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Peter Ellis

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Re: The 2015 melting season
« Reply #2350 on: July 22, 2015, 12:09:42 AM »
... when the website has fixed itself three days later?

ktonine

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Re: The 2015 melting season
« Reply #2351 on: July 22, 2015, 12:15:08 AM »

Looking at compactness for the same region right now. It is 0.4992, or half open water, half ice. Sounds alarming? Portends disaster?

Well, no, actually it's in the normal range for recent years.

...

But what of the post 2007 period? Here is the data:

   Comp         Anomaly   StdDevs
2007   0.4729   -0.0721   -1.47
2008   0.5903   0.0453   0.93
2009   0.5696   0.0246   0.50
2010   0.6171   0.0720   1.47
2011   0.5323   -0.0127   -0.26
2012   0.4997   -0.0453   -0.93
2013   0.5372   -0.0079   -0.16
2014   0.5870   0.0420   0.86
2015   0.4992   -0.0459   -0.94

As greatdying2 pointed out, rather than 'ho hum' this data says that 2015 is on the same course as 2007 and 2012.

....this 18 July is low, but not exceptionally so. 2013 alone shows how compactness is not the whole story, in 2013 on 18 July compactness was as near as damn it 1/2, it did not result in a record low, rather the second highest minimum extent for the post 2007 period.

1) There is no indication in ice state, as measured by compactness, of an iminent crash as the behaviour over the last few years does not show strong deviations from the range of post 2007 behaviour. (This applies equally to other indices)

Chris, perhaps you were overly tired, but the data is at odds with your analysis. 2007, 2012, and now 2015 stand out having the largest negative SDs. 2008 and 2014, two of the large rebound years stand out as having large positive deviations.

Another way to look at the same data is that 2015's compactness is 20% lower than 2008 or 2014.

None of this speaks directly to a correlation between compactness in July versus final extent values, but  on the basis of this admittedly small dataset I wouldn't rule one out.  And rather than dismissing any link, I'd want to dig deeper with an eye towards refining the rather crude compactness measure we're using.

greatdying2

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Re: The 2015 melting season
« Reply #2352 on: July 22, 2015, 12:31:04 AM »
The Slater forecast appears to perhaps be about to bottom out at around 4.5 .

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.

Neven

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Re: The 2015 melting season
« Reply #2353 on: July 22, 2015, 12:55:26 AM »
... a several week's journey at n million pounds per day in order to find out why a gif on a website is slightly the wrong colour according to the numbers produced by that same website?

Sounds better than invading a country looking for WMDs!  ;D
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greatdying2

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Re: The 2015 melting season
« Reply #2354 on: July 22, 2015, 01:03:44 AM »
I'm not sure how the 'reply' button works here, so I may have missed something, so just replied here.
Just use the Quote or Insert Quote buttons (top right of the post you want to quote).

Quote
I understand. I just wondered if there could be thinner areas in old ice (not overall volume) that could turn into 'fjords' eating into the ice-pack, and/or areas where it is thinning in the interior that could turn into fissures in the ice-pack. In other words, if there are thinner places, compared to historical data, those could be what really count if it breaks up.
Regarding 'fjords' in the ice, for example, I can see several inroads into the ice pack right now that did not appear at this time in 2012 as far as I can see.
Absolutely, the "Laptev bite" for example. Also, polynyas.

Quote
1. The Pacific Blob of warm water is seeping into the Western Arctic and causing that big melt you see there in the image on the left below. That warm water would likely stay near the surface (because it is warmer), and eat around the edges as you see in the image, it is eating around Northern Siberia? there, much more than in 2012. That is the warm water from the Pacific Blob doing that. Once those ice dams that still connect to Northern Russia/Siberia melt, then that warmer water from the Pacific Blob will flow around the ice cap and melt even more. Some warm water from the Atlantic could increase the effect, although I don't know how much that is happening. I think that warm water from the Pacific Blob will be the biggest factor this year, and that the Pacific is never really going to cool down again (sad, but true).
Yeah, huge melt from Pacific warm waters this year. I'm looking forward to see how much will it continue into the next few weeks as the ice gets even weaker but insolation drops... Moreover, next year looks even worse, with a possibly record El Nino: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html .

I agree with your other points as well. Here we are, intently watching a canary in the coal mine. Scary to think what we will be watching in a few (?) years, once the canary is dead and the ice is melting out each summer. I guess the antarctic will have gathered a lot of momentum by then...
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.

greatdying2

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Re: The 2015 melting season
« Reply #2355 on: July 22, 2015, 01:05:49 AM »
... a several week's journey at n million pounds per day in order to find out why a gif on a website is slightly the wrong colour according to the numbers produced by that same website?

Sounds better than invading a country looking for WMDs!  ;D
I wish there were a "like" function for posts...

Like!  :)
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.

jdallen

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Re: The 2015 melting season
« Reply #2356 on: July 22, 2015, 01:23:18 AM »
The Slater forecast appears to perhaps be about to bottom out at around 4.5 .


