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F.Tnioli

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Re: The 2017 melting season
« Reply #1600 on: May 29, 2017, 04:01:59 PM »
...
while your general feeling/concern is well based i strongly believe that "ice-free by july" is vastly exagerated. i don't even believe we shall be ice-free this year but that's at least remotely possible.

should that happen it would have to be in september but as is said, i personally don't think so.
If we define "ice-free" as "less than 1M km2 of ice area", which we can; then if we consider positive feedbacks known to massively accelerate ice melt when ice is thin and low-extent; then if we imagine totally melt-conducting weather for the rest of this season; then if we agree "by july" includes something like "by july 30th", -

THEN it's still exaggerated, but not "vastly" anymore. At best...

Me, so far, i think it's "somewhat" possible we'll get ice-free late August or September.

Thomas Barlow

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Re: The 2017 melting season
« Reply #1601 on: May 29, 2017, 04:08:38 PM »
...
while your general feeling/concern is well based i strongly believe that "ice-free by july" is vastly exagerated. i don't even believe we shall be ice-free this year but that's at least remotely possible.

should that happen it would have to be in september but as is said, i personally don't think so.
If we define "ice-free" as "less than 1M km2 of ice area",
Does the number being discussed include the Greenland Sea, Baffin Bay, Nares, CAA, even Hudson Bay?

nukefix

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Re: The 2017 melting season
« Reply #1602 on: May 29, 2017, 04:25:45 PM »
The probabilistic extent 50 days from now is in freefall..:

http://cires1.colorado.edu/~aslater/SEAICE/

F.Tnioli

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Re: The 2017 melting season
« Reply #1603 on: May 29, 2017, 04:30:17 PM »
...
while your general feeling/concern is well based i strongly believe that "ice-free by july" is vastly exagerated. i don't even believe we shall be ice-free this year but that's at least remotely possible.

should that happen it would have to be in september but as is said, i personally don't think so.
If we define "ice-free" as "less than 1M km2 of ice area",
Does the number being discussed include the Greenland Sea, Baffin Bay, Nares, CAA, even Hudson Bay?
Every square meter of oceanic water surface in NH - is included for this "practically ice-free ocean in NH" quantification idea / agreement (sorry i don't remember where exactly i've read about it, i just remember i've been seeing it multiple times in the past). Why?
« Last Edit: May 29, 2017, 04:57:46 PM by F.Tnioli »

Lord M Vader

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Re: The 2017 melting season
« Reply #1604 on: May 29, 2017, 04:57:02 PM »
Nukefix: Interesting! How did the forecast look back in 2010-2016? I don't know if Neven made some dumps over the forecast during those years, but it surely would be interesting to see how this forecast corresponds to earlier years forecasts!

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Re: The 2017 melting season
« Reply #1605 on: May 29, 2017, 04:57:55 PM »
...
while your general feeling/concern is well based i strongly believe that "ice-free by july" is vastly exagerated. i don't even believe we shall be ice-free this year but that's at least remotely possible.

should that happen it would have to be in september but as is said, i personally don't think so.
If we define "ice-free" as "less than 1M km2 of ice area",
Does the number being discussed include the Greenland Sea, Baffin Bay, Nares, CAA, even Hudson Bay?
Yes

Thomas Barlow

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Re: The 2017 melting season
« Reply #1606 on: May 29, 2017, 05:00:58 PM »
Does the number being discussed include the Greenland Sea, Baffin Bay, Nares, CAA, even Hudson Bay?
Every square meter of oceanic water surface in NH - is included for this "practically ice-free ocean in NH" quanitification idea / agreement (sorry i don't remember where exactly i've read about it, i just remember i've been seeing it multiple times in the past). Why?
Thanks.
I'm just focus on the Arctic Ocean now, since I think (theoretically) there could be ice all over the place, even when (if) the ocean icepack ever starts to break up significantly, or shrink. What's happening in the Arctic Ocean is the main thing, re. global effect I think.
« Last Edit: May 29, 2017, 05:10:07 PM by Thomas Barlow »

