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magnamentis

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Re: The 2019 melting season
« Reply #2500 on: June 25, 2019, 09:40:48 PM »
It's not only the most northerly ice that is harder to melt. Historically it has also been the ice along the caa coast which has been most resilient. So just when we thought we were safe, here comes the return of the caa-cab crack with rubble as supporting cast. ;)
worldview aqua modis caa, jun10-25  https://go.nasa.gov/31Smjgf

absolutely, i meant to cover this with:

...........as a tendency with local exceptions due to currents and weather patterns.

thanks for fasten it to an example for better comprehensibility ;)

El Cid

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Re: The 2019 melting season
« Reply #2501 on: June 25, 2019, 09:56:03 PM »
Slater's projection has extent of 5,33 m sq. km on Aug 14. It would be second place as on that date we had

5,63 in 2016
5,52 in 2017
5,51 in 2007
4,93 in 2012

also, he has the NP under attack:


Rich

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Re: The 2019 melting season
« Reply #2502 on: June 25, 2019, 10:27:56 PM »
It's not only the most northerly ice that is harder to melt. Historically it has also been the ice along the caa coast which has been most resilient. So just when we thought we were safe, here comes the return of the caa-cab crack with rubble as supporting cast. ;)
worldview aqua modis caa, jun10-25  https://go.nasa.gov/31Smjgf

The crack returns because the low pressure came back and is spinning the ice in reverse of it's usual spin.

At this point, the condition of that ice is pretty ragged with a lot of exposed surface area so it:s not changing the condition very much.

It's favorable for melt in that it is pushing ice toward the warm 5C+ water on the coast. It also provides temporary inflation of extent.

When the low pressure leaves, the crack closes.


SirLurkALot

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Re: The 2019 melting season
« Reply #2503 on: June 25, 2019, 10:33:25 PM »
The Arctic does tend to surprise us, as for me perhaps the biggest realisation has been how resilient the ice really is. Everything seems to be heading to total oblivion every year, but hey, then it just ends up more or less the same as last year.

But looking at the bigger picture, on average in the 2010s, about 2/3 of the annual max melts out, in other words, the annual melt is double the residual. In the 1980s it was closer to par, slightly more than half the annual maximum melted out.

The decadal average is falling by 1 million km2 each decade, so that gives us 40 years to reach 0 average extent.

To me these numbers imply that the ice is not likely to melt out this year, and that reaching a new record is going to be very difficult (average is 4,4 this decade, the record is 3,2) but reaching second place not so very difficult (4,1) and third place is really just average melt for this decade.
But the 40 year extrapolation  assumes that the melt will proceed in a linear fashion as we get closer to 0 extent.
Many predict that as the ice reduces, positive feedbacks such as lower albedo of open water compared to ice, easier export of less rigid ice masses  and changes to the jet stream mean that ice loss could accelerate and reach a tipping point which could mean 0 ice much sooner.
« Last Edit: June 25, 2019, 11:30:52 PM by SirLurkALot »

uniquorn

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Re: The 2019 melting season
« Reply #2504 on: June 25, 2019, 10:48:09 PM »
return of the caa-cab crack with rubble as supporting cast. ;)
worldview aqua modis caa, jun10-25  https://go.nasa.gov/31Smjgf
The crack returns because the low pressure came back and is spinning the ice in reverse of it's usual spin.
Yes. The crack returns and the rubble doesn't resist.

Steerpike

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Re: The 2019 melting season
« Reply #2505 on: June 25, 2019, 11:18:40 PM »
Hi folks,

Long time (well 3 or 4 years) lurker, throwing in my tuppence worth.

Although I graduated in Physics (focussing on Atmospheric Physics) 40 years ago, and have closely followed climate change since then, I'm no scientific expert, so I'm enormously grateful for all the info posted in the forum and I follow posts avidly on a daily basis.

My thoughts ...

1) We are all (scientists particularly) conditioned to analyse data and give them an elevated status, even when we know there are inaccuracies, caveats and relevant externalities. While sea ice extent is a great indicator of trend, it is only really useful at September minimum to show the trend - and even then conditions leading up to the annual minimum can change the final outcome appreciably.

2) Volume/thickness is key. Yet, as far as I can see, no-one seems to be able to measure it accurately (again, measurements published are useful to show trends, but otherwise, unreliable). The clear trend is that thickness is dropping, but by how much? It doesn't matter how much the extent is, but if the thickness is 1mm, it's going to all disappear in a few days, whatever has happened in similar conditions in previous years...

3) ... and I think that's what's missing from all the extent/area predictions I see on the forum. We can guess at thickness, we see the structure is changing (responsible, I believe, for ice fragility, leading to greater extent on the Atlantic side), but all of a sudden - and no-one knows when - we will see a collapse. My guess (and it's just that) is one autumn soon, the ice will break up and a lot of it flushed out of Fram/Barents. It would probably happen in the late summer when thickness is lowest, and might happen too late for all the ice to be flushed out, leading to a winter re-freeze over the whole of the Arctic, only for the job to be completed the following year.

