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F.Tnioli

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Re: The 2017 melting season
« Reply #3350 on: August 01, 2017, 04:08:26 PM »
...
Thank you Oren. This is how it is done.
You're being harsh to us. Ouch! It hurts! :D
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Pavel

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Re: The 2017 melting season
« Reply #3351 on: August 01, 2017, 04:10:52 PM »
This year is even worse for the Arctic's best MYI than 2012. Almost no thicker than 2m ice will remain except small area north of CAA. Most of the remainig relatively thick ice will prone to exit throu the Fram and the Nares straits in winter. Considering the extremely warm Pacific side the freezing season promised to be exciting

Tor Bejnar

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Re: The 2017 melting season
« Reply #3352 on: August 01, 2017, 04:18:46 PM »
As F. Tnioli posted (an hour ago), Arctic ice volume has not been static since 2007.  Per another thread on this forum (Volume vs Extent), one can see the disconnect between the two measures.  At least one model there supports the idea that extent (and area, for that mater) will drop much more slowly than volume, until the end.  (The calm before the storm...)
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

F.Tnioli

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Re: The 2017 melting season
« Reply #3353 on: August 01, 2017, 04:54:35 PM »
As F. Tnioli posted (an hour ago), Arctic ice volume has not been static since 2007.  Per another thread on this forum (Volume vs Extent), one can see the disconnect between the two measures.  At least one model there supports the idea that extent (and area, for that mater) will drop much more slowly than volume, until the end.  (The calm before the storm...)
Thank you, Tor! I couldn't have said better. In addition, we know from Physics that it is exactly volume of ice which represents energy balance of the Arctic summer: you don't spend X Joules of energy to melt "1 square meter" of unknown-thickness ice, you spend it to melt 1 cubic meter of ice. Which is why whenever one uses the term like "minima" without any specific clarification _which_ metric is being meant, - by default is has to be the volume of ice, and nothing else.
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numerobis

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Re: The 2017 melting season
« Reply #3354 on: August 01, 2017, 05:03:32 PM »
oren: Do you have any math to claim that that the extent trend is flat? Are you (as tamino constantly warns people not to do -- albeit usually on temperature trends) inadvertently modelling a discontinuous piecewise linear trend with a jump in 2007?

The long-term trend will of course be sublinear because you can't get negative extent, and it gets harder and harder to melt the remaining ice. But in the satellite era it appears pretty close to linear.

Unless this season magically stops melting immediately, that's going to continue no matter the precise final value.

Thawing Thunder

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Re: The 2017 melting season
« Reply #3355 on: August 01, 2017, 05:05:45 PM »
So since 2007 it has been mostly first-year ice that melts and then refreezes, leading to a more stable pattern.

That's why I called the choice of the timeframe willfully – and sorry, no harshness intended – because it doesn't show the drop of 2007 itself. It really can create the illusion of a flat graph, especially with the "recovery" of 2013/14 outweighing the "exceptional" low of 2012.

And I don't think the destruction of MYI finished back in 2007, it just started. It's rather the year 2016 that hammered the last nail into the coffin. We'll see the next years – or even this one – how all this is going to play out.
The Thunder was father of the first people, and the Moon was the first mother. But Maxa'xâk, the evil horned serpent, destroyed the Water Keeper Spirit and loosed the waters upon the Earth and the first people were no more.

Daniel B.

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Re: The 2017 melting season
« Reply #3356 on: August 01, 2017, 05:14:22 PM »
If so, could we have entered an era in which the sea ice maxima start falling, but the minima start rising or remain flat?  Afterall, the minima has been flat over the past decade.  Granted the spread has been much greater than previously.
Actually, the last decade, since 2007, HAS been rather flat. And there is an underlying physical reason for the phase shift - 2007 saw most of the multi-year ice (MYI) flushed out, and changed the arctic fundamentally. Due to the warming all around, the MYI has never recovered. So since 2007 it has been mostly first-year ice that melts and then refreezes, leading to a more stable pattern.
However, what you see on the surface (minima rather flat) hides other factors. The weather required to reach the "new normal" minimum used to be exceptionally ice-unfriendly. Last year and even more so this year, it required exceptionally ice-friendly weather just to stay within the norm rather than reach a new record. Last year had a lot of MYI in the Beaufort and ESS that helped prevent a new record when the great cyclone came, this year has no MYI in those areas. So I would say the ice fundamentals continue to deteriorate, even as the headline numbers seem to be stable. This won't last, IMHO.

Thank you Oren.  Some people are so caught up in their own conclusions, that they cannot see straight.  As both you and several posters have commented, the changes in both the winter and summer weather may have been a bigger factor than the overall temperature increase.

Thawing Thunder

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Re: The 2017 melting season
« Reply #3357 on: August 01, 2017, 05:23:38 PM »
Thank you Oren.  Some people are so caught up in their own conclusions, that they cannot see straight.  As both you and several posters have commented, the changes in both the winter and summer weather may have been a bigger factor than the overall temperature increase.

My conclusion is that you better have a look at the whole picture, especially at volume. And no, there's no danger to start squinting by doing it. Give it a try!
The Thunder was father of the first people, and the Moon was the first mother. But Maxa'xâk, the evil horned serpent, destroyed the Water Keeper Spirit and loosed the waters upon the Earth and the first people were no more.

