Support the Arctic Sea Ice Forum and Blog

Author Topic: The 2017 melting season  (Read 1843875 times)

Jim Hunt

  • First-year ice
  • Posts: 6268
  • Don't Vote NatC or PopCon, Save Lives!
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 893
  • Likes Given: 87
Re: The 2017 melting season
« Reply #1000 on: April 29, 2017, 12:46:19 PM »
Something to do with the extra meltwater?

I assume from his quotation marks that David is implying that much of the extra "sea ice" around Newfoundland is actually ex "glacier ice".
"The most revolutionary thing one can do always is to proclaim loudly what is happening" - Rosa Luxemburg

Bill Fothergill

  • Frazil ice
  • Posts: 278
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: The 2017 melting season
« Reply #1001 on: April 29, 2017, 02:15:38 PM »
TotTor, oren, Terry, Rob,  {Oops, just noticed the fat-finger syndrome}

I think there has been some gibbering in Flatland recently concerning the amount of ice around Newfoundland. One suspects that this is export related, and that any such ice is basically "dead man walking".
The ice around Newfoundland is almost certainly the result of collapsing glaciers not sea ice. Its one area where an increase in 'sea ice' can be expected as glacier collapse in Greenland becomes more prevalent.

Yeah. My first response when I saw the comment(s) about ice in the Newfoundland region was that it was almost certainly a mixture of (a) detritus that had calved from a glacier front, and (b) an artefact caused by freshwater lensing as a result of melt.

However, there was also a remark about the thickness being at record level.

Having a totally useless memory, I cannot recall the article source. HOWEVER, I pretty sure it would have been something associated with a very recent entry on the "Arctic Image of the Day" thread. There was a photo (#835) on that thread of a grounded 'berg off the coast near Ferryland. It was just after seeing that image, that I read (somewhere) about there being sea ice of record thickness near Newfoundland.

Being in an unusually generous mood, I was prepared to accept the description as having some basis in fact - as opposed to the normal Flatland bollocks. As I mentioned in the original post, if that genuinely is sea ice - as opposed to glacial ice - then it has come from further north, and is on its way to a rather rapid phase change.

Perhaps I was being overly generous. (Perhaps there is no "perhaps" about it?)

Thomas Barlow

  • Guest
Re: The 2017 melting season
« Reply #1002 on: April 29, 2017, 02:25:53 PM »
Interesting graphic, really looks like where ice is close to 100% concentration it's thinner and areas with thicker ice are more fractured.

My take on it is that there are areas of thick, concentrated ice, and thinner ice. The Beaufort, for example, is relatively thick and relatively concentrated at this time compared to the main area of weakness which is towards the Russian (east) side, where the blue areas are thinner and less concentrated, and the intrusions of blue into the thicker areas should be note for concern, since those look more advanced than usual.  It's early days yet, but still gives an overall sense.
« Last Edit: April 29, 2017, 09:25:31 PM by Thomas Barlow »

iceman

  • Frazil ice
  • Posts: 285
    • View Profile
  • Liked: 7
  • Likes Given: 19
Re: The 2017 melting season
« Reply #1003 on: April 29, 2017, 02:35:59 PM »
   ....
I'm more concerned about 'volume'. If the ice is the Arctic is really as thin as PIOMAS suggests, the melting could start to accelerate once temperatures are above freezing.
Rob, I totally agree.

Likewise, even though volume is set to look a bit better as of April (PIOMAS model appears to track extent or area anomaly to some degree).
    It seems unusually tricky to assess pre-conditioning this year.  Volume is poorly distributed but concentration and compactness measures don't look too bad, and extent anomaly could continue improving through the first or second week of May.  The lack of early open areas at lower latitudes of the Arctic (notably excepting Chukchi, but that's small) also helps on the insolation count.
    My sense is that the season will hinge on which exerts the greater influence on volume: concentration or melt ponding.  Western Beaufort and adjoining CAB might be an early tell.

Niall Dollard

  • Nilas ice
  • Posts: 1154
    • View Profile
  • Liked: 460
  • Likes Given: 117
Re: The 2017 melting season
« Reply #1004 on: April 29, 2017, 02:40:13 PM »
Regarding this melt season and what the extent min will be like this year, at Jan 1st I was fully expecting to see a new record set this year (given the state of the ice last September). Now I'm not so sure. A few things of note, that have been mentioned already in various threads on the forum:

- NH Snow cover is up this spring
- Little opening yet in the Beaufort (compared to last year)
- The Kara Sea ice "rally" during the month of April, after opening considerably at the end of March.
- Practically no melt so far in Greenland.

All of these help buy time, keep the albedo up, as we head towards peak insolation. Even the snow papering over the cracks, serves to help.

June will tell a lot and whether we have an LP dominated cloudy summer. If this is to be the pattern we could be in a prolonged situation where the "rubble" remains, sloshing about for several summers to come. Thickness and PIOMAS numbers continuing to decline but with the rubble/veneer continuing to keep the extent numbers up circa 3 to 4 million square kilometres. It could be a while yet before we see a blue ocean summer.