What's clear to me is the structure of the Arctic sea ice is changing. It seems to be becoming more fragile. This will probably lead to greater extent (possibly area) before over a single year or maybe two it will all go - and we'll all be surprised as the data didn't warn us. Because nature is like that - earthquakes, lightning strikes, volcanoes, atomic quantum levels - the pressure builds, nature tries desperately to maintain the equilibrium, then it suddenly snaps, moves to a different equilibrium state and then desperately tries to maintain that.

As I say, just a few thoughts, and thanks again to all contributors to this forum. It's riveting.

S.
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Neven

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Re: The 2019 melting season
« Reply #2506 on: June 25, 2019, 11:33:01 PM »
In previous years, when some people announced a new record or even a BOE, a) they were quite adamant, b) there was a lot of push-back from various people (including myself), and most importantly c) they used lots of dodgy evidence, such as the DMI volume map or the ACNFS/HYCOM thickness maps. Most of these commenters have either disappeared, or learned from these mistakes.

This year people aren't even all that adamant, but rather say that it's still possible records will be broken. They don't get push-back from people who know how melting seasons work. And most importantly, no dodgy data is being used, and the caveats are known.

That's a big difference with 2016, 2017 and 2018. But it doesn't mean there will be a new record. It's just possible, that's all, while in 2017 and 2018 we already knew by now there was almost zero chance of records being broken. 2016 a bit later.
« Last Edit: June 26, 2019, 06:55:44 AM by Neven »
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petm

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Re: The 2019 melting season
« Reply #2507 on: June 25, 2019, 11:50:33 PM »
Extreme export into the Atlantic throughout the season, which has taken a lot of the MYI - shown in lighter shades on Ascat - out of the basin (courtesy of A-Team in the Test Space thread). The FYI has now reached the North Pole.

Fantastic graphic!

Is it just me, or does the main pack stretch out (while maintaining near 100% concentration) for many weeks (March & April), as a huge amount of ice is exported and melted in the Atlantic, before finally pulling away from the Russian coast (in early May)? I wonder what are the elastic properties of the pack -- does it actually stretch and contract at constant (max) concentration? -- and how such properties are being affected by the dramatic changes in ice characteristics (thickness, age, density, etc.) in recent years.

Another apparently key property affected in recent years seems to be cohesion. I don't recall export east of Svalbard being so fluid in past years.

P.S. (Edit): Not surprisingly, the scientists are already aware of this (and struggling to figure it out), e.g.
https://www.researchgate.net/profile/Gunnar_Spreen/publication/318196769_Sea-ice_deformation_in_a_coupled_ocean-sea-ice_model_and_in_satellite_remote_sensing_data/links/59a53bff45851570311b34fc/Sea-ice-deformation-in-a-coupled-ocean-sea-ice-model-and-in-satellite-remote-sensing-data.pdf
« Last Edit: June 26, 2019, 12:13:00 AM by petm »

Michael Hauber

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Re: The 2019 melting season
« Reply #2508 on: June 26, 2019, 12:22:14 AM »
I think it has no chance.

5th or 6th IMO

In what criteria?

Thats almost impossible at this point.

The weather would have to abruptly go to cloudy and cold and not change back.

I recall 2010.  That was a massive year for volume drop, with a substantial record set for PIOMAS.  June 2010 was a brutal melt month and at about this time extent was well clear of 2007, with a record well on the cards.  Most of the drop in volume anomaly happened in June, and I remember looking at the numbers at the end of June and noting that if the anomaly drop was repeated in July we would be getting pretty close to 0 volume.  The size and speed of the drop caused a few comments in the blogosphere at the time.

First week in July cooler low pressure dominated weather set in, and the melt season stuttered.  2010 found its way to 3rd at the time for extent, or 10th if you include the years 2011-2018.  I think a repeat this year might put us somewhere near 6th this year.  The break from pre-2007 to post 2011 was huge so I think a repeate would put us further back then 3rd, but given 9 years of general warming since 2010 I'd think we'd do better than 10th.  The volume record set in 2010 was beaten in both 2011 and 2012, but has not been beaten since.

I certainly consider top 2 a much better prediction than 5th or 6th, but I wouldn't go so far as to say 5th or 6th is almost impossible.  Maybe a roughly 1 in 10 chance.

Extended GFS does have a low pressure taking over around day 10, but EC doesn't agree.  Extended GFS has forecast something similar for a while, but it seems to be something that is staying out near day 10 and not coming closer.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

magnamentis

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Re: The 2019 melting season
« Reply #2509 on: June 26, 2019, 12:38:27 AM »
3) ... and I think that's what's missing from all the extent/area predictions I see on the forum.

while i read your comment with interest and agree basically with everything, i have to say that because i agree, i also blew into the same horn for years now and in this forum. i used almost the same example of thin ice covering an entire lake and with a bit of foehn wind it's all gone in the morning to meet open water as as far as the eyes can see.

if you want i can seek those post out for you but they are there an BBR at times when he didn't predict a new ice-age also expressed similar thoughts. (and others of course)

as a child about 60 years ago i had the luck to live lake side about 800m above sea-level and at that time lakes that high regularly froze. then my way to school, we didn't have mama-taxis back then but walked on foot about 8 km all shoreline to the lake and each time were able to watch the ice melt and disappear first hand.

