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F.Tnioli

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Re: The 2019 melting season
« Reply #5000 on: July 30, 2019, 06:10:10 PM »
...
Anyone care comment on the North African heat bomb that roasted Europe and has just lit up Greenland and Ellesmere heading for the Lincoln Sea?
Well, i commented about it 7 pages ago - i mean this one. And if you mean to comment current situation - well, not much to say. It's insane and it's happening:



As for what exactly consequences for sea ice and melt season will be - remains to be seen...

« Last Edit: July 30, 2019, 06:35:34 PM by F.Tnioli »

Freegrass

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Re: The 2019 melting season
« Reply #5001 on: July 30, 2019, 06:27:15 PM »
Still a little extreme.
Yes, it sure is weird. I also checked SST, and they show an increase all over the place. 4°C may be some exaggeration from me, but the temperature went from -1.5°C to above freezing in most places.

I thought satellites could only measure the top 1/10 mm of the ocean. Perhaps a still warm day with little mixing?

There was always a nice breeze over that water, so I doubt there was little mixing.
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Glen Koehler

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Re: The 2019 melting season
« Reply #5002 on: July 30, 2019, 06:31:45 PM »
Climate Reanalyzer / GFS forecast for precipitable water shows low pressure system movement swiping from west to east (looking from North American side) just south of the North Pole on days 1-10.
 https://climatereanalyzer.org/wx/fcst/#gfs.arc-lea.pwtr

  In addition, a low pressure system over NW Russia goes below the 980mb Category 1 hurricane pressure threshold at times but weakens and dissipates by the time it moves over to FJL/Barents Sea at end of the 10 day forecast.  If that all happens it would contribute to the air flow to move less than solid CAB ice towards Atlantic side and eventual export to melt in the Barents and Greenland seas.  Not a repeat of 2012 GAC by any stretch, but another potential contributing weather factor to move ice and possibly stir up water enough to bring up subsurface heat.

   As PETM said upthread, the destruction is interesting to watch, but this is getting scary. 
Yes, there will be overwintering ice from which to rebuild over what is likely going to be another wimpy (relative to pre-2015) Arctic winter.  But it will be thinner, less volume, younger and less melt resistant at start of 2020 melt season than in the past.  Nothing new in that I guess, it's been following that trajectory for decades now.  If more of the same can be called news, the news is that the progressive disruption of the Arctic sea ice, and interference with the roles it plays in the climate system, isn't turning around or slowing down.

F.Tnioli

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Re: The 2019 melting season
« Reply #5003 on: July 30, 2019, 06:36:27 PM »
As of today, the Greenland's highest point surface temperature became above 0C (just 1 pixel above 0C line) and stays there for a few hours already (this is measurement, not modelling). Means even the summit, which is ~3200m above sea level, will see at least some melt despite all the elevation. The amount of heat at lower elevations (and thus melt, and thus meltwater going to do bottom melt to sea ice later on in the season) - will thus be huge.

Shared Humanity

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Re: The 2019 melting season
« Reply #5004 on: July 30, 2019, 07:09:37 PM »
July 22 to July 29 gradual shift. UH concentration.
A 'rubble' extent very distinguished from a more solid pack

Cracks will often form over the northwest or northeast coast of Greenland as well as the western CAA, less frequently perhaps over the eastern CAA and open water in the Lincoln Sea is a regular occurrence. I don't believe I have ever seen the ice pack lift off the entire length!

We have lift off!!!!

Steven

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Re: The 2019 melting season
« Reply #5005 on: July 30, 2019, 07:38:12 PM »
Note to Oren .. Geronto's  NSIDC graph yesterday showed ESS this year in a clear lead .. bbr was being factual with his CAPS .. but facts vary .. not just in Trump's world .. b.c.
Thanks b.c., I didn't think to check that, though it seems I was correct anyhow. NSIDC area chart shows the same behavior, 2015 and 2017 on same leading path as 2019, with 2012 and 2016 coming from behind and overtaking them soon.

Don't forget 2007, which was much lower than the other years for the ESS at this time of year:



(Image from Wipneus' regional NSIDC area graphs.)

aslan

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Re: The 2019 melting season
« Reply #5006 on: July 30, 2019, 08:29:31 PM »
Could any climate model aficionados comment on whether (no pun intended) the model runs are responding to the rapid increases in open ocean (and should we expect them to)? Or if they are not responding, is there a noticeable systematic divergence between forecasts and observed weather?