As I believe there are a lot of super sensitive (and equally super sensible ! ) contributors to this forum, let me clarify that I do not believe that we are in for anything that you could remotely call a "recovery".I have an aversion to even typing that word!  :)

I fully subscribe to the anthropogenic global warming theory. One thing you should not do though is trivialise the Arctic. It will always be two steps back one step forward and visa versa   

Tor Bejnar

  • Young ice
  • Posts: 4606
    • View Profile
  • Liked: 879
  • Likes Given: 826
Re: The 2017 melting season
« Reply #1005 on: April 29, 2017, 04:31:27 PM »
TotTor, oren, Terry, Rob,  {Oops, just noticed the fat-finger syndrome}
...
...
...
You made me feel young (very young) again!  :)
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

Bill Fothergill

  • Frazil ice
  • Posts: 278
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: The 2017 melting season
« Reply #1006 on: April 29, 2017, 05:09:57 PM »
...
You made me feel young (very young) again!  :)

All part of the service  :-[

Shared Humanity

  • Guest
Re: The 2017 melting season
« Reply #1007 on: April 29, 2017, 05:13:39 PM »
I've copied 5 of the extent graphs from the Regional Graphs page: three have lots of ice and two have record(?) low ice.
 
The Barentsz Sea (Dutch spelling, and the guy was Dutch) is 'quite full' of ice - I don't have an opinion why.  The Greenland Sea is also 'quite full' - I think ice export from the Arctic Ocean is high (despite so much melting around Svalbard in the mid- and late winter).  Baffin / Newfoundland Bay is 'quite full' too - I think the lack of any sustained ice arch within Nares Strait has allowed much (thin) export of ice (ice that grows within the Strait over a 2 to 8 week period as it drifts southwards), and thin ice counts as extent. 

I note both the Bering Sea and Sea of Okhotsk have unseasonably low amounts of ice - I don't have an opinion why.

What opinions do other's have concerning these 5 regions?

(And yes, much of the ice is thinner than ever before at this time of year.)

I believe, as others have said, that the current, relatively high extent and area in the Barents and Greenland Sea is due to a new dynamic, the increased mobility of Arctic sea ice. This is the result of a number of changes in the Arctic, thinner ice, stormier weather and warmer surface waters (intrusion and upwelling?), figuring as three of the most prominent. In the dead of winter this spreading of the ice cover first results in increased extent, allowing for a subsequent increase in area as freezing causes this dispersed ice to be stitched together with very thin FYI. This process is in play not only in the Barents and Greenland Seas but also is vividly present in the CAB in the areas which have transported ice into these seas throughout the winter by a succession of storms (the cyclone cannon) from the North Atlantic into the CAB. This area of the CAB also sports remarkably thin ice, comprised mainly of highly mobile early season FYI that has been continuously stitched together with newer, much thinner FYI. Early in the freeze season, we all remarked how quickly this transported ice was melting as it encountered the warm waters around Franz Josef and Svalbard. As the freeze season deepened this ice began to survive. It won't for long, I fear. Nor will the areas of the CAB that have been transporting ice into these seas.
« Last Edit: April 29, 2017, 05:27:47 PM by Shared Humanity »

romett1

  • Frazil ice
  • Posts: 286
    • View Profile
  • Liked: 32
  • Likes Given: 2
Re: The 2017 melting season
« Reply #1008 on: April 29, 2017, 05:25:58 PM »
I thought maybe these two bigger blocks survive bit longer near Wrangel Island, Chukchi Sea. But as the first block hit the coast yesterday, it just disintegrated into smaller pieces. Images: Worldview, Apr 26 - Apr 28.

Shared Humanity

  • Guest
Re: The 2017 melting season
« Reply #1009 on: April 29, 2017, 05:54:44 PM »
We can clearly see the effects of increased sea ice mobility during the melt season as there is a 4 decade long trend of increasing dispersion at minimum. One of the most interesting characteristics of this trend is the step behavior we see. There are three distinct shifts upward in dispersion, occurring in 1989, 1998 and 2008. Each of these occurred after devastating melt seasons wiped out a huge amount of MYI. Unless we begin to see seasonal increases in MYI (I don't think this will occur.), this new mobility has become a persistent feature.

When I first created this dispersion chart, I realized it would be fascinating to see how dispersion behaved throughout the melt and freeze season, essentially charting this weekly throughout the year. It would be particularly interesting to see what changes occurred at the point when these MYI killing seasons happened. Alas, I haven't had the time.
« Last Edit: April 29, 2017, 06:01:13 PM by Shared Humanity »

Shared Humanity

  • Guest
Re: The 2017 melting season
« Reply #1010 on: April 29, 2017, 06:13:49 PM »
Paradoxically, the very low SIE in the Bering and Sea of Okhotsk is also the result of thinner ice, stormier weather and warmer surface waters (intrusion and upwelling?). That this results in anomalously low SIE while the opposite occurs on the Atlantic side is because these seas are not replenished by ice transported from the CAB.