Glen Koehler

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Re: The 2019 melting season
« Reply #2510 on: June 26, 2019, 12:39:02 AM »
+1 Steerpike.

   No need for arguments about the 2019 minimum, having a different opinion doesn't make you a denier.  We will all have our hunches confirmed or refuted soon enough. 

    The next 6 weeks will be interesting no matter what happens.
For those of you keeping score at home.


be cause

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Re: The 2019 melting season
« Reply #2511 on: June 26, 2019, 01:29:15 AM »
  my core would be the 6 weeks of 4 and more , and my peak would be the 6 weeks with 37.5 % (3/8) of the total melt , we are 2 days into the peak .. eek !  ..
  I appreciate the info , would love to see recent years in comparison .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Ice Shieldz

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Re: The 2019 melting season
« Reply #2512 on: June 26, 2019, 01:41:47 AM »
Check out Nullschool North Pacific SSTA from 4/27-6/21 (in weekly increments)  In addition to the obvious bespoke heat buildup in bearing sea - note the pacific northwest 'Blob' coming online. Most that research the blob's effects say that it is not necessarily a forcing agent on the jet-stream, because jet forcing primarily comes from tropical waters. However, the jury is still out as to the degree that the blob is responsible for maintaining the persistence of ridging/troughing in the wider area.

Shared Humanity

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Re: The 2019 melting season
« Reply #2513 on: June 26, 2019, 01:53:29 AM »
It's not only the most northerly ice that is harder to melt. Historically it has also been the ice along the caa coast which has been most resilient. So just when we thought we were safe, here comes the return of the caa-cab crack with rubble as supporting cast. ;)
worldview aqua modis caa, jun10-25  https://go.nasa.gov/31Smjgf

That is a frightening video. Ice north of the CAA did not use to look like this. Did it lift off from the CAA? Yes but it consisted of large sheets of MYI, not the rubble you see here.

Frivolousz21

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Re: The 2019 melting season
« Reply #2514 on: June 26, 2019, 02:00:34 AM »
This bullshit about June not being the most important month is just embarrassing.

Whatever.  Going to look stupid come August.



Also anyone who thinks the ice isn't heading into July in the worst shape we have ever seen it overall is clueless.

I'm sorry for the hard line language but there should be an intellectual integrity here but whatever.

As soon June 15th 2019 THIS YEAR WAS SECOND LOWEST VOLUME ON RECORD.

SINCE JUNE 15TH:

2012 VERSUS 2019.

NOT EVEN CLOSE.


A lot of times BBR can really go nuts with the hyperbole.  Way more than myself and others.  But his claims of 2019 being the worse off are dead on.

The only difference is the Western CAB and parts of the CAA in 2012 got hit good in a warm sunbath by now.

This year the ESS region has taken a bath in the heat.

Half of the Arctic is getting pulverized with solar max insolation and highly anomolous mid level temps.



« Last Edit: June 26, 2019, 02:17:18 AM by Frivolousz21 »
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Re: The 2019 melting season
« Reply #2515 on: June 26, 2019, 02:06:54 AM »
Friv...pretty stark contrast...I am feeling a little uneasy and would welcome a shift into a weather pattern that is less conducive to melt.

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Re: The 2019 melting season
« Reply #2516 on: June 26, 2019, 02:13:42 AM »
This bullshit about June not being the most important month is just embarrassing.

Whatever.  Going to look stupid come August.



Also anyone who thinks the ice isn't heading into July in the worst shape we have ever seen it overall is clueless.

I'm sorry for the hard line language but there should be an intellectual integrity here but whatever.

As soon June 15th 2019 THIS YEAR WAS SECOND LOWEST VOLUME ON RECORD.

SINCE JUNE 15TH:

2012 VERSUS 2019.

NOT EVEN CLOSE.
What are your thoughts on the forecast for the next 5-7 days?

Tor Bejnar

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Re: The 2019 melting season
« Reply #2517 on: June 26, 2019, 02:22:58 AM »
Welcome, Steerpike!
As some have said, the first post is the hardest.

Quote
one autumn soon, the ice will break up and a lot of it flushed out of Fram/Barents.
I sometimes forget how big the Arctic Ocean is.  (It, after all, fits on my computer screen, right? :o )  A-Team occasionally posts movies that trace identifiable features through a season or two (e.g., here - 3rd movie).  At 'real life' rates, it would take several months to move ice from the North Pole to a graveyard sea in a good-for-export year (as last 6 months have been).  Even those of us who are 'slow' would see the possibilities.  (We never know if it is a good-for-export year until we're most of the way through it.)
A-Team wrote in that linked May post:
Quote
Normally [the ice] just sits there but over the last 172 days a great unprecedented swath of ice has steadily moved from islands off central Siberia across the pole nearly to and out the Fram.
And a BOE is not likely this year.  [In 2013 I predicted 'ice-free Arctic' in 2019 ..., so I'm not declaring this outcome definitively, yet!  ::) :P )
Arctic ice is healthy for children and other living things.