Thomas Barlow

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Re: The 2017 melting season
« Reply #1607 on: May 29, 2017, 05:06:02 PM »
Heads up. New large crack showing up in one day.
https://media.giphy.com/media/3ohzdFa2IUWIukaxu8/giphy.gif


magnamentis

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Re: The 2017 melting season
« Reply #1609 on: May 29, 2017, 05:25:20 PM »
As to ice free this year. I don't think so. I think we'll see a new record low but ice has a way of piling up on the Greenland side of the pole.

When there was a lot of MYI. Now it's all flushing through Fram Strait and other places. That extent and area in this season didn't show new record lows yet, is because of the spread of fractioned ice all over the Arctic. Given the right conditions, an ice free Arctic in September could very well be probable.

But as an average melting season is the most probable thing to assume, there's still a mayor probability of the polar region being covered by ice in September. But all in all the Arctic is becoming something similar to Hudson Bay ...

if you replace the word "probabel" with the word "possible" i'm with you, because IMO it is possible but NOT probable.

magnamentis

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Re: The 2017 melting season
« Reply #1610 on: May 29, 2017, 05:28:27 PM »
is it likely that all the ice in the arctic will become one huge clockwise flowing iceberg and then refreeze back to the coasts in September leaving more multiyear ice once again?

A glass very half full assumption

the amount of MYI will depend of how much ice will survive this melting season and i can't see the correlation between clockwise rotation and the amout itself, what did i miss?

if i didn't miss a point the answer would be no IMO

Thawing Thunder

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Re: The 2017 melting season
« Reply #1611 on: May 29, 2017, 06:31:38 PM »
As to ice free this year. I don't think so. I think we'll see a new record low but ice has a way of piling up on the Greenland side of the pole.

When there was a lot of MYI. Now it's all flushing through Fram Strait and other places. That extent and area in this season didn't show new record lows yet, is because of the spread of fractioned ice all over the Arctic. Given the right conditions, an ice free Arctic in September could very well be probable.

But as an average melting season is the most probable thing to assume, there's still a mayor probability of the polar region being covered by ice in September. But all in all the Arctic is becoming something similar to Hudson Bay ...

if you replace the word "probabel" with the word "possible" i'm with you, because IMO it is possible but NOT probable.

Absolutely! We'll see what's going to happen. 2013 I was expecting a big event which never came to happen. Now I've got a similar gut feeling. But maybe the ice holds and over the next years extent and volumen will go down on a gentle path - or there will be a tipping point that changes everything. Who knows ...
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romett1

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Re: The 2017 melting season
« Reply #1612 on: May 29, 2017, 06:32:21 PM »
Looks like the whole face gave up, there's still another day of high winds so its not over yet.


Some difference between 2017 vs 2016 (May 29). I would rather believe those pilots who said in April that they have never seen ice like that on Lincoln Sea. Images: Worldview, 2017 is nighttime imagery.
« Last Edit: May 29, 2017, 06:39:08 PM by romett1 »

FishOutofWater

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Re: The 2017 melting season
« Reply #1613 on: May 29, 2017, 07:57:38 PM »
As to ice free this year. I don't think so. I think we'll see a new record low but ice has a way of piling up on the Greenland side of the pole.

When there was a lot of MYI. Now it's all flushing through Fram Strait and other places. That extent and area in this season didn't show new record lows yet, is because of the spread of fractioned ice all over the Arctic. Given the right conditions, an ice free Arctic in September could very well be probable.

But as an average melting season is the most probable thing to assume, there's still a mayor probability of the polar region being covered by ice in September. But all in all the Arctic is becoming something similar to Hudson Bay ...

if you replace the word "probabel" with the word "possible" i'm with you, because IMO it is possible but NOT probable.

