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epiphyte

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Re: The 2019 melting season
« Reply #300 on: April 03, 2019, 09:58:39 AM »
Let's be nice, this isn't the Trump-thread.

I live in Minnesota, so nice pretty much goes with the territory.

I do have to say that I find it hard to believe that KK is for real though. How nice must one be in the face of unashamed trollery? (or is that trollericiousness? - my spell-checker is failing me on this point.)


Jim Hunt

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Re: The 2019 melting season
« Reply #301 on: April 03, 2019, 01:27:01 PM »
I do have to say that I find it hard to believe that KK is for real though.

Here you go:

"Are 3 dimensions better than 2?"

Quote
A place to be nice whilst debating volume/thickness versus area/extent whilst not cluttering up the 2019 melting season thread.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

magnamentis

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Re: The 2019 melting season
« Reply #302 on: April 03, 2019, 01:46:08 PM »
The warm anomalies have extended to the north of 80 latitude but it still very far from melting in the high Arctic

far from melting but impacts peak thickness and volume, which, depending on summer weather can make a huge difference in the final outcome of this melting season

magnamentis

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Re: The 2019 melting season
« Reply #303 on: April 03, 2019, 01:48:45 PM »
Funny, but irrelevant to the discussion at hand.

declaration of irrelevance is the only way to avoid admitting a "faux pas"

hope it's nice enough, at least the nicest way to answer the question "why....."

Jim Hunt

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Re: The 2019 melting season
« Reply #304 on: April 03, 2019, 01:51:47 PM »
Since we seem to getting back to referencing the science at long last, here's a recent paper by Stefan Hendricks of this parish et al.:

"Arctic warming interrupts the Transpolar Drift and affects long-range transport of sea ice and ice-rafted matter"

Quote
Due to the recently observed acceleration in sea ice drift, it has been assumed that more matter is advected by the transpolar Drift from shallow shelf waters to the central Arctic ocean and beyond. However, this study provides first evidence that intensified melt in the marginal zones of the Arctic ocean interrupts the transarctic conveyor belt and has led to a reduction of the survival rates of sea ice exported from the shallow Siberian shelves (−15% per decade). As a consequence, less and less ice formed in shallow water areas (<30 m) has reached Fram Strait (−17% per decade), and more ice and ice-rafted material is released in the northern Laptev Sea and central Arctic Ocean.
« Last Edit: April 03, 2019, 05:30:05 PM by Jim Hunt »
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Jim Hunt

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Re: The 2019 melting season
« Reply #305 on: April 03, 2019, 01:53:51 PM »
declaration of irrelevance is the only way to avoid admitting a "faux pas"

Perhaps I spoke too soon? At the risk of repeating myself - Here you go:

"Are 3 dimensions better than 2?"
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Klondike Kat

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Re: The 2019 melting season
« Reply #306 on: April 03, 2019, 02:08:18 PM »
Funny how one comment can be misconstrued and amplified to mean something else altogether.  For the record, I never said that either thickness or volume was irrelevant - that was Oren.  I was referring to epiphyte's comment about one dimension going to zero, and being the only one that is relevant.  Obviously, one dimension of a three-dimensional object cannot go to zero, without the other dimensions following simultaneously (this is not abstract math).  Consequently, it is not relevant to this thread to talk about one dimension going to zero, while the others do not.

Jim Hunt

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Re: The 2019 melting season
« Reply #307 on: April 03, 2019, 02:09:26 PM »
Funny how one comment can be misconstrued

At the risk of repeating myself repeating myself - Here you go:

"Are 3 dimensions better than 2?"
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Davidsf

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Re: The 2019 melting season
« Reply #308 on: April 03, 2019, 03:48:13 PM »
Jim thanks for posting the article on transpolar drift, but when I followed the link, the text of article was broken up and unreadable. Advice welcome.

Jim Hunt

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Re: The 2019 melting season
« Reply #309 on: April 03, 2019, 03:57:29 PM »
When I followed the link, the text of article was broken up and unreadable. Advice welcome.