If it's derived from some of the same statistical methodology and relying on the same history some of us here have been using, this is no surprise.

One storm or one week of persistent cloudiness and cool weather can still give it a whack 500K KM2 either way, easily.

Confidence of extent coming in above 2012 is increasing.  2007 and 2011 are still threatened.
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Nick_Naylor

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Re: The 2015 melting season
« Reply #2357 on: July 22, 2015, 01:26:51 AM »
Nice bit of 4-5 meter fast ice has broken free, possibly headed for a sunny vacation in the Beaufort.

This was mentioned in a separate thread, and dismissed as unreliable Hycom speculation. Granted, the ice might stay parked close to home, but I think it's more likely to join the drifting rubble as Hycom is projecting.

Villabolo

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Re: The 2015 melting season
« Reply #2358 on: July 22, 2015, 01:34:09 AM »
... a several week's journey at n million pounds per day in order to find out why a gif on a website is slightly the wrong colour according to the numbers produced by that same website?

How much does a satellite cost? We all know that models have their limitations and spending that amount of money even for a month should be worth it in order to give direct and useful information. In any case I'm having problems giving HYCOM much credibility.

jdallen

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Re: The 2015 melting season
« Reply #2359 on: July 22, 2015, 01:36:58 AM »
Nice bit of 4-5 meter fast ice has broken free, possibly headed for a sunny vacation in the Beaufort.

This was mentioned in a separate thread, and dismissed as unreliable Hycom speculation. Granted, the ice might stay parked close to home, but I think it's more likely to join the drifting rubble as Hycom is projecting.

Been "bits" (if consider a Delaware sized block of ice a bit...) chipping off the fast ice north of Greenland for a couple of weeks.  They haven't been moving a lot, nor breaking up particularly.

I'm more interested in what's happening near the the pack north of the Lincoln Sea, which has been a Bastion for a while. Peering through the cloud cover gives some tantalizing hints of it having taken a serious beating, but I haven't been confident enough about it to post.  Maybe now's the time to direct some more attention that way.
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jdallen

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Re: The 2015 melting season
« Reply #2360 on: July 22, 2015, 01:38:32 AM »
... a several week's journey at n million pounds per day in order to find out why a gif on a website is slightly the wrong colour according to the numbers produced by that same website?

How much does a satellite cost? We all know that models have their limitations and spending that amount of money even for a month should be worth it in order to give direct and useful information. In any case I'm having problems giving HYCOM much credibility.
Start at 1 billion $US and go up from there.
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Greenbelt

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Re: The 2015 melting season
« Reply #2361 on: July 22, 2015, 01:43:13 AM »
Nice bit of 4-5 meter fast ice has broken free, possibly headed for a sunny vacation in the Beaufort.

This was mentioned in a separate thread, and dismissed as unreliable Hycom speculation. Granted, the ice might stay parked close to home, but I think it's more likely to join the drifting rubble as Hycom is projecting.

Don't know what would prevent it from drifting east as Hycom indicates. Models in tight agreement on easterly flow around big high near the pole for several days, perhaps shifting a bit more northerly if that low develops in the Beaufort. But not much ice in "Delaware" ice flow's path to keep it bottled by the coast? Unless there's a countervailing current?


greatdying2

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Re: The 2015 melting season
« Reply #2362 on: July 22, 2015, 01:58:48 AM »
Nice bit of 4-5 meter fast ice has broken free, possibly headed for a sunny vacation in the Beaufort.

This was mentioned in a separate thread, and dismissed as unreliable Hycom speculation. Granted, the ice might stay parked close to home, but I think it's more likely to join the drifting rubble as Hycom is projecting.
Sweet animation!  :) 

If I'm not mistaken, that chunk is also shown in this DMI thickness map: the 'head' of orange with 'wings' of red.

Also, if these volume estimates are close to accurate, 2015 may well be a major volume loss year (as some have said), similar to 2011. (2011 was to 2012 as 2015 will be to 2016?)


(Larger images and animations on their website:
http://polarportal.dk/en/havisen-i-arktis/nbsp/sea-ice-extent/ ).
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.

Andreas T

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Re: The 2015 melting season
« Reply #2363 on: July 22, 2015, 02:06:49 AM »
Nice bit of 4-5 meter fast ice has broken free, possibly headed for a sunny vacation in the Beaufort.

This was mentioned in a separate thread, and dismissed as unreliable Hycom speculation. Granted, the ice might stay parked close to home, but I think it's more likely to join the drifting rubble as Hycom is projecting.
The attached image is from 2014/07/19 i.e. some similar detatchment occurred last year. If it travelled to the beaufort from there it would explain why there are some pretty tough floes holding out in water which was open to the sun since the start of June. To replace it with 5m ice in a year would require a lot of compaction. Basically the thick ice there is so thick because it doesn't move fast and the transpolar drift keeps pushing more ice up against the land. Breaking is not what destroys ice.