Michael Hauber

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Re: The 2019 melting season
« Reply #2518 on: June 26, 2019, 02:27:06 AM »

Also anyone who thinks the ice isn't heading into July in the worst shape we have ever seen it overall is clueless.

As soon June 15th 2019 THIS YEAR WAS SECOND LOWEST VOLUME ON RECORD.

SINCE JUNE 15TH:

2012 VERSUS 2019.

NOT EVEN CLOSE.


Is one week of 'NOT EVEN CLOSE' hotter weather in 2019 enough to catch up to 2012?

Consider also that that week of cooler weather in 2012 was due to a strong but short lived low pressure system which had a dramatic impact on the visual appearance of the ice, introducing stripes of open water to a large part of the pack, which then proceeded to melt  through the rest of the season.  2013 showed that constant low pressure which causes ice dispersion helps maintain ice overall, but I suspect that 2012 was strongly assisted by short periods of low pressure increasing dispersion and allowing warm weather afterwards to have a much larger impact over a larger area of the ice.

Climate change:  Prepare for the worst, hope for the best, expect the middle.

Ice Shieldz

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Re: The 2019 melting season
« Reply #2519 on: June 26, 2019, 02:31:40 AM »
In regards to the visual quality of the ice north of CAA, below are Worldview comparisons of 2019 June 25th, 2016 June 13th and 2012 Jun 29th. These are the closest corollaries that i can find to our current situation, especially given that the CAA is usually quite cloud covered around these dates. Recently we've had several days of anomalously clearer skies that enabled uniquorn to provide that killer animation.

Rich

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Re: The 2019 melting season
« Reply #2520 on: June 26, 2019, 02:55:21 AM »
This bullshit about June not being the most important month is just embarrassing.

Whatever.  Going to look stupid come August.



Also anyone who thinks the ice isn't heading into July in the worst shape we have ever seen it overall is clueless.

I'm sorry for the hard line language but there should be an intellectual integrity here but whatever.

As soon June 15th 2019 THIS YEAR WAS SECOND LOWEST VOLUME ON RECORD.

SINCE JUNE 15TH:

2012 VERSUS 2019.

NOT EVEN CLOSE.


A lot of times BBR can really go nuts with the hyperbole.  Way more than myself and others.  But his claims of 2019 being the worse off are dead on.

The only difference is the Western CAB and parts of the CAA in 2012 got hit good in a warm sunbath by now.

This year the ESS region has taken a bath in the heat.

Half of the Arctic is getting pulverized with solar max insolation and highly anomolous mid level temps.

Don't let 'em get to you Friv. The smart people know what's up.

In a few days this thread is going to collectively have an OMG moment when they see the Laptev open water expand.

Frivolousz21

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Re: The 2019 melting season
« Reply #2521 on: June 26, 2019, 03:02:54 AM »

Also anyone who thinks the ice isn't heading into July in the worst shape we have ever seen it overall is clueless.

As soon June 15th 2019 THIS YEAR WAS SECOND LOWEST VOLUME ON RECORD.

SINCE JUNE 15TH:

2012 VERSUS 2019.

NOT EVEN CLOSE.


Is one week of 'NOT EVEN CLOSE' hotter weather in 2019 enough to catch up to 2012?

Consider also that that week of cooler weather in 2012 was due to a strong but short lived low pressure system which had a dramatic impact on the visual appearance of the ice, introducing stripes of open water to a large part of the pack, which then proceeded to melt  through the rest of the season.  2013 showed that constant low pressure which causes ice dispersion helps maintain ice overall, but I suspect that 2012 was strongly assisted by short periods of low pressure increasing dispersion and allowing warm weather afterwards to have a much larger impact over a larger area of the ice.

I'm not sure what short lived matters????  The weather in June of 2019 has been worse for the ice than in 2012.

And since the mid month piomas update showing 2019 closing the gap.  The weather has been dramatically worse in 2019.  That's 8 more days during the peak insolation.

The next 30 hours will continue to show 2019 getting the hammer while 2012 still had cloudy much cooler conditions.


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oren

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Re: The 2019 melting season
« Reply #2522 on: June 26, 2019, 03:16:30 AM »
For those who asked about the Ascat animation, here are some further explanations by A-Team. I recommend to browse the Test Space thread to get more of this A-level stuff.

Quote
Why are Ascat and SMOS affected in summer?
Testing the common daily observational products for systemic interpretation-altering 'transitions' over the last 24 days since Jun 1st, Ascat, SMOS and SMOS-SMAP are the most affected whereas AMSR2, SMOS-TB, Sentinel-1, Osisaf, and WorldView are not.

Although AMSR2 shows passing fuzzy weather artifacts throughout the spring (1st mp4), it still gets the peripheral concentration right into the summer (and indeed through the summer going by past years). The UH product uses the passive 89 GHz (0.3 cm) channel.

