Support the Arctic Sea Ice Forum and Blog

Author Topic: The 2020 melting season  (Read 574669 times)

Rodius

  • Frazil ice
  • Posts: 335
    • View Profile
  • Liked: 229
  • Likes Given: 9
Re: The 2020 melting season
« Reply #2500 on: July 10, 2020, 04:21:26 AM »
This probably belongs in the stupid questions section......

In my mind, if the melt ponds have drained away, that is "warm" water moving beneath the ice, which will melt the ice from below even more. Give the large amount of drainage, the bottom melt from the warmer water is going to be significant in my mind.

So... does this mean, at the moment, the ice is being massively attacked on both sides?
And with cracks in the ice, that is more surface area exposed to melting.

If my thinking is correct (ish), the next few weeks are unlikely to slow down in terms of volume loss.

Is this line of thinking moving along the right lines?

Tor Bejnar

  • Young ice
  • Posts: 3542
    • View Profile
  • Liked: 606
  • Likes Given: 374
Re: The 2020 melting season
« Reply #2501 on: July 10, 2020, 04:25:53 AM »
Would a month of high pressure over the CAB in July pretty much melt it out? 
5 cm/day x 30 days = 1.5 meters - not quite
10 cm/day x 30 days = 3.0 meters - definitely

Might we be approaching this sort of territory?

Arctic ice is healthy for children and other living things.

Pagophilus

  • Frazil ice
  • Posts: 496
    • View Profile
  • Liked: 271
  • Likes Given: 402
Re: The 2020 melting season
« Reply #2502 on: July 10, 2020, 04:50:23 AM »
Hi,Rodius: Here is a partial response.  Theoretically, the water in contact with the ice should be at 0 C.  Incoming solar radiation that is absorbed goes to melting the ice, not heating the water.  The meltponds themselves encourage further melting because they lower the net albedo of the system, not because their water gets warmer.  So the water draining from the ponds will be theoretically at 0 C and should not melt the ice from the bottom.  Indeed, because the water that drains would be fresh and of lower density, that cold fresh water might even pool beneath the ice surface and 'shield' the base of the ice from warmer saline water that was originally beneath the ice. 

That's all theoretical and the thermodynamics as I understand them.  Other things might happen in reality in the Arctic.  There are factors like the salinity of water, the salt content of the ice etc that come into play, and I have very limited knowledge of these.  Hope this helps.

This probably belongs in the stupid questions section......

In my mind, if the melt ponds have drained away, that is "warm" water moving beneath the ice, which will melt the ice from below even more. Give the large amount of drainage, the bottom melt from the warmer water is going to be significant in my mind.

So... does this mean, at the moment, the ice is being massively attacked on both sides?
And with cracks in the ice, that is more surface area exposed to melting.

If my thinking is correct (ish), the next few weeks are unlikely to slow down in terms of volume loss.

Is this line of thinking moving along the right lines?
Person.  Woman.  Man.  Vote.  November.

Rodius

  • Frazil ice
  • Posts: 335
    • View Profile
  • Liked: 229
  • Likes Given: 9
Re: The 2020 melting season
« Reply #2503 on: July 10, 2020, 04:54:21 AM »
Hi,Rodius: Here is a partial response.  Theoretically, the water in contact with the ice should be at 0 C.  Incoming solar radiation that is absorbed goes to melting the ice, not heating the water.  The meltponds themselves encourage further melting because they lower the net albedo of the system, not because their water gets warmer.  So the water draining from the ponds will be theoretically at 0 C and should not melt the ice from the bottom.  Indeed, because the water that drains would be fresh and of lower density, that cold fresh water might even pool beneath the ice surface and 'shield' the base of the ice from warmer saline water that was originally beneath the ice. 

That's all theoretical and the thermodynamics as I understand them.  Other things might happen in reality in the Arctic.  There are factors like the salinity of water, the salt content of the ice etc that come into play, and I have very limited knowledge of these.  Hope this helps.

This probably belongs in the stupid questions section......

In my mind, if the melt ponds have drained away, that is "warm" water moving beneath the ice, which will melt the ice from below even more. Give the large amount of drainage, the bottom melt from the warmer water is going to be significant in my mind.

So... does this mean, at the moment, the ice is being massively attacked on both sides?
And with cracks in the ice, that is more surface area exposed to melting.

If my thinking is correct (ish), the next few weeks are unlikely to slow down in terms of volume loss.

Is this line of thinking moving along the right lines?


Thanks, that helps improve my understanding.

ArcTickTock

  • New ice
  • Posts: 80
    • View Profile
  • Liked: 65
  • Likes Given: 97
Re: The 2020 melting season
« Reply #2504 on: July 10, 2020, 05:29:39 AM »
The PSC June 2020 PIOMAS update reported thicker than normal ice in the Barents.  That obviously can no longer be true, did that ice drift into the CAB or just go poof?

oren

  • Moderator
  • First-year ice
  • Posts: 6180
    • View Profile
  • Liked: 2242
  • Likes Given: 1878
Re: The 2020 melting season
« Reply #2505 on: July 10, 2020, 05:42:50 AM »
The PSC June 2020 PIOMAS update reported thicker than normal ice in the Barents.  That obviously can no longer be true, did that ice drift into the CAB or just go poof?
Some of it melted, some of it was imported back. Check out the very useful gifs by Aluminium that help make sense of it all.
July 4-8.