Not sure if this is a practical question, but the circumstances seem to warrant it...

Edit: E.g. The attached forecast seems to respond, with the little remaining jet following the *current edge of the Pacific ice (*which will likely have moved considerably by the time of the forecast arrives in over a week).

Outside the question of the jet, there is also others consequences. Models are showing more influence of diabatic process and warm core process in cyclogenesis for example. The european guy (I don't bother wit GFS) this morning is forecasting TCU/CB in Beaufort around 72H with the weak low, and some warm core process definitively going on.

It was not fully intended, but by the way and by way of illustration, GFS has come closer to others global models, and is showing more deepening forced by diabatic heating. But it is still shy. IFS this evening is down to 993 hPa for this low, with stronger convection, and an another global model is down to 992 hPa. This has also consequences for sea state, as the aforementioned other global model is showing a sea of 4 meters and 10 seconds -again, probably a pleasant day for an Irish sailor, but for Arctic this is significant- while the sea state for 12Z IFS is not yet available. In the same time GFS is not able to build up a strong sea, as weaker low and weaker convection inhibit surface wind. But this is not specific to Arctic here, GFS is generally not the best global model. It is just a good illustration of the effect of changing surface flux. And of course, this would not have been possible 10 years ago with sea ice as thick as a glacier in Beaufort - surface flux being not significantly different from zero...- when sea was closed up to near the coast.

P.S. : Be patient just a few minutes :p Sea state of 3m and 7s at max for IFS, but still more than the sea state of GFS with less than 2m and 6s max period...
« Last Edit: July 30, 2019, 08:41:46 PM by aslan »

oren

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Re: The 2019 melting season
« Reply #5007 on: July 30, 2019, 08:34:22 PM »
To anybody who was hoping that the recent slowdown in area loss per NSIDC will translate to an extent loss slowdown (including me), I believe the UH AMSR2 area data is signalling the opposite. The last few days has seen a serious crash in the inner basin. The UH animation (July 21st-29th, CLICK) shows this visually.
Looking at the low concentration rubble, I expect the ESS to provide a GAC-like extent loss, without a GAC, in the next week or two.
« Last Edit: July 30, 2019, 10:00:30 PM by oren »

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Re: The 2019 melting season
« Reply #5008 on: July 30, 2019, 10:06:22 PM »
I thought it would be interesting to get a good view of the separation happening.  This kind of separation is what moved me to make my first post a bit back and it looks to be worse than any before it.

I used the 28th when there was less cloud cover.

The closest I've seen is 2008 in September.



Michael Hauber

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Re: The 2019 melting season
« Reply #5009 on: July 30, 2019, 10:09:04 PM »
Comparing 2019 vs 2012 using Jaxa's analysis shows the central arctic basin ice is healthier than in 2012, while the ice towards the fringes is weaker/less of it.  This seems to correspond well with what I'm seeing in EOSDIS.





I believe the slater projection is significantly above record, which would seem to fit in with the above observation.  Considering the latest heatwave is now winding down and forecasts show a week of mild conditions with very slack wind, vs 2012's GAC,  I'd say a record this year is now quite unlikely.
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UCMiami

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Re: The 2019 melting season
« Reply #5010 on: July 30, 2019, 10:39:30 PM »
I think people discount the amount of ocean heat the GAC unleashed in 2012 and the impact that had on what should have been the standard slow fade to the melt season. I still think 2019 needs some ocean stirring to keep the melt strong throughout August. Maybe the series of small lows being project to circle the high pressure will be enough, but they seem pretty weak in the forecasts.

That said while looking at various comparison coverage maps, what people also forget is that while 2019 may have more 'solid ice' in the CAB than 2012, that ice is significantly younger and thinner if we believe PIOMAS and it will take less energy to melt it.

Shared Humanity

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Re: The 2019 melting season
« Reply #5011 on: July 31, 2019, 12:09:54 AM »
Comparing 2019 vs 2012 using Jaxa's analysis shows the central arctic basin ice is healthier than in 2012, while the ice towards the fringes is weaker/less of it.  This seems to correspond well with what I'm seeing in EOSDIS.