It looks fine to me in Opera on Windows 10. Can you not even try to download the PDF and examine it in Acrobat or similar?
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LRC1962

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Re: The 2019 melting season
« Reply #310 on: April 03, 2019, 04:04:54 PM »
Jim thanks for posting the article on transpolar drift, but when I followed the link, the text of article was broken up and unreadable. Advice welcome.
another readable link can be found here: https://www.nature.com/articles/s41598-019-41456-y (sharing link points to an epdf file that is not working)
« Last Edit: April 03, 2019, 04:14:10 PM by LRC1962 »
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Jim Hunt

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Re: The 2019 melting season
« Reply #311 on: April 03, 2019, 05:38:27 PM »
Another readable link can be found here

Thanks LRC. I've modified the link in my original post. Another brief extract from the paper:

Quote
Sea ice thickness measurements from the AWI IceBird program are available via the project’s homepage:

https://www.awi.de/en/science/climate-sciences/sea-ice-physics/projects/ice-bird.html.

Results from the tracking experiments were uploaded to PANGAEA and will be available soon. The gridded thickness fields from the radar altimeters onboard the Envisat and CryoSat-2 satellite platforms are available at the CCI Data Portal.

Does anyone know if "the CCI Data Portal" is open to the average "citizen scientist" in the street? In the meantime I'm happily using the gridded thickness fields available via the "FMI Data Portal" at:

http://ice.fmi.fi/data/arctic/cs2-smos-nrt-sea-ice-thickness/

Reality is merely an illusion, albeit a very persistent one - Albert Einstein

shendric

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Re: The 2019 melting season
« Reply #312 on: April 03, 2019, 06:16:57 PM »
Quote
Does anyone know if "the CCI Data Portal" is open to the average "citizen scientist" in the street?

All CCI data (and ESA data for this matter) is open and public:

ftp://anon-ftp.ceda.ac.uk/neodc/esacci/sea_ice/data/sea_ice_thickness/

GoSouthYoungins

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Re: The 2019 melting season
« Reply #313 on: April 04, 2019, 03:08:00 AM »
Let's be nice, this isn't the Trump-thread.

He won, the dirty orange goblin. It is a Trump world now. ASIF isn't immune.


I think the ice looks good. Thick, old, and stable. I'm not worried.   ;)
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Paladiea

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Re: The 2019 melting season
« Reply #314 on: April 04, 2019, 08:04:43 AM »
I think you're missing something important in your analysis, and that is the fact that ice isn't 2 dimensional, but 3.

Ice volume is also very important in how resistant it is to melt, and correlating extent and area to melt isn't going to hold on for much longer if it held up at all.

Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.

I think you misunderstand me, the issue isn't that you should take all three separately, but that you should use volume, or perhaps even better, density.


Quote
Conversely, the third dimension cannot go to 0, without the extent going to 0.  The extent will change based on the dimension which has the greatest influence.  The factors influencing thickness, like wave action, are small compared to those acting on the overall area, sunlight and seawater.  Thickness changes does not drive the sea ice, rather they occur through these other factors.


While technically this might be true, the volume of sea ice can tell us a lot about how resistant it is to melting. Thick compact multiyear ice is much fresher (has less salt), much colder, and generally more resistant to melting than say slush even though they might cover the same area.

And the reason I suggested 'density' was because volume only gives the total 3d space the ice occupies, not how solid the ice is in that 3d space. Using the example I said above, everyone would agree that said thick multiyear ice is far more resistant than first year ice that might have the same volume.
« Last Edit: April 04, 2019, 08:20:29 AM by Paladiea »
The most enjoyable way to think about heat transfer through radiation is to picture a Star Wars laser battle, where every atom and molecule is constantly firing at every other atom and molecule.

b_lumenkraft

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Re: The 2019 melting season
« Reply #315 on: April 04, 2019, 08:14:11 AM »
density

Boy, oh boy. Yet another dimension.  ;D

Paladiea, can you or someone briefly elaborate on how density would influence melting, please.

Paladiea

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Re: The 2019 melting season
« Reply #316 on: April 04, 2019, 08:15:49 AM »
density

Boy, oh boy. Yet another dimension.  ;D

Paladiea, can you or someone briefly elaborate on how density would influence melting, please.