OSI-SAF shows some of this drift, as well as some renewed Fram export after a very long lull.

ArcTickTock

  • New ice
  • Posts: 80
    • View Profile
  • Liked: 65
  • Likes Given: 97
Re: The 2020 melting season
« Reply #2506 on: July 10, 2020, 05:44:09 AM »
Another question, in the Antarctic draining melt ponds are highly destructive to ice shelves as to the best of my understanding they sort of cleave the shelves apart physically.  Now ice shelves are a different animal but does something similar happen to sea ice?

Rod

  • Guest
Re: The 2020 melting season
« Reply #2507 on: July 10, 2020, 05:48:17 AM »
Theoretically, the water in contact with the ice should be at 0 C.  Incoming solar radiation that is absorbed goes to melting the ice, not heating the water.  The meltponds themselves encourage further melting because they lower the net albedo of the system, not because their water gets warmer.

I’m not sure this is correct. There is a lot of very complicated thermodynamics involved in answering his question. You are clearly very knowledgeable, and I might be wrong. But, I have always understood that the water in the melt ponds can warm considerably above 0C before they drain.

Again, maybe my understanding is wrong. Hopefully, the Mosaic data will help answer these questions  when they start releasing it.

oren

  • Moderator
  • First-year ice
  • Posts: 6180
    • View Profile
  • Liked: 2242
  • Likes Given: 1878
Re: The 2020 melting season
« Reply #2508 on: July 10, 2020, 06:22:50 AM »
Cross-post from the buoys thread.

Pond surface freezing (or floe breakup) is much more common than pond draining. This is however different for fast ice that can hold much more meltwater. Here is a clear example of drainage in the CAA yesterday. The sky was clear and sunny and temps in nearby Resolute were 12C to 4C, so no surface freezing took place and no new snow fell, and yet the blue on the ice diminished visibly.
Click to animate.

Bruce Steele

  • Nilas ice
  • Posts: 1839
    • View Profile
  • Liked: 473
  • Likes Given: 23
Re: The 2020 melting season
« Reply #2509 on: July 10, 2020, 06:32:32 AM »
Post #2480 by Blum shows same. I think tides might play some role within inlets and pictures of day to day variation might need to compare low tide to low tide , or high tide to high tide. Notice around edges where fast ice locked to land seems to whiten more than the center of the inlets/ channels.,
« Last Edit: July 10, 2020, 06:43:00 AM by Bruce Steele »

Frivolousz21

  • Nilas ice
  • Posts: 1845
  • Live in Belleville, IL..15 miles SE of St. Louis.
    • View Profile
  • Liked: 550
  • Likes Given: 6
Re: The 2020 melting season
« Reply #2510 on: July 10, 2020, 06:39:06 AM »
Melting didn't just stop.  It's straight scorching up there.

You don't melt slow with WAA fog and sunny skies on the nose of 10C 925mb temps all over the Arctic and 5-8C 850s almost covering the entire basin

I got a nickname for all my guns
a Desert Eagle that I call Big Pun
a two shot that I call Tupac
and a dirty pistol that love to crew hop
my TEC 9 Imma call T-Pain
my 3-8 snub Imma call Lil Wayne
machine gun named Missy so loud
it go e-e-e-e-ow e-e-e-e-e-e-blaow

Rod

  • Guest
Re: The 2020 melting season
« Reply #2511 on: July 10, 2020, 06:46:49 AM »
Nice animation Oren, but I don’t get your point. How can you say pond surface freezing is more common than pond draining? That depends on location, weather and time of year.

If you are trying to explain the area numbers to people I see where you are going. Area numbers are always very tricky in the summer. That is why the official numbers are always reported as extent. Extent is not perfect either, but it does not suffer as badly from melt pond effects.

oren

  • Moderator
  • First-year ice
  • Posts: 6180
    • View Profile
  • Liked: 2242
  • Likes Given: 1878
Re: The 2020 melting season
« Reply #2512 on: July 10, 2020, 07:23:15 AM »
Sorry Rod my post was out of context. From watching old buoy movies both me and Bruce concluded that pond surface freezing is much more common in general than pond draining. I honestly don't know if surface freezing explains recent area numbers (I doubt it actually), this is a general observation and mostly based on cloudier years.

Link to discussion:
https://forum.arctic-sea-ice.net/index.php/topic,327.msg272954.html#msg272954
« Last Edit: July 10, 2020, 07:54:46 AM by oren »

ajouis

  • Frazil ice
  • Posts: 163
    • View Profile
  • Liked: 55
  • Likes Given: 34
Re: The 2020 melting season
« Reply #2513 on: July 10, 2020, 07:24:41 AM »
Oren, that animation is a bit disquieting, informative beyond your broader point, this is a pretty big area to break up, especially within a day, about 2000 square kilometres if my estimation is correct on the scale
After a thousand steps on the ice, it cracked.
The Man looked down at the infinite blue of the sea.
On the horizon, standing still, the polar bear had just scented his next meal.

