothing new or unusual about this type of ice being widespread, and breaking up quite rapidly in the spring thaw.

You mean ice melts in summer! Well blow me away, here's me thinking this was some kind of phenomenal event. It's rather amusing watching those warmers clutching at every straw to keep the faith. As I say every year, lets see what September brings!

[Gray-Wolf]

To bring our understanding of the recent 'vogue' of using the term 'rotten ice' into clearer perspective it is currently used, post Dr Barbers discoveries, to describe ice that showed up as 'old perennial' on the sat. maps released by the Canadian ice service and turned out to be thin 'rotten' ice.

If you look up 'rotten ice' you'll find it generally describes lake ice in the melt season and seeing as Barbers study was in the southern Beaufort seas you'll see that his 'rotten ice' is not lake ice at all but the possible chamelion like ice that was old perennial but which then collapsed into teeny bits which was then frozen into a matrix of FY ice.

Since 07' we could have lost a great deal of our existing perennial without knowing it due to it giving resposes identical to perennial which has not collapsed. At the End of Barbers mission he witnessed the collapse of a mighty chunk of old perennial over a half hour period.........lots of 1/2 hour periods at the end of melt season!

[stewfox]

Gray-Wolf, on 22 June 2010 - 07:21 , said:

Since 07' we could have lost a great deal of our existing perennial without knowing it due to it giving resposes identical to perennial which has not collapsed. At the End of Barbers mission he witnessed the collapse of a mighty chunk of old perennial over a half hour period.........lots of 1/2 hour periods at the end of melt season!

I know IJIS is not an ideal measurement but it seems to be one we use, on here at least.

How is that Satellite doing re volume data ? .

http://www.ijis.iarc...nt_L.png<br />

This report suggest ice volume up 25% since May 2008


http://wattsupwithth...since-may-2008/

Edited by stewfox, 22 June 2010 - 08:09 .

[4wd]

stewfox, on 22 June 2010 - 08:09 , said:

This report suggest ice volume up 25% since May 2008


http://wattsupwithth...since-may-2008/

I only look at Watts occasionally and hadn't seen that so thanks.

Quote

A few weeks ago, when extent was highest in the JAXA record, our friends were asking for “volume, not extent.” Their wishes have been answered. Ice volume has increased by 25% in the last two years, and those looking for a big melt are likely going to be disappointed.

Edited by 4wd, 22 June 2010 - 08:36 .

[Climate Man]

I am a "denier" but for the first time ever I share the concerns of GW, however I do believe that their will be dramatic changes in the autumn that will reflect the changing conditions in the Pacific.

[Gray-Wolf]

Sorry that you find yourself in such an uncomfortable position C.M.!!!

As for the Pacific I'd been mooting the impacts on the temperate zone weather/climate patterns of the growing Arctic Amplification. For the first time this June the conference in Oslo looked at the past few winters (the AO negativity) as being driven by the loss of ice across the pole. If this proves accurate then the wind/current movements could now be being driven by the alterations at the root of the worlds weather/climate system in the Arctic (the 'weather maker').

The failure of the PDO to manifest a consistent negative may well have a lot to do with the overturning of the cold upwelling along the NW coast of the U.S./Canada by wind driven warmer waters/surface warming due to reduced cloudiness. Our current Bath hot Atlantic may also have had some of it's influence in the 'extreme weather patterns' across the pole this year (and a dollop of Nino') so we will have to wait and see.

Though solar min is ending and ENSO is now neutral any return to a similar synoptic this winter (big AO-ve) will lend even more weight to the argument that ice loss (and the heat absorbed by the exposed 'Dark Water') is now playing an ever bigger role in the weather of the N.H. and it's climate.

[Devonian]

Gray-Wolf, on 21 June 2010 - 17:56 , said:

A fellow 'concerned' chap posted this over on another site. It shows Nares from june 3rd to 15th. If you track the 'big chunk' of ice you'll see it didn't log jam the straight but rather just collapsed???? Is this thin ice or rotten ice?

Interesting, because normaly the Nares get blocked by these kinds of chunks but that this chunk may be one of Barber's structually weak(end) multi year ice perhaps?

[Gray-Wolf]

Devonian, on 22 June 2010 - 13:42 , said:

Interesting, because normaly the Nares get blocked by these kinds of chunks but that this chunk may be one of Barber's structually weak(end) multi year ice perhaps?

This was my thinking. The 'old perennial' that formed most of the Archipelago was in 'channels' and so could remain in place, like shore ice, for decades. With it's melt back from the shore lines it has been collapsing, due to 'offloading' as well as warming ever since (you have to wonder at the 2m slabs that Dr Barber saw the perennial flow calve into?). By now you'd expect that the type of old ice/new ice thin skim combination to be ever more common both in the Beaufort sea and across the Archipelago (where the majority of the perennial used to be found) as the ice volume continues to plummet..

The sad thing is if you look at the shape/colour/size of the piece of ice we see consumed in the clip is a good example of the 'biggest', oldest looking ice all across the Arctic basin (as a squiz with the Modis site helps show

http://rapidfire.sci...altime/2010173/ )

[NorthNorfolkWeather]

Gray-Wolf, on 22 June 2010 - 07:21 , said:

To bring our understanding of the recent 'vogue' of using the term 'rotten ice' into clearer perspective it is currently used, post Dr Barbers discoveries, to describe ice that showed up as 'old perennial' on the sat. maps released by the Canadian ice service and turned out to be thin 'rotten' ice.