With ASCAT, a real aperture active radar operating at 5.3 GHz (5.7 cm wavelength), the most noticeable changes are darkening of whitish multi-year ice in the CAB, washing out of contrast off Siberia, flashing intensities over open water, and appearance of swath lines over the 24 hour build. You can see those in the archived originals, the enhanced, and the June 24th. These are large format pngs so need a click to open at full size.

With SMOS, a passive radar operating at 1.3 GHz (21 cm wavelength), the output gradually sheds its reliable interpretation as thinness beginning in May; adding SMAP helps some but is not a complete fix. SMOS has not gone completely crazy as it first appears: open water is still accurately detected, colors are still palette-radial, and correlations with shorter wavelength satellites can still be seen.

A number of factors associated with summer weather contribute to change (or even loss) of interpretability, among them melt of snow cover, loss of surface roughness, warming of surface ice, advection of moist warm sea air, rain affecting upward extruded brine channels, localized and variable rfi (radio frequency interference), and so on.

A certain level of weather reanalysis -- to replace dodgy forecasts -- would be very useful. However there is not a single instrument currently deployed on the Arctic Ocean that could validate weather parameters.

Since weather events affect the Arctic Basin unevenly, the explanation of changes has to be region-specific and time-dependent. So a lot of information is at hand but easy answers are not. Here we are not "making animations"  but rather testing various ways of viewing disparate data simultaneously (rather than as static GIS layers).

Frivolousz21

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Re: The 2019 melting season
« Reply #2523 on: June 26, 2019, 03:22:35 AM »
Another comparison.

That's pretty amazing.  2012 lost about 10 days of insolation centered around the peak.

The weather forecast is just brutal.

The gfs model around day 7-8 goes towards a weak vortex over parts of the Arctic.

But it keeps losing it and pushing it back.

The Euro is awful. 

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Ice Shieldz

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Re: The 2019 melting season
« Reply #2524 on: June 26, 2019, 03:36:28 AM »
For those who asked about the Ascat animation, here are some further explanations by A-Team. I recommend to browse the Test Space thread to get more of this A-level stuff.
Indeed! Thanks Oren. Here is the link to A-Team's post in Test Space (might require scroll down to get to it: https://forum.arctic-sea-ice.net/index.php/topic,2558.msg208347.html#msg208347

What a treasure trove of A-level material. Got some homework to do for sure.

oren

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Re: The 2019 melting season
« Reply #2525 on: June 26, 2019, 03:39:35 AM »
Is it just me, or does the main pack stretch out (while maintaining near 100% concentration) for many weeks (March & April), as a huge amount of ice is exported and melted in the Atlantic, before finally pulling away from the Russian coast (in early May)? I wonder what are the elastic properties of the pack -- does it actually stretch and contract at constant (max) concentration? -- and how such properties are being affected by the dramatic changes in ice characteristics (thickness, age, density, etc.) in recent years.
The pack does not actually stretch, as it is not cohesive, and ice is not stretchable anyway. What is really happening is that open water is created at the top of the "stretch", and due to the low wintertime temps the open water freezes, thus completing the ice cover and keeping constant max concentration. But this hides the process of effective thinning of the central pack, which this year has been extra-active.
When air temps rise above -10C or thereabouts, the open water has a much harder time keeping up, and eventually the mobile ice is seen to break away from the shore-fast ice.
This process can be seen in animations like this one posted by A-Team.

petm

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Re: The 2019 melting season
« Reply #2526 on: June 26, 2019, 03:41:50 AM »
My thoughts ...

Exactly! Volume is the key.

Or at least it's a helluvalot better than 2D (extent/area) measures, although it still doesn't incorporate other properties like strength, density, etc. But hopefully it broadly correlates with them.

And we can't measure volume. I'm skeptical about models like PIOMAS, given how many unknowns there are, likely with increasing importance. Hopefully ICESat-2 will help soon (https://nsidc.org/data/icesat-2/products/level-3b).

At equal volume, 2D minimums can differ dramatically based on ice distribution, and can even be heavily influenced by winds even in the week(s) immediately prior to minimum. This seems to account for much of the supposedly huge anomaly in 2012 -- the PIOMAS volume residual (insofar as it can be trusted) wasn't nearly as high as extent. Are we trying to measure September winds, or ice melt?

The ice goes from meters deep to cm's to mm's to... poof! 2D measures detect only the poof.

vox_mundi

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Re: The 2019 melting season
« Reply #2527 on: June 26, 2019, 03:49:32 AM »
Here’s an animation of the upper-air pattern forecast for the next 10 days. CAA looks to be on the warm side.  A piece of the Polar Vortex, may try to dip back down into central Canada in early July.



https://www.mlive.com/weather/2019/06/polar-vortex-shifting-north-for-at-least-a-short-term-warm-up.html?outputType=amp
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ajouis

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Re: The 2019 melting season
« Reply #2528 on: June 26, 2019, 04:03:09 AM »
The slater model seems to indicate vulnerabilities, matching with the nsidc concentration map, on the laptev bite and north of greenland. Those could clearly result in a partitioned pack with open water traversing the pole. What would happen to the smaller, non land-fast, section, in the atlantic side, in that scenario?

petm

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Re: The 2019 melting season
« Reply #2529 on: June 26, 2019, 04:13:00 AM »
What is really happening is that open water is created at the top of the "stretch", and due to the low wintertime temps the open water freezes

You're right. It was just getting papered over in the Laptev by new, thin ice -- while thick ice poured down the Atlantic drain.