Tor Bejnar

  • Young ice
  • Posts: 4606
    • View Profile
  • Liked: 879
  • Likes Given: 826
Re: The 2017 melting season
« Reply #1011 on: April 29, 2017, 06:59:16 PM »
Very interesting pair of graphs, SH. (Thanks!)  Do you 'see anything' if you plot 'difference' vs. 'ratio'?  Is it basically the same if you use '% difference' [(A-B)/B] instead of 'ratio' [A/B]? (If you don't respond, I'll know it's because you don't have time - you already said so  :) )
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

Shared Humanity

  • Guest
Re: The 2017 melting season
« Reply #1012 on: April 29, 2017, 08:31:17 PM »
Very interesting pair of graphs, SH. (Thanks!)  Do you 'see anything' if you plot 'difference' vs. 'ratio'?  Is it basically the same if you use '% difference' [(A-B)/B] instead of 'ratio' [A/B]? (If you don't respond, I'll know it's because you don't have time - you already said so  :) )

I still have the data I used for this chart. Would be easy to do. Maybe today.

Cate

  • Frazil ice
  • Posts: 199
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: The 2017 melting season
« Reply #1013 on: April 29, 2017, 10:52:43 PM »
Re current Newfoundland ice: there is certainly a lot of hilarious mileage being made on that Ferryland iceberg. All looks like typical media hype to me. 

The most recent Canadian Ice Service "stages of development" chart shows that the vast majority of ice on our NE coast is first-year ice of various thicknesses. This is in the context of bergy water in the entire Labrador Sea and coastal Newfoundland environs. So, current ice around Newfoundland is a combo of both sea ice and glacial ice----and 'twas ever thus, as far as I can recall. Nothing so remarkable about this year at all.

When I was a child in the 1960s, ice forecasts on the wireless would routinely mention "blue ice" as part of the mix: thus, "concentration 4/10ths grey ice, 1/10 blue ice". I was always told that blue ice came from glaciers, and was therefore different from all the surrounding pack ice, which incidentally forms the whelping grounds of the harp and hood seals.

The blue ice is the stuff that sparkles in your G&T, btw. Tourism operators will not tell you this. ;)

magnamentis

  • Guest
Re: The 2017 melting season
« Reply #1014 on: April 29, 2017, 11:06:39 PM »
I've copied 5 of the extent graphs from the Regional Graphs page: three have lots of ice and two have record(?) low ice.
 
The Barentsz Sea (Dutch spelling, and the guy was Dutch) is 'quite full' of ice - I don't have an opinion why.  The Greenland Sea is also 'quite full' - I think ice export from the Arctic Ocean is high (despite so much melting around Svalbard in the mid- and late winter).  Baffin / Newfoundland Bay is 'quite full' too - I think the lack of any sustained ice arch within Nares Strait has allowed much (thin) export of ice (ice that grows within the Strait over a 2 to 8 week period as it drifts southwards), and thin ice counts as extent. 

I note both the Bering Sea and Sea of Okhotsk have unseasonably low amounts of ice - I don't have an opinion why.

What opinions do other's have concerning these 5 regions?

(And yes, much of the ice is thinner than ever before at this time of year.)

thanks for the effort but beside that, there will always be regions with more and others with less ice than usual, reason is simple, once winds and/or currents pile up the ice on one side and empty the other side while during the next season and/or time span things turn around and depending on prevailing winds and currents the ice will pile up in another place.

this is, and no matter how much headwind i get, i think that these regional stuff is not useful, same applies to temps one season sibiria is colder and alaska is warmer and the other year or period of time it's vice versa and so on. nice to watch, interesting to know but has no value as to global warming and the overall development of arctic sea-ice IMO.

Neven

  • Administrator
  • First-year ice
  • Posts: 9470
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1333
  • Likes Given: 617
Re: The 2017 melting season
« Reply #1015 on: April 29, 2017, 11:48:43 PM »
this is, and no matter how much headwind i get, i think that these regional stuff is not useful, same applies to temps one season sibiria is colder and alaska is warmer and the other year or period of time it's vice versa and so on. nice to watch, interesting to know but has no value as to global warming and the overall development of arctic sea-ice IMO.

And that's why this is called the 2017 melting season thread, and not the 'global warming and the overall development of arctic sea-ice' thread. If you think a certain thread has no value, you simply look for one that has value for you. That's how an Internet forum works.
The enemy is within
Don't confuse me with him

E. Smith

Niall Dollard

  • Nilas ice
  • Posts: 1154
    • View Profile
  • Liked: 460
  • Likes Given: 117
Re: The 2017 melting season
« Reply #1016 on: April 30, 2017, 12:12:58 AM »
thanks for the effort and no matter how much headwind i get, i think that these regional stuff is not useful has no value as to global warming and the overall development of arctic sea-ice IMO.

Well I for one like to keep a weather eye open on all events. Lake Agassiz was once regional stuff too  ;)

be cause

  • Nilas ice
  • Posts: 2441
    • View Profile
  • Liked: 1012
  • Likes Given: 1034
Re: The 2017 melting season
« Reply #1017 on: April 30, 2017, 01:34:11 AM »
I know it's only a small part of the Arctic involved :) , but North of 80'N temperatures are nearly normal !  It is 2 years since they slipped significantly below normal . The Atlantic warmth that for 6 months was entering the Arctic is turning it's attention elsewhere for the present . The forecasts suggest a return to more general warming in a week . What ever the weather the dmi. 80'N temps are worth watching . The current flat topped mean may not be the shape of things to come ..
Conflict is the root of all evil , for being blind it does not see whom it attacks . Yet it always attacks the Son Of God , and the Son of God is you .