LRC1962

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Re: The 2015 melting season
« Reply #2364 on: July 22, 2015, 02:34:13 AM »
The definition I think of and is used and understood by those like Dr. Barber is the quality of the ice. i.e. ice with high amounts of impurities, water and/or air is rotten. Low compactness is something else altogether different.
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AySz88

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Re: The 2015 melting season
« Reply #2365 on: July 22, 2015, 03:04:16 AM »
... a several week's journey at n million pounds per day in order to find out why a gif on a website is slightly the wrong colour according to the numbers produced by that same website?

How much does a satellite cost? We all know that models have their limitations and spending that amount of money even for a month should be worth it in order to give direct and useful information. In any case I'm having problems giving HYCOM much credibility.
Start at 1 billion $US and go up from there.

I believe that was his point - sailing is cheaper than satellites - but yeah, collecting data just to improve one model is a bit too narrow-focused.  A trip like that can collect many more valuable lines of data that can validate or disprove a whole host of hypotheses and theories.  A problem with just one model, well, you already know it's wrong, so why a special trip just to re-confirm it's wrong, right? Better to invest in fixing that model....

And unfortunately, the arctic ice piece of the modeling puzzle is decreasing in importance....

The code written does one million runs. In each run the 18 July 2015 extent is used as the start extent, and for each day a daily loss is chosen at random from the available 8 year dataset. These losses are summed and applied to the 18 July 2015 extent to create a simulated extent for 15 September 2015. The resulting 1,000,000 extent values are then combined in a histogram and normalised to 1 to produce a probability distribution.

This sounds slow (was it?), so you and others may be interested to learn that there's a fast way for an "exact" solution:
  • Split volume into tiny, effectively rounding-error-sized bins (i.e. one digit past the sig fig in your data, say 0.001 million kmsq)
  • Initialize an array currPDF with 100% probability in the bin corresponding to current sea volume
  • For each next day:
  • * Create new array nextPDF
  • * Go through each currPDF bin, and split its probability among the nextPDF bins, as implied by your data
  • * currPDF = nextPDF
« Last Edit: July 22, 2015, 03:14:42 AM by AySz88 »

Villabolo

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Re: The 2015 melting season
« Reply #2366 on: July 22, 2015, 03:39:51 AM »
... a several week's journey at n million pounds per day in order to find out why a gif on a website is slightly the wrong colour according to the numbers produced by that same website?

How much does a satellite cost? We all know that models have their limitations and spending that amount of money even for a month should be worth it in order to give direct and useful information. In any case I'm having problems giving HYCOM much credibility.
Start at 1 billion $US and go up from there.

I believe that was his point - sailing is cheaper than satellites - but yeah, collecting data just to improve one model is a bit too narrow-focused.  A trip like that can collect many more valuable lines of data that can validate or disprove a whole host of hypotheses and theories.  A problem with just one model, well, you already know it's wrong, so why a special trip just to re-confirm it's wrong, right? Better to invest in fixing that model....

And unfortunately, the arctic ice piece of the modeling puzzle is decreasing in importance....


Thank you AySz88, that was exactly my point.


slow wing

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Re: The 2015 melting season
« Reply #2367 on: July 22, 2015, 03:56:27 AM »
U. Bremen's daily update shows continuing losses at the edges and for isolated large floes in all of Laptev, ESS, Chukchi and Beaufort.
http://www.iup.uni-bremen.de:8084/amsr2/arctic_AMSR2_nic.png


Click on .gif to flash through previous two days as well...
« Last Edit: July 22, 2015, 08:51:57 AM by slow wing »

Juan C. García

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Re: The 2015 melting season
« Reply #2368 on: July 22, 2015, 05:08:09 AM »
I'm impressed with the way it has deteriorated the Arctic sea ice on the Pacific Ocean side in just one week.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

wili

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Re: The 2015 melting season
« Reply #2369 on: July 22, 2015, 06:57:55 AM »
Thanks for the nice animation, slow wing. Note, though, that it's UBremen, not Hamburg (though all those northern German towns do kind of blur together after a while.  :) )

It looks like the NorthEast Passage is about to open up, and the NW may not be too far behind.

« Last Edit: July 22, 2015, 07:04:31 AM by wili »
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ChrisReynolds

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Re: The 2015 melting season
« Reply #2370 on: July 22, 2015, 08:05:00 AM »

Looking at compactness for the same region right now. It is 0.4992, or half open water, half ice. Sounds alarming? Portends disaster?

Well, no, actually it's in the normal range for recent years.

...

But what of the post 2007 period? Here is the data:

   Comp         Anomaly   StdDevs
2007   0.4729   -0.0721   -1.47
2008   0.5903   0.0453   0.93
2009   0.5696   0.0246   0.50
2010   0.6171   0.0720   1.47
2011   0.5323   -0.0127   -0.26
2012   0.4997   -0.0453   -0.93
2013   0.5372   -0.0079   -0.16
2014   0.5870   0.0420   0.86
2015   0.4992   -0.0459   -0.94

As greatdying2 pointed out, rather than 'ho hum' this data says that 2015 is on the same course as 2007 and 2012.