I am very aware of the dismal state of the ice right now. However, high pressure creates convergence towards the center of the high. The ice forms ridges and can literally pile up. Those piles are hard to melt out.

When there's low pressure the clouds keep the sunlight off the ice so it melts slowly. So either way it is hard to get rid of the ice until the whole climate system reaches a critical point and warm water obliterates much of the ice from below. Chris Reynolds had a good point about how hard it will be to melt out all the first year ice once the multi-year ice is almost gone. However, I see another record low coming on. The plunge in Slater's 50 day forecast method is based on real data.

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Re: The 2017 melting season
« Reply #1614 on: May 29, 2017, 08:03:40 PM »

Lord M Vader

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Re: The 2017 melting season
« Reply #1615 on: May 29, 2017, 08:31:14 PM »
FishOutofWater: Seems like a "July cliff" and not a "June cliff" coming up...

IMeretricious: Yes, it's hot around Hudson Bay. Given the forecast and the state of the ice we should see some major drops there over the next two weeks or so.

rboyd

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Re: The 2017 melting season
« Reply #1616 on: May 29, 2017, 09:53:34 PM »
At least a July cliff may reduce the amount of additional energy taken in by the Arctic waters, and therefore help the follow on freezing season.

Thomas Barlow

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Re: The 2017 melting season
« Reply #1617 on: May 29, 2017, 10:19:39 PM »
May 29 2017 compared to June 11 2016 (nearest clear day).
Strong contrast added.
North of Greenland:
« Last Edit: May 29, 2017, 10:29:57 PM by Thomas Barlow »

FishOutofWater

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Re: The 2017 melting season
« Reply #1618 on: May 29, 2017, 10:47:56 PM »
The very heavy snowfall held out through May slowing the predicted May decline in the 50 day sea ice model. That snow is almost gone in north America now so I think the melt rates are going to start reflecting the model prediction soon. Siberia is warming up fast, but has more snow to melt. For predictive purposes it's probably better to smooth that curve out instead of predicting a cliff, in my opinion. But we all know how hard it is to predict the weather so let's not get overconfident in forecasts. No matter how we look at it, the forecast for the ice looks bad.

Cook

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Re: The 2017 melting season
« Reply #1619 on: May 29, 2017, 10:58:55 PM »
My money is on the cliff. The ice pack seems to lack integrity. There has been, and probably will continue to be strong ice export, essentially spreading. The ice that is left appears to be quite homogeneous. It therefore  seems logical to think that much of the ice will melt at a similar rate and therefore disappear around the same time, giving rise to the cliff.

The disintegration north of Greenland looks ominous to say the least. 

Jim Pettit

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Re: The 2017 melting season
« Reply #1620 on: May 29, 2017, 11:11:23 PM »
My money is on the cliff. The ice pack seems to lack integrity. There has been, and probably will continue to be strong ice export, essentially spreading. The ice that is left appears to be quite homogeneous. It therefore  seems logical to think that much of the ice will melt at a similar rate and therefore disappear around the same time, giving rise to the cliff.

The disintegration north of Greenland looks ominous to say the least.

There will almost certainly be a cliff of very large proportions. It may be one with an earlier onset, such as that seen in 2012, which leapt off the precipice during the first week of June. Or it could be a few weeks later such as that seen in 2007, which waited until the end of June (but which then fell faster). But I do believe we are in for one.

It's going to get very interesting in another couple of weeks. Keep your arms and legs inside the vehicle, and remain seated at all times...

jai mitchell

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Re: The 2017 melting season
« Reply #1621 on: May 29, 2017, 11:31:16 PM »
7/9/2016 vs 5/29/2017

CLICK IMAGE TO SEE ANIMATION COMPARISON

note the image with the large gap north of the Greenland Archipelago is May 29th

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subgeometer

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Re: The 2017 melting season
« Reply #1622 on: May 30, 2017, 03:06:05 AM »
The very heavy snowfall held out through May slowing the predicted May decline in the 50 day sea ice model. That snow is almost gone in north America now so I think the melt rates are going to start reflecting the model prediction soon. Siberia is warming up fast, but has more snow to melt. For predictive purposes it's probably better to smooth that curve out instead of predicting a cliff, in my opinion. But we all know how hard it is to predict the weather so let's not get overconfident in forecasts. No matter how we look at it, the forecast for the ice looks bad.