Hyperion

  • Frazil ice
  • Posts: 375
  • Admiral Franklin of the McGillicuddy Highland Navy
    • View Profile
  • Liked: 127
  • Likes Given: 64
Re: The 2017 melting season
« Reply #1018 on: April 30, 2017, 05:45:54 AM »
Quote
I know it's only a small part of the Arctic involved :) , but North of 80'N temperatures are nearly normal ! 

IMHO that is a sign of the melt process beginning in earnest everywhere the winds approaching the area are coming from. And the porosity of the ice and above normal snow, ice crystals in the air, making for more surface area for the moving air to get at than ever before.
The sublimation and melt and evaporation are sucking the heat out of the air before it gets to the 80+ Nth area?
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
https://en.wikipedia.org/wiki/McGillicuddy_Serious_Party

Hyperion

  • Frazil ice
  • Posts: 375
  • Admiral Franklin of the McGillicuddy Highland Navy
    • View Profile
  • Liked: 127
  • Likes Given: 64
Re: The 2017 melting season
« Reply #1019 on: April 30, 2017, 05:56:32 AM »
Funny thing with your animation Romitt, is that that berg disintergrating did not show on my worldview animations of the same days on the last page. Mysterious. Even more so its still there on the 29th imagery today when I check worldview. Below.

Heres a crack at cheeting the 700px wide rule by turning laptev 21-29 on its side. I am sick of the fiddly biz of selecting and cropping exact frames out of each image to get the best image.

Yep. that worked but you gotta click it. And zoom in with your browzer. (mine anyway)

Some speculation....
even assuming the ice density figures are correct and the free-board estimates calculate the volume are therefore near accurate and Piomass etc are not over-estimating Ice thickness due to that factor. Isn't the extreme youth and lack of deep freeze seasoning with the big FDD anomaly going to mean that a significant fraction of the berg volume is actually brine, and the percentage of crystalline ice lower than usual? Could this mean less ice to melt essentially? And perhaps it would melt at a lower temp than usual, delaying the onset of initial melt advance a little, until suddenly ... FWOOSH! it all goes very quick?

The way the bergs in the laptev animation quickly round off all their corners with a little jostling is suggestive they are very structurally unsound.
« Last Edit: April 30, 2017, 06:08:13 AM by Hyperion »
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
https://en.wikipedia.org/wiki/McGillicuddy_Serious_Party

romett1

  • Frazil ice
  • Posts: 286
    • View Profile
  • Liked: 32
  • Likes Given: 2
Re: The 2017 melting season
« Reply #1020 on: April 30, 2017, 10:25:42 AM »
Bering Sea and Chukchi Sea have temperatures near zero and above zero for quite a while. In addition to earth.nullschool there is good real-time overview (last 24 - 72 hours) how heat and moisture enter the Arctic from Pacific side.
http://tropic.ssec.wisc.edu/real-time/mtpw2/product.php?color_type=tpw_nrl_colors&prod=alaska&timespan=48hrs&anim=html5

Jim Hunt

  • First-year ice
  • Posts: 6268
  • Don't Vote NatC or PopCon, Save Lives!
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 893
  • Likes Given: 87
Re: The 2017 melting season
« Reply #1021 on: April 30, 2017, 12:06:02 PM »
Funny thing with your animation Romitt, is that that berg disintergrating did not show on my worldview animations of the same days on the last page. Mysterious. Even more so its still there on the 29th imagery today when I check worldview.

If you take a close look at the Terra image for the 28th you can see that two tiles taken at very different times have been pasted together:

https://go.nasa.gov/2ql25sI

Flip to Aqua and the mystery is explained.
"The most revolutionary thing one can do always is to proclaim loudly what is happening" - Rosa Luxemburg

Andreas T

  • Nilas ice
  • Posts: 1149
    • View Profile
  • Liked: 18
  • Likes Given: 4
Re: The 2017 melting season
« Reply #1022 on: April 30, 2017, 12:10:13 PM »
When you talk of "bergs" along the siberian coast, Hyperion, I assume you are thinking of floes of sea ice rather than actual icebergs? It would be better to make the distinction in your use of language. Is that usage a southern hemisphere thing?
I don't think icebergs are present in that part of the arctic since there are no glaciers terminating into the sea. Where those exist they don't produce bergs visible in those satellite images.
The idea of porous ice increasing contact with the air is fanciful (to put it politely) and while first year ice contains more brine than multiyear ice the effects won't be as dramatic as is often speculated here.