....this 18 July is low, but not exceptionally so. 2013 alone shows how compactness is not the whole story, in 2013 on 18 July compactness was as near as damn it 1/2, it did not result in a record low, rather the second highest minimum extent for the post 2007 period.

1) There is no indication in ice state, as measured by compactness, of an iminent crash as the behaviour over the last few years does not show strong deviations from the range of post 2007 behaviour. (This applies equally to other indices)

Chris, perhaps you were overly tired, but the data is at odds with your analysis. 2007, 2012, and now 2015 stand out having the largest negative SDs. 2008 and 2014, two of the large rebound years stand out as having large positive deviations.

Another way to look at the same data is that 2015's compactness is 20% lower than 2008 or 2014.

None of this speaks directly to a correlation between compactness in July versus final extent values, but  on the basis of this admittedly small dataset I wouldn't rule one out.  And rather than dismissing any link, I'd want to dig deeper with an eye towards refining the rather crude compactness measure we're using.

But not much worse than 2013, the second highest Sept extent after 2007...

And although the dataset is short there are no 2 and 3 sigma deviations, and no indication of an increase in deviation with time. 1SD is not unusual.

I'm not at all tired. This year we've had a storm in June that wrecked the ice in the peripheral  region(US Navy HYCOM), followed by an excellent dipole set up in July. Yes this year is tracking 2007 and 2012, but it is telling the same story as the other post 2007 years - preconditioning + weather. If anyone thinks it is telling the story of a prelude to a rapid crash, then the data is there. Wipneus takes time to provide it daily, make his hard work worth it, download the data and get cracking. Despite all the time I spend going over the data I may have missed something critical, so I might be wrong, demonstrate that I am.  :)

Great Dying, Neven,

Have any reports talked of ice full of holes? The impression I got regards rotten ice was of lumps of ice in a lot of water, precisely what the satellites spot. Determining how 'odd' the state of individual  lumps of ice is would not be possible as there is no consistent dataset going back to 1979. So the default position must be: We don't know. With compactnes we have a consistent dataset, and it shows that this year is much worse than decades ago, but not much worse than recent years.

jdallen

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Re: The 2015 melting season
« Reply #2371 on: July 22, 2015, 08:28:21 AM »
Nice bit of 4-5 meter fast ice has broken free, possibly headed for a sunny vacation in the Beaufort.

This was mentioned in a separate thread, and dismissed as unreliable Hycom speculation. Granted, the ice might stay parked close to home, but I think it's more likely to join the drifting rubble as Hycom is projecting.

Clouds cleared out from the area in question.  At the bottom center of the top image are some of the "bits" I was referring to north of coast of Ellesmere.  The biggest is 800-1000KM2.  Since I last looked at it, it split from the smaller 400KM2-ish chunk(s) to the due east.

In the second image I zero in on the area north of Peary Channel west of Axel Heidelberg; it shows some of what's been disturbing me (and others) over the last few years.  Largest chunk there in the middle is about 200KM2.

That's supposed to be 4+ Meter think MYI.  <head shake>  I'm not sure to make of it, but it seems one good SMACK and we'd be looking at a very different Arctic.   Makes the 2016 +/- 3 years seem less remote.

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Andreas T

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Re: The 2015 melting season
« Reply #2372 on: July 22, 2015, 08:45:04 AM »
This http://www.lifeonthinice.org/#mi=2&pt=1&pi=10000&s=43&p=10&a=0&at=0
photo illustrates what people seem to think off as rotten ice. Wadhams talks of ice which is easily broken by an icebreaker, it is plausible that ice looses strength when it has warmed to melting point and brine inclusions have melted vertical channels through the ice.
To what degree this ice is widespread and deceives the sensors and models by being voluminous but of little actual ice mass, is the question.
The thermodynamics of freezing and melting are still there, the heat loss during winter is still there. Chris is looking to quantify what is going on and without that analysis, I find opinions not so persuasive.

jdallen

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Re: The 2015 melting season
« Reply #2373 on: July 22, 2015, 08:47:31 AM »
Beaufort detail for 2015-07-21.

At this point, most of the interstitial ice that formed during the winter between the surviving MYI floes is now gone.  Note extensive discoloration and probable melt ponds on the surviving MYI floes.

All of this is due to be swept to the south west and into the very warm (4C+) water now along the Canadian and Alaskan coasts.  If you zoom in, its pretty apparent that the two very large plates of ice (about 2500 and 3000 KM2 respectively, I think...) are showing signs of disintegration.
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slow wing

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Re: The 2015 melting season
« Reply #2374 on: July 22, 2015, 08:53:03 AM »
Thanks for the nice animation, slow wing. Note, though, that it's UBremen, not Hamburg (though all those northern German towns do kind of blur together after a while.  :) )
Oops! Fixed. Thanks. I knew that...  :-[

seaicesailor

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Re: The 2015 melting season
« Reply #2375 on: July 22, 2015, 08:55:32 AM »
Beaufort detail for 2015-07-21.

