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Robert Greer

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Re: The 2019 melting season
« Reply #4750 on: July 27, 2019, 07:46:40 AM »
I could actually smooth out the purples more. E.g., At one point I was using this rule: change everything to dark purple if it had 2 or more days of 5 above 90%. But for various reasons I decided it's better to just use a simple median.

These images are the best I've seen in a while for actually trying to suss out what's happening.  Thanks for this awesome resource!

To my (entirely untrained) eye, 2019 looks overall much worse for the ice than 2012.  The integrity of the ice in the CAB and along the CAA is much easier to see for 2012 -- it's just solid purple the whole run, whereas the same regions in 2019 run thin at several points.  It may get more purple as it gets mashed together again, but it's still fundamentally small floes that will be easily dispersed once the high-pressure system starts to really dominate.

At the end of July in 2012, weather had torched a LOT of the ice, but was starting to run up against a resilient core of ice.  At the same point in 2019, the ice is set up to be divided-and-conquered.

I bet we get a surprising amount of dispersion in the next few weeks, which will allow for high melt rates we haven't seen sustained this long into the season.
« Last Edit: July 27, 2019, 07:51:48 AM by Robert Greer »

grixm

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Re: The 2019 melting season
« Reply #4751 on: July 27, 2019, 07:48:54 AM »
I value a model by its merits and if it shows 3m thick ice stay there and go to zero almost overnight, something is very very wrong.

When have the DMI thickness done that?
« Last Edit: July 27, 2019, 11:02:23 AM by grixm »

El Cid

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Re: The 2019 melting season
« Reply #4752 on: July 27, 2019, 08:09:36 AM »
can you do the same median for 2012 so that we can compare the two?

Good idea. I've done better: Here are 5-day trailing medians for July 7-25 for both 2012 and 2019.

Thanks, that is great! To me, 2012 still looks worse than 2019 as it had yellow green all the way to 85 deg at the Laptev bite and a much smaller pink/purple area than 2019. So I still say second place, though I know many would stone me for it :)

petm

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Re: The 2019 melting season
« Reply #4753 on: July 27, 2019, 08:17:10 AM »
Is this the same map?

Not exactly. The ones I posted are lagging 5-day medians. I.e., The middle concentration value for each pixel over the preceding 5 days. Roughly speaking, this cleans up much of the noise and tells you about where the ice was 3 days before.

oren

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Re: The 2019 melting season
« Reply #4754 on: July 27, 2019, 08:21:43 AM »
Thanks petm for these excellent animations. 2012 does look worse, in 2019 there is a larger core od purple that is a candidate for surviving the minimum. And there's also the more resilient CAA this year.
OTOH, 2019's purple ice is possibly thinner, as attested by PIOMAS and by the Ascat animations and sea ice age animations from earlier in the season. So it is still possible for 2019 to take record volume, and catch up with 2012 on area should melt overcome typical remaining FYI thickness in the CAB. And a GAC is possible too. My bet is still on 2nd overall in terms of probability, but it's an open race.

grixm

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Re: The 2019 melting season
« Reply #4755 on: July 27, 2019, 08:24:16 AM »
Look at this melting in the Beaufort!

The biggest of these floes were over 10km long in the first picture, with sharp edges. Then two days later: Poof. Just unrecognizable foam.

petm

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Re: The 2019 melting season
« Reply #4756 on: July 27, 2019, 08:27:13 AM »
July 22-26.

Continued large movement on the Pacific side and signs of deterioration well north of 75. Will it continue into the coming week or fizzle out?!

sark

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Re: The 2019 melting season
« Reply #4757 on: July 27, 2019, 08:32:50 AM »
The Arctic atmosphere conditions are unpredictable.  I think what's happening is the chaos of this turbulent and complicated atmosphere makes the behavior unpredictable.  Systems noises.

This is the Arctic Oscillation forecast.  Will we get a weak or strong PV this winter?

Or will we get reinforcing feedbacks?

I am not a scientist

petm

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Re: The 2019 melting season
« Reply #4758 on: July 27, 2019, 08:38:23 AM »
My bet is still on 2nd overall in terms of probability, but it's an open race.