 Less than 3000 cubic kilometers this Piomas minimum.

wallen

  • New ice
  • Posts: 78
    • View Profile
  • Liked: 40
  • Likes Given: 2
Re: The 2020 melting season
« Reply #2514 on: July 10, 2020, 07:52:20 AM »
At this rate any thoughts of several large polynas opening well inside 80N and added impact?

bbr2315

  • Frazil ice
  • Posts: 387
    • View Profile
  • Liked: 113
  • Likes Given: 61
Re: The 2020 melting season
« Reply #2515 on: July 10, 2020, 09:02:13 AM »
00z EURO maintains the now-ordained GAAC-20 event through D10.

Killian

  • Frazil ice
  • Posts: 283
    • View Profile
  • Liked: 58
  • Likes Given: 8
Re: The 2020 melting season
« Reply #2516 on: July 10, 2020, 09:06:43 AM »
These are the daily average ASI extent reductions for the five lowest years in the record for the next 15 days:

2012 July 9 - 24 =   93.33

2019 July 9 - 24 =   88.66

2016 July 9 - 24 =   80.00

2007 July 9 - 24 = 108.66

2015 July 9 - 24 = 108.66

The daily average for the 5 is 479.31/5 = 95.86. Over 15 days, that totals 1473.93. The current record low on the 24th is 6620. Current extent is 7760. 7760 - 1437.93 = 6322.07.

Just average for the five lowest extent years puts 2020 298 sq km. below 2019 two weeks from now. Hold on to your hats.

jdallen

  • Young ice
  • Posts: 3233
    • View Profile
  • Liked: 498
  • Likes Given: 204
Re: The 2020 melting season
« Reply #2517 on: July 10, 2020, 10:05:11 AM »
Would a month of high pressure over the CAB in July pretty much melt it out? 
5 cm/day x 30 days = 1.5 meters - not quite
10 cm/day x 30 days = 3.0 meters - definitely

Might we be approaching this sort of territory?
We are, which is exactly why, over a week ago, I responded "Dear God" to one of Friv's earliest posts about the weather we see now.

At the very least, presuming this pattern persists, I think we are going to see substantial melt of "lead" that formed late in the season generally.

Even if we don't see (more) dramatic area and extent drops, volume is going to be butchered.

And then there's the heat going into the Barents, Laptev, ESS and Chukchi.

The Barents and Laptev may be moot as they melt out, probably before the end of the month.  Any ice that gets exported to them will vanish rapidly.

The longer this weather persists, the more concerned I get that we're going blow past 2012 into unknown country.  In some ways, we are already there. 

We need the 850MB level to cool down.  We need high overcast.  We need rain and clouds in Siberia. The list goes on, but unlike some of the previous years we've seen like 2013 & 2016 where we were seriously worried about the melt season, more factors are consistently lining up *against* preservation of the ice than for it.  The only sea that isn't showing signs of being beaten limp is the Beaufort, and with this insolation, I'm suspicious even of that, as it may shortly start looking like swiss cheese as interstitial ice melts out.

So yes, again, I think we're approaching that territory.  I'm hoping for a miracle, frankly.
This space for Rent.

El Cid

  • Nilas ice
  • Posts: 1185
    • View Profile
  • Liked: 495
  • Likes Given: 95
Re: The 2020 melting season
« Reply #2518 on: July 10, 2020, 10:43:20 AM »

Just average for the five lowest extent years puts 2020 298 sq km. below 2019 two weeks from now. Hold on to your hats.

So you take the lowest value for the date (this year) and extrapolate from there the biggest losses, and you get a new record low? Who would have thought?

 :) ;)

uniquorn

  • Young ice
  • Posts: 2664
    • View Profile
  • Liked: 1187
  • Likes Given: 232
Re: The 2020 melting season
« Reply #2519 on: July 10, 2020, 10:49:44 AM »
Cloudy over the Laptev again so here is uni-hamburg amsr2-uhh, jun1-jul9
click to run, 6MB
Wipneus regional, jul8 (laptev and surround)
« Last Edit: July 10, 2020, 10:56:01 AM by uniquorn »

bluice

  • Guest
Re: The 2020 melting season
« Reply #2520 on: July 10, 2020, 11:05:49 AM »

Just average for the five lowest extent years puts 2020 298 sq km. below 2019 two weeks from now. Hold on to your hats.

So you take the lowest value for the date (this year) and extrapolate from there the biggest losses, and you get a new record low? Who would have thought?

 :) ;)
Yep, it's not a great mathematical surprise but thinking about it, what are the odds 2020 is not among the top five loss years for the rest of the month? Or the rest of the season?

CO2e forcing is stronger every year, 3 out of last 5 years are among the top five and 2020 has certainly proven to be a strong melt season.

oren

  • Moderator
  • First-year ice
  • Posts: 6180
    • View Profile
  • Liked: 2242
  • Likes Given: 1878
Re: The 2020 melting season
« Reply #2521 on: July 10, 2020, 11:58:19 AM »
Cloudy over the Laptev again so here is uni-hamburg amsr2-uhh, jun1-jul9
click to run, 6MB
Wipneus regional, jul8 (laptev and surround)
Thanks uniquorn.
The fast ice breaks in the Laptev every year, though not this early I think. But to see large parts of it melt out completely so fast is disturbing.
(Note to self to compare past years behavior.)