I believe the slater projection is significantly above record, which would seem to fit in with the above observation.  Considering the latest heatwave is now winding down and forecasts show a week of mild conditions with very slack wind, vs 2012's GAC,  I'd say a record this year is now quite unlikely.

I guess I'm not seeing what you are seeing. The ice in the CAB adjacent to the CAA looks much worse in 2019 and it also looks worse on the Pacific side. The only place 2019 has more concentration is along the Atlantic side.

petm

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Re: The 2019 melting season
« Reply #5012 on: July 31, 2019, 12:16:37 AM »
It was not fully intended, but by the way and by way of illustration, GFS has come closer to others global models, and is showing more deepening forced by diabatic heating.

Fascinating. So we should keep our eyes peeled for underestimated lows?

petm

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Re: The 2019 melting season
« Reply #5013 on: July 31, 2019, 12:31:36 AM »
I guess I'm not seeing what you are seeing.

Me neither. These concentration maps have high daily variability due to clouds, but looking at averages (https://forum.arctic-sea-ice.net/index.php/topic,2792.msg217403.html#msg217403), 2019 currently looks quite a bit worse than 2012 almost everywhere. But of course the 2012 GAC will be dominating in a few days, so such comparisons can be moot or misleading.


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Re: The 2019 melting season
« Reply #5014 on: July 31, 2019, 12:34:55 AM »

That said while looking at various comparison coverage maps, what people also forget is that while 2019 may have more 'solid ice' in the CAB than 2012, that ice is significantly younger and thinner if we believe PIOMAS and it will take less energy to melt it.

Are you sure that CAB is significantly thinner in 2019 v. 2012? Perhaps you can share some numbers.

Michael Hauber

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Re: The 2019 melting season
« Reply #5015 on: July 31, 2019, 01:02:47 AM »
I guess I'm not seeing what you are seeing.

Me neither. These concentration maps have high daily variability due to clouds, but looking at averages (https://forum.arctic-sea-ice.net/index.php/topic,2792.msg217403.html#msg217403), 2019 currently looks quite a bit worse than 2012 almost everywhere. But of course the 2012 GAC will be dominating in a few days, so such comparisons can be moot or misleading.

IUP Bremen makes 2019 look worse compared to 2012, but Jaxa is the other way around.  I'm pretty sure this is regardless of 5 day average or not - the daily comparisons I do each day in Jaxa have told a similar story over the last few weeks.  From my time watching both images, and comparing carefully to EOSDIS visual images I trust Jaxa over IUP.

Lines added to highlight where I'm saying 2019 looks better than 2012





edit to add Slater projections.  The map is for a week or maybe two after minimum, but gives an idea of the significance of the current edge of the boundary between good/weak ice I've drawn.  Given the accuracy of past Slater projections to minimum, a record should not happen this year, but I don't think a Slater projection for 2012 is available.



« Last Edit: July 31, 2019, 01:12:46 AM by Michael Hauber »
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petm

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Re: The 2019 melting season
« Reply #5016 on: July 31, 2019, 01:26:56 AM »
Hard to see how you can get any information from those maps you're using. Why don't you use better maps? I repeat, it's hard to see where 2019 is better than 2012, including in the areas you draw lines.

https://forum.arctic-sea-ice.net/index.php/topic,2792.msg217403.html#msg217403

FishOutofWater

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Re: The 2019 melting season
« Reply #5017 on: July 31, 2019, 01:40:27 AM »
Worldview has much better resolution than the little JAXA image. Yes, it has clouds but you can look at many days to see what's happening. And seaice.de has higher resolution and uses similar input as JAXA.

Looking at all of those sources and PIOMAS, I think it's pretty much a dead heat between 2012 and 2019, but the GAC tapped into ocean heat down to the Atlantic water layer according to buoy data. It's going to be hard to top the effects of the GAC because of the heat it tapped into, but then again it's still July and who knows what will happen in the next six weeks.

petm

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Re: The 2019 melting season
« Reply #5018 on: July 31, 2019, 01:49:39 AM »
And seaice.de has higher resolution and uses similar input as JAXA.

The maps I linked to above are from there. I agree about the GAC, also as mentioned in the 2019 vs 2012 thread.

Frivolousz21

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Re: The 2019 melting season
« Reply #5019 on: July 31, 2019, 02:04:10 AM »
I have already simply proven the ice was already almost about to mass melt before the GAC.