Sounds about right to me too. I'd say 2012 is leading by a length, but several laps to go. Decreased thickness is indeed a wild card, and also don't forget the open and warm Chukchi.

bbr2314

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Re: The 2019 melting season
« Reply #4759 on: July 27, 2019, 08:53:38 AM »
My bet is still on 2nd overall in terms of probability, but it's an open race.

Sounds about right to me too. I'd say 2012 is leading by a length, but several laps to go. Decreased thickness is indeed a wild card, and also don't forget the open and warm Chukchi.
You are wrong. 2019 is leading by every metric -- extent, area, and volume. You can say what you want, but it is still wrong.  :)

Stephan

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Re: The 2019 melting season
« Reply #4760 on: July 27, 2019, 09:16:53 AM »
Take your pick. dmi, hycom jul3-25 and piomas jul3-15

Is there any chance to measure sea ice thickness (at least at some points) by ships/expeditions in the CAB and to compare the measured data with the modeled data and (maybe) adjust the models to the reality?

Rob Dekker

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Re: The 2019 melting season
« Reply #4761 on: July 27, 2019, 09:28:49 AM »
ARCUS Sea Ice Prediction Network published their July report.
These are predictions of the September minimum based on June data.
https://www.arcus.org/sipn/sea-ice-outlook/2019/july

The median is 4.28 million km^2.
Which would put 2019 behind 2012, and very close to second place 2007.
This is our planet. This is our time.
Let's not waste either.

Killian

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Re: The 2019 melting season
« Reply #4762 on: July 27, 2019, 09:43:11 AM »
7/26/2012 stood at 6.51M km sq. on this date, a drop of 110k.
7/25/2019 stands at 6.51M km sq. 2019 needs a drop > 0k km sq. for a record low on this date.

...Looks like a recipe for an extant drop of 80 to 110. 95k, then.

Or something.

Or something wins as the reduction came in at 124k, 19k higher than I estimated, for another record low of 6.39M km sq. So, yes, bbr has been proven right... it's hard.

7/27/2019 stood at 6.37M km sq. on this date, a big drop of 140k.
7/26/2019 stands at 6.39M km sq. 2019 needs a drop > 20k km sq. for a record low on this date.

Pretty likely, but the winds today are no friend for compaction. Everything from the Alaska coast around the entirety of the Siberian coast and around to Svalbard is set for expansion. I'd expect a small number for the 27th. Only the heat present makes me not want to call an increase. Let's say -50k, but really could be an increase in extent.

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

8/10/2012 stood at 4.94M km sq. on this date.
2019 needs an average daily drop of > 96.33k km sq. for a record low on this post-GAC date. (15 days)

Upcoming conditions with the dipole, et all., should drive consistently large extent drops through the 30th or more (though maybe not the 27th). Warm temps in the upper atmosphere, dipole shoving ice toward Franz Joseph, et al., and a myriad of large and small cyclonic structures projected into the 30th = "Martha! I'm comin', Martha! It's the Big One!"

Maybe.

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 62.86k km sq. for a record low on this date. (51 days)

Big days dropping this slowly. Is a big early August setting us up for a run at the record? Gotta get through that GAC period first... then I'll get more excited about this stat if '19 comes in under '12 on 8/10.

Rich

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Re: The 2019 melting season
« Reply #4763 on: July 27, 2019, 09:53:12 AM »
My bet is still on 2nd overall in terms of probability, but it's an open race.

Sounds about right to me too. I'd say 2012 is leading by a length, but several laps to go. Decreased thickness is indeed a wild card, and also don't forget the open and warm Chukchi.
You are wrong. 2019 is leading by every metric -- extent, area, and volume. You can say what you want, but it is still wrong.  :)

Gerontocrat's area data has 2019 in second place at the moment. And the anchor leg for 2012 will be run by the Usain Bolt of melting seasons.
2012 extent losses from this point forward we're 33% above average. 2019 only needs to beat the average by 30% to win the extent crown.