I've edited my above reply to reflect your question.
The most enjoyable way to think about heat transfer through radiation is to picture a Star Wars laser battle, where every atom and molecule is constantly firing at every other atom and molecule.

b_lumenkraft

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Re: The 2019 melting season
« Reply #317 on: April 04, 2019, 08:43:59 AM »
I've edited my above reply to reflect your question.

Thank you! Makes sense to me now. :)

Jim Hunt

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Re: The 2019 melting season
« Reply #318 on: April 04, 2019, 09:35:07 AM »
All CCI data (and ESA data for this matter) is open and public:

Thanks very much Stefan. At first glance the new FMI merged thickness product is easier to use than the CCI data you linked to. Does the FMI product suffer from any significant disadvantages?
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Jim Hunt

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Re: The 2019 melting season
« Reply #319 on: April 04, 2019, 09:36:15 AM »
Paladiea, can you or someone briefly elaborate on how density would influence melting, please.

(Repeating myself)^n

https://forum.arctic-sea-ice.net/index.php/topic,2618.0.html
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Jim Hunt

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Re: The 2019 melting season
« Reply #320 on: April 04, 2019, 09:37:35 AM »
There's no sign of a significant slowdown in early season melt just yet:
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shendric

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Re: The 2019 melting season
« Reply #321 on: April 04, 2019, 03:23:46 PM »
All CCI data (and ESA data for this matter) is open and public:

Thanks very much Stefan. At first glance the new FMI merged thickness product is easier to use than the CCI data you linked to. Does the FMI product suffer from any significant disadvantages?

Hi Jim,

what do you mean with "easier"? The file format (netCDF) is the same.

The biggest difference between the CCI climate data record and the FMI/AWI CryoSat-2/SMOS (CS2SMOS) data is that the CCI objective is on consistency over longer periods. There was no SMOS-like data back in 2002, so the CCI uses radar altimetry from Envisat and CryoSat-2 only. Also, there is no interpolation or gap-filling to be as close to the actual observation as possible. Thats why the CCI data set as both the track data (L2P: Level-2 pre-processed) and the gridded maps (L3C: Level-3 collated).

The CS2SMOS product however uses interpolation as an integral part of the CryoSat-2/SMOS data merging and thus is much smoother than the actual observations of either satellite. The CryoSat-2 contribution to CS2SMOS is quite similar to the CryoSat-2 part in the CCI data record.

Cheers, Stefan

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Re: The 2019 melting season
« Reply #322 on: April 04, 2019, 05:04:38 PM »

El Cid

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Re: The 2019 melting season
« Reply #323 on: April 04, 2019, 07:03:59 PM »
-6˚ to 0˚C over Beaufort and Chukchi forecasted by GFS.


It's not there on the latest run and it is not there on ECMWF. Besides, anything beyond 5 days is always suspect.
ECMWF has bering/chukchi, and generally the whole arctic very warm the next 3 days, and then Greenland is very warm, but gets cooler at other places

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Re: The 2019 melting season
« Reply #324 on: April 04, 2019, 09:09:50 PM »
-6˚ to 0˚C over Beaufort and Chukchi forecasted by GFS.


It's not there on the latest run and it is not there on ECMWF. Besides, anything beyond 5 days is always suspect.
ECMWF has bering/chukchi, and generally the whole arctic very warm the next 3 days, and then Greenland is very warm, but gets cooler at other places
Agree, but it does indicate a trend.  While the specific regions affected haven't necessarily followed the 5+ day forecasts, the intrusions of heat and moisture have tended to follow.

Cold over the thickest ice (which is what appears to be indicated) won't help as much as if it happened over areas forecast to be torched. If the heat does continue to surge on the pacific side we could we early disintegration of both the Chukchi and outer Beaufort.  Early increases in heat uptake could be as bad or worse than melt ponds.  Ill be watching what Tealights tools show us.
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El Cid

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Re: The 2019 melting season
« Reply #325 on: April 04, 2019, 09:24:50 PM »
And I agree with you :)

Pacification is the new trend after Atlantification. The Bering and Chukci will likely "evaporate" pretty fast.