F.Tnioli

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Re: The 2017 melting season
« Reply #3358 on: August 01, 2017, 05:48:23 PM »
So since 2007 it has been mostly first-year ice that melts and then refreezes, leading to a more stable pattern.

That's why I called the choice of the timeframe willfully – and sorry, no harshness intended – because it doesn't show the drop of 2007 itself. It really can create the illusion of a flat graph, especially with the "recovery" of 2013/14 outweighing the "exceptional" low of 2012.

And I don't think the destruction of MYI finished back in 2007, it just started. It's rather the year 2016 that hammered the last nail into the coffin. We'll see the next years – or even this one – how all this is going to play out.
We are starting to see how this plays out, yes. Though i can't agree 2016 was the last nail. Still some MYI is present, and no small amount. Most of it is fragmented into flows of all sizes between thinner FYI, but it's still significant MYI amount. The "soup" thing we see is much because of that. And yes, i intended no harsness as well. Did not mean Daniel B with my joke about flat brains; meant . P.S. Did i say the thing you quoted me saying? I think the honors are not mine.
« Last Edit: August 01, 2017, 06:29:33 PM by F.Tnioli »
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Dharma Rupa

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Re: The 2017 melting season
« Reply #3359 on: August 01, 2017, 05:54:34 PM »
The long-term trend will of course be sublinear because you can't get negative extent, and it gets harder and harder to melt the remaining ice. But in the satellite era it appears pretty close to linear.

I keep seeing it said that "it gets harder and harder to melt the remaining ice," or words with that meaning, but I cannot remember ever seeing an explanation why that might be so.  Seems to me that just like in a margarita, the last of the ice would go quickest.  By then you have run out of cold.

epiphyte

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Re: The 2017 melting season
« Reply #3360 on: August 01, 2017, 05:58:39 PM »
I've noticed that each of those years had warmer the DMI north of 80 temperatures in summer than 2017. This year it still below average for the entire melting season but was above average for the whole freezing season.
...

However, comparing it with 2012...
...

This makes perfect sense to me. Aren't temps uniformly close to but very slightly above 0C just what one would expect give the combination of rapid melt, high insolation, and robust atmospheric  transport/mixing across the 80th parallel?

I don't think it's too simplistic to draw the analogy with defrosting a freezer by directing the airstream from a fan at it. The basement gets cold for a while, but the ice melts 10x as fast as it would otherwise.

Subjectively, there's been a lot of hazy cloud / fog forming quickly over clear areas throughout the season. If spring in Minneapolis is anything to go by, that's what you get above and downwind of a still-frozen but rapidly melting lake on an otherwise hot day.

Dharma Rupa

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Re: The 2017 melting season
« Reply #3361 on: August 01, 2017, 06:09:31 PM »
I've noticed that each of those years had warmer the DMI north of 80 temperatures in summer than 2017. This year it still below average for the entire melting season but was above average for the whole freezing season.
...

However, comparing it with 2012...
...

This makes perfect sense to me. Aren't temps uniformly close to but very slightly above 0C just what one would expect give the combination of rapid melt, high insolation, and robust atmospheric  transport/mixing across the 80th parallel?

I don't think it's too simplistic to draw the analogy with defrosting a freezer by directing the airstream from a fan at it. The basement gets cold for a while, but the ice melts 10x as fast as it would otherwise.

Subjectively, there's been a lot of hazy cloud / fog forming quickly over clear areas throughout the season. If spring in Minneapolis is anything to go by, that's what you get above and downwind of a still-frozen but rapidly melting lake on an otherwise hot day.

Maritime climate.  The Arctic is no longer a desert.

oren

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Re: The 2017 melting season
« Reply #3362 on: August 01, 2017, 06:10:38 PM »
oren: Do you have any math to claim that that the extent trend is flat? Are you (as tamino constantly warns people not to do -- albeit usually on temperature trends) inadvertently modelling a discontinuous piecewise linear trend with a jump in 2007?
I am not modelling anything. The extent trend is very much down, but if you take a chart of just the last 10 years 2007-2016, and just of the extent minima, you will see a relatively flat chart. I have answered the question of a relatively new poster in regards to this "flatness". The ice will do what it wants regardless of my answer, so I didn't feel I was letting it down somehow by acknowledging something which may not mean much but is still there.
In reality volume trend is not flat, the weather provided a saving grace for the last couple of years, and this seeming flatness is not gonna last. 2016 - which despite its poor melting weather passed 2007 and 2011, its severe area crash in August, and its record low refreeze - proved already that things have not rebounded anywhere, stability is far off, and fundamentals are strongly deteriorating.


I keep seeing it said that "it gets harder and harder to melt the remaining ice," or words with that meaning, but I cannot remember ever seeing an explanation why that might be so.  Seems to me that just like in a margarita, the last of the ice would go quickest.  By then you have run out of cold.
It gets hard to melt the remaining ice just because the remaining ice is in higher latitudes in the CAB, where the melting season is much shorter. 2016 was the first year that really breached the center of the CAB, with a huge region of low concentration around the pole. However, it had an early minimum, as that region started freezing in mass around Sept 7th, while more southern ice continued melting. Again, weather will not always intervene for the ice. Should a summer like 2012, 2011, 2007 (and others?) arrive, a new record will be easily made.

epiphyte

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Re: The 2017 melting season
« Reply #3363 on: August 01, 2017, 06:11:33 PM »
I've noticed that each of those years had warmer the DMI north of 80 temperatures in summer than 2017. This year it still below average for the entire melting season but was above average for the whole freezing season.
...