Neven

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Re: The 2019 melting season
« Reply #4764 on: July 27, 2019, 10:09:53 AM »
I have just returned from Croatia. Thanks to everyone for the condolences. In coming days, I'll try and get things in order here on the Forum.
Il faut comparer, comparer, comparer, et cultiver notre jardin

RealityCheck

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Re: The 2019 melting season
« Reply #4765 on: July 27, 2019, 10:19:08 AM »
Welcome back Neven.
All best wishes to you and your family over the coming weeks and months...
Kind regards,
RC
Sic transit gloria mundi

Rich

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Re: The 2019 melting season
« Reply #4766 on: July 27, 2019, 12:12:28 PM »
Good luck / skill with your continuing navigation of a challenging transition. Take care of yourself first.

F.Tnioli

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Re: The 2019 melting season
« Reply #4767 on: July 27, 2019, 12:40:25 PM »
Take your pick. dmi, hycom jul3-25 and piomas jul3-15

Is there any chance to measure sea ice thickness (at least at some points) by ships/expeditions in the CAB and to compare the measured data with the modeled data and (maybe) adjust the models to the reality?
Measure - yes. Compare - no. See, the measurements are being done all the time. Problem is, for some reasons publishing those measurements - is not possible for any modern times. Historical measurements - pre-2000 - are easily available, as mentioned, for example, here.

edit:
I have just returned from Croatia. Thanks to everyone for the condolences. In coming days, I'll try and get things in order here on the Forum.
It is great to see you back and to see your spirit strong, man! But you sound still grim. I understand. Been there, 28 years ago... Please, do always remember: he's not dead yet - as long as you are alive and your memories of him are alive, he is in a certain and very real way still alive. Nothing mystical, pure neuro-biology here. I'm sure you can see how it works if you'd think about it. Salute!
« Last Edit: July 27, 2019, 12:50:40 PM by F.Tnioli »

Neven

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Re: The 2019 melting season
« Reply #4768 on: July 27, 2019, 01:13:07 PM »
I'll need a few days to get up to speed. But given that this is probably the only thread that is worth reading on the Internet, I would kindly ask everyone to stay as much on-topic as possible and/or keep it short.

Edit: Getting up to speed a bit already today, and just two words for now: Lord Almighty...
« Last Edit: July 27, 2019, 01:48:14 PM by Neven »
Il faut comparer, comparer, comparer, et cultiver notre jardin

Sterks

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Re: The 2019 melting season
« Reply #4769 on: July 27, 2019, 01:53:30 PM »
The median is 4.28 million km^2.
Which would put 2019 behind 2012, and very close to second place 2007.
Hey Rob nice to see you and Neven back, pleasant surprise

F.Tnioli

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Re: The 2019 melting season
« Reply #4770 on: July 27, 2019, 01:54:56 PM »
Few pages ago, i wrote about my concern about gigatons of melt water going from northern side of Greenland into the ocean, adding to bottom melt of ice in the region. I'd like to have better estimate about how significant this effect is. I checked few places, and i found clear confirmation of the effect in the form of darker shades of green for 2m temperatures over both open water and still ice-covered areas of the ocean adjucent to northern side of Greenland in this forecast - click "right arrow" button there to animate.

A bit of those darker shades of green move somewhat towards the pole (and eastwards) and as far as more than half distance to the pole, at some point, as one can see.

Thing is, those are 2m temps - not SSTs. Means, while warm melt water affects it - many other things affect it also. Thus, i'd like to know SSTs of the open water areas north of Greenland. What would then be the most respected resource which would demonstrate SSTs for the area, either observed or forecasted or both, real-time?

P.S. Checking under-ice topography of Greenland, it's obvious quite many within-ice configurations of melt water bodies and channels will result in much, if not most, of melt water discharge from central greenland to end up running to the ocean through north and north-east edges of Greenland. So, given forecasted and massive snow cover melt i mentioned earlier in the topic and that topography, dozens-gigatons melt water pulse soon after the peak of the forecasted high over Greenland seems quite unavoidable, to me. Anywhere i am hopefully would be mistaken about this all - please tell...
« Last Edit: July 27, 2019, 02:01:16 PM by F.Tnioli »

jplotinus

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Re: The 2019 melting season
« Reply #4771 on: July 27, 2019, 01:55:53 PM »
Welcome back, Neven. We continue to grieve with you and some of us also posted responsibly.
😌

Rich

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Re: The 2019 melting season
« Reply #4772 on: July 27, 2019, 02:26:27 PM »
I

Edit: Getting up to speed a bit already today, and just two words for now: Lord Almighty...

