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Bad in simulations but even worse in real life


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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......
Sorry, I must have missed something; what are you two disagreeing about?

:o P

I think I may have duplicated your post on Corrinth thread (cryosphere link). I cannot believe that folk are arguing here about trends (or short term trends) when you can see the year on year decline since the 70's (and it's acceleration since mid 80's).

The planet is slow to respond but unstoppable once change is established. Change (IMO) is now established.

By the end of winter the Greenland/Canadian contact with the sea ice may be severed leading to the potential drift of the multi year ice away from the central pole region (into the shallow/warmer regions) further accelerating the decline.

Single year ice will take nothing to ablate, unlike the multi year ice which has some depth and potential to maintain. No matter where the ice extent reaches by winters end it'll all be gone in no time flat if only single year pack.

Soon be time to watch the Ross (even though they've had a proper winter down there this year.....or so it seems) and my crack again. Watching prophesy become flesh is dreary yet interesting and I still think our problems lie with the Ross and it's sudden slippage/collapse.

He-ho, back to my hammock and German beer..........

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Posted
  • Location: Sunny Southsea
  • Location: Sunny Southsea

Naah: by the end of winter, the ice will look much as it has in previous years, but there will still probably be a little bit less of it; did you mean 'by the end of Summer'? Antarctic is still slightly above normal for the time of year. I'd look a bit further along from the Ross sea, around King George VI Island, for the next lot of Antarctic loss; I still can't see the whole of the Ross vanishing quite yet...

:)P

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......
Naah: by the end of winter, the ice will look much as it has in previous years, but there will still probably be a little bit less of it; did you mean 'by the end of Summer'? Antarctic is still slightly above normal for the time of year. I'd look a bit further along from the Ross sea, around King George VI Island, for the next lot of Antarctic loss; I still can't see the whole of the Ross vanishing quite yet...

:o P

Some areas lose ice in a slow predictable way, as with the glacial retreats you mention, some areas catastrophically collapse (as with a dam) and the Ross embayment is one such area. The fact that the loss (or partial loss) has sea level implications is really a side point as the real danger is the unlocking of the glacier fields to it's rear and the implications they place on our Sea Level predictions. At present we hardly notice the rises in sea level (unless you live on an equatorial coral reef atoll) but 2/3m in a year is a different matter.

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Posted
  • Location: Steeton, W Yorks, 270m ASL
  • Location: Steeton, W Yorks, 270m ASL
Naah: by the end of winter, the ice will look much as it has in previous years, but there will still probably be a little bit less of it; did you mean 'by the end of Summer'? Antarctic is still slightly above normal for the time of year. I'd look a bit further along from the Ross sea, around King George VI Island, for the next lot of Antarctic loss; I still can't see the whole of the Ross vanishing quite yet...

:) P

I think the subtle point is in the word "look". I agree that extent should almost recover, and might even bounce back beyond that: the question might be over the overall depth, and so mass.

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Posted
  • Location: Sunny Southsea
  • Location: Sunny Southsea
I think the subtle point is in the word "look". I agree that extent should almost recover, and might even bounce back beyond that: the question might be over the overall depth, and so mass.

Trouble is, there hasn't been a depth survey since Rothrock '99, and until those remote submarines start getting picked up and the data analysed, mass balance is almost impossible to estimate accurately. BTW; if anyone has a boat. next month we might be able to sail right around the Arctic Ocean in a complete circle. When was the last time this was possible?

:)P

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

Hi P3, Just picking up on the notion that an ice free North isn't as troublesome as an ice free south. True enough very little (these days) of the northern ice is grounded ice and so the spectre of rapid sea level rise does not exist but you have to look to the dynamics of an ice free north. Do we get much evaporation from the ice cap compared to what we would expect from all that 'dark water'? I would imagine a whole new type of weather moving down on our northerlies once the air mass is able to saturate itself over the open water.

We saw what an arctic storm can mean to antarctic ice shelf/pack with the breakup of B15b which was effectively fractured and smashed by the swell that travelled down from Bearing. What does an ice free north mean in terms of storm swell (when the 'dampening of ice pack is removed)?

It isn't all about sea level rise ......to me at least.

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Posted
  • Location: Sunny Southsea
  • Location: Sunny Southsea

GW; you misread me. No way do I think an ice free North isn't a problem! I was actually just pointing out that the seasonal variability will see the pack grow again, much as it always has; this doesn't mean that I think the long term trend is not both a direct and an indirect threat. Current thinking is speculating when the hypothesised 'ice albedo effect' tipping-point might kick in; this is the point where the surrounding warming and reduced albedo produces a strong enough feedback that a 'feedback-cycle' kicks in; such an event would be a bad thing.

On the South; I see there are quite a few 'weak spots' in the ice sheets near the coast this year; are you keeping a close eye on the 'polynya watch' sites?

:)P

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......
GW; you misread me. No way do I think an ice free North isn't a problem! I was actually just pointing out that the seasonal variability will see the pack grow again, much as it always has; this doesn't mean that I think the long term trend is not both a direct and an indirect threat. Current thinking is speculating when the hypothesised 'ice albedo effect' tipping-point might kick in; this is the point where the surrounding warming and reduced albedo produces a strong enough feedback that a 'feedback-cycle' kicks in; such an event would be a bad thing.