Michael Hauber

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Re: The 2019 melting season
« Reply #2530 on: June 26, 2019, 05:18:41 AM »
Quote from: Frivolousz21

I'm not sure what short lived matters???? 
A short lived low creates dispersion with only a short period of cooler weather.  A long lived low creates dispersion with a long period of weather.

Quote from: Frivolousz21
The weather in June of 2019 has been worse for the ice than in 2012.

Its been hotter than 2012.  But I don't think heat is the only factor.  Have a look at some of the dispersion created in 2012.  Look at the same area today
Climate change:  Prepare for the worst, hope for the best, expect the middle.

slow wing

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Re: The 2019 melting season
« Reply #2531 on: June 26, 2019, 06:22:37 AM »
2019 is certainly still in the running for a top 2 finish (+/- 1), with the two main reasons besides the relentless weather:
Low area inside the Inner Basin (courtesy of Wipneus).
Extreme export into the Atlantic throughout the season, which has taken a lot of the MYI - shown in lighter shades on Ascat - out of the basin (courtesy of A-Team in the Test Space thread). The FYI has now reached the North Pole.
[link to post]

Thanks A-Team, and to Oren for posting it in this thread.

That is impressive differentiation between MYI and FYI in the ASCAT gif!

A-Team has posted in the Test space thread that ASCAT uses microwaves: "a real aperture active radar operating at 5.3 GHz (5.7 cm wavelength)".

That Test space post also refers to the other microwave data we are looking at regularly here: "SMOS, a passive radar operating at 1.3 GHz (21 cm wavelength)".

A-Team has also been reading the SMOS literature and reports:

"SMOS is not a melt pond tool. If it were, they would be shouting hooray. Elsewhere, over land, it measure moisture in soil. It does not measure moisture per se in ice/snow/re-frozen melt. At 21 cm wavelength, it is greatly affected by an assortment of surface properties, most but not all salinity-related."

  So, referring that back to the ASCAT gif, given that SMOS and ASCAT are both microwave measurements -- albeit with significant differences -- may I ask this: does the good ASCAT differentiation between (lighter) MYI and (darker) FYI come from picking up the characteristic differences in ice thickness, or does it instead come from the characteristic differences in ice salinity, or even something else?

Asked briefly: is that gif showing ice thickness or, instead, ice salinity?
« Last Edit: June 26, 2019, 06:36:52 AM by slow wing »

subgeometer

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Re: The 2019 melting season
« Reply #2532 on: June 26, 2019, 06:24:24 AM »
Focussing on "the numbers", as you put it, is an example of the streetlight effect. Area and extent are useful in sometimes indicating anomalous regions, regions where one might want to try to figure out what's happening, but nothing more. (Obviously just my opinion.)

Really it just comes down to the weather now.

Area and extent are imperfect indicators, but at least can be directly and fairly reliably measured, unlike, say, volume. Area and extent numbers and maps from the various outfits that produce them (NOAA, uni Bremen, Jaxa ...) stay in general agreement while what volume maps exist are much more idiosyncratic.

Changes in area and extent have to be read in context - time of year, weather conditions, the quantitative(eg thickness) and qualitative(eg solid pack or loose rubble, rottenness) state of the ice. JAXA flatlined because of ice export and dispersion from June12-16 (losing only 40000km2 of extent in that period) while the weather was terrible for ice and volume was clearly taking a hammering - all those deep blue meltponds, and the huge amount of wet ice that appeared around then.

These are subjective and complex judgements to make for anyone. Its easy to get (maybe over)excited by some event. especially for us interested newbies with only a few or less seasons under our belt.

Speakin' of exciting, here's an area of the ESS in meltdown over the past week(the big bay just to the west of the centre of the ESS coast), under heat and full sun at solstice, including plenty of in situ melt. I've also attached an image of the whole sea today

subgeometer

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Re: The 2019 melting season
« Reply #2533 on: June 26, 2019, 06:46:51 AM »
What is really happening is that open water is created at the top of the "stretch", and due to the low wintertime temps the open water freezes

You're right. It was just getting papered over in the Laptev by new, thin ice -- while thick ice poured down the Atlantic drain.