So why isn't this accepted?

This isn't the better animation I posted before.

But here is July 22nd 2012 and August 4th 2012.

Its clear the ice already collapsed before the GAC.

The ice on the August 4th image is almost transparent.

That's because to this scanning frequency its really thin and the ocean below is being picked up.

This tells us the ice was already about to melt.

Erase the GAC and the entire Pacific side melts anyways

There seems to be this romantic novelty about the impact of the GAC.


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DrTskoul

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Re: The 2019 melting season
« Reply #5020 on: July 31, 2019, 02:18:34 AM »
I have already simply proven the ice was already almost about to mass melt before the GAC.

So why isn't this accepted?

This isn't the better animation I posted before.

But here is July 22nd 2012 and August 4th 2012.

Its clear the ice already collapsed before the GAC.

The ice on the August 4th image is almost transparent.

That's because to this scanning frequency its really thin and the ocean below is being picked up.

This tells us the ice was already about to melt.

Erase the GAC and the entire Pacific side melts anyways

There seems to be this romantic novelty about the impact of the GAC.

But its fun!! Simple forcings ( e.g. a GAC) are easy to explain, conceptualize.

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Re: The 2019 melting season
« Reply #5021 on: July 31, 2019, 02:26:57 AM »
In a sense there are 2 Arctic Ocean's.

The shallow perimeter portion we expect to melt out and the deep inner portion which generally does not.

2012 was exceptional in it's ability to dent the deep inner portion.

2019 has been at the front of the pack in efficiently dealing with the portions we expect to melt but hasn't YET demonstrated the exceptional qualities necessary to make a significant dent in the deep inner portion. Most prominent is limited advance on the Atlantic side.

There doesn't appear to be a lot of empirical basis for extrapolating 2019 performance to date to major CAB reductions and a record.

Can it happen? Of course. But it will take something exceptional that is not yet on the radar.

2012 was a freak weather finish all the way around. The extent surge in early August was unparalleled, but the volume finish may have been even more impressive. 2012 as a melt season finish was analagous to Hurricane Harvey as a rain storm or Bob Beamon's long jump in the 1968 Olympics.

Predicting freak weather that isn't yet anywhere in a weather forecast isn't science. Extrapolating performance in easy to melt areas to rarely melted area isn't science. The CAB is looking pretty damn good at the moment, all things considered.

petm

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Re: The 2019 melting season
« Reply #5022 on: July 31, 2019, 02:27:29 AM »
So why isn't this accepted?

Yes the ice was weak before the GAC. But there was also accelerated melt that coincided with the GAC in time and space, which melted not only the low concentration ice but a wide swath of high concentration ice as well. Sure, much of it would have all melted out anyways -- but how much? Given the dramatic effects of even smaller cyclones, it's hard to see how such a massive and unprecedented storm did not play some role in the coincident massive and unprecedented melt...

Rod

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Re: The 2019 melting season
« Reply #5023 on: July 31, 2019, 02:31:03 AM »
I have already simply proven the ice was already almost about to mass melt before the GAC.

So why isn't this accepted?


It is impossible to prove what would have happened in the absence of the GAC.  You, and several others have put forth compelling evidence that the ice was already in trouble before the GAC took over.

However, it is also impossible to ignore the huge drops in extent that occurred during the GAC.  Correlation does not equal causation, but that does not mean it should be ignored. 

Common sense would dictate that if you take a lot of crushed up ice and put it in a blender and shake it around, that will have an effect.  It is less clear to me that in 2012 the halocline was breached and warm waters mixed upwards.  If that had happened we might have seen a BOE.

In any event, what makes this season interesting is that we can compare what happens to the fragile ice in the absence of a GAC with what happened in 2012. 

Of course, if the weather changes again and brings strong storms into the arctic in the next couple of weeks, that will screw up our control. 

It is unfortunate, that we have to watch this experiment play out in real time on the only planet we have. 

petm

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Re: The 2019 melting season
« Reply #5024 on: July 31, 2019, 02:34:08 AM »
There doesn't appear to be a lot of empirical basis for extrapolating 2019 performance to date to major CAB reductions and a record.

There are several clues that we may be moving in that direction, such as:
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-regional.png

Or maybe not. The next week or 2 will tell a lot.