There are still vestiges of humor in that comment. Either a sign of great patience or that you really haven't gotten far yet.

Neven

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Re: The 2019 melting season
« Reply #4773 on: July 27, 2019, 02:46:49 PM »
There are still vestiges of humor in that comment. Either a sign of great patience or that you really haven't gotten far yet.

A bit of both.  ;)  :'(
Il faut comparer, comparer, comparer, et cultiver notre jardin

petm

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Re: The 2019 melting season
« Reply #4774 on: July 27, 2019, 02:53:18 PM »
You are wrong. 2019 is leading by every metric -- extent, area, and volume.

Perhaps, especially volume. But the configuration is much different. But on this date, 2012 was about to be divided and conquered -- and you can already see that occurring in the concentration maps -- while 2019 shows few signs that similar will happen. Not that it won't (given the right weather), and not that such is necessarily required for a record. But who knows?

Anyways, I do hope you're right in the end...


And welcome back Neven.
« Last Edit: July 27, 2019, 03:09:01 PM by petm »

petm

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Re: The 2019 melting season
« Reply #4775 on: July 27, 2019, 02:58:33 PM »
The last week of ice drift. The last 3 days have seen strong and increasing movement.

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?prod=LR-Drift&area=NH

Click to animate.

uniquorn

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Re: The 2019 melting season
« Reply #4776 on: July 27, 2019, 03:10:39 PM »
Bearing in mind some of the comments on the ice thickness products upthread, here is ascat overlayed with unihamburg amsr2-uhh at 55% transparency. To allow the ascat features to show through, amsr2 100% concentration ice, normally white, has also been set to fully transparent.
Although weather/other interference obscure many ascat features recently, I think the animation still gives a rough guide to the position of the older and possibly still thicker/more resilient ice that remains.
mar21-jul26.
ffmpeg -crf 27 switch to reduce file size. Where ascat data is missing or poor quality the nearest days have been duplicated, causing some stutter

Sterks

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Re: The 2019 melting season
« Reply #4777 on: July 27, 2019, 03:11:13 PM »
The last week of ice drift. The last 3 days have seen strong and increasing movement.

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?prod=LR-Drift&area=NH

Click to animate.
I agree that there's a divergence after July 20 between 2012 and this melting season.
But looking at your OSI-SAF animation there is a huge response of the pack to stimuli, like the current dipole is sinking Beaufort/ Chukchi edge at incredible speed, and all that is toward the Asian side is the ESS melange that does not seem solid and thick enough to survive.

uniquorn

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Re: The 2019 melting season
« Reply #4778 on: July 27, 2019, 03:54:36 PM »
Lincoln sea coast looking a bit worse today  https://go.nasa.gov/2K7eGuq

Rich

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Re: The 2019 melting season
« Reply #4779 on: July 27, 2019, 03:56:04 PM »
At the moment, the GFS is reporting an Arctic wide temperature anomaly of 0.0 C.

(at climatereanalyzer.org, there is an option under today's weather map for temp anomaly)

Nominal average temps are ~2C on the American side of the pole and 1C over most of the rest of the ice covered areas.

The high pressure is quite high...approaching 1040.

The strong winds which played a role in compacting the Chuchki yesterday have shifted direction and are now blowing  from the Beaufort toward Siberia. .

Wind looms large Arctic wide in the forecast window. In about a week, the NAC crack could go whack (expand).

Davidsf

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Re: The 2019 melting season
« Reply #4780 on: July 27, 2019, 04:11:51 PM »
Aluminum, your animations are gold. Thank you, and also for expanding the view so we can see more of the CAA (or am I hallucinating?)

Shared Humanity

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Re: The 2019 melting season
« Reply #4781 on: July 27, 2019, 04:43:17 PM »
Take your pick. dmi, hycom jul3-25 and piomas jul3-15
DMI is garbage
All are consistent with themselves.

As such, year over year, they provide metrics for comparison with their previous states, which in and of itself is useful in understanding how the system is changing.

yes...this.

Shared Humanity

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Re: The 2019 melting season
« Reply #4782 on: July 27, 2019, 04:55:44 PM »
Is this the same map?