The Laptev Sea has always been getting papered over by new ice, in the olden times it was referred to as an ice nursery, a major source of what would go on to become multi year ice, doing the circuit thru the CAB and Beraufort etc(and a considerable amount exiting via Fram Strait). Winter southerly winds from Siberia made creation of new ice volume very rapid, and efficient

Someone recently posted references here to a paper on this topic(sorry, I haven;t time to find it now), the conclusion being that under the new warming regime, with longer melt and shorter, insipid, freeze, a lot of the nursery ice doesn't survive long enough to exit the Laptev Sea, let alone become MYI, or exit via Fram (though at the same time, a mobile pack is easier to push through the door when conditions favour export)


subgeometer

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Re: The 2019 melting season
« Reply #2534 on: June 26, 2019, 07:05:15 AM »
Volume is key for us here maybe, but I wouldn't write off 2D measurements as necessarily secondary for everything. Eg in its effects on the the weather and climate, extent/area measures  (where ice is) are the key thing. That sets the albedo, in part determines location of the jetstream, etc

oren

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Re: The 2019 melting season
« Reply #2535 on: June 26, 2019, 07:23:56 AM »
  So, referring that back to the ASCAT gif, given that SMOS and ASCAT are both microwave measurements -- albeit with significant differences -- may I ask this: does the good ASCAT differentiation between (lighter) MYI and (darker) FYI come from picking up the characteristic differences in ice thickness, or does it instead come from the characteristic differences in ice salinity, or even something else?

Asked briefly: is that gif showing ice thickness or, instead, ice salinity?
Not thickness. Some property of the ice surface, perhaps roughness, perhaps salinity, perhaps snowcover, perhaps a combination. This is way above my pay grade. But certainly a property affected by surface weather events.

epiphyte

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Re: The 2019 melting season
« Reply #2536 on: June 26, 2019, 07:38:18 AM »
I've been looking hard and I see nowhere in the entire arctic that looks substantively better off than 2012, and much that is worse. There is apparent serious fragmentation and/or at least some melting at just about every point on the compass.  Whilst there are areas which at first glance appear to be holding up, for the most part they too seem at risk: 

 - Michael H posted an image depicting more apparent solidity in the Northern part of ESS, but the water has only just opened up to the south and the wind has been compacting that area for a few days now, so it's susceptibility to fragmentation would not yet be apparent. Also, it's all FYI except for a swath toward the southern edge, which is currently being hammered, and it's just starting to turn blue. Absent some cold air and/or snow materializing from somewhere, it's toast.

- Kara still has some ice, whereas in 2012 it had been gone for a while at this point. Half of it, however, has disapparated in the last week.  Prognosis: Fission products on toast.

- A couple of weeks ago Friv pointed out that CAA seemed to be shaping up to be something of a bastion against the possibility of total collapse, and at that time I would have agreed, but since then, not only has it gone downhill fast, but also there are signs of melting/fragmentation in the  remaining FYI to the North on both the Atlantic and Beaufort sides.

- All of which leaves the MYI north of the central CAA + eastern Greenland as the last vestige of normalcy - except that it isn't;To add insult to injury, the failure of the Nares strait to close over last winter has, since before the sun came up, been steadily undermining the only part of the arctic not currently susceptible to existentially threatening melting conditions. Furthermore, the concomitant fragmentation to both east and west has led to the separation from the continent and ongoing dispersal of the last remaining MYI in the Arctic. 

So where does all this leave us? For my own part I'm thinking that we're somewhere we've never been before. In the past, from this time of year on, extraordinary weather has always been needed to see a record low. Right now, we're going to need something extraordinary to _prevent_ one.
 
« Last Edit: June 26, 2019, 07:43:48 AM by epiphyte »

Frivolousz21

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Re: The 2019 melting season
« Reply #2537 on: June 26, 2019, 09:03:41 AM »
Quote from: Frivolousz21

I'm not sure what short lived matters???? 
A short lived low creates dispersion with only a short period of cooler weather.  A long lived low creates dispersion with a long period of weather.

Quote from: Frivolousz21
The weather in June of 2019 has been worse for the ice than in 2012.

Its been hotter than 2012.  But I don't think heat is the only factor.  Have a look at some of the dispersion created in 2012.  Look at the same area today

Short or long.  2012 had an anomously cold 10 days in June centered on the solstice.

2019 is Torching it's way to the warmest June on record.



At 00z at OSTROV KOTELNYJ:

TEMP: 19.4C
DP: 12.4C
WINDS:. FROM THE SSE AT 12KTS.

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Viggy

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Re: The 2019 melting season
« Reply #2538 on: June 26, 2019, 10:31:49 AM »
There is continuous and incredible Fram export on all 10 days of the GFS forecast ... absolutely insane to picture the amount of ice that's gonna flow out of the Arctic, if that happens.

Curious to see how it looks on the Fram export graph that accompanies Wipneus' bi-monthly Piomas updates.

aslan

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Re: The 2019 melting season
« Reply #2539 on: June 26, 2019, 10:47:22 AM »



At 00z at OSTROV KOTELNYJ:

TEMP: 19.4C
DP: 12.4C
WINDS:. FROM THE SSE AT 12KTS.