RikW

  • Frazil ice
  • Posts: 221
    • View Profile
  • Liked: 39
  • Likes Given: 14
Re: The 2020 melting season
« Reply #2522 on: July 10, 2020, 12:04:39 PM »

Just average for the five lowest extent years puts 2020 298 sq km. below 2019 two weeks from now. Hold on to your hats.

So you take the lowest value for the date (this year) and extrapolate from there the biggest losses, and you get a new record low? Who would have thought?

 :) ;)
Yep, it's not a great mathematical surprise but thinking about it, what are the odds 2020 is not among the top five loss years for the rest of the month? Or the rest of the season?

CO2e forcing is stronger every year, 3 out of last 5 years are among the top five and 2020 has certainly proven to be a strong melt season.

Well, main reason you can't just extrapolate the arctic as a whole that you can't have a negative amount of ice; Especially in the seas that almost/completely melt out every year and 'just' have a headstart in melting out. If seas melt out 2 weeks faster you will have in that melting period a lot of records and the 2 weeks following probably lower melt, because there is less left to melt

Gray-Wolf

  • Grease ice
  • Posts: 890
    • View Profile
  • Liked: 122
  • Likes Given: 318
Re: The 2020 melting season
« Reply #2523 on: July 10, 2020, 12:37:44 PM »
I'm always left wondering what a little 'tweak', mid summer, would mean to the final figures...

How much ice ,in previous years, was on the cusp of melt out before refreeze spared it?

The advantage 2020 is calving out for itself over peak insolation might lead to some surprises when those bits that have been being spared (with only a few cm's left to melt?) succumb in late Aug and we see a very dispersed pack emerge.
KOYAANISQATSI

ko.yaa.nis.katsi (from the Hopi language), n. 1. crazy life. 2. life in turmoil. 3. life disintegrating. 4. life out of balance. 5. a state of life that calls for another way of living.
 
VIRESCIT VULNERE VIRTUS

gerontocrat

  • First-year ice
  • Posts: 9077
    • View Profile
  • Liked: 3584
  • Likes Given: 26
Re: The 2020 melting season
« Reply #2524 on: July 10, 2020, 12:55:23 PM »
Not a lot of comfort in the temperature forecasts from Environment Canada and the Russian Met Office.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

dnem

  • Grease ice
  • Posts: 581
    • View Profile
  • Liked: 255
  • Likes Given: 177
Re: The 2020 melting season
« Reply #2525 on: July 10, 2020, 01:36:43 PM »

Just average for the five lowest extent years puts 2020 298 sq km. below 2019 two weeks from now. Hold on to your hats.

So you take the lowest value for the date (this year) and extrapolate from there the biggest losses, and you get a new record low? Who would have thought?

 :) ;)
Yep, it's not a great mathematical surprise but thinking about it, what are the odds 2020 is not among the top five loss years for the rest of the month? Or the rest of the season?

CO2e forcing is stronger every year, 3 out of last 5 years are among the top five and 2020 has certainly proven to be a strong melt season.

That's why I've always thought the top two lines in Gero's standard table, where he appends the average loss for the last 10, and 5, years to the current extent is very useful.  It is the simplest empirical way to predict where the season will go.  Both lines now predict 2020 will end up in a solid 2nd position.  Only three years in 10 (two of which are 13 and 14) result in a non 2nd place finish. The odds of finishing >4 mil sq km are very low IMO.

Jim Hunt

  • Young ice
  • Posts: 4742
  • Stay Home, Save Lives
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 507
  • Likes Given: 44
Re: The 2020 melting season
« Reply #2526 on: July 10, 2020, 02:13:16 PM »
But, I have always understood that the water in the melt ponds can warm considerably above 0C before they drain.

That's my understanding too, and I even have some measurements to back that up. Cross posting from the buoys thread.

Note that salty sea water remains liquid well below 0 °C

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

marcel_g

  • Frazil ice
  • Posts: 126
    • View Profile
    • Art by Marcel Guldemond
  • Liked: 55
  • Likes Given: 362
Re: The 2020 melting season
« Reply #2527 on: July 10, 2020, 02:38:40 PM »
Theoretically, the water in contact with the ice should be at 0 C.  Incoming solar radiation that is absorbed goes to melting the ice, not heating the water.  The meltponds themselves encourage further melting because they lower the net albedo of the system, not because their water gets warmer.

I’m not sure this is correct. There is a lot of very complicated thermodynamics involved in answering his question. You are clearly very knowledgeable, and I might be wrong. But, I have always understood that the water in the melt ponds can warm considerably above 0C before they drain.

Again, maybe my understanding is wrong. Hopefully, the Mosaic data will help answer these questions  when they start releasing it.