At this point, most of the interstitial ice that formed during the winter between the surviving MYI floes is now gone.  Note extensive discoloration and probable melt ponds on the surviving MYI floes.

All of this is due to be swept to the south west and into the very warm (4C+) water now along the Canadian and Alaskan coasts.  If you zoom in, its pretty apparent that the two very large plates of ice (about 2500 and 3000 KM2 respectively, I think...) are showing signs of disintegration.

Nice.
One thing about Beaufort is that early in the season when Gyre strngthened for a while, it imported very thick CAA ice (those two floes I bet for instance), then been melting slowly in "appearance". (Now it will import some more...)

So Beaufort and then Chukchi I bet account for much of the volume loss. The grinding area of the Arctic ocean this year.
A bit like Greenland but without the warm Atlantic waters.

Andreas T

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Re: The 2015 melting season
« Reply #2376 on: July 22, 2015, 09:03:08 AM »
when talking of 4 - 5 m thick ice it helps to remember that this is average thickness of ice which consists of floes turned sideways and piled up by compaction. It can break and does so frequently. To consider that a new feature would be a misunderstanding.

measurements from an aeroplane showing thickness of two year and multiyear ice

Jim Hunt

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Re: The 2015 melting season
« Reply #2377 on: July 22, 2015, 09:09:57 AM »
This photo illustrates what people seem to think off as rotten ice.

See the video and David Barber's paper here:

http://GreatWhiteCon.info/2015/07/is-time-running-out-for-arctic-sea-ice/#RottenIce

Barber's "rotten ice" looks solid to a satellite and is identified as MYI on CIS maps, but on close inspection from an in situ icebreaker:

Quote
It was a mixture of a few small MY ice floes (1 tenth coverage) interspersed in a cover dominated by small (10–100 m) rounded floes of heavily decayed first year sea ice (4 tenths). These floes were overlain by a thin layer of new ice (7 tenth) where freeboard was negative and thin ice growing between remnant pieces when the ice had a positive freeboard.


« Last Edit: July 22, 2015, 09:21:31 AM by Jim Hunt »
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cesium62

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Re: The 2015 melting season
« Reply #2378 on: July 22, 2015, 11:21:19 AM »
... a several week's journey at n million pounds per day in order to find out why a gif on a website is slightly the wrong colour according to the numbers produced by that same website?

How much does a satellite cost? We all know that models have their limitations and spending that amount of money even for a month should be worth it in order to give direct and useful information. In any case I'm having problems giving HYCOM much credibility.

Start at 1 billion $US and go up from there.

At the risk of being evicted by Neven for being so far off topic...

http://www.sciencedirect.com/science/article/pii/S0924271614000720
"
However, there are some examples where costs are known. The costs associated with the largest civilian earth-observing satellite launched so far (the European Space Agency’s Envisat) cost 1450 million euro to build (ESA, 2013). It carried 11 different sensors, measured 10 by 4 by 4 m and weighed 8200 kg. Launching this enormous piece of equipment cost 140 million euro. Developing the ground segment cost a further 160 million, and annual running costs were 60 million euro. The US too has gone on record concerning the costs of the Landsat 8 program; the flight segment (satellite and sensors), the launch, 100-days of in-flight commissioning and system engineering totaled USD 855 million (Irons, 2013). South Africa’s microsatellite Sumbandilasat programme costs too are in the public domain (Martin, 2012 and SunSpace, 2013); around 100 million rand was spent on the program (this is equivalent to just over 9 million euro at the time of launch). Sumbandilasat carried a single sensor, measured 0.7 by 0.5 by 0.5 m and at 81 kg was more than a hundred times lighter than Envisat.
"

So for a small single sensor satellite, perhaps $10M to build and launch plus another $10M to $100M to operate the satellite for ten years.  Apparently the "earth observing" part requires some relatively complicated tracking that makes really small cube-sats unsuitable platforms.


S.Pansa

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Re: The 2015 melting season
« Reply #2379 on: July 22, 2015, 12:18:40 PM »
Yes, this is key. We have to wait for the "80 North" bug in HYCOM/CICE to be fixed, until then, any model which takes the problematic outputs as its own input is thus affected by the bug.

Yes, I thought so too. There seems to be no way around the hycom bug.

But I had a closer look  at Topaz4 and now I am not so sure anymore. If I understand it correctly the Hycom-bug is related to their salinity data. Is that right?

The sss-data from hycom do indeed look odd (see first image).
The sss-data from TOPAZ4 on the other hand look quite different (second image, same date). They say they get their salinity numbers from the Argo float, if I got that right.

So perhaps there is some value to the TOPAZ4 thickness data?