If you look up 'rotten ice' you'll find it generally describes lake ice in the melt season and seeing as Barbers study was in the southern Beaufort seas you'll see that his 'rotten ice' is not lake ice at all but the possible chamelion like ice that was old perennial but which then collapsed into teeny bits which was then frozen into a matrix of FY ice.

Since 07' we could have lost a great deal of our existing perennial without knowing it due to it giving responses identical to perennial which has not collapsed. At the End of Barbers mission he witnessed the collapse of a mighty chunk of old perennial over a half hour period.........lots of 1/2 hour periods at the end of melt season!

Hi G.W.

What's your take on the 2007 ice low being due to wind pushing the ice out to the Atlantic?

I personally have a problem with the "Rotten Ice" scenario, who did teh measurements and calibration on ice BEFORE "rotten ice" was the vogue

[Gray-Wolf]

NorthNorfolkWeather, on 22 June 2010 - 20:29 , said:

Hi G.W.

What's your take on the 2007 ice low being due to wind pushing the ice out to the Atlantic?

I personally have a problem with the "Rotten Ice" scenario, who did the measurements and calibration on ice BEFORE "rotten ice" was the vogue

2007 was more than it first appeared (IMHO) and was a clue to the stability of the 'old perennial' which had already been in collapse since the 80's. Because the 'reflection' of rotten ice is so close to that of 'old perennial' we kept on plotting it even though portions were rotten and awaiting final melt so we went into 07' thinking the pack was diminishing but not knowing that the perennial was fatally compromised. The clear skies and prevailing wind not only allowed for surface melt to continue but they also 'herded' the remaining ice together to form a close nit central pack (the opposite of 09' when the ice was strewn about by wind/current giving a 'false high' reading of 'ice extent').

Most (if not all) of the final 'extent' figures, through the noughties, were bolstered by the continued collapse of the perennial (IMHO) which spread out on collapse (Barber's ice floe was thick enough to land the chopper on but then collapsed into 2m slabs [offloading?] which will have covered over 8 times the sea surface than the original floe) giving much healthier figures at melt seasons end.

There comes a point where this can no longer happen due to loss of ice.

This year ,should the conditions prove conducive, we may see a sub 4 million minimum (any lower and I have things skewed!) final extent and ,yes, wind and currents will play their part but the final melt out of the 'rotten ice' will also drive a big hole into the 'perennial' amounts.

After watching that time lapse of 'Nares straight' I am ever more convinced of this scenario as the ice island that floats in and gets mangled would have blocked the straight in years past but ,just like Barbers floe, it collapses into nothing. If you take my advice (above) and look around the central Basin ice you'll see that this piece is similar to the largest floes out there and how many of them will act the same through July/Aug???

The Arctic Mosaics (from Modis) are very good at the moment as it is clear and sunny across the Basin.

Edited by Gray-Wolf, 23 June 2010 - 07:27 .

[4wd]

Gray-Wolf, on 23 June 2010 - 07:26 , said:

After watching that time lapse of 'Nares straight' I am ever more convinced of this scenario as the ice island that floats in and gets mangled would have blocked the straight in years past but ,just like Barbers floe, it collapses into nothing. If you take my advice (above) and look around the central Basin ice you'll see that this piece is similar to the largest floes out there and how many of them will act the same through July/Aug???

You're reading too much into this IMO.
It's only a small area and exactly what the ice chunks do when passing through will depend on a range of variables and not a little pure chance.

[cooling climate]

Gray-Wolf, on 23 June 2010 - 07:26 , said:

2007 was more than it first appeared (IMHO) and was a clue to the stability of the 'old perennial' which had already been in collapse since the 80's. Because the 'reflection' of rotten ice is so close to that of 'old perennial' we kept on plotting it even though portions were rotten and awaiting final melt so we went into 07' thinking the pack was diminishing but not knowing that the perennial was fatally compromised. The clear skies and prevailing wind not only allowed for surface melt to continue but they also 'herded' the remaining ice together to form a close nit central pack (the opposite of 09' when the ice was strewn about by wind/current giving a 'false high' reading of 'ice extent').

Most (if not all) of the final 'extent' figures, through the noughties, were bolstered by the continued collapse of the perennial (IMHO) which spread out on collapse (Barber's ice floe was thick enough to land the chopper on but then collapsed into 2m slabs [offloading?] which will have covered over 8 times the sea surface than the original floe) giving much healthier figures at melt seasons end.

There comes a point where this can no longer happen due to loss of ice.

This year ,should the conditions prove conducive, we may see a sub 4 million minimum (any lower and I have things skewed!) final extent and ,yes, wind and currents will play their part but the final melt out of the 'rotten ice' will also drive a big hole into the 'perennial' amounts.

After watching that time lapse of 'Nares straight' I am ever more convinced of this scenario as the ice island that floats in and gets mangled would have blocked the straight in years past but ,just like Barbers floe, it collapses into nothing. If you take my advice (above) and look around the central Basin ice you'll see that this piece is similar to the largest floes out there and how many of them will act the same through July/Aug???

The Arctic Mosaics (from Modis) are very good at the moment as it is clear and sunny across the Basin.

Keep banging the drum GW but its not going to happen. Maybe next year, now that has a familiar ring to it
doesn't it. I'm still optimistic ice area will remain above 2009 levels but we shall see.