Not exactly. The ones I posted are lagging 5-day medians. I.e., The middle concentration value for each pixel over the preceding 5 days. Roughly speaking, this cleans up much of the noise and tells you about where the ice was 3 days before.

Some of that noise is due to a highly mobile, fractured pack getting pushed around IMHO. Your smoothing may be hiding the fragile nature of portions of the CAB.

Shared Humanity

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Re: The 2019 melting season
« Reply #4783 on: July 27, 2019, 04:59:03 PM »
My bet is still on 2nd overall in terms of probability, but it's an open race.

Sounds about right to me too. I'd say 2012 is leading by a length, but several laps to go. Decreased thickness is indeed a wild card, and also don't forget the open and warm Chukchi.

All metrics show that 2019 is leading by a length but the horse is showing fatigue and the jockey on 2012 is about to start using his whip for the finishing stretch.

Shared Humanity

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Re: The 2019 melting season
« Reply #4784 on: July 27, 2019, 05:03:04 PM »
I have just returned from Croatia. Thanks to everyone for the condolences. In coming days, I'll try and get things in order here on the Forum.

Welcome back Neven. I am sorry for your loss. may you and your extended family find comfort together. Don't worry about this blog. It has become highly resilient, a lot of 5YO and 6YO ice to sustain it.

Shared Humanity

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Re: The 2019 melting season
« Reply #4785 on: July 27, 2019, 05:10:45 PM »
Bearing in mind some of the comments on the ice thickness products upthread, here is ascat overlayed with unihamburg amsr2-uhh at 55% transparency. To allow the ascat features to show through, amsr2 100% concentration ice, normally white, has also been set to fully transparent.
Although weather/other interference obscure many ascat features recently, I think the animation still gives a rough guide to the position of the older and possibly still thicker/more resilient ice that remains.


Thank you for this. I've always liked visuals to help us expand on our understanding that the metrics provide and this one is beautiful. You can vividly see the destruction of the MYI in the Beaufort as this sea has become an absolute killing zone. If more ice gets transported into the Beaufort, very little will survive the melt season.

UCMiami

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Re: The 2019 melting season
« Reply #4786 on: July 27, 2019, 05:25:51 PM »
Is this the same map?

Not exactly. The ones I posted are lagging 5-day medians. I.e., The middle concentration value for each pixel over the preceding 5 days. Roughly speaking, this cleans up much of the noise and tells you about where the ice was 3 days before.

Some of that noise is due to a highly mobile, fractured pack getting pushed around IMHO. Your smoothing may be hiding the fragile nature of portions of the CAB.
The highly mobile pack just means ice may move 10km in 24 hours - the issue with the daily charts is they often show shifts of 100s of km in a single day and then shifts back the next day or flashes showing thin ice that becomes thick ice again in the next day. Not sure what the artifacts are that cause them but they are clearly not actual reflections of the ice.

By creating an 'average' of values for each day, it is like creating the 5 day trailing average for area that gets posted daily - it helps smooth out obviously strange daily results.

There is still some issue with the animations specifically if you watch the dark purple shifting around the pack 100s of km from image to image, but I think it gives a better approximation of the arctic ice and hides some of the noise.

Rich

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Re: The 2019 melting season
« Reply #4787 on: July 27, 2019, 05:26:17 PM »
My bet is still on 2nd overall in terms of probability, but it's an open race.

Sounds about right to me too. I'd say 2012 is leading by a length, but several laps to go. Decreased thickness is indeed a wild card, and also don't forget the open and warm Chukchi.

All metrics show that 2019 is leading by a length but the horse is showing fatigue and the jockey on 2012 is about to start using his whip for the finishing stretch.

This is kinda cool. I've been considering the horse race analogy as well with Secretariat as the proxy for 2012. The record from the '73 Belmont still stands. Worth a YouTube view if you've never seen it.