S.Pansa

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Re: The 2015 melting season
« Reply #2380 on: July 22, 2015, 12:21:42 PM »
Well, here are some comparisons.

First image is piomas-thickness for 06/30 (stolen from Wipneus animation on the piomas-thread, hope he doesn't mind).
Second image is Topaz4 thickness for the same date.

There are some differences, notably in the Atlantic sector close to the pole. But on the Pacific side they seem to agree pretty well, perhaps piomass has thinner ice there (of course, pure eyeballing again).

Third image is the topas4 thickness for 07/22

Finally, they have also a forecast which reaches out to 07/30 (last image)

Looks quite strange especially on the Atlantic side (very thin or even no ice way up north). But there might be at least some truth to that if you look at yesterdays Worldview (here).

Whatever, it will be interesting to see how fare Topaz4 is off in a week's time. But 2011 should be doable and 2015 will most probably be followed by 2016 - at least one of this two should be spot on ;-)
« Last Edit: July 22, 2015, 12:31:40 PM by S.Pansa »

cesium62

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Re: The 2015 melting season
« Reply #2381 on: July 22, 2015, 12:37:57 PM »
Eyeballing Wipneus' wonderful area and extent graphs...  In most regions, 2015 is either tracking 2012 or the region is on track to melt out by the middle of September.  The exceptions are the Beaufort and the CAB.  2015 is behind 2012 in the Beaufort and might end up with an extra 100,000 to 200,000 km^2 of ice area and extent from this region.

In the CAB, 2015 is tracking both 2012 and 2013.  The tracks diverge in about two weeks.  2015 would seem to have a good solid 10% chance of following the 2012 CAB track during August.  This would suggest a 10% chance of an overall NSIDC minimum Arctic extent of 3.6M km^2 of ice in September. 

I'd have to stare at a lot more data to figure out where to place the remaining 90% of my bets.  Without looking at that data but eyeballing Charctic, I'd guess a 35% chance to have a lower extent than 2011.

So I think I've ended up at about the same kind of estimate as some others in this thread, but I wasn't quite sure how you had gotten there...



nukefix

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Re: The 2015 melting season
« Reply #2382 on: July 22, 2015, 01:39:33 PM »
How much does a satellite cost? We all know that models have their limitations and spending that amount of money even for a month should be worth it in order to give direct and useful information. In any case I'm having problems giving HYCOM much credibility.
CryoSat-2 cost 140M€, I don't remember if launch costs were included or not..

slow wing

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Re: The 2015 melting season
« Reply #2383 on: July 22, 2015, 02:06:54 PM »
  Nice comparisons, thanks S.Pansa.

  Concerning that model prediction for a week's time, do we have any Worldview or other real data support for the collapse of the East-Atlantic sector (0 to 90 degrees East) almost all of the way to the Pole?

  As counter-evidence, the U. Bremen concentration maps have shown little in the way of concentration  loss anywhere near the Pole in that sector, so I'll remain skeptical until I see some supporting evidence.

This Worldview image for 19 July shows the ice extent edge for most of that 90 degrees sector...

(Update: sorry, image probably isn't showing.)

Note no signs of weakness or imminent disappearance in the ice interior. (With the caveat that I am new to this game and not good at identifying regions covered in cloud. Could someone more experienced please inform on how much of the interior view is ice and how much is cloud?)
« Last Edit: July 22, 2015, 02:13:43 PM by slow wing »

S.Pansa

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Re: The 2015 melting season
« Reply #2384 on: July 22, 2015, 02:24:07 PM »
Hi slow wing,

I agree with you. The melt out on the Atlantic side does not seem likely to me within the next week. There might be some thinning going on - it is very cloudy most of the time but the images for the 17th and the 21th on worldview allow a glimpse here and there  -  but imho no way near enough for the ice to disappear so quickly.

But I am fare from an expert either so ...



Neven

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Re: The 2015 melting season
« Reply #2385 on: July 22, 2015, 02:54:48 PM »
ECMWF now definitely has the high pressure moving over to the Siberian side of the Arctic. It's still pretty high pressure for a couple of days (forecast for days 7-10 show basically the same set-up), but of course no Beaufort Gyre or transport, and more clouds over the vulnerable ice in the Beaufort and CAA. I'm very curious to see what this will bring!
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LRC1962

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Re: The 2015 melting season
« Reply #2386 on: July 22, 2015, 03:29:01 PM »
Apparently the "earth observing" part requires some relatively complicated tracking that makes really small cube-sats unsuitable platforms.
Earth wobbles cause major difficulties for measuring anything from space. The math behind it is extremely complicated. This also causes problems when dealing with the poles as it is impossible for a satellite to stay in space and achieve a true polar orbit. This causes everything you see to be at an angle and therefore you end up with greater atmospheric distortions.
In terms of percentages of accuracy you still end up with incredible outcomes, but in terms of surface numbers you still end up with variants that can be in the metres. For measuring ASI that still can end up with you having numbers that do not match reality.
As for satellites, the bigger the platform the more stable the orbit is in relation to earth. The bigger the platform the more it costs to get it there. The more it costs the more sense it makes to add more stuff. The more stuff you add the more it costs to maintain and convert the raw data into usable data. All this ends up in the laps of bean counters who determine if the money can be found in the first place. Also if the new data is quantifiable enough superior to justify the expense.
Makes me wonder how it was that Pythagoras got so close to the actual polar circumference of the earth when all he had was 2 sticks and a beach to work with.
"All truth passes through three stages: First, it is ridiculed; Second,  it is violently opposed; and Third, it is accepted as self-evident."
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Nightvid Cole