However, comparing it with 2012...
...

This makes perfect sense to me. Aren't temps uniformly close to but very slightly above 0C just what one would expect give the combination of rapid melt, high insolation, and robust atmospheric  transport/mixing across the 80th parallel?

I don't think it's too simplistic to draw the analogy with defrosting a freezer by directing the airstream from a fan at it. The basement gets cold for a while, but the ice melts 10x as fast as it would otherwise.

Subjectively, there's been a lot of hazy cloud / fog forming quickly over clear areas throughout the season. If spring in Minneapolis is anything to go by, that's what you get above and downwind of a still-frozen but rapidly melting lake on an otherwise hot day.

Maritime climate.  The Arctic is no longer a desert.

Yes I think that sums it up quite nicely.

greatdying2

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Re: The 2017 melting season
« Reply #3364 on: August 01, 2017, 06:16:10 PM »
If so, could we have entered an era in which the sea ice maxima start falling, but the minima start rising or remain flat?  Afterall, the minima has been flat over the past decade.  Granted the spread has been much greater than previously.
Possibly, but as you point out the high inter-annual variability makes it impossible to know with so few data points.
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

F.Tnioli

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Re: The 2017 melting season
« Reply #3365 on: August 01, 2017, 06:24:45 PM »
...
Maritime climate.  The Arctic is no longer a desert.
Partially true; oversimplified. The change is gradual. It's still a desert say April, for example. But direction of change is indeed towards maritime climate year-around. We know Arctic ocean had crocodyles inhabiting it in the past. Still we're far from that, for now. Late summer and autumn are much maritime already, yes; even now, Arctic looks much like a part of Pacific system at 850 hPa, for example. Switch to 250 hPa, though, and it's not (yet). Remains of Jet Stream in action...
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Daniel B.

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Re: The 2017 melting season
« Reply #3366 on: August 01, 2017, 06:34:24 PM »
The long-term trend will of course be sublinear because you can't get negative extent, and it gets harder and harder to melt the remaining ice. But in the satellite era it appears pretty close to linear.

I keep seeing it said that "it gets harder and harder to melt the remaining ice," or words with that meaning, but I cannot remember ever seeing an explanation why that might be so.  Seems to me that just like in a margarita, the last of the ice would go quickest.  By then you have run out of cold.

Dharma,
The first ice to go was that furthest from the Arctic land masses, in the North Atlantic and the Bering straits.  This was in closest proximity to the [relatively] warmer waters of the North Atlantci and Pacific.  This has been followed by the ice in the open Arctic.  The warmer waters can inflowing can melt this ice from all sides, similar to the ice in your margarita.  The ice abutting the colder Artic archipelago and Greenland does not experience this same physical condition, as the warmer waters approach from one side only.  That is why this ice will be harder to melt. 

Bill Fothergill

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Re: The 2017 melting season
« Reply #3367 on: August 01, 2017, 06:38:17 PM »
Regarding the highly dubious practice of looking at an extremely short time period (~ 10 years), Ned W has posted some excellent graphs on the Volume vs Extent thread.

There's been some discussion about "flattening" (or not) on the 2017 melt season thread, and up above on this thread as well.  To avoid "broken trends" here are LOESS smoothed versions of the September monthly volume and extent series...

I am somewhat reluctant to give them any publicity, but here is an example of the type of bollocks that the GWPF have come out with in the past. The title of the piece rather says it all...

https://www.thegwpf.com/a-ten-year-hiatus-in-arctic-ice-decline/


What Whitehouse has done is precisely what Thawing Thunder mentioned upthread - hide the enormous 2007 extent loss by starting the "trend" measurement from that date. The 4 largest reductions in the record-lows for NSIDC September extent were...

0.59 million sq kms when 2005 replaced 2002 as the record holder
0.67 million sq kms when 1990 replaced 1985 as the record holder
0.69 million sq kms when 2012 replaced 2007 as the record holder
and
1.27 million sq kms when 2007 replaced 2005 as the record holder

In other words, the amount by which 2007 lowered the previous record was about the same as the next two biggest reductions combined. Starting from that date is the Arctic sea ice equivalent of taking surface temperatures from 1998.

Thawing Thunder

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Re: The 2017 melting season
« Reply #3368 on: August 01, 2017, 06:43:34 PM »
P.S. Did i say the thing you quoted me saying? I think the honors are not mine.

It was Oren. Sorry, I quit the wrong name in that quote.

Maritime climate.  The Arctic is no longer a desert.

You nailed it so simple, it's eyeopening! When I read it, many details I soaked up on this forum just concentrated into those words. Thank you! (@Tnioli: Yes, it's oversimplifyed, but focuses very helpful on the right issue. At least for me.)

I keep seeing it said that "it gets harder and harder to melt the remaining ice," or words with that meaning, but I cannot remember ever seeing an explanation why that might be so.  Seems to me that just like in a margarita, the last of the ice would go quickest. By then you have run out of cold.

I imagine this refers to the idea that the Arctic is becoming a giant Hudson Bay. That means, ice covered in winter and free in summer. Even with much higher temperatures, there will probably always be freeze in winter, that's why there will probably never exist zero ice all over the year.