DrTskoul

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Re: The 2019 melting season
« Reply #4788 on: July 27, 2019, 05:27:55 PM »
Bearing in mind some of the comments on the ice thickness products upthread, here is ascat overlayed with unihamburg amsr2-uhh at 55% transparency. To allow the ascat features to show through, amsr2 100% concentration ice, normally white, has also been set to fully transparent.
Although weather/other interference obscure many ascat features recently, I think the animation still gives a rough guide to the position of the older and possibly still thicker/more resilient ice that remains.
mar21-jul26.
ffmpeg -crf 27 switch to reduce file size. Where ascat data is missing or poor quality the nearest days have been duplicated, causing some stutter

If you notice ASCAT looks like the DMI distribution ( maybe not the magnitude).

philopek

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Re: The 2019 melting season
« Reply #4789 on: July 27, 2019, 05:43:41 PM »
At the moment, the GFS is reporting an Arctic wide temperature anomaly of 0.0 C.

(at climatereanalyzer.org, there is an option under today's weather map for temp anomaly)

Nominal average temps are ~2C on the American side of the pole and 1C over most of the rest of the ice covered areas.

The high pressure is quite high...approaching 1040.

The strong winds which played a role in compacting the Chuchki yesterday have shifted direction and are now blowing  from the Beaufort toward Siberia. .

Wind looms large Arctic wide in the forecast window. In about a week, the NAC crack could go whack (expand).

Let's first remember that this is the "melting" season thread.

That means arctic wide anomalies  that contains a lot of land and not only water, is not directly relevant, what counts is the anomaly value over the arctic ocean and the CAA where there is ice to wait melting.

If we look at that value for the arctic ocean and the CAA, where the ice-melting mainly occurs at this time of the year, the temps are above average, not below and not zero.

So this is how a true statement can draw a wrong picture for noobs and those who don't pay closest attention.

Further the temp anomaly is -0.2C on GFS Climate Reanalyzer as illustrated below.

Last but not least, even though it's not sure whether we shall see a GAC or not, it's possible that the difference in Ice-Thickness compared to 2012 can compensate some of that event, means, because the ice is thinner, there will be areas where simple and normal surface and bottom melt will suffice to reach zero thickness in areas where 2012 had thick MYI.

Therefore you conclusion that the lag concentration maps make a 2nd place certain are not that certain.

Nobody knows whether it will be 1st or 2nd or perhaps even 3rd, but 1st is still possible and you attempts to PROOF that everyone who believes in a possible 1st place doesn't get it, at least this is how it sounds a bit, is that you are on "THIN ICE" with that attitude IMO

« Last Edit: July 27, 2019, 05:53:24 PM by philopek »

Shared Humanity

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Re: The 2019 melting season
« Reply #4790 on: July 27, 2019, 06:04:47 PM »
Take your pick. dmi, hycom jul3-25 and piomas jul3-15
DMI is garbage
It's a shame that you sometimes place so little value on the work of others
So it's my fault that they are wrong? Would you rather it be used by deniers to counter the truth? DMI has some great tools but their thickness charts are clearly incorrect and far too generous.

All models are wrong. Some models are useful and I would argue that all three of these fall into the useful category. Far better to do a little research on how these models are constructed and what they are saying before declaring one as garbage IMHO. Of course, that's just me.

DrTskoul

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Re: The 2019 melting season
« Reply #4791 on: July 27, 2019, 06:09:04 PM »
Hear hear. A wrong model can teach you more than a correct one. By finding why is it wrong...regarding the choices for volume presented before. All are wrong, combine together they give a better picture than any single one alone...

Rich

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Re: The 2019 melting season
« Reply #4792 on: July 27, 2019, 06:09:23 PM »
If someone doesn't like what I post on the meaningless chatter thread or elsewhere, I'll be happy to engage there. Not taking the bait here.

Thanks for the comment that the Arctic GFS temp anomaly includes land values. That is educational for me. Happy to learn something.

Shared Humanity

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Re: The 2019 melting season
« Reply #4793 on: July 27, 2019, 06:10:11 PM »
Is this the same map?

Not exactly. The ones I posted are lagging 5-day medians. I.e., The middle concentration value for each pixel over the preceding 5 days. Roughly speaking, this cleans up much of the noise and tells you about where the ice was 3 days before.

Some of that noise is due to a highly mobile, fractured pack getting pushed around IMHO. Your smoothing may be hiding the fragile nature of portions of the CAB.

The highly mobile pack just means ice may move 10km in 24 hours - the issue with the daily charts is they often show shifts of 100s of km in a single day and then shifts back the next day or flashes showing thin ice that becomes thick ice again in the next day.