Hyperion

  • Frazil ice
  • Posts: 375
  • Admiral Franklin of the McGillicuddy Highland Navy
    • View Profile
  • Liked: 127
  • Likes Given: 64
Re: The 2017 melting season
« Reply #1023 on: April 30, 2017, 03:28:45 PM »
Thanks for pointing out my mistake in the nomenclature Andreas. Not many bergs or floes here in NZ. We may be fresh faced plebs from the colonies here in NZ but I'd hate to be thought as a "berger".
 We did have some giant Bergs visit about ten years ago. Larsen remnants I believe they were believed to be. They actually helicoptered Shrek the rogue merino ram out to be shorn of his ten year 12kg fleece on one as a publicity stunt, would you believe.

Are you sure that the roughness factor is not significant? The constant mobility, pulverisation, slushy mixing in magnitudes more lead area thats been going on all winter suggests to me that a lot of it is barely solid or frozen, loosely bound, waxy rubble, only weeks old. Perhaps more akin to a slushy that's been half-melted, drained, then refrozen. I guess surface area aside, the energy per volume required to melt it is a question.
 I suppose that the question could be answered by getting some sea water, freezing it with some partial thaw, mix and and drain cycles at intervals, and comparing melt energy with a sample prepared by undisturbed deep freeze.

Have plenty of seawater myself but no freezer. Refuse to part with any of the solar electrickeries I net for that. Tri-generation system with wind powered refrigeration pumps and a heavy brine cold store, solar thermal heavy brine hot store, with organic Kalina cycle turbine is on the ship to do list and most of the parts and materials are aboard, but there are other priorities right now.

Thanks Jim.  ;D I assumed it was my use of the Suomi imageset on worldview, not the Gods treating us to a snapshot of a parallel time-stream in the multiverse. ;D
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
https://en.wikipedia.org/wiki/McGillicuddy_Serious_Party

CognitiveBias

  • New ice
  • Posts: 90
    • View Profile
  • Liked: 1
  • Likes Given: 1
Re: The 2017 melting season
« Reply #1024 on: April 30, 2017, 04:02:04 PM »
...

The idea of porous ice increasing contact with the air is fanciful (to put it politely) and while first year ice contains more brine than multiyear ice the effects won't be as dramatic as is often speculated here.

http://authors.library.caltech.edu/45129/1/Anderson_1958p632.pdf

An interesting study including effects of brine and temperature on the strength of sea ice.  While it has been plenty cold, the change in strength of briny (1st year) sea ice seems to extend well into the range of temperatures we have been witnessing.  Deeply frozen multi year ice may well be an order of magnitude stronger than what's out there now. 

 

Andreas T

  • Nilas ice
  • Posts: 1149
    • View Profile
  • Liked: 18
  • Likes Given: 4
Re: The 2017 melting season
« Reply #1025 on: April 30, 2017, 06:06:24 PM »
Cate has just linked to some great photos taken by a member of NASAs icebridge team from low level flights over the ice in Beaufort.
https://photos.smugmug.com/Field-WorkExpeditions/OIB-Arctic-2017-Daily-Galleries/March-12th-2017-North-Beaufort-Loop/n-NLq4fv/i-L6R4v92/0/3d205ada/XL/i-L6R4v92-XL.jpg
This is the "slush" which occurs when ice breaks and compacts.
Sea ice has always broken and ridged, that thinner and younger ice breaks more easily and in smaller pieces I do not doubt.
The important question is what that means for melting.
Stating the obvious plainly: 1kg of ice requires the same energy input to melt regardless of the shape it is in. The question then becomes: does breaking it into pieces change the transfer of energy to the ice.
If ice is dispersed in a large amount of water warmer than its melting point it will melt faster than a compact lump, it will also cool the water quicker. So it is a question of how much energy is available. Certainly open water absorbs much more sunlight than ice covered water but how much difference is there between 10sq km of ice next to 10sq km of water and 20sq km of smaller floes interspersed with water?
I don't mean to say there are no differences, clearly there may well be differences in convection and salinity around the floes. I just don't expect the dramatic differences some people seem to expect. Last summer there were some spectacular predictions of huge ice loss "a certainty" because of breaks. I have seen nothing to make me think this has a sound basis.
At some point in the future we will see ice so thin it will disperse and melt, how soon that happens is too dependent on many factors to be predictable by eyeballing.

seaicesailor

  • Guest
Re: The 2017 melting season
« Reply #1026 on: April 30, 2017, 07:31:51 PM »
Let's try using the long-range weekly CFS-v2 predictions. I bring the 1st and 2nd weeks of May. I will repeat this in the future only if these predictions really make sense (they did for April!)
According to these maps, we should see some more drift in Beaufort sea this first week of May and the next. During the second week, that dome of high pressure mentioned before, pulling heat from America and pushing ice toward the Atlantic.
Temperatures should be anomalously warm in Siberia, then we get the heat fro the American side associated to that high pressure system by the second week. Positive anomalies dominate, certainly in Siberia, certainly not in the Central Arctic.
That the peripheral seas are warm especially the Pacific side does not mean it will be sunny. No cloudiness predictions here. But polynya near the coasts should begin to stay open at both sides.
Note that these forecasts are mean values of different simulations, therefore get diluted with time.
Maps Courtesy of Levi Cowan - tropicaltidbits.com