DrTskoul

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Re: The 2019 melting season
« Reply #5025 on: July 31, 2019, 02:51:40 AM »
Current vector is awful....

oren

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Re: The 2019 melting season
« Reply #5026 on: July 31, 2019, 02:57:48 AM »
2012 was exceptional in it's ability to dent the deep inner portion.

2019 has been at the front of the pack in efficiently dealing with the portions we expect to melt but hasn't YET demonstrated the exceptional qualities necessary to make a significant dent in the deep inner portion. Most prominent is limited advance on the Atlantic side.

There doesn't appear to be a lot of empirical basis for extrapolating 2019 performance to date to major CAB reductions and a record.
2012 was exceptional in several metrics, but actually not in the CAB. 2016 (green) ran neck and neck with 2012 (yellow orange) all the way to the bottom, before being hit by an early CAB refreeze. This is supported by both UH AMSR2 (see petm's post #5024) and NSIDC.

UCMiami

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Re: The 2019 melting season
« Reply #5027 on: July 31, 2019, 03:07:41 AM »
Friv - I really appreciated your earlier posts related to the late July collapse in 2012 pre-GAC and your current post as I wasn't following the arctic ice very carefully back then, and hadn't seen the rapid collapse in real time nor realized how big that July period was.

But, there is also no question that the first two weeks of August in 2012 were also terrible for the ice and unlike most years did not show a slowing of the melt, but a continued very strong progression. To deny that the GAC did considerable damage and 2012 late season and the resulting final minimum were and still are unprecedented doesn't make sense. Maybe 2012 would still have been a record year, but to end at 20% less extent than any year before or after is a stunning result - records typically don't get smashed like that and do not continue to stand such a distance beyond following years. And the most obvious reason for that collapse is the GAC. It is the unique aspect of 2012 post July input into the arctic system.

petm

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Re: The 2019 melting season
« Reply #5028 on: July 31, 2019, 03:16:50 AM »
Ok, the attached is d+10 so obviously it won't happen... but it's still fun to ponder... Also, what is that string of bombs lined up on the Pacific side?

vox_mundi

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Re: The 2019 melting season
« Reply #5029 on: July 31, 2019, 03:25:45 AM »
.. .. Also, what is that string of bombs lined up on the Pacific side?
They appear to be reminants of some of the typhoons pinballing in the Pacific

See https://forum.arctic-sea-ice.net/index.php/topic,2569.msg217494.html#msg217494
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Re: The 2019 melting season
« Reply #5030 on: July 31, 2019, 03:30:27 AM »
Ok, the attached is d+10 so obviously it won't happen... but it's still fun to ponder... Also, what is that string of bombs lined up on the Pacific side?

Many are too much focused on dates of the past. I'm not of the opinion that if an event would happen in 20 days from now that this wouldn't give the the ice kind of a "coup de grace"

So at this moment in time I'd say "it won't happen during the same time or during the next 5 days" further out we have little clue as we all know.

Further it has been mentioned several times before that the volume is way smaller and that will sooner or later be good for surprising openings in the ice cover simply because the melting process ate it all up from above and from below (and the sides i know)

petm

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Re: The 2019 melting season
« Reply #5031 on: July 31, 2019, 03:30:35 AM »
4 at once! What are the odds that one of those pinballs will bounce through the Being? Very low I suppose.

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Re: The 2019 melting season
« Reply #5032 on: July 31, 2019, 03:41:39 AM »
Given the accuracy of past Slater projections to minimum, a record should not happen this year, but I don't think a Slater projection for 2012 is available.

Slater's prediction for 2012 can be seen at http://cires1.colorado.edu/~aslater/SEAICE/Slater_AGU_2013_poster.pdf.


His model did successfully predict a record low extent minimum 2012, but not as low as reality. The predicted 2012 minimum was just a bit under 4 million km2 - which is also what the Slater model predicts for this year.

Given its similar predictions for the extent minima in the record year 2012 and in 2019, the Slater model can't be said to rule out a new record low extent this year.

Rich

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Re: The 2019 melting season
« Reply #5033 on: July 31, 2019, 03:45:46 AM »
2012 was exceptional in it's ability to dent the deep inner portion.