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Re: The 2015 melting season
« Reply #2387 on: July 22, 2015, 03:36:21 PM »
ECMWF now definitely has the high pressure moving over to the Siberian side of the Arctic. It's still pretty high pressure for a couple of days (forecast for days 7-10 show basically the same set-up), but of course no Beaufort Gyre or transport, and more clouds over the vulnerable ice in the Beaufort and CAA. I'm very curious to see what this will bring!

Definitely will be good viewing weather. I also expect area graphs to drop precipitously as a result of the cloud-effects (which tend to bias measured concentration high) dropping out.

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Re: The 2015 melting season
« Reply #2388 on: July 22, 2015, 03:45:45 PM »
To Slow Wing  and Juan Garcia:
And anyone else who can answer my layman questions below

Yes, it looks like the Pacific Blob has been seeping into the Arctic, the warm water staying on the surface, melting a much bigger area than equivalent date in 2012, and snaking around the edges melting those places.
What will happen when the last ice-bridge to land in Northern Siberia melts through and that Pacific Blob water on the surface breaks all the way through?
What is the state of the temperature of the waters coming on from the Atlantic?
Or does the Arctic water flow into the Atlantic, not the Atlantic into the Arctic?
If there is a current through the Arctic from the Pacific that has any strength ( warm water at the surface ), will that warm water current actually quickly pull MORE warm water into the Arctic from the Pacific Blob, once that last ice barrier  once that melts in Northern Russia, and the gates are open?

Tommy.
« Last Edit: July 22, 2015, 03:51:22 PM by Tommy »

Nightvid Cole

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Re: The 2015 melting season
« Reply #2389 on: July 22, 2015, 03:53:38 PM »
To Slow Wing  and Juan Garcia:
And anyone else who can answer my layman questions below

Yes, it looks like the Pacific Blob has been seeping into the Arctic, the warm water staying on the surface, melting a much bigger area than equivalent date in 2012, and snaking around the edges melting those places.
What will happen when the last ice-bridge to land in Northern Siberia melts through and that Pacific Blob water on the surface breaks all the way through?
What is the state of the temperature of the waters coming on from the Atlantic?
Or does the Arctic water flow into the Atlantic, not the Atlantic into the Arctic?
If there is a current through the Arctic from the Pacific that has any strength ( warm water at the surface ), will that warm water current actually quickly pull MORE warm water into the Arctic from the Pacific Blob, once that last ice barrier  once that melts in Northern Russia, and the gates are open?

Tommy.

No, you've got the direction of the currents backwards. Between Severnaya Zemlya and the mainland, the flow is West to East (i.e. Atlantic to Pacific).

Tor Bejnar

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Re: The 2015 melting season
« Reply #2390 on: July 22, 2015, 03:59:40 PM »
From an article I just posted in USCGC Healy: scientific mission to the Arctic
Over 50 Arctic Researchers on Coast Guard Cutter Healy Preparing North Pole Voyage


A map provided by Geotraces of their route to the North Pole this summer. Image: Geotraces.

Excerpts from article:
Quote
[The Geotraces project] — part of an international effort to study the chemistry of Arctic waters.
...
Another reason for the trip north: observing how waters from different parts of the planet mix in the Arctic. That includes warmer water passing through the Bering Strait from the Pacific, but also “heavy water” from the Atlantic.
Arctic ice is healthy for children and other living things.

Tommy

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Re: The 2015 melting season
« Reply #2391 on: July 22, 2015, 04:00:00 PM »
@greatdying2

Yes, thanks. the heating from the Pacific is never going to turn back now, sad but true.
I think that one of the reasons many people watch this ice melt is because of a hope that it will be dramatic enough one year to really scare regular people and governments into action, but not big enough to have any real destructive effect. People are so asleep, it is bad when we have to hope for a dramatic warning from nature, big enough to scare the world, but then a slow down for a couple of decades, long enough for humans to adjust their habits.
I think this year could be a big wake up call.