But interpreting it only for the melt season, I think your margarita-observation makes totally sense.
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F.Tnioli

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Re: The 2017 melting season
« Reply #3369 on: August 01, 2017, 07:11:53 PM »
...

I imagine this refers to the idea that the Arctic is becoming a giant Hudson Bay. That means, ice covered in winter and free in summer. Even with much higher temperatures, there will probably always be freeze in winter, that's why there will probably never exist zero ice all over the year.

But interpreting it only for the melt season, I think your margarita-observation makes totally sense.
For now, current stage is that, yes. But you're wrong about "always be freeze in winter". Nope. Thermal capacity of water is HUGE, which means that a) it takes a long, long time to warm up oceans, but also b) it takes a long, long time to cool down warm oceans. Once Arctic is warm enough, it will (again) be ice-free completely, 365/centuries. Zero ice all year long. Crocodyles, remember? Those can't survive under ice, you know. Not for a month, nor a week, nor a day.
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greatdying2

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Re: The 2017 melting season
« Reply #3370 on: August 01, 2017, 07:30:50 PM »
I keep seeing it said that "it gets harder and harder to melt the remaining ice," or words with that meaning, but I cannot remember ever seeing an explanation why that might be so.  Seems to me that just like in a margarita, the last of the ice would go quickest.  By then you have run out of cold.
I like your analogy, but at least regionally there is always some ice clinging on in some especially ice-friendly spots long after most has melted. Look at Hudson Bay, for example, and consider the bottom of the area curve, att. (from Wipneus). There was some discussion earlier of ice that seems to survive longest on its western shore every year. Regardless, if and when we reach this point for the CAB, I think the fate of the last cube of ice will be the least of our concerns.

Edit: I see TT already said basically the same thing :)
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Daniel B.

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Re: The 2017 melting season
« Reply #3371 on: August 01, 2017, 07:35:00 PM »
...

I imagine this refers to the idea that the Arctic is becoming a giant Hudson Bay. That means, ice covered in winter and free in summer. Even with much higher temperatures, there will probably always be freeze in winter, that's why there will probably never exist zero ice all over the year.

But interpreting it only for the melt season, I think your margarita-observation makes totally sense.
For now, current stage is that, yes. But you're wrong about "always be freeze in winter". Nope. Thermal capacity of water is HUGE, which means that a) it takes a long, long time to warm up oceans, but also b) it takes a long, long time to cool down warm oceans. Once Arctic is warm enough, it will (again) be ice-free completely, 365/centuries. Zero ice all year long. Crocodyles, remember? Those can't survive under ice, you know. Not for a month, nor a week, nor a day.

You may wish to check some of graphs posted earlier today concerning the Arctic temperatures.  It barely rises above freezing, and for less than three months.  This past quite warm winter averaged -23C for over four months!  The surface waters will continue to freeze for quite a long time yet.  I doubt we will be seeing crocodiles in the Arctic.
« Last Edit: August 01, 2017, 08:15:22 PM by Daniel B. »

sedziobs

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Re: The 2017 melting season
« Reply #3372 on: August 01, 2017, 07:50:28 PM »
Can we move some of these discussions to more specific threads?  Very few of the recent posts have offered information or insights into current conditions in the Arctic.

Some options:
Year-round ice-free Arctic
Ice free predictions and their uncertainty
When Will We See <1,000 km^2 Arctic Sea Ice Extent
What is a model?

F.Tnioli

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Re: The 2017 melting season
« Reply #3373 on: August 01, 2017, 07:58:01 PM »
... Regardless, if and when we reach this point for the CAB, I think the fate of the last cube of ice will be the least of our concerns.
Oh, for sure. I bet we'll be, even by then, way more busy still healing our wounds. Which wounds? Ones we are going to be inflicted with quite very soon, - namely when Neven will get back to see us talking multi-year things in this topic for way too long now. He'll slap our collective buttocks real bad, for sure! :o So, back on-topic. Wipneus reports century area drop in the CAB _alone_, and the largest extent drop is in the ESS. This is the worst of the worst combination possible!!!
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cesium62

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Re: The 2017 melting season
« Reply #3374 on: August 01, 2017, 07:59:38 PM »
It barely rises above freezing, and for less than three months.

The summer temperature north of 80 degrees is clamped to the melting temperature of the ice.  It occurs to me that the slight drop in summer temperature over the past few years suggests that the ice contains more salt than it used to, which is what we would expect from a loss of MYI.  Or am I reading too much between the lines?

F.Tnioli

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Re: The 2017 melting season
« Reply #3375 on: August 01, 2017, 08:05:21 PM »
...
You may wish to check some of graphs posted earlier today concerning the Arctic temperatures.  It barely rises above freezing, and for less than three months.  This past quite warm winter averaged -23C for over four months!  The surface waters will continue to freeze for quite a long time yet.  I doubt we will be seeing crocodiles in the Arctic.
1st, please edit your post to format the quote properly, thanks! 2nd, i know what is in graphs you mention, thank you. 3rd, i did not talk about last winter, nor any winter during next 10 years (the least) in the post you quote. 4th, sure, we won't see crocs in the Arctic - they'll go extinct by then. Year-round ice-free Arctic - if you're young and healthy, may be you will see. P.S. we continue to do off-topic here, which is a bad idea. Enough is enough. Sorry, but i won't continue this talk (here).
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Bill Fothergill

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Re: The 2017 melting season
« Reply #3376 on: August 01, 2017, 08:13:07 PM »
... Even with much higher temperatures, there will probably always be freeze in winter, that's why there will probably never exist zero ice all over the year...