 If the Atlantic side keeps playing the role  of the killzone, and the Pacific side gets wiped out early, then this year we could really see amazing records.

bbr2314

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Re: The 2019 melting season
« Reply #326 on: April 04, 2019, 09:26:47 PM »
-6˚ to 0˚C over Beaufort and Chukchi forecasted by GFS.


It's not there on the latest run and it is not there on ECMWF. Besides, anything beyond 5 days is always suspect.
ECMWF has bering/chukchi, and generally the whole arctic very warm the next 3 days, and then Greenland is very warm, but gets cooler at other places
Agree, but it does indicate a trend.  While the specific regions affected haven't necessarily followed the 5+ day forecasts, the intrusions of heat and moisture have tended to follow.

Cold over the thickest ice (which is what appears to be indicated) won't help as much as if it happened over areas forecast to be torched. If the heat does continue to surge on the pacific side we could we early disintegration of both the Chukchi and outer Beaufort.  Early increases in heat uptake could be as bad or worse than melt ponds.  Ill be watching what Tealights tools show us.
I think this year is a perfect storm of both early heat uptake AND melt ponds. There are probably large melt ponds already forming across most of the Beaufort. I think this very early 1-2 punch will be sufficient to melt out the Beaufort entirely this year, which will be unlike most recent years, although this is also due to the lack of any substantial areas of thick ice this year as well. The same goes for ESS and Chukchi although both of those have been melting out most completely with more consistency than Beaufort.

bbr2314

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Re: The 2019 melting season
« Reply #327 on: April 04, 2019, 09:30:39 PM »
PS, here is March 2019 minus 2012. I guess this is what -1M KM^2 of extent in seven years looks like. It certainly appears we may have a running leap leading into the melt season this year.

Jim Hunt

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Re: The 2019 melting season
« Reply #328 on: April 04, 2019, 10:46:57 PM »
What do you mean with "easier"? The file format (netCDF) is the same.

I wasn't referring to the file format. Obviously FMI is "easier" for NRT updates on threads like this one, and CCI's "easier" for historical comparisons!

Compare and contrast the two images below. SMOS fills in some gaps around the edges in the FMI based image, and the interpolation you refer to is visually evident. That makes the FMI image easier on the eye (IMHO), and thanks for explaining what gets lost during the processing.
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uniquorn

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Re: The 2019 melting season
« Reply #329 on: April 05, 2019, 12:01:36 AM »
I think this year is a perfect storm of both early heat uptake AND melt ponds. There are probably large melt ponds already forming across most of the Beaufort.
While I tend to agree with the first part, I would say that melt ponds in the beaufort are working towards investigating the processes involved in the possibility of forming. ;)

Some 'on the ice' temperatures in and around the beaufort are available from the whoi ITP buoys (ITP103-110) released late sep-oct. Also shown is ITP89, released in 2015 and currently lodged in the CAA, which gives an idea at what point from recent years we might expect melt ponds to activate the above intention.
http://www.whoi.edu/page.do?pid=163197

edit: the recent warm spell can be seen after day450 on last years buoys
 
« Last Edit: April 05, 2019, 12:08:41 AM by uniquorn »

jdallen

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Re: The 2019 melting season
« Reply #330 on: April 05, 2019, 02:40:41 AM »
I think this year is a perfect storm of both early heat uptake AND melt ponds. There are probably large melt ponds already forming across most of the Beaufort.
While I tend to agree with the first part, I would say that melt ponds in the beaufort are working towards investigating the processes involved in the possibility of forming. ;)
<Laughter>
I concur.  April melt ponds, no.  May meltponds, a distinct and unpleasant possibility.

Also in play - increased and earlier snow melt outflow from peri-arctic drainages, which I think may further accelerate the melt.  Anyone have eyeballs on what the Mackenzie is doing currently, for example?
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bbr2314

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Re: The 2019 melting season
« Reply #331 on: April 05, 2019, 05:54:35 AM »
JAXA -70K. 2016's final descent below our current number occurred on 4/16 that year (a record for the date). If we follow 2010s averages we will maintain the record quite easily through early May, and in a month we should be below 12M KM^2 (avg loss of 1.2M KM^2 through 5/5).