2019 has been at the front of the pack in efficiently dealing with the portions we expect to melt but hasn't YET demonstrated the exceptional qualities necessary to make a significant dent in the deep inner portion. Most prominent is limited advance on the Atlantic side.

There doesn't appear to be a lot of empirical basis for extrapolating 2019 performance to date to major CAB reductions and a record.
2012 was exceptional in several metrics, but actually not in the CAB. 2016 (green) ran neck and neck with 2012 (yellow orange) all the way to the bottom, before being hit by an early CAB refreeze. This is supported by both UH AMSR2 (see petm's post #5024) and NSIDC.

2016  and 2012 we're both exceptional with respect to the CAB.

Oren shared a chart in the PIOMAS thread showing 2012 far ahead in CAB volume loss vs. other years.

Michael Hauber

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Re: The 2019 melting season
« Reply #5034 on: July 31, 2019, 04:13:59 AM »
Given the accuracy of past Slater projections to minimum, a record should not happen this year, but I don't think a Slater projection for 2012 is available.

Slater's prediction for 2012 can be seen at http://cires1.colorado.edu/~aslater/SEAICE/Slater_AGU_2013_poster.pdf.


His model did successfully predict a record low extent minimum 2012, but not as low as reality. The predicted 2012 minimum was just a bit under 4 million km2 - which is also what the Slater model predicts for this year.

Given its similar predictions for the extent minima in the record year 2012 and in 2019, the Slater model can't be said to rule out a new record low extent this year.

Thanks for that.  I should have said 'couldn't find a 2012 prediction'. 

It looks to me like a repeat of 2012 would be roughly at the lower limits of what is likely based on Slater's methods and history.  The current forecast suggests that it will be hard to get to the lower limits of what is likely.
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Re: The 2019 melting season
« Reply #5035 on: July 31, 2019, 04:39:23 AM »
2012 was exceptional in it's ability to dent the deep inner portion.

2019 has been at the front of the pack in efficiently dealing with the portions we expect to melt but hasn't YET demonstrated the exceptional qualities necessary to make a significant dent in the deep inner portion. Most prominent is limited advance on the Atlantic side.

There doesn't appear to be a lot of empirical basis for extrapolating 2019 performance to date to major CAB reductions and a record.
2012 was exceptional in several metrics, but actually not in the CAB. 2016 (green) ran neck and neck with 2012 (yellow orange) all the way to the bottom, before being hit by an early CAB refreeze. This is supported by both UH AMSR2 (see petm's post #5024) and NSIDC.

2016  and 2012 we're both exceptional with respect to the CAB.

Oren shared a chart in the PIOMAS thread showing 2012 far ahead in CAB volume loss vs. other years.
I wish you would post less... oren's CAB volume chart in the PIOMAS thread shows 2019 in the lead. You post inaccuracies interspersed with useless conjecture, the combination is understandably off-putting yet for some reason here you are, still posting...

Sublime_Rime

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Re: The 2019 melting season
« Reply #5036 on: July 31, 2019, 05:15:43 AM »
I'm pretty amazed at the speed of the ESS collapse. Combined with the remnants in the Chukchi and west Beaufort, Laptev, all of which seem poised to rapidly dissolve, I'd guess extent and area might take quite a plummet in the next week. I'd expect the area loss to be especially steep, this large amount of low-concentration ice seems likely to have been suppressing area losses. July 30th 2019 AMSR image from Uni Bremen


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Re: The 2019 melting season
« Reply #5037 on: July 31, 2019, 06:01:36 AM »
2012 was exceptional in it's ability to dent the deep inner portion.

2019 has been at the front of the pack in efficiently dealing with the portions we expect to melt but hasn't YET demonstrated the exceptional qualities necessary to make a significant dent in the deep inner portion. Most prominent is limited advance on the Atlantic side.

There doesn't appear to be a lot of empirical basis for extrapolating 2019 performance to date to major CAB reductions and a record.
2012 was exceptional in several metrics, but actually not in the CAB. 2016 (green) ran neck and neck with 2012 (yellow orange) all the way to the bottom, before being hit by an early CAB refreeze. This is supported by both UH AMSR2 (see petm's post #5024) and NSIDC.

2016  and 2012 we're both exceptional with respect to the CAB.