What you are discussing is the transition of the Arctic Ocean from being perennially ice covered, through seasonally ice covered, and ending up in a perennially ice free condition.

One such study appeared last year in the Journal of the American Meteorological Society. Their findings, in a nutshell, were that the vast bulk of winter sea ice could be a thing of the past by as soon as ~2130.

I'll put more flesh on this later, but I'm off to sink a few pints.

F.Tnioli

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Re: The 2017 melting season
« Reply #3377 on: August 01, 2017, 08:21:00 PM »
It barely rises above freezing, and for less than three months.

The summer temperature north of 80 degrees is clamped to the melting temperature of the ice.  It occurs to me that the slight drop in summer temperature over the past few years suggests that the ice contains more salt than it used to, which is what we would expect from a loss of MYI.  Or am I reading too much between the lines?
No, you're quite right there in principle, that's one of factors alright. Not sure how significant it is, though, but must be worth at least something of the 0.1° order of magnitude, i guess. Plus the thing i mentioned some time earlier today, - more fragmentation -> more ice-water boundary total surface -> more intensive ice-water heat flux -> lower water temps at the surface. Then cloudy June on top of both, too; and still it's almost 2012 summer SSTs, still. You know? Scary.
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Re: The 2017 melting season
« Reply #3378 on: August 01, 2017, 08:23:16 PM »
quote author=Daniel B. link=topic=1834.msg123175#msg123175 date=1501605264]
The long-term trend will of course be sublinear because you can't get negative extent, and it gets harder and harder to melt the remaining ice. But in the satellite era it appears pretty close to linear.

I keep seeing it said that "it gets harder and harder to melt the remaining ice," or words with that meaning, but I cannot remember ever seeing an explanation why that might be so.  Seems to me that just like in a margarita, the last of the ice would go quickest.  By then you have run out of cold.

Dharma,
The first ice to go was that furthest from the Arctic land masses, in the North Atlantic and the Bering straits.  This was in closest proximity to the [relatively] warmer waters of the North Atlantci and Pacific.  This has been followed by the ice in the open Arctic.  The warmer waters can inflowing can melt this ice from all sides, similar to the ice in your margarita.  The ice abutting the colder Artic archipelago and Greenland does not experience this same physical condition, as the warmer waters approach from one side only.  That is why this ice will be harder to melt.
[/quote]

----

TLDR Summary: We don't really have a clue what the arctic looks like at say 1.0 or 2.0m total extent ice (god knows that volume looks like at that extent) Maybe the ice is in very different places than we're expecting in that case, since as fragmentation increases weather has a much larger effect.

------

Regarding this I'm a little skeptical that say 1.0 m to 0.0 ice in some theoretical summer some year in the future, be it 1 or 20 is going to be the hardest. Certainly in the case of the ice sitting on the north pole shrinking into a smaller and smaller cap each each with the ice at the north pole at the highest latitude the last go makes some sense.

However based on the fragmentation at the north pole in 2012, and the possible fragmentation this year due to the state of the ice. (BTW I'm in the ICE is total shit camp, and the only reason we're not going to hit a new record that includes a dramatic free fall is that the weather has been very tender).

Anyway I have strong doubts that it will stay a continuous lump of ice that sits there, and as that central pack fragments earlier and earlier, the weather is going to have a stronger and stronger effect on it, it doesn't seem unlikely that a storm could make some crazy shapes and end up in warmer waters if it hits at the wrong time. At some point an export from a pole region to the general basin is going to eat ice as fast as an export to the Atlantic as sea temps keep climbing.

In regard to the landmass argument, I think going forward to assume that it will be cold there.. might be premature . Irrc the only reason England is a "nice" place to live is an Gulf steam, and to assume that with the extra albedo heat and the general extra heat in the ocean, coupled with less and less ice in the arctic ice is going to leave the ocean currents / circulation unaffected seems unlikely...


My theory is that there's some barrier point, for a while there's that middle cap that is going to stay solid and be slower to melt, but at some point it's going to fragment at the same time as unhelpful weather system, this all becomes extra extra unstable (as opposed to the regular kind instability we've been observing since 1950. But I think that's closer to the 2-3 million extent, and once the pack get pushed through that point, it'll free fall rapidly.

Now noes anyone know if anyone has done any studies / modeling from the opposite direction? take a warm climate with no summer ice, and look at how much the the climate has to cool off to start forming an arctic ice pack again? And then compare that to the global temperature range that can simply sustain an existing Cap but not grow / shrink it on average,  compared to the global temp required to create one? (they could be the same I suppose, but I have doubts). Looking at how an artic ice cap forms might give just insight in what to look for when it might be disintegrating.

Liam

*P.S. Three other things I want to get my two cents in on while I'm writing a book. I debated separate poses for these, but the first two do really apply to this melting season.