Aluminium

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Re: The 2019 melting season
« Reply #332 on: April 05, 2019, 08:12:45 AM »
March 30 - April 4.

Ice has broken in upper Ob and Yenisei rivers. Slightly earlier than usual.

oren

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Re: The 2019 melting season
« Reply #333 on: April 05, 2019, 08:35:26 AM »
March 30 - April 4.
Thanks a lot for these periodic animations.
It looks like continued two-sided wind movement/ice compaction/melting: From the Pacific through the Bering Strait and into the Chukchi, and from the Atlantic into the Kara Sea. At the same time, ice is being exported in mass from the CAB via the Fram into the Greenland Sea and via the FJL-Svalbard gap into the Barents. Such a persistent overall movement is really bad at the start of the melting season, and the more it continues the more damage is incurred.
Should the winds reverse Chukchi and Kara can regrow to their max level, but the thick exported ice will not come back from the Atlantic kill zone.

bbr2314

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Re: The 2019 melting season
« Reply #334 on: April 05, 2019, 09:00:37 AM »
I know I was made fun of re: melt ponds a few posts back but a look at the graphic from Aluminum shows that there has indeed been widespread sporadic melt ponding over much of the Arctic (IMO). It may not be incredibly consistent but even temps of -5C, when combined with increasing sun angle, can yield melting snowpack and growing melt ponds. As anyone who has been outside on a sub-32F spring day in can attest, bright sunshine can more than overwhelm marginally cold temps to result in melt.

I think this pre-conditioning is setting the stage for an epic collapse of the Beaufort, ESS, and Chukchi come May->June. Kara also looks to be in staunch retreat already although I guess regrowth is still possible there.

binntho

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Re: The 2019 melting season
« Reply #335 on: April 05, 2019, 09:35:37 AM »
I know I was made fun of re: melt ponds a few posts back but a look at the graphic from Aluminum shows that there has indeed been widespread sporadic melt ponding over much of the Arctic (IMO).

So a "look" at Aluminiums graphic "shows" melt ponding - whatever that means. Perhaps it's possible to convince yourself that the black smudges are "widespread sporadic melt ponding". Or not. Sometimes it's better to stop digging.
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Re: The 2019 melting season
« Reply #336 on: April 05, 2019, 10:09:59 AM »
The nice folks over at the RAMMB CIRA site from Colorado State University have added Suomi and N20 imagery to their slider at 51 minute intervals.  Perhaps some will find this of interest.
Here's the last 2 days focused on the Kara Sea.  There are additional bands available, along with the ability to overlay and zoom.  Unfortunately, it can't be rotated in the slider.

http://rammb-slider.cira.colostate.edu/?sat=jpss&z=2&im=54&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_m07&x=13379&y=12292
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b_lumenkraft

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Re: The 2019 melting season
« Reply #337 on: April 05, 2019, 10:22:29 AM »


That's truly amazing! Thank you for that link.

johnm33

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Re: The 2019 melting season
« Reply #338 on: April 05, 2019, 11:31:21 AM »
"melt ponds" Looks more like weak 2 dimensional ice being pushed around by winds/currents as much opening as there is compaction followed by rapid surface freezing.
"I think this pre-conditioning is setting the stage for an epic collapse of the Beaufort, ESS, and Chukchi come May->June. Kara also looks to be in staunch retreat already although I guess regrowth is still possible there. " I agree.