Lord M Vader

  • Nilas ice
  • Posts: 1406
    • View Profile
  • Liked: 60
  • Likes Given: 39
Re: The 2017 melting season
« Reply #1027 on: April 30, 2017, 09:36:45 PM »
Dmi shows temps below normal for the first time this year wrt Arctic 80N+

JayW

  • Grease ice
  • Posts: 607
    • View Profile
  • Liked: 226
  • Likes Given: 292
Re: The 2017 melting season
« Reply #1028 on: May 01, 2017, 12:39:28 AM »
First attachment is April 27-30 Suomi VIIRS imagery from the puffin feeder site at the University of Alaska at Fairbanks.
http://feeder.gina.alaska.edu/npp-gina-alaska-truecolor-images?search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1

Second attachment is the NCEP polar drift model 7 day forecast.
http://mag.ncep.noaa.gov/model-guidance-model-parameter.php?group=Model%20Guidance&model=POLAR&area=POLAR&ps=area#
"To defy the laws of tradition, is a crusade only of the brave" - Les Claypool

bbr2314

  • Nilas ice
  • Posts: 1817
    • View Profile
  • Liked: 158
  • Likes Given: 53
Re: The 2017 melting season
« Reply #1029 on: May 01, 2017, 01:04:35 AM »
Looks like we are about to see a pre-cursor to the CAA garlic press commencing in full force. DMI and HYCOM show the thickest ice breaking off of the CAA with potential breakage of the Lincoln Sea ice bridge as well... once this happens it should allow significantly more impact from any cyclones on the ice, and subsequent movement of the CAA ice to the south.

VeliAlbertKallio

  • Frazil ice
  • Posts: 286
  • Eheu fugaces labuntur anni
    • View Profile
    • Sea Research Society (SRS)
  • Liked: 118
  • Likes Given: 134
Re: The 2017 melting season
« Reply #1030 on: May 01, 2017, 01:15:13 AM »
The increase of 3-dimensional surface area of pulverised sea ice versus solid sea ice cover:

1) the thermal inertia of water is transferred  into broken, pulverised ice more easily. This means that the transfer of heat is faster or more efficient when ice passes through water.

2) the long-wave radiation loss from water is reduced when pulverised ice is heavily mixed into water. The water areas stay cooler and loose less heat into space and more goes into melting ice.

3) the vertical mixing of water is stronger with pulverised sea ice than it is with ocean covered with ice film which keeps water beneath ice still and reduces mixing: dipping of ice floes in waves, the ploughing effect of wind pushing ice floes in water, constant rise and dip of water surface due to wave crests and troughs, and air contact with water keeps energy moving around more.

4) the pulverised sea ice surface allows evaporation causing water vapour to form fog, low level clouds that tend to send long wave radiation back to sea surface where it heats and melts ice. Ice film without cloud cover allows heat to escape space provided snow and thickness are not great. With 'ice film' I refer to thin, generally unbroken ice without snow cover on the top.

5) Although the same amount of energy is required to melt solid piece of ice to that of pulverised ice, the accessibility (contact with more water) of heat grows towards infinity the more ice moves and the more ocean mixes vertically, and the faster heat is captured by increasingly pulverised ice.

Cate has just linked to some great photos taken by a member of NASAs icebridge team from low level flights over the ice in Beaufort.
https://photos.smugmug.com/Field-WorkExpeditions/OIB-Arctic-2017-Daily-Galleries/March-12th-2017-North-Beaufort-Loop/n-NLq4fv/i-L6R4v92/0/3d205ada/XL/i-L6R4v92-XL.jpg
This is the "slush" which occurs when ice breaks and compacts.
Sea ice has always broken and ridged, that thinner and younger ice breaks more easily and in smaller pieces I do not doubt.
The important question is what that means for melting.
Stating the obvious plainly: 1kg of ice requires the same energy input to melt regardless of the shape it is in. The question then becomes: does breaking it into pieces change the transfer of energy to the ice.
If ice is dispersed in a large amount of water warmer than its melting point it will melt faster than a compact lump, it will also cool the water quicker. So it is a question of how much energy is available. Certainly open water absorbs much more sunlight than ice covered water but how much difference is there between 10sq km of ice next to 10sq km of water and 20sq km of smaller floes interspersed with water?
I don't mean to say there are no differences, clearly there may well be differences in convection and salinity around the floes. I just don't expect the dramatic differences some people seem to expect. Last summer there were some spectacular predictions of huge ice loss "a certainty" because of breaks. I have seen nothing to make me think this has a sound basis.
At some point in the future we will see ice so thin it will disperse and melt, how soon that happens is too dependent on many factors to be predictable by eyeballing.
« Last Edit: May 01, 2017, 01:41:56 AM by VeliAlbertKallio »
"Setting off atomic bombs is considered socially pungent as the years are made of fleeting ice that are painted by the piling up of the rays of the sun."