1. Piomas and 2017 vs crappy satellite volume metrics. I think the science behind Piomas is SOLID, and all the measurements that have cross checked the model over the years bear it out, and I've watched it over the last couple years and I consider it the gold standard for volume. But lately I'm getting nervous, the largest problem with this model is that you have underlying assumptions, and some point the underlying assumptions that govern the Piomas model are going to fall out of wack with the reality of our warming planet. Hopefully it'll cause a small error, or maybe a large one. I also have a feeling that it (like most climate models seem to in an effort not to cry wolf) errs towards being conservative, and I've wonder if it's a bit out of sync with the current Year due to the weird freeze up last year, etc.

2.
Something that comes up a lot, and that might be be worth melt pondering on, everyone uses the GAC of 2012 as that ultimate disaster, implying it was almost like that "100 year storm", and it does seem like it was a perfect storm in the right(wrong?) place at the right(wrong?) time. Maybe it was, but I have a hard time imagining that, I saw a link somewhere about how a meteorologist said systems similar to the GAC setup every 4-5 years on average. It still has to be in the right place at the right time, but if the GAC setup is the 5 year storm... what's everyone's theory of an actual 100 even looks? if the 2012 GAC is only the bad dream, what's everyone's nightmare specifically as it applies to this melting season.

3.
This forum feels a bit more acrimonious than previous years. I do wonder if the waiting is getting to us a bit?... humans are not made to be patient in terms of a single melting season let alone year to year, and every year we're all thinking is this the one? is the sudden drop theory correct? or does the system stabilize for a decade or two due to negative feed backs such as the increased snowfall / cloudiness of a arctic that's not always a desert (I was pretty convinced it was going to be a record shattering year based on the slow freeze up until those started popping up, and I'm not convinced they're a one off).... Anyway... I think it might be worth remembering, we're all on the same side here... I'm pretty sure based on the comments on the forum that in regard to the climate we pretty much all of us think that instead of just crying about the that lone wolf snacking on the odd sheep, we should be using a megaphone to scream about the goddam fucking zombie horde of genetically altered super wolfs at the gate... even if we disagree how it might come about. I work as an Engineering, and when we're doing group designs with no obvious solution, and trying to decide what leads to use resources on, tempers can get heated... so we have a policy/philosophy that we ask everyone to hold on to and try and remember.... if you're feeling picked on and start to substitute anger and derision instead of reasoned debate.....remember this isn't art class, this is fucking grade A science, it has a right answer and wrong one (a over simplification perhaps but generally true), and the best part about that is that you don't need to yell, if you're convinced you're right but get veto/out voted, get your piece on the record in a reasonable matter, and if everyone disagree's and we don't go that way, just know that if you are right, someday you'll get to send an email (I guess in this case post) "I was right and you'll where wrong" (You're even allowed to use all caps, a huge font and and bold if you want)...Anyway if you made it this far, thanks for reading! cheers!

<I'll let this stand because it's your 3rd post, but next time be more on-topic and be shorter, or I will have to get my scissors; N.>
« Last Edit: August 01, 2017, 09:33:42 PM by Neven »

numerobis

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Re: The 2017 melting season
« Reply #3379 on: August 01, 2017, 08:30:08 PM »
Back on topic...

I'm finally starting to believe there might be ice leftover on Baffin this year. June was warm, but it was at or below "average" (1980-2010) temperature almost all July, and unusually cloudy and rainy.

The sun seems much more important than the air temperature when it comes to melting the ice.

Edit: also, there hasn't been much transport South towards south baffin or quebec/labrador, where the ice might face warmer sea temperatures.

oren

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Re: The 2017 melting season
« Reply #3380 on: August 01, 2017, 08:49:06 PM »
I'm finally starting to believe there might be ice leftover on Baffin this year. June was warm, but it was at or below "average" (1980-2010) temperature almost all July, and unusually cloudy and rainy.
It could be, but looking at AMSR2 area comparison it doesn't seem out of the ordinary. Whatever remains should be negligible.

F.Tnioli

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Re: The 2017 melting season
« Reply #3381 on: August 01, 2017, 09:37:47 PM »
Back on topic...

I'm finally starting to believe there might be ice leftover on Baffin this year. June was warm, but it was at or below "average" (1980-2010) temperature almost all July, and unusually cloudy and rainy.

The sun seems much more important than the air temperature when it comes to melting the ice.

Edit: also, there hasn't been much transport South towards south baffin or quebec/labrador, where the ice might face warmer sea temperatures.
Air temperature by itself is relatively minor thing, yes. However, humidity is not. Warm near-surface masses of air at near 100% relative humidity is comparable to full sunlight in terms of sea ice melting potential (comparable does not mean "same", and much depends on ice condition). It is so especially when it's raining - and you mentioned rains yourself.
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Quantum

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Re: The 2017 melting season
« Reply #3382 on: August 01, 2017, 09:48:27 PM »
Ryan Maue posted this image recently on twitter.


I know people have mixed feelings about this guy but his visualizations are 2nd to none. Anyway colder weather and unusual snowfall across the arctic is interesting in of itself even if it doesn't matter much in August.

Shared Humanity

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Re: The 2017 melting season
« Reply #3383 on: August 01, 2017, 10:05:22 PM »
Courtesy of Espen over on the IJIS thread....

(See 1st image)

In a couple of days, 2012 began its race to the bottom. Will 2017 continue to play with the pack or will it make a similar dive?

The SIE dive occurred during the GAC of 2012...

http://onlinelibrary.wiley.com/doi/10.1029/2012GL054259/abstract

...and a large amount of ice extended precariously into the Chukchi and ESS, vulnerable to such a storm.