Yes, as well, some wavelengths of light pass through the ice and are absorbed by the water under the ice. The theory is that 2012’s preconditioning set up the massive bottom melt that just kept going and going in August, with a big assist from the GAC. I read that on this forum a couple of years ago. 2020 looks like it’s setting up to have significant bottom melt too, so the theory will be tested out in August, when we see if the melt rates slow down like normal, or if they keep going like 2012.

BornFromTheVoid

  • Nilas ice
  • Posts: 1176
    • View Profile
  • Liked: 447
  • Likes Given: 140
Re: The 2020 melting season
« Reply #2528 on: July 10, 2020, 03:41:51 PM »
The run of 100k+ losses on the daily NSIDC extent ended today, just barely, with a drop of 96k. The gap to the next lowest year, 2019, is now just 61k.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

tybeedave

  • New ice
  • Posts: 37
    • View Profile
  • Liked: 22
  • Likes Given: 47
Re: The 2020 melting season
« Reply #2529 on: July 10, 2020, 03:52:10 PM »
#2020 - the year new records became commonplace#

i see 4 events affecting the ice this year so far.  some are records (Fram export), some are not (Nares arch breaking-up date).

the persistent great Fram export event.  the persistent cyclone event.  the persistent  (albeit a small positive) nares event.  the current persistent anticyclone event. the current persistent insolation event.

the keyword is persistent.   read extreme melt.


Fram export- wind-aided export 40 strait days

Nares arch- cold winter temps caused no export until later than average

cyclone- it was brought to our attention a week before it began by a poster showing nullsoft data.
lasted about 15 strait days

anticyclone- ongoing: clearer than normal sky. how long wiil it continue?

insolation- ongoing: How long has the temp been above zero at the pole? 20 days?


the rules seem to have changed.  in the past (excepting 2012), extreme events hurting the ice happened, but nowhere near in the durations, we have witnessed this year.

i'm afraid that this year will mark a new minimum.  the perfect melt-storms have hit all in one year.  i hate negativity, but as far as excessive melt/export is concerned, i am really bummed out.

the CAB (not just the Beaufort) is beginning to spin. another poster keeps us abreast of what she calls the ?crack?.  the arrival date of the BOE is being accelerated i fear.

the weather has sucked

imo, the wind has been the big player this year and is getting stronger it seems.
 
the current insolation...who would have thought that a damn virus would have made the air so much clearer that insolation in actuality has been upped massively in it's ice killing effectiveness.

because i do hate negativity, i'm not even going to discuss the insidious bottom melt.

from a physics perspective.  the wind has caused or assisted extreme melt/export. read turbulence causes increased heat transfer.

i have sat back and watched the posts made as requested. it's not fun, i'm horrified.

i want to list all the really cool contributors to this forum, but my typewriter ribbon isn't long enough.
ty oren.  you have continued moderation par excellence (the great N must be thanked as moderator emiritus).  flower man and uniqorn continue to amaze me with their animations.  the time and effort that you all spend informing us non-scientists must be massive.  you are world-class cryosphere posters and deserve worldwide recognition.

:)  This has to be the most informative forum in the whole damn world for those of us concerned with our children's future.

that being said, I will make not only a prediction but a promise.


                           * I predict we will see a new record minimum this year.* 


if I am wrong (it happens occasionally), if my view is squed like my spelling, it means I'm suffering from that syndrome that illustrates that one's opinion on their own smarts is overestimated and my opinions are f*****-up. 

so I promise that I will discontinue posting my observations hereafter the minimum if there is not a record minimum.

i hope to see you on the other side.

ps  I bought my house in 1983.  it was built in '79 (the CAB was frozen year-round then).  the original faucet in the kitchen had never dripped.  it started dripping today.  it reminded me that S*** happens with time, but the arctic concerns me more than my sink, hence i write this post instead of fixing the faucet.

pss  Over the years, friv, you have been so enlightening.

td
thinking good thoughts, doing good deeds, enjoying good results - steve

Sublime_Rime

  • New ice
  • Posts: 37
    • View Profile
  • Liked: 37
  • Likes Given: 8
Re: The 2020 melting season
« Reply #2530 on: July 10, 2020, 04:01:14 PM »
The Beaufort's swiss-cheese distribution seems to be working its way farther into the pack over the last several days, with pretty consistent insolation and only light intermittent clouds. A mix of melt-ponding and this small gaps in the ice could lower the overall albedo by quite a bit I'd guess. I'm focusing on this area, as I think the consensus is its the only region that stands a decent chance at protecting the CAB over the next two months. I'm not particularly surprised that area and extent decline are slowing, as the HP has compacted the ice by quite a bit and can only do that to a certain degree. Its more volume I'm concerned about in general, and invasions of open water into the Laptev, and soon ESS as its ice is pushed into the warm Laptev.