Insane

And getting more insane at 06Z with 22.4°C and 14.8°C

https://www.ogimet.com/cgi-bin/gsynres?ind=21432&lang=en&decoded=yes&ndays=5&ano=2019&mes=06&day=26&hora=09

The record high Tx of yesterday could be break today. As a side note, à Td above 18°C is usualy consider as tropical... Temperatures  at this island would be normal for this time of year for cities usualy around 45° to 50°N. And it is not only Kotelnyj even though this is were the anomalies are the most extreme

https://www.ogimet.com/cgi-bin/gsynop?lang=en&zona=artico&base=bluem&proy=orto&ano=2019&mes=06&day=26&hora=06&vte=Te&Send=send

Forecast were definitely not exagerated.

oren

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Re: The 2019 melting season
« Reply #2540 on: June 26, 2019, 10:55:12 AM »
The temp graph for Kotelny Island. 11 days in June have hit a record for the date, and the month is still not over. I am out of superlatives...
For anyone who is not aware of the location, it's in the New Siberian Islands, separating the Laptev from the ESS and the CAB.

iceman

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Re: The 2019 melting season
« Reply #2541 on: June 26, 2019, 11:23:43 AM »

Accumulated albedo anomalies are actually almost above 2016 again:


The distribution of the anomaly is bad news, especially for ice volume.

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Re: The 2019 melting season
« Reply #2542 on: June 26, 2019, 11:24:12 AM »
I remember when the Arctic used to be colder than the British Isles.

Remember when that was a ridiculous statement for someone to even imagine saying.

Now though we are getting temperatures into the 20s today most of June has been 12 to 15c (54 to 59F) whilst parts of the Arctic have been 22 or 23c (72 to 73F)

uniquorn

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Re: The 2019 melting season
« Reply #2543 on: June 26, 2019, 11:28:25 AM »
Greenland sea ice extent dropping fast recently. Maybe due to the current stall in export, maybe due to the export being thinner, or both.
wipneus amsr2 uh, regional extent, jun25.
piomas(model), fram, jan1-jun15
edit: the piomas animation ends before the recent stall and drop.
« Last Edit: June 26, 2019, 12:32:56 PM by uniquorn »

be cause

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Re: The 2019 melting season
« Reply #2544 on: June 26, 2019, 11:31:11 AM »
 re posts @ heat ^^  thank goodness ( as has been argued up thread ) the weather in June has no bearing on the melt season outcome .

   Z Labe's arctic monthly graph shows 2005 was the warmest June recently with 2007 and 2012 (funnily enough) lying 2nd and 3rd . In otherwords we have not had a warm June recently to test the hypothesis.

 The last 2 july's have been only 29th and 30th warmest in the satellite era and we have to look back to 2007 for the warmest and all the way to 1998 for the 2nd warmest . Are cool July's a trend or will things change ?

I for one cannot believe the weather in June will not affect the season's outcome .. b.c.
 
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

SirLurkALot

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Re: The 2019 melting season
« Reply #2545 on: June 26, 2019, 11:51:21 AM »
Greenland sea ice extent dropping fast recently. Maybe due to the current stall in export, maybe due to the export being thinner, or both.
wipneus amsr2 uh, regional extent, jun25.
piomas(model), fram, jan1-jun15
From the gif, towards the end of the period,
it looks like there is a substantial drop near the south east coast of Greenland.
Could be due to  melting of already exported ice  to warming waters rather than a drop in export?

LRC1962

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Re: The 2019 melting season
« Reply #2546 on: June 26, 2019, 12:34:24 PM »
The temp graph for Kotelny Island. 11 days in June have hit a record for the date, and the month is still not over. I am out of superlatives...
For anyone who is not aware of the location, it's in the New Siberian Islands, separating the Laptev from the ESS and the CAB.
As a Canadian, the map has a small typo. Saint John is in New Brunswick. St. John's is in Newfoundland. Canada likes making map makers life interesting.
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uniquorn

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Re: The 2019 melting season
« Reply #2547 on: June 26, 2019, 12:35:42 PM »
From the gif, towards the end of the period,
it looks like there is a substantial drop near the south east coast of Greenland.
Could be due to  melting of already exported ice  to warming waters rather than a drop in export?
yes, the animation doesn't include the recent drop. I've edited the post upthread.

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Re: The 2019 melting season
« Reply #2548 on: June 26, 2019, 12:55:15 PM »
Greenland sea ice extent dropping fast recently. Maybe due to the current stall in export, maybe due to the export being thinner, or both.
wipneus amsr2 uh, regional extent, jun25.
piomas(model), fram, jan1-jun15
From the gif, towards the end of the period,
it looks like there is a substantial drop near the south east coast of Greenland.
Could be due to  melting of already exported ice  to warming waters rather than a drop in export?

Most likely this is due to the wind aided stall in export. Without a steady supply of ice, the water warms up quickly.

uniquorn

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Re: The 2019 melting season
« Reply #2549 on: June 26, 2019, 01:43:03 PM »
Western Fram Strait is the main exit for the cold surface current out of the arctic so it tends not to heat up quickly despite a lack of ice. Even so, there is plenty of melt, especially further south.
mercator (model), sea temperature 0m, greenland, mar21-jun25
worldview, greenland sea, jun25.
edit: note also the current from greenland sea to labrador warming up.
forgot scale
« Last Edit: June 26, 2019, 04:31:39 PM by uniquorn »