Tommy

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Re: The 2015 melting season
« Reply #2392 on: July 22, 2015, 04:08:33 PM »
Nightvid Cole

Ok, I see. Thanks.
Does that mean that when the last ice-bridge to Russia melts, cooler water will flow in from the Atlantic, dive under the warm surface water coming from the Pacific Blob, ultimately pushing that water back towards the Pacific?
I could see the Atlantic surface waters pushing back the Pacific Blob waters, but pushing them towards Canada and NW passage, not back out to Pacific. Those Blob waters will still push in along Northern Canada, while the Atlantic waters will dive down (if they are cooler), and flow out into the Pacific along Russia?
Although there could be an ocean pump set up, a bit like the Gulf Stream, that pulls the warm water over the surface towards the Atlantic, while the cool waters from the Atlantic dive down.
What is the temperature of the Northern Atlantic-Arctic surface waters compared to other years?
Is there a site that updates a good graphic or chart for surface water temperatures in N. Atlantic and East Arctic? Maybe showing comparisons to other years?

I think that last ice-bridge to Russia melting is a turning point.
What do people think will happen to the intermixing surface waters when that last ice-bridge to Russia melts?

Thanks

Tommy
« Last Edit: July 22, 2015, 04:16:12 PM by Tommy »

Tommy

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Re: The 2015 melting season
« Reply #2393 on: July 22, 2015, 04:20:19 PM »
Quote
"No, you've got the direction of the currents backwards. Between Severnaya Zemlya and the mainland, the flow is West to East (i.e. Atlantic to Pacific)."

.
To Nightvid Cole, and anyone else:

Ok, I see. Thanks.
Does that mean that when the last ice-bridge to Russia melts, cooler water will flow in from the Atlantic, dive under the warm surface water coming from the Pacific Blob, ultimately pushing that water back towards the Pacific?
I could see the Atlantic surface waters pushing back the Pacific Blob waters, but pushing them towards Canada and NW passage, not back out to Pacific. Those Blob waters will still push in along Northern Alaska, while the Atlantic waters will dive down (if they are cooler), and flow out into the Pacific along Russia?
Although there could be an ocean pump set up, a bit like the Gulf Stream, that pulls the warm water over the surface towards the Atlantic, while the cool waters from the Atlantic dive down.
What is the temperature of the Northern Atlantic-Arctic surface waters compared to other years?
Is there a site that updates a good graphic or chart for surface water temperatures in N. Atlantic and East Arctic? Maybe showing comparisons to other years?

I think that last ice-bridge to Russia melting is a turning point.
What do people think will happen to the intermixing surface waters when that last ice-bridge to Russia melts?

Thanks

Tommy
« Last Edit: July 22, 2015, 04:28:44 PM by Tommy »

Neven

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Re: The 2015 melting season
« Reply #2394 on: July 22, 2015, 04:22:41 PM »
Tommy, a couple of years ago I wrote an article on Ocean Heat Flux in the Arctic. It contains a lot of info on what water goes where and how.
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Tommy

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Re: The 2015 melting season
« Reply #2395 on: July 22, 2015, 04:27:56 PM »
Neven.
Great thanks !

Vergent

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Re: The 2015 melting season
« Reply #2396 on: July 22, 2015, 04:35:49 PM »

iceman

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Re: The 2015 melting season
« Reply #2397 on: July 22, 2015, 04:46:46 PM »

Speaking of quality, the ice in the NWP is in a hurry:

Looks like I was wrong about "mostly in situ melting" in the CAA last week.  Under warm conditions when the ice is prone to cracking, even moderate winds perpendicular to the crack lines can move a lot of ice.
   Some company on the way for those big MYI floes on the Beaufort that have gone astray from the flock.

greatdying2

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Re: The 2015 melting season
« Reply #2398 on: July 22, 2015, 05:19:09 PM »

   Comp         Anomaly   StdDevs
2007   0.4729   -0.0721   -1.47
2008   0.5903   0.0453   0.93
2009   0.5696   0.0246   0.50
2010   0.6171   0.0720   1.47
2011   0.5323   -0.0127   -0.26
2012   0.4997   -0.0453   -0.93
2013   0.5372   -0.0079   -0.16
2014   0.5870   0.0420   0.86
2015   0.4992   -0.0459   -0.94
Quote
But not much worse than 2013, the second highest Sept extent after 2007...

And although the dataset is short there are no 2 and 3 sigma deviations, and no indication of an increase in deviation with time. 1SD is not unusual.
True, 1SD is not unusual, but if the only 2 occurrences in a small dataset happen to coincide with 2 outliers, it may raise at least one eyebrow...  ???

Quote
Have any reports talked of ice full of holes? The impression I got regards rotten ice was of lumps of ice in a lot of water, precisely what the satellites spot. Determining how 'odd' the state of individual  lumps of ice is would not be possible as there is no consistent dataset going back to 1979. So the default position must be: We don't know. With compactnes we have a consistent dataset, and it shows that this year is much worse than decades ago, but not much worse than recent years.
What Andreas and Jim said...
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.

sofouuk

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Re: The 2015 melting season
« Reply #2399 on: July 22, 2015, 05:34:03 PM »
'Makes me wonder how it was that Pythagoras got so close to the actual polar circumference of the earth when all he had was 2 sticks and a beach to work with.'

... Eratosthenes?