The 00Z Euro gives the Beaufort a short respite with lower pressure and cooler temps over the next 2-3 days, but then back on with positive anomalies and HP by d4-5. Overall the 00Z Euro is pretty brutal, with only modest weakening of the HP until d10 and pretty significant WAA at 850mb centered over the pole and spanning most of the central arctic seas.
Max
Know thyself
Here to learn and connect in these wondrous and quickly changing times.

blumenkraft

  • Guest
Re: The 2020 melting season
« Reply #2531 on: July 10, 2020, 06:10:09 PM »
RE: #2478 bathymetry

Phoenix

  • Guest
Re: The 2020 melting season
« Reply #2532 on: July 10, 2020, 06:14:29 PM »
Link to GFS 10 day temperature anomaly forecast.

https://climatereanalyzer.org/wx/fcst/#gfs.arc-lea.t2anom

Over the 10 days, the Arctic region temperature anomaly is forecast to drop from +1.3C to +0.1C.

When was the last time Arctic temperatures were close to the long term average? Is this just a blip or is the continuous seven month regional inferno letting up? Does the GAAC have a role in this?

NotaDenier

  • New ice
  • Posts: 98
    • View Profile
  • Liked: 43
  • Likes Given: 28
Re: The 2020 melting season
« Reply #2533 on: July 10, 2020, 07:32:40 PM »
One thing that occurred to me regarding the area rebound in the CAS. We see this happen every year in the ESS and laptev if Siberia is hot and we have the wind from the south for a week or more. The snow melts -> melt ponds form -> area drops due the sensors being confused -> melt ponds drain -> area rebounds somewhat -> ice start breaking up due to the melting momentum -> ice area drops again.

CAS = central Arctic Sea

It feels like the same process is occurring in the CAS due to the GAAC. I don’t remember this ever occurring before. I’ve been lurking sine 2012 and I really don’t remember a rebound due to the melt ponds draining before.

So to those with access to such spreadsheets.
Has the CAS had a period of massive area losses, followed by a rebound of 83k like now?
Has the CAS ever had such a massive one day drop of area? We had a one day area drop of 85k. Is this a record? That is a massive amount of ice to lose in one day, in one sea.

These comments are based on Gero’s area spreadsheet.

TIA
« Last Edit: July 10, 2020, 07:38:23 PM by NotaDenier »

GoSouthYoungins

  • Nilas ice
  • Posts: 1417
    • View Profile
  • Liked: 170
  • Likes Given: 109
Re: The 2020 melting season
« Reply #2534 on: July 10, 2020, 07:50:30 PM »
I agree, NAD. Very much so. The area drop, rise, drop is happening far deeper into the CAB than ever before.

This year may be near 2012 in min area and extent, but the real problem is the overall level of melt above 80N. The volume is going to be low and near the exit doors. Terrible for 2021. Average weather might cause BOE.


Or we could GAAC for 2 more weeks and then GAC for 2 weeks, and that would cause a BOE in Sep. And the NH weather would get wuaky quacky starting this fall.
big time oops

Tor Bejnar

  • Young ice
  • Posts: 3542
    • View Profile
  • Liked: 606
  • Likes Given: 374
Re: The 2020 melting season
« Reply #2535 on: July 10, 2020, 08:13:40 PM »
I'd like to remind folks of Jim Petit's graphs (https://sites.google.com/view/pettitclimategraphs) and particularly this favorite of mine.  (Click to enlarge, etc.) 
Arctic ice is healthy for children and other living things.

gerontocrat

  • First-year ice
  • Posts: 9077
    • View Profile
  • Liked: 3584
  • Likes Given: 26
Re: The 2020 melting season
« Reply #2536 on: July 10, 2020, 08:42:17 PM »
I'd like to remind folks of Jim Petit's graphs (https://sites.google.com/view/pettitclimategraphs) and particularly this favorite of mine. 
Is it just me & my tired old eyes (& tired old laptop) that wish the colour contrast between some of the months was far stronger. Blink blink.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Lord M Vader

  • Nilas ice
  • Posts: 1330
    • View Profile
  • Liked: 46
  • Likes Given: 29
Re: The 2020 melting season
« Reply #2537 on: July 10, 2020, 09:34:48 PM »
Sea ice thickness and its anomaly in June. H/t to Zack Labe.


https://mobile.twitter.com/ZLabe/status/1281212689973272576/photo/1

Pagophilus

  • Frazil ice
  • Posts: 496
    • View Profile
  • Liked: 271
  • Likes Given: 402
Re: The 2020 melting season
« Reply #2538 on: July 10, 2020, 09:49:59 PM »
RE: #2478 bathymetry

Exactly what I was trying to point out for the Atlantic margin in an earlier post, only done way, way, way better, Blumenkraft, and for the whole Arctic.  Thank you.  The icecap edge seems to be aligning remarkably closely with the 200m submarine contour.  Coincidence maybe, but it means, IMHO, that the conversation here should include what is happening with waters beneath the ice more extensively than our replies do now.
Person.  Woman.  Man.  Vote.  November.

Ken Feldman

  • Nilas ice
  • Posts: 1374
    • View Profile
  • Liked: 203
  • Likes Given: 127
Re: The 2020 melting season
« Reply #2539 on: July 10, 2020, 10:53:53 PM »
Maybe this belongs in the stupid questions thread, but I see this come up a lot in this thread.