On the South; I see there are quite a few 'weak spots' in the ice sheets near the coast this year; are you keeping a close eye on the 'Polynya's watch' sites?

:unsure: P

http://www.sciencedaily.com/releases/2007/...70813162438.htm

When you read things like this you start to realise just how bad things already are before any further 'complications' set in.

I'm sorry if I appeared brusque in my earlier reply, I didn't mean too! I just have my own set of concerns about the broader implications of that amount of 'dark water' adding into the already impossible heat budget equations.

From last years paper on the amount of mixing the flagellations of micro organisms cause even things like the nutrient rich erosion pulses of former permafrost coastlines could lead to algal blooms (and population explosions of their predators) which in turn could help influence 'new' cross polar currents bringing warm waters further north even through winter months.

Even the prospect of single year ice build up brings with it it's own set of modelling headaches (smashed 'ice plates ' riding up onto the pack and helping it be better wind driven come springtime etc.)

Sorry again if I mis-read/interpreted your post.

Ian.

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Posted
  • Location: Cheddar Valley, 20mtrs asl
  • Weather Preferences: Snow and lots of it or warm and sunny, no mediocre dross
  • Location: Cheddar Valley, 20mtrs asl
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Posted
  • Location: Cheddar Valley, 20mtrs asl
  • Weather Preferences: Snow and lots of it or warm and sunny, no mediocre dross
  • Location: Cheddar Valley, 20mtrs asl

Positive feedbacks, do we know what we're doing?

http://climatesci.colorado.edu/2007/08/14/...by-roy-spencer/

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

It is starting to look very clear that Greenlands height is the only thing protecting the last vestiges of multiyear ice at the North Pole. It is very worrying to see the decay in multiyear ice opposite Greenland getting ever closer to the geographic pole.

I would now project a new image of summer ice cover only surviving in the 'shadow' to the North of Greenland with it's ablation being purely a function of warming waters (plenty of 'dark water' soaking up the sun up there this year). Sad, very sad.

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Posted
  • Location: Dorset
  • Location: Dorset

The article on the NASA site. http://www.nasa.gov/vision/earth/lookingat...c-20070403.html

Show how thicknesses have declined in recent years.

What's most noticable is that the thickness chart for 2006 so closely resembles the August 2007 ice situation.

People haven't really been paying enough attention to this. The winter total area seems to be going back to normalish levels, but all that's happening is that we are storing up more problems for the following summer.

Could be what's happening down there in Antarctica.

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......
The article on the NASA site. http://www.nasa.gov/vision/earth/lookingat...c-20070403.html

Show how thicknesses have declined in recent years.

What's most noticeable is that the thickness chart for 2006 so closely resembles the August 2007 ice situation.

People haven't really been paying enough attention to this. The winter total area seems to be going back to normalish levels, but all that's happening is that we are storing up more problems for the following summer.

Could be what's happening down there in Antarctica.

I guess people just don't think long enough about it. There is a 'Break point' to look forward to yet when the remaining 'multiyear ice' is no longer strong enough to sustain through winter storm swells (it'll all look fine from sat images and only the spring thaw will reveal the 'changes' to the structure ,there may even be a bit of 'cock-adoodle-doing from the folk who think the 'infill's' between the cracks are showing an overall increase in ice cover/maintenance through early summer). By summers end wind and wave will show the rapidly ablating 'multiyear chunks' as they move apart and vary in their individual melt rates.

As long as warming (relative) waters constantly 'loosen' the parts of the 'multiyear' ice sheet still 'glued' to coastlines/shallows it will finally allow the 'breakaway' and 'drift' of this remaining stronghold of 'multiyear ice' (until it too is submitted to the Bearing Straight melt zone), and the alteration in the rapidity of this 'breakpoint' ablation. All of this seems ,to me, to be very rapidly approaching (not helped by constant/continuous reminders, via the admissions from the folk in the field who,year on year, find other reasons to concern themselves at the increased speed of the phenomena that they thought had modelled when they compare it to what they are witnessing on/in the ice.

The south polar region is different but far more concerning to me (purely for it's potential to cause massive collateral damage,over a very short period of time), when it too fails. The Ross is my major concern and 'water' not initial increased ablation will be the cause of it's failure (water is already +ve in temp unless kept fluid by pressure which brings with it it's own erosional potentials) Ross will go quickly and have it's own 'instant impact' but the monster it unleashes will wreak havoc for over 20yrs allowing no time for action ,only retreat.

Edited by Gray-Wolf
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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

http://arctic.atmos.uiuc.edu/cryosphere/se....movie.2007.mov

Piggin' edit features gone.

Very big file from 'cryosphere today' but 'chillingly' (tee-hee) shows that this year was nearly 'the break point'.

Compare the single year ice, in it's 'circulations, with the block of 'multiyear ice', and it's movements, as it fractures and shears (and starts a 'free northerly drift' in the last few frames?).

Edited by Gray-Wolf
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