Oren shared a chart in the PIOMAS thread showing 2012 far ahead in CAB volume loss vs. other years.
I wish you would post less... oren's CAB volume chart in the PIOMAS thread shows 2019 in the lead. You post inaccuracies interspersed with useless conjecture, the combination is understandably off-putting yet for some reason here you are, still posting...

Oren's chart shows 2012 CAB beating every other year by close to 1,000 km3 in the final month of the melting season.

Like I said earlier, the finish of the 2012 melt season was parallel to Hurricane Harvey as a rain event. Unparalleled and off the charts.

This season will need a finish approaching that to top it.

Thanks for the compliment.




bbr2314

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Re: The 2019 melting season
« Reply #5038 on: July 31, 2019, 06:12:22 AM »
2012 was exceptional in it's ability to dent the deep inner portion.

2019 has been at the front of the pack in efficiently dealing with the portions we expect to melt but hasn't YET demonstrated the exceptional qualities necessary to make a significant dent in the deep inner portion. Most prominent is limited advance on the Atlantic side.

There doesn't appear to be a lot of empirical basis for extrapolating 2019 performance to date to major CAB reductions and a record.
2012 was exceptional in several metrics, but actually not in the CAB. 2016 (green) ran neck and neck with 2012 (yellow orange) all the way to the bottom, before being hit by an early CAB refreeze. This is supported by both UH AMSR2 (see petm's post #5024) and NSIDC.

2016  and 2012 we're both exceptional with respect to the CAB.

Oren shared a chart in the PIOMAS thread showing 2012 far ahead in CAB volume loss vs. other years.
I wish you would post less... oren's CAB volume chart in the PIOMAS thread shows 2019 in the lead. You post inaccuracies interspersed with useless conjecture, the combination is understandably off-putting yet for some reason here you are, still posting...

Oren's chart shows 2012 CAB beating every other year by close to 1,000 km3 in the final month of the melting season.

Like I said earlier, the finish of the 2012 melt season was parallel to Hurricane Harvey as a rain event. Unparalleled and off the charts.

This season will need a finish approaching that to top it.

Thanks for the compliment.

....you said


Oren shared a chart in the PIOMAS thread showing 2012 far ahead in CAB volume loss vs. other years.

2019 is AHEAD of 2012. You did not qualify it as September, you said it as if it were current, and how would you make a statement about 2019's September volume at this point anyways? It isn't even August yet.

You make falsifiable statements and then twist them around and keep arguing for no good reason. I hope you are banned.

bbr2314

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Re: The 2019 melting season
« Reply #5039 on: July 31, 2019, 06:48:06 AM »
The 00z models have a couple interesting features to watch.

In the short term, there is going to be a ~980MB low pressure system in the Kara. It will be BROAD, more than anything else. I wonder if this will result in negative impact to ATL and Laptev fronts.

In the medium term, I think the biggest thing to keep an eye out for is actually not in the Arctic. The Pacific looks set to generate a series of major typhoons, some impacting land, some recurving more quickly without doing so. The 18z GFS stalled a Category 4 or 5 around Okinawa for a week or so. The 00z GFS has a very different solution. The output is likely to be highly variable until these storms begin to form.



However, I think the key takeaway from ^ is that there will be MULTIPLE opportunities for major +500MB heat injections in the Western Pacific. This ridging is ultimately going to make it up into the Arctic by D7+ (IMO). This is likely to result in a worsening of conditions once more. The 00z GFS has a major heatwave blasting the entire Laptev / ESS fronts, it would ensure we maintain #1 spot through 8/10 with EASE. 

binntho

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Re: The 2019 melting season
« Reply #5040 on: July 31, 2019, 07:41:15 AM »
Given the accuracy of past Slater projections to minimum, a record should not happen this year, but I don't think a Slater projection for 2012 is available.

Slater's prediction for 2012 can be seen at http://cires1.colorado.edu/~aslater/SEAICE/Slater_AGU_2013_poster.pdf.
Good link, interesting to see how bad the Slater model is at predicting the timing or the level of the minimum over a range of years.

Wich makes me want to ask Michael Hauber, what did you mean by "Given the accuracy of past Slater projections to minimum"? What accuracy and what projections? If you feel like answering, perhaps we should take the discussion to the Slater's thred
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DrTskoul

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Re: The 2019 melting season
« Reply #5041 on: July 31, 2019, 07:50:19 AM »
I reply to the Slater thread...