Rob Dekker

  • Nilas ice
  • Posts: 2386
    • View Profile
  • Liked: 120
  • Likes Given: 119
Re: The 2017 melting season
« Reply #1031 on: May 01, 2017, 08:06:48 AM »
While it is true that fragmented ice still melts with the same amount of Joules per kg as solid floes, I can't suppress the notion that the mere fact that it is fragmented is an indication that it is thin and fragile.
This is our planet. This is our time.
Let's not waste either.

meddoc

  • Frazil ice
  • Posts: 264
    • View Profile
  • Liked: 11
  • Likes Given: 0
Re: The 2017 melting season
« Reply #1032 on: May 01, 2017, 09:06:07 AM »
While it is true that fragmented ice still melts with the same amount of Joules per kg as solid floes, I can't suppress the notion that the mere fact that it is fragmented is an indication that it is thin and fragile.

And that, fragile, fragmented ice can be swept out easily into warmer waters, so that it'll melt faster.
/common sense, peer- reviewed by almost everyone with a brain/

Bill Fothergill

  • Frazil ice
  • Posts: 278
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: The 2017 melting season
« Reply #1033 on: May 01, 2017, 11:39:49 AM »
... Not many bergs or floes here in NZ. ... We did have some giant Bergs visit about ten years ago. Larsen remnants I believe they were believed to be ...

It's OT for this thread, but there could be some more en route to a place near you in the not too distant future...
https://forum.arctic-sea-ice.net/index.php/topic,1175.0.html


Shrek's had a haircut?  :'(

meddoc

  • Frazil ice
  • Posts: 264
    • View Profile
  • Liked: 11
  • Likes Given: 0
Re: The 2017 melting season
« Reply #1034 on: May 01, 2017, 12:02:45 PM »
<snip, off-topic; N.>
« Last Edit: May 01, 2017, 01:29:23 PM by Neven »

Tigertown

  • Nilas ice
  • Posts: 1678
    • View Profile
  • Liked: 24
  • Likes Given: 20
Re: The 2017 melting season
« Reply #1035 on: May 01, 2017, 02:02:43 PM »
The Bering Sea & Strait starting to open up.
"....and the appointed time came for God to bring to ruin those ruining the earth." Revelation 11:18.

Ajpope85

  • New ice
  • Posts: 41
    • View Profile
  • Liked: 8
  • Likes Given: 0
Re: The 2017 melting season
« Reply #1036 on: May 01, 2017, 03:59:34 PM »
While it is true that fragmented ice still melts with the same amount of Joules per kg as solid floes, I can't suppress the notion that the mere fact that it is fragmented is an indication that it is thin and fragile.

And that, fragile, fragmented ice can be swept out easily into warmer waters, so that it'll melt faster.
/common sense, peer- reviewed by almost everyone with a brain/

That and it has more total exposed surface area for heat to attack it.

Peter Ellis

  • Grease ice
  • Posts: 619
    • View Profile
  • Liked: 33
  • Likes Given: 14
Re: The 2017 melting season
« Reply #1037 on: May 01, 2017, 04:47:31 PM »
That and it has more total exposed surface area for heat to attack it.

No.

To see why, try the following calculation.  The Earthwatch MODIS data source has a resolution of 250m, and so the smallest detectable ice floe from this data source is around that size.

Please estimate for me the total exposed surface area for a 250m x 250m floe. Let's assume it's thick first year ice of ~2m average thickness. Then, identify what proportion of the total surface areas is:

1)  Top face (exposed to Sun)
2)  Bottom face (exposed to water)
3)  Side faces (exposed to a mix of both)

Fragmentation is not relevant to the total exposed surface area of sea ice until the floes are too small to be seen by MODIS. The dynamics we so avidly watch - whether fragmented or not - do not appreciably alter the total surface area of the ice.

dnem

  • Grease ice
  • Posts: 709
    • View Profile
  • Liked: 319
  • Likes Given: 278
Re: The 2017 melting season
« Reply #1038 on: May 01, 2017, 05:45:47 PM »
Satellite resolution aside, wouldn't this dynamic come into play at some level of fragmentation?

Csnavywx

  • Grease ice
  • Posts: 572
    • View Profile
  • Liked: 82
  • Likes Given: 2
Re: The 2017 melting season
« Reply #1039 on: May 01, 2017, 06:05:07 PM »
The recent cooldown was well forecast and should last around 10-15 days. A strong -NAO ridge is building and should eventually retrograde into Canada proper and perhaps all the way to the Pacific side. It would be a good idea to keep an eye on the development and evolution of this ridging pattern because it could easily set up a +AD later in the month. In fact, the GEFS, EPS, Euro weeklies and CFS weeklies all show a transition to that type of pattern around or after mid-month. Something to watch in the days ahead as the critical early melt pond window gets closer.

miki

  • Frazil ice
  • Posts: 149
    • View Profile
  • Liked: 49
  • Likes Given: 223
Re: The 2017 melting season
« Reply #1040 on: May 01, 2017, 06:35:01 PM »
Everything considered, it does fell that by the end of May the famous "Oh, Jesus!" may become an understatement.