(See 2nd image)

The ice this year is more compact and thus not as vulnerable to storms.

(See 3rd image)

I do not believe the conditions are right for a repeat and expect that 2017 will continue to dance with the lower end of the pack. 2nd place for SIE is still a strong possibility. Would not be surprised to see 4th and 7th place is not out of the question.

F.Tnioli

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Re: The 2017 melting season
« Reply #3384 on: August 01, 2017, 10:06:18 PM »
... Their findings, in a nutshell, were that the vast bulk of winter sea ice could be a thing of the past by as soon as ~2130.

I'll put more flesh on this later, but I'm off to sink a few pints.
Excellent! Please, do put more flesh on this, i'm HIGHLY curious for details. But, not here! Please go this topic, i've already made a response for you there, including your full quote from here. Daniel, and also other gentlemen who are interested in the subject: i hope you'll join the discussion there, too!
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numerobis

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Re: The 2017 melting season
« Reply #3385 on: August 01, 2017, 10:11:55 PM »
Raining a lot in terms of number of days -- in Iqaluit, 21 of 27 days in July (3 days are missing and the last day isn't tabulated yet). But the rainfall totals are quite low:
http://climate.weather.gc.ca/climate_data/daily_data_e.html?StationID=42503

Meanwhile this report has Iqaluit at 0.9 C below the climatology, and Clyde at 1.2 C below. These are July temperatures for Baffin like it's the early 1980s:
https://www.facebook.com/NunatsiaqNews/photos/a.114066714441.96954.100174284441/10155204747774442/?type=3&theater

Given that the temperatures are from the 1980s, the ice melt potential in this little region might also be. We'll see what August brings.

F.Tnioli

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Re: The 2017 melting season
« Reply #3386 on: August 01, 2017, 10:19:14 PM »
Raining a lot in terms of number of days -- in Iqaluit, 21 of 27 days in July (3 days are missing and the last day isn't tabulated yet). But the rainfall totals are quite low:
http://climate.weather.gc.ca/climate_data/daily_data_e.html?StationID=42503
...
We have detailed discussions in this forum about how it is not rain itself which melts alot of ice, but condensation of water vapour. When it's raining, it's usually 100% relative humidity. Condensation happens. Lots of latent heat is released when it does. That's the main physical mechanism i meant above. For now, me, i stick with what Oren said about AMSR2 area. I, too, would be much surprised if Baffin would have any mch ice surviving in the end of the season.
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NeilT

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Re: The 2017 melting season
« Reply #3387 on: August 01, 2017, 10:32:37 PM »
I do not believe the conditions are right for a repeat and expect that 2017 will continue to dance with the lower end of the pack. 2nd place for SIE is still a strong possibility. Would not be surprised to see 4th and 7th place is not out of the question.

Currently 2017 is in 4th for extent. That will be 3rd in 2 or three days as it drops below 2011.

This season, for me, is incredibly interesting.  Pack weakness and lack of volume is driving extremely odd results.  Meaning that if even slightly out of the ordinary weather should evolve in August, then the results are going to be magnified by the state of the pack.

Right at this moment it is all in the hands of the weather and that is being agitated by a significantly fragmented pack wrapping almost all the way around the 80N line and, in places reaching up to and above 85N.

Trying to call 2017 now is close to wishful thinking and I'm not doing any wishing at all, except a wish to be able to watch it all evolving.

I did vote on the polls but that is nothing more than a guess.  The way 2017 is swinging about it could go in any direction from catastrophic loss to large re-growth.  It is set up for either.
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werther

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Re: The 2017 melting season
« Reply #3388 on: August 01, 2017, 10:44:49 PM »
Does a 'black swan'-event pass unnoticed? We have just a handfull of sources we hold to be fact. Whatever these sources present to us at a certain moment, there's a trend. And that trend is bad for climate as we knew it.
Looking at today's MODIS tiles, I'm reminded of July 2013. All that fragmentation. And when winter settled that year, it was called a 'rebound'-year. I still doubt that. The system passes through these stages. And the Arctic pack ice is just one aspect of that system.
Anyway, I'm quite sure that when 2017 gets into the record books our sources will put it at the lowest mean ranks.
It's not just a still in September that matters.

Thawing Thunder

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Re: The 2017 melting season
« Reply #3389 on: August 01, 2017, 11:08:58 PM »
The area north of Laptev is breaking up and thinning big time.
« Last Edit: August 02, 2017, 12:10:28 AM by Thawing Thunder »
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Dharma Rupa

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Re: The 2017 melting season
« Reply #3390 on: August 01, 2017, 11:09:30 PM »
...
Maritime climate.  The Arctic is no longer a desert.
Partially true; oversimplified. The change is gradual. It's still a desert say April, for example. But direction of change is indeed towards maritime climate year-around. We know Arctic ocean had crocodyles inhabiting it in the past. Still we're far from that, for now. Late summer and autumn are much maritime already, yes; even now, Arctic looks much like a part of Pacific system at 850 hPa, for example. Switch to 250 hPa, though, and it's not (yet). Remains of Jet Stream in action...

That was my entire objective...a bumper sticker.

Last Winter was warm enough I might need to be convinced about April.