How can you tell the difference on a satellite photo between a ice covered in melt ponds and frozen ice that isn't covered by snow?  Both would appear blue from a distance and I don't think most satellite photos have the resolution to show the difference.  Is there something I'm missing?

vox_mundi

  • Young ice
  • Posts: 3825
    • View Profile
  • Liked: 2249
  • Likes Given: 298
Re: The 2020 melting season
« Reply #2540 on: July 10, 2020, 11:16:52 PM »
I don't usually have anything relevant to add here, but this came out today and seems to be topical ...

Arctic Ocean Changes Driven by Sub-Arctic Seas
https://phys.org/news/2020-07-arctic-ocean-driven-sub-arctic-seas.html

New research explores how lower-latitude oceans drive complex changes in the Arctic Ocean, pushing the region into a new reality distinct from the 20th-century norm.



The University of Alaska Fairbanks and Finnish Meteorological Institute led the international effort, which included researchers from six countries. The first of several related papers was published this month in Frontiers in Marine Science.

The Arctic Ocean, which covers less than 3% of the Earth's surface, appears to be quite sensitive to abnormal conditions in lower-latitude oceans.

"With this in mind, the goal of our research was to illustrate the part of Arctic climate change driven by anomalous [different from the norm] influxes of oceanic water from the Atlantic Ocean and the Pacific Ocean, a process which we refer to as borealization," said lead author Igor Polyakov, an oceanographer at UAF's International Arctic Research Center and FMI


This conceptual model shows the influx of Pacific and Atlantic water into the Arctic Ocean in the past compared to recent years. Blue indicates cool water and red indicates warm water. Arrows indicate the direction of water flow.

Since the first temperature and salinity measurements taken in the late 1800s, scientists have known that cold and relatively fresh water, which is lighter than salty water, floats at the surface of the Arctic Ocean. This fresh layer blocks the warmth of the deeper water from melting sea ice.

In the Eurasian Basin, that is changing. Abnormal influx of warm, salty Atlantic water destabilizes the water column, making it more susceptible to mixing. The cool, fresh protective upper ocean layer is weakening and the ice is becoming vulnerable to heat from deeper in the ocean. As mixing and sea ice decay continues, the process accelerates. The ocean becomes more biologically productive as deeper, nutrient-rich water reaches the surface.

By contrast, increased influx of warm, relatively fresh Pacific water and local processes like sea ice melt and accumulation of river water make the separation between the surface and deep layers more pronounced on the Amerasian side of the Arctic. As the pool of fresh water grows, it limits mixing and the movement of nutrients to the surface, potentially making the region less biologically productive. ...


Vertical profiles of winter (NDJFMA) potential temperature (θ, left column, °C, A,C,E,G) and salinity (S, right column, psu, B,D,F,H) for the central points of the four selected regions of the Arctic Ocean (regions are identified in the right column, their geographical locations are shown in Figure 1) from the 1970s (blue) and 2000s-2010s (red). CHL, NSTM, PSW, and PWW identify Cold Halocline Layer, Near-Surface Temperature Maximum, Pacific Summer Water and Pacific Winter Water.

Igor V. Polyakov et al, Borealization of the Arctic Ocean in Response to Anomalous Advection From Sub-Arctic Seas, Frontiers in Marine Science (2020).
https://www.frontiersin.org/articles/10.3389/fmars.2020.00491/full



“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

Greenbelt

  • Frazil ice
  • Posts: 167
    • View Profile
  • Liked: 39
  • Likes Given: 24
Re: The 2020 melting season
« Reply #2541 on: July 10, 2020, 11:22:57 PM »
How can you tell the difference on a satellite photo between a ice covered in melt ponds and frozen ice that isn't covered by snow?  Both would appear blue from a distance and I don't think most satellite photos have the resolution to show the difference.  Is there something I'm missing?

Here's a natural color Worldview pic from June 26 (much bluer in most areas) vs. the same area from today July 10.  That ice didn't refreeze, it just has less standing water on it is my interpretation. The bluish tint seems to fade to grayish as the melt pond drain I think.

uniquorn

  • Young ice
  • Posts: 2664
    • View Profile
  • Liked: 1187
  • Likes Given: 232
Re: The 2020 melting season
« Reply #2542 on: July 10, 2020, 11:40:06 PM »
Arctic Ocean Changes Driven by Sub-Arctic Seas
https://phys.org/news/2020-07-arctic-ocean-driven-sub-arctic-seas.html
Thanks vox_mundi. I struggle a bit with spatial alignment so I roughly overlaid the conceptual model of earlier/recent. Quite a conceptual push from the atlantic.
ctr
« Last Edit: July 10, 2020, 11:51:27 PM by uniquorn »

Sublime_Rime

  • New ice
  • Posts: 37
    • View Profile
  • Liked: 37
  • Likes Given: 8
Re: The 2020 melting season
« Reply #2543 on: July 11, 2020, 12:05:15 AM »
I think part of the slowdown in extent loss has to do with changes in the wind leading to dispersion that will continue over the next few days (as the massive uptick in extent loss was partially due to compaction of the HP). The GAAC is interacting with a trough forming over Beaufort that will lead to stronger winds exporting ice into Chukchi and shifting ESS ice into Laptev. This dispersion of the ice will lower extent losses, but also push ice into warming waters where it will melt out faster in the long run.