IceConcerned

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Re: The 2019 melting season
« Reply #339 on: April 05, 2019, 11:52:08 AM »
When looking at Aluminium animation, I am marked by the appearnce of big, long cracks within the ice. The wind force and derive must be very strong :
This time they appear mainly off the north Siberian coast, but there is a small one in Beaufirt too. And I remember seeing them on other previous animation too : do I have bad memories, or is it indeed a first ?

be cause

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Re: The 2019 melting season
« Reply #340 on: April 05, 2019, 12:21:26 PM »
When looking at Aluminium animation, I am marked by the appearnce of big, long cracks within the ice. The wind force and derive must be very strong :
This time they appear mainly off the north Siberian coast, but there is a small one in Beaufirt too. And I remember seeing them on other previous animation too : do I have bad memories, or is it indeed a first ?

this is the norm .. or at least the new norm when winds are blowing off-shore . Last year it was an almost continuous process. New ice will form in the cracks and contribute to volume .. and the cracks allow heat to escape .  b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

uniquorn

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Re: The 2019 melting season
« Reply #341 on: April 05, 2019, 01:51:11 PM »
Fast ice in ess looking a bit weaker than last year.
Worldview, terra modis, apr5 2018 and 2019.

@bbr, agreed on preconditioning but not about melt ponds. Please check clouds over the beaufort on worldview vs amsr2.
edit: thanks JayW
« Last Edit: April 05, 2019, 02:02:56 PM by uniquorn »

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Re: The 2019 melting season
« Reply #342 on: April 05, 2019, 02:33:58 PM »
Melt onset usually occurs under clouds. The snow then refreezes, but its structure has changed, making it easier for melt ponds to form some time later.
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oren

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Re: The 2019 melting season
« Reply #343 on: April 05, 2019, 02:42:45 PM »
I think the date and the weather is still too early for melt ponds and other snow structure effects.
OTOH the Kara ice in JayW's animation looks pretty bad.

uniquorn

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Re: The 2019 melting season
« Reply #344 on: April 05, 2019, 06:12:33 PM »
Melt onset usually occurs under clouds. The snow then refreezes, but its structure has changed, making it easier for melt ponds to form some time later.
Apologies to all then, especially bbr.

Neven

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Re: The 2019 melting season
« Reply #345 on: April 05, 2019, 06:26:27 PM »
No need to apologize, you were right that it's too early for melt pond formation. There may be some melt onset here and there, and this may have an effect in a couple of weeks on melt pond formation. You could call it pre-preconditioning.  ;)

But melt onset usually occurs earlier under cloudy conditions.
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Thomas Barlow

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Re: The 2019 melting season
« Reply #346 on: April 05, 2019, 07:27:03 PM »
A slight "rebound" in high resolution AMSR2 area, with extent flatlining for the last couple of days:
Yes. One more day of the same angle of descent on NSIDC graph right now would have been be pretty concerning. It can still crawl back among the crowd and stay there (among the lowest crowd on record that is).

Thomas Barlow

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Re: The 2019 melting season
« Reply #347 on: April 05, 2019, 07:31:13 PM »
No need to apologize, you were right that it's too early for melt pond formation. There may be some melt onset here and there, and this may have an effect in a couple of weeks on melt pond formation. You could call it pre-preconditioning.  ;)
But melt onset usually occurs earlier under cloudy conditions.
Unless it has been raining on the Arctic sea-ice as well. Unlikely, but I don't discount any wierd development these days.
https://www.bbc.com/news/science-environment-47485847

Sterks

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Re: The 2019 melting season
« Reply #348 on: April 05, 2019, 09:23:24 PM »
I share a certain gloomy feeling about this year compared to what happened in the past two seasons
* NH temp anomalies back to record territory
* A distinct ring of negative snow cover anomaly is forming all around the NH including US and Canada where abundant winter snowfall is now melting quickly. Google rutgers ice lab (sorry getting too old to download resize and crop as needed). This signals early Spring, generalized, did not happen since 2016.
* Oceanic anomalous heat input since beginning of year is apparent esp. thru Bering.
* Record low extent may not be determinant, but sure won’t help
* The preconditioning in Kara and Chukchi may be real, will refreeze but again, won’t help
* The thickest ice is again tilted against the Atlantic
Anything can happen but I have a bad feeling that I didn’t have since 2015. Ok I thought that was it in 2017 too, but fell again in the trap of “low thickness will trump weather”. Weather trumps all.

Tor Bejnar

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Re: The 2019 melting season
« Reply #349 on: April 05, 2019, 09:59:17 PM »
Quote
Weather trumps all.
Especially blow-it-out-into-the-Atlantic weather!
Arctic ice is healthy for children and other living things.