This animation is not measuring the thickness of the ice. It is measuring concentration. As fractured ice moves around, some areas become more concentrated while adjacent areas thin out with more open water. This is why you can see the effects of a low pressure system in the image as it disperses ice from the low pressure. I like to see these fluctuations because it gives me a sense of the mechanical forces coming to play on a fractured, mobile ice pack.

gerontocrat

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Re: The 2019 melting season
« Reply #4794 on: July 27, 2019, 06:26:18 PM »
The CAB thickness I quoted yesterday(?) assumed the Wipneus regional volume data related to the CAB as defined by NSIDC.

It does not. Wipneus confirmed that to me today. So the CAB average thickness as at 15 July I stated as 2.6 metres is more like 2.1. (NSIDC CAB Sea is 3.2 million km2, Wipneus CAB sea is 4.45 million km2. Also depends on losses in the 1.25 million km2 extra area of the Wipneus CAB)

To add to my dismay, it means that the average thicknesses of the Beaufort, Chukchi, ESS, Laptev and Kara are correspondingly understated at any time I have quoted them (unless zero).

A large amount of work and analysis is currently being examined for possible recycling or consignment directly to landfill..

The graphs and tables for total Arctic volume and thickness are not affected.
_____________________________________________________________
This is one reason for not choosing what may be optimal divisions for a particular purpose, choosing instead to opt for standard regional classifications for the different data types involved, thus allowing easy comparisons and combinations.

I am unable to maintain 2 sets of area and extent tables (by NSIDC & Wipneus) so detailed thickness graphs will be dumped, and volume tables for individual seas will have warning caveats to ensure people do not attempt to compare extent, area with volume at individual sea level.
________________________________________

Maybe I've got that right this time - maybe not.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
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petm

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Re: The 2019 melting season
« Reply #4795 on: July 27, 2019, 06:39:58 PM »
As fractured ice moves around, some areas become more concentrated while adjacent areas thin out with more open water.

Absolutely. The technique is pixel-by-pixel and does not do anything sophisticated like trying to track the motion of floes. As you point out, it smooths out all rapid changes regardless of whether they real or artifactual. You see changes that persist and not those that don't, and is only useful when reality persists and artifacts don't, which seems usually true, but not always. It also is delayed in showing changes by a few days.

For the most recent and rapid changes, watch Aluminum's daily animations and use the "squinting" technique (aka. brain filter).

Quote
I like to see these fluctuations because it gives me a sense of the mechanical forces coming to play on a fractured, mobile ice pack.

Sure, if you have enough experience to tell the difference between artifacts and real changes. Most of the fast moving purple artifacts do seem to closely track clouds...
« Last Edit: July 27, 2019, 06:45:57 PM by petm »

Shared Humanity

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Re: The 2019 melting season
« Reply #4796 on: July 27, 2019, 06:42:11 PM »
gerontocrat...please do not question the value of all of the work you have done...I cannot possibly count the number of times that I discovered measurement problems in the manufacturing facilities that I managed. Each discovery presented opportunities to learn more about the processes we were trying to understand.

Shared Humanity

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Re: The 2019 melting season
« Reply #4797 on: July 27, 2019, 06:43:48 PM »
As fractured ice moves around, some areas become more concentrated while adjacent areas thin out with more open water.

Absolutely. The technique is pixel-by-pixel and does not do anything sophisticated like trying to track the motion of floes. As you point out, it smooths out all rapid changes regardless of whether they real or artifactual. You see changes that persist and not those that don't, and is only useful when reality persists and artifacts don't, which seems usually true, but not always. It also is delayed in showing changes by a few days.

For the most recent and rapid changes, watch Aluminum's daily animations and use the "squinting" technique (aka. brain filter).

I think both approaches have merit and viewing them side by side would be informative.

petm

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Re: The 2019 melting season
« Reply #4798 on: July 27, 2019, 06:48:23 PM »
I think both approaches have merit and viewing them side by side would be informative.

Oddly enough, I originally was doing exactly that: side by sides of smoothed vs. original. I'll see if I can resurrect that code.

petm

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Re: The 2019 melting season
« Reply #4799 on: July 27, 2019, 06:50:22 PM »
gerontocrat...please do not question the value of all of the work you have done

+1