I therefore expect for a sort of stalling of extent losses under the long-term average, followed by a resumption in above average decline by early next week, once the trough exits the basin. On the other hand this might increase area losses once again as extent losses drop. We'll see...
Max
Know thyself
Here to learn and connect in these wondrous and quickly changing times.

GoSouthYoungins

  • Nilas ice
  • Posts: 1417
    • View Profile
  • Liked: 170
  • Likes Given: 109
Re: The 2020 melting season
« Reply #2544 on: July 11, 2020, 01:00:07 AM »
I think the Lincoln Sea will empty out in the next week. The ice in the north sea will float towards Beaufort and the ice closer to Nares will enter Nares. IMO.

The last of the Kara Sea ice (near severnaya zemlya) looks set for destruction as a LP system looks set to stir the ice while pushing it into warmer waters.


QUESTION: If a 2012esque GAC occurs and everything gets stirred up, what is the likelihood of mixing to the point where afterwards the stratified layer of cold fresh water/ice is only a fraction of what it was before? If this happened, would a near BOE be most likely every year heretofore?
big time oops

Ken Feldman

  • Nilas ice
  • Posts: 1374
    • View Profile
  • Liked: 203
  • Likes Given: 127
Re: The 2020 melting season
« Reply #2545 on: July 11, 2020, 01:10:27 AM »
How can you tell the difference on a satellite photo between a ice covered in melt ponds and frozen ice that isn't covered by snow?  Both would appear blue from a distance and I don't think most satellite photos have the resolution to show the difference.  Is there something I'm missing?

Here's a natural color Worldview pic from June 26 (much bluer in most areas) vs. the same area from today July 10.  That ice didn't refreeze, it just has less standing water on it is my interpretation. The bluish tint seems to fade to grayish as the melt pond drain I think.

This doesn't address my question.  How do you know that the blue on the June 26 photo is from melt ponds, not ice?  Ice appears blue from a distance.

https://www.carleton.edu/departments/geol/links/alumcontributions/blueice/blue.html

Quote
Snow is white because full spectrum, or white, light is scattered and reflected at the boundary between ice and air.

Quote
In ice, the absorption of light at the red end of the spectrum is six times greater than at the blue end. Thus the deeper light energy travels, the more photons from the red end of the spectrum it loses along the way. Two meters into the glacier, most of the reds are dead. A lack of reflected red wavelengths produces the color blue in the human eye.


ArcTickTock

  • New ice
  • Posts: 80
    • View Profile
  • Liked: 65
  • Likes Given: 97
Re: The 2020 melting season
« Reply #2546 on: July 11, 2020, 02:07:54 AM »
At this rate any thoughts of several large polynas opening well inside 80N and added impact?

I mentioned the possibility a few days ago and it certainly could happen.  On the flip side I have been watching the ice many years and a polynya opening inside 80N, well, I do not recall ever seeing one that wasn’t small and quickly closed off.

ArcTickTock

  • New ice
  • Posts: 80
    • View Profile
  • Liked: 65
  • Likes Given: 97
Re: The 2020 melting season
« Reply #2547 on: July 11, 2020, 02:20:29 AM »
Would a month of high pressure over the CAB in July pretty much melt it out? 
 

...The only sea that isn't showing signs of being beaten limp is the Beaufort, and with this insolation, I'm suspicious even of that, as it may shortly start looking like swiss cheese as interstitial ice melts out.

So yes, again, I think we're approaching that territory.  I'm hoping for a miracle, frankly.

My uneducated guess is that the Beaufort ice will hold out for the most part.  Cannot count how many times I have seen the Beaufort “Swiss Cheesed” yet stubbornly refuse to melt out and 2020 has a long way to go to catch up to other years there.  Am expecting this to be the one bright sea.  Things don’t look great everywhere else but am at a loss to guess where the CAA is going this year.
« Last Edit: July 11, 2020, 02:31:25 AM by ArcTickTock »

Jim Hunt

  • Young ice
  • Posts: 4742
  • Stay Home, Save Lives
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 507
  • Likes Given: 44
Re: The 2020 melting season
« Reply #2548 on: July 11, 2020, 02:22:11 AM »
Ice appears blue from a distance.

You're quoting selectively from an article about glacier ice, not sea ice. Don't forget that:

Quote
Ice only appears blue when it is sufficiently consolidated that bubbles do not interfere with the passage of light.

Try flipping between MODIS bands 7/2/1 and "true colour" whilst scrolling forwards a few days on this famous example:

https://go.nasa.gov/2W8lJtp
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

ArcTickTock

  • New ice
  • Posts: 80
    • View Profile
  • Liked: 65
  • Likes Given: 97
Re: The 2020 melting season
« Reply #2549 on: July 11, 2020, 02:29:02 AM »
Cloudy over the Laptev again so here is uni-hamburg amsr2-uhh, jun1-jul9
click to run, 6MB
Wipneus regional, jul8 (laptev and surround)

Uniquorn, so both uni-bremen and uni-hamburg are both using the same AMSR2 data??  Is there a reason to prefer one output to the other, I have tended to follow Bremen?