Killian

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Re: The 2019 melting season
« Reply #5042 on: July 31, 2019, 08:49:54 AM »
So, said this: I see little reason to adjust this after perusing the various images/data. Call it 105k +/-10k, so around 5.975M km sq.

Then this:
Quote
Revise to 120k +/-10k, so around 5.96M km sq.

Got this: -80k km sq. Always trust your first instinct. The original wasn't a great result, but off by 15k is better than off by 30k.

Quote
7/30/2012 stood at 6.13M km sq. on this date , a drop of 70k.
7/29/2019 stands at 6.08M km sq., a record low for the date. 2019 needs an increase of < 50k km sq. for a record low on this date.

7/30/2019 stands at 6.00M km sq., a record low for the date.

Tomorrow:
7/31/2012 stood at 6.10M km sq. on this date , a drop of 30k.
7/30/2019 stands at 6.00M km sq. 2019 needs an increase of < 100k km sq. for a record low on this date.

Analysis: Everything looks calmer, winds are supportive of expansion, looks like a very low day unless a bunch of thin stuff melts away.

Call it -50 +/-10k km sq.

-----------------------------------

8/10/2012 stood at 4.94M km sq.
2019 needs an average daily drop of > 96.36k km sq. for a record low on this post-GAC date. (11 days)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 60.00k km sq. for a record low on this date. (47 days)

bbr2314

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Re: The 2019 melting season
« Reply #5043 on: July 31, 2019, 08:59:29 AM »
Bye bye Laptev!

This would be GAC equivalent damage due to the worsened overall state of the ice in 2019

I believe as volume approaches 0, rate of extent and area declines will hasten relative to volume losses (it is necessary as 0 in one is 0 in the other but 1,000 KM^3 of volume remaining could easily be 1,000,000KM^2+ area and extent). At that point 1,000,000 has a lot farther numerically speaking to fall to hit 0 than volume does. When it happens, it will happen QUICKLY.

I think we could see the same effect, but dulled given our current and possible final position, as we fall a substantial % below 2012 this year. But it won't be a BOE. We will still have 2M KM^2ish+ of area and extent, IMO, at minimum. This is still potentially an order of magnitude worse than 2012 in terms of overall climactic impact (both in the Arctic and the mid-latitudes and beyond, as open water and OHC are much worse than seven years ago).



The Laptev ice is almost entirely .5M or less in thickness at this point. One major cyclonic event with borderline temps and it will go the way of the ESS. It could finally be on the horizon, at least according to tonight's 00z EURO at D7.

Finally, a comparison between the models shows the GFS has a similar event around D9 as the low responsible for the rapid deepening is delayed.



The Canadian is also a bit more delayed, and winds the low up on the ATL / Laptev boundary instead of closer to the heart of the CAB.



There is certainly increasing support for some kind of event in the D6-9 range.

be cause

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Re: The 2019 melting season
« Reply #5044 on: July 31, 2019, 09:12:46 AM »
interesting to note at this stage 2012 there was no GAC in the forecast . That there is none in the current forecast therefore means little .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Jontenoy

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Re: The 2019 melting season
« Reply #5045 on: July 31, 2019, 09:25:52 AM »
A friend living north of St Petersburg told me that the blueberries are ripe one month early this month .... Nobody can remember them this ready at this time.  Surely this is a natural indication of a high soil temperature. Not good for Arctic ice assuming this can be extrapolated across the edges of Laptev and Kara .

gerontocrat

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Re: The 2019 melting season
« Reply #5046 on: July 31, 2019, 10:09:12 AM »
When nothing comes down the Fram, this is what you get North & North-East of Greenland in late summer?
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DrTskoul

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Re: The 2019 melting season
« Reply #5047 on: July 31, 2019, 10:14:30 AM »
A hole with lots of ice going poof..

Aluminium

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Re: The 2019 melting season
« Reply #5048 on: July 31, 2019, 10:17:57 AM »
July 26-30.

2018.

be cause

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Re: The 2019 melting season
« Reply #5049 on: July 31, 2019, 11:25:22 AM »
Indded Gerontocrat .. the ice beyond N. Greenland is beginning to look like it did Feb 2018 .. I'm only suprised that what was achievable mid winter is so much more of a challenge mid summer . b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...