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Re: The 2017 melting season
« Reply #3391 on: August 01, 2017, 11:28:35 PM »
This one doesn't flatter the sea ice at all.
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Shared Humanity

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Re: The 2017 melting season
« Reply #3392 on: August 02, 2017, 12:08:38 AM »
This one doesn't flatter the sea ice at all.


The ice is in the worst shape that it has ever been in human history.

Dharma Rupa

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Re: The 2017 melting season
« Reply #3393 on: August 02, 2017, 12:15:56 AM »
This one doesn't flatter the sea ice at all.


The ice is in the worst shape that it has ever been in human history.

Some of us think so....but the metrics make that a hard call.

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Re: The 2017 melting season
« Reply #3394 on: August 02, 2017, 12:18:27 AM »
End of the month, so some updates of my charty-farty creations.

a. 2017 June-July vs 10yr rolling averages for June-July (the psychedelic toothpaste one)

b. 2017 May-July daily extent vs. 2010s average (i.e. 2010-2016) for each day.

c. Cumulative days in the bottom 3.

Combined, these help to emphasise that 2017 remains a low extent year despite some pretty unspectacular melt conditions, as discussed above.
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F.Tnioli

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Re: The 2017 melting season
« Reply #3395 on: August 02, 2017, 12:33:46 AM »
Thank you, Deeenngee. Grand work. I wonder what Shared Humanity has to say about those, eh.
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Re: The 2017 melting season
« Reply #3396 on: August 02, 2017, 12:41:25 AM »
Off-topic or not off-topic ?

After doing almost nothing this season, Greenland melting suddenly woke up a few days ago, with intense melting meaning up to 8 gigatonne (8 cubic kilometres) of cold fresh water is being dumped per day into the ocean from the peripheral regions of Greenland. This is about twice the daily average for this time of year. This looks set to continue for a few days yet.

One wonders how much effect this has, for example, on the sea ice attached north of Greenland and in the Nares strait.

ps: Posted some stuff from http://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/ on the greenland melting thread.

Hi, I am a lurker to this site from May 2016; an interesting lurk in interesting time I must say.  So, as usual, I've come up with some ideas and theories.  This one is one of them, please don't be harsh on me, I am just sharing what I think might be true...  Let's talk about it and find out.

On August 1st, we might have an answer to the effect of the huge Greenland melted water release that happened few days ago.  I believe the sudden melt that Wip reported today for yesterday is linked to the sudden Greenland melt (see his report in extent & area thread).  The Wip attached map shows the MYI near Greenland has melted quite a bit.  I think the melt is due to a melt event under the Greenland ice cap, due to a magmatic plume that is located there. Here is Wipneus melt map:



 It's well-known plume, documented in the literature. Some element of proof; a GRACE satellite picture of the relative elevation of Earth's crust to the mean level, as you can see in the attachment below.  The whole Greenland appears as a lower than average surface, due to the weight of the ice cap, but the north end is in the positive.  That's the place of the magmatic plume.

Note that on july 23-24th, another huge Greenland cap water was released, but that one resulted in a local freeze in the Svalbard area.  That event released cold, near freezing water that cool the area near its release.  It froze and smachted the ice in the following day of the release.

I think the lack of Greenland melt is an important factor in this late strong melt of this year, because it has not provided the cool fresh water blanket it usually provide to the ASI.
« Last Edit: August 02, 2017, 01:24:42 AM by Apia »

Shared Humanity

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Re: The 2017 melting season
« Reply #3397 on: August 02, 2017, 02:11:21 AM »
Thank you, Deeenngee. Grand work. I wonder what Shared Humanity has to say about those, eh.

I think Deeenngee summarizes it well....

"Combined, these help to emphasise that 2017 remains a low extent year despite some pretty unspectacular melt conditions, as discussed above."

Due to the ridiculously warm winter, 2017 had an enormous head start at the beginning of this melt season, most readily seen in the PIOMAS chart. Because of the weak growth in volume, we entered this melt season with very thin ice as compared to years prior. 2017 remains a low extent year due, in large part, to this head start. Yes, the melt season has been unspectacular but I am still surprised by the resiliency of this thin ice. I don't understand why we are not racing towards a record low in SIE.

F.Tnioli

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Re: The 2017 melting season
« Reply #3398 on: August 02, 2017, 03:11:51 AM »
... I don't understand why we are not racing towards a record low in SIE.
You sure do, come on? Atlantic's relatively cold this year, for one. Late melt ponding due to higher than normal snow cover, for two. Much broken Jet Stream, which - for a change, - gives among other things the negative feedback of more clouds in the Arctic during summer solstice - for three. And there is possibly the fourth thing which perhaps cools things down more than the three above combined, but i don't feel fancy even mentioning it here and now. And it's still a low extent year.
« Last Edit: August 02, 2017, 12:05:41 PM by F.Tnioli »
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jai mitchell

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Re: The 2017 melting season
« Reply #3399 on: August 02, 2017, 03:56:56 AM »
I don't understand why we are not racing towards a record low in SIE.

If you do a melt season monthly correlation between Piomas volumes and NSIDC SIE you will find a break since 2004 with SIE declines much less than PIOMAS.  this indicates that SIE has a positive feedback as the thicker ice has melted out, leading to increased ice mobility and residual SIE Values.

This leads to a common-sense conclusion that as SIE reaches a critical threshold, under ideal melt conditions that a rapid collapse will occur, but it looks like this won't happen above 2.2 X 10^6 km^2 (or so)
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