Neven

  • Administrator
  • First-year ice
  • Posts: 9470
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1333
  • Likes Given: 617
Re: The 2017 melting season
« Reply #1041 on: May 01, 2017, 09:33:01 PM »
Welcome to the ASIF, miki. Your profile has been released, so you can post freely now.
The enemy is within
Don't confuse me with him

E. Smith

S.Pansa

  • Frazil ice
  • Posts: 175
    • View Profile
  • Liked: 45
  • Likes Given: 5
Re: The 2017 melting season
« Reply #1042 on: May 02, 2017, 08:52:25 AM »
Just had a look at the latest weather forecast. While the models seem to agree pretty well on the general pattern, I realized that they are differing quite a bit in regards  to temperatures - especially over the Beaufort and Chukchi Sea.

For comparison, the 850 hPa temp anomalies from the latest GFS and ECMWF runs (00z Tue 02 May) - 48h and 144h out respectively (for easier comparison open in separate tabs).

Is there a way to find out - in retrospective - which one was closer to the truth (from earlier runs I get the impression that GFS might have a small cold bias at the moment, but that is pure guesswork)? And would this even make a difference on the surface level?


Glenn Tamblyn

  • Frazil ice
  • Posts: 128
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: The 2017 melting season
« Reply #1043 on: May 02, 2017, 12:24:42 PM »
We did have some giant Bergs visit about ten years ago. Larsen remnants I believe they were believed to be.

WOW. Larsen fragments in NZ!

Neven

  • Administrator
  • First-year ice
  • Posts: 9470
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1333
  • Likes Given: 617
Re: The 2017 melting season
« Reply #1044 on: May 02, 2017, 01:09:16 PM »
In the meantime NH snow cover keeps going down steadily. Last week's uptick has been negated now that all that late snow in Canada has melted out again. There's still some snow lingering in at relatively lower latitudes, in China and the US. Once that melts out, the trend line could possibly go lowest.
The enemy is within
Don't confuse me with him

E. Smith

Bill Fothergill

  • Frazil ice
  • Posts: 278
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: The 2017 melting season
« Reply #1045 on: May 02, 2017, 01:45:20 PM »
The NSIDC daily figures have just come in, and they show a rather abrupt loss of ~ 259k sq kms between 30th April and 1st May.

Is this a "1st of the month" effect?

Is it merely a form of "correction" caused by cells dropping out of the >15% threshold, after only losing ~100k over the last 8 or 9 days?

Or is Mr S*%t meeting Mr Fan?

Tigertown

  • Nilas ice
  • Posts: 1678
    • View Profile
  • Liked: 24
  • Likes Given: 20
Re: The 2017 melting season
« Reply #1046 on: May 02, 2017, 01:57:57 PM »
The Bering air(and water) has remained warmer than elsewhere of late and has experience accelerated melt. Perhaps that at least contributed to the large drop.
"....and the appointed time came for God to bring to ruin those ruining the earth." Revelation 11:18.

Jim Pettit

  • Nilas ice
  • Posts: 1175
    • View Profile
  • Liked: 41
  • Likes Given: 11
Re: The 2017 melting season
« Reply #1047 on: May 02, 2017, 02:13:51 PM »
The NSIDC daily figures have just come in, and they show a rather abrupt loss of ~ 259k sq kms between 30th April and 1st May.

Is this a "1st of the month" effect?

Is it merely a form of "correction" caused by cells dropping out of the >15% threshold, after only losing ~100k over the last 8 or 9 days?

Or is Mr S*%t meeting Mr Fan?

Mostly a first of the month thing; for NSIDC extent, May 1 nearly always experiences a century break or two. The average decrease over the past ten years for the date has been 166k. However, this year's is the largest, eclipsing even last year's 242k drop, for what that's worth.,

iceman

  • Frazil ice
  • Posts: 285
    • View Profile
  • Liked: 7
  • Likes Given: 19
Re: The 2017 melting season
« Reply #1048 on: May 02, 2017, 02:21:44 PM »
   .... Last week's uptick has been negated now that all that late snow in Canada has melted out again....
I guess that means the spring thaw is getting underway in the upper reaches of the Mackenzie.  Peak discharge into Beaufort will probably be later and less spiky than last year, when the big wildfire was just getting going in early May.

More generally, it looks like the steeper part of the seasonal decline will begin around May 4th, with large and sustained drops in Baffin/Newfoundland, and most of the remaining ice in Bering and Okhotsk disapperaring.  Barents will be a little late to join the party, but will likely be a big contributor in 2nd half of May.

crandles

  • Young ice
  • Posts: 3379
    • View Profile
  • Liked: 239
  • Likes Given: 81
Re: The 2017 melting season
« Reply #1049 on: May 02, 2017, 02:23:04 PM »
The NSIDC daily figures have just come in, and they show a rather abrupt loss of ~ 259k sq kms between 30th April and 1st May.

Is this a "1st of the month" effect?

Is it merely a form of "correction" caused by cells dropping out of the >15% threshold, after only losing ~100k over the last 8 or 9 days?

Or is Mr S*%t meeting Mr Fan?

Mostly a first of the month thing; for NSIDC extent, May 1 nearly always experiences a century break or two. The average decrease over the past ten years for the date has been 166k. However, this year's is the largest, eclipsing even last year's 242k drop, for what that's worth.,

Mainly due to different land mask for a different month IIRC