The GFS may overcook snow melt, but for what it's worth here's the forecast loss over the next week. It may be too aggressive, but if the forecast heat materialises in Siberia the snow can't last much longer there.

edit: - I added the attachment I'd had forgotten, and the replaced with one that will play /edit

With the state of the ice on that side and a series of lows in the Kara Sea blowing into the Barents and sucking warm moist air in, more and more open water will appear and start warming. Does the ongoing weather setup of a high surrounded by lows cause rotation and compaction of  the centre, while lows disperse ice at the edges? With the mobility and fragility and thinness could the pack become entirely separated from the margins of the Arctic Ocean, or even split into pieces rather than develop arms.

If the summer is sunny and the Ocean takes up a large amount of heat, then the autumn turns stormy like last year the minimum could come very late. During the winter on the freezing thread it was suggested(if I can trust my memory) that when we go sub 1million km2 sometime in the next few years, it could happen in October.

It's too early to discount the possibility of going icefree this year. Things have started ominously. We just have to watch what unfolds
« Last Edit: May 30, 2017, 03:20:19 AM by subgeometer »

subgeometer

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Re: The 2017 melting season
« Reply #1623 on: May 30, 2017, 03:22:25 AM »
From the previous post

bbr2314

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Re: The 2017 melting season
« Reply #1624 on: May 30, 2017, 03:22:59 AM »
The very heavy snowfall held out through May slowing the predicted May decline in the 50 day sea ice model. That snow is almost gone in north America now so I think the melt rates are going to start reflecting the model prediction soon. Siberia is warming up fast, but has more snow to melt. For predictive purposes it's probably better to smooth that curve out instead of predicting a cliff, in my opinion. But we all know how hard it is to predict the weather so let's not get overconfident in forecasts. No matter how we look at it, the forecast for the ice looks bad.

The GFS may overcook snow melt, but for what it's worth here's the forecast loss over the next week. It may be too aggressive, but if the forecast heat materialises in Siberia the snow can't last much longer there.

edit: - I added the attachment I'd had forgotten, and the replaced with one that will play /edit

With the state of the ice on that side and a series of lows in the Kara Sea blowing into the Barents and sucking warm moist air in, more and more open water will appear and start warming. Does the ongoing weather setup of a high surrounded by lows cause rotation and compaction of  the centre, while lows disperse ice at the edges? With the mobility and fragility and thinness could the pack become entirely separated from the margins of the Arctic Ocean, or even split into pieces rather than develop arms.

If the summer is sunny and the Ocean takes up a large amount of heat, then the autumn turns stormy like last year the minimum could come very late. During the winter on the freezing thread it was suggested(if I can trust my memory) that when we go sub 1million km2 sometime in the next few years, it could happen in October.

It's too early to discount the possibility of going icefree this year. Things have started ominously. We just have to watch what unfolds
That attachment would explain why UBremen is now showing huge black/grey patches over Beaufort and Chuchki. HYCOM shows large concentration drops beginning soon across Chuchki as well. I suspect that large parts of both seas will be open by 7/1, and while we haven't yet surpassed 2016, we aren't far off. When we *do* finally surpass it -- which I think is almost guaranteed, comparing thicknesses in both Beaufort and Chuchki -- the advance will come much quicker than it did last year, and the rest of the CAB will soon follow/quickly melt into oblivion.

I also suspect that despite the seemingly delayed momentum in melt this year, the relative lack of volume compared to all other years on record means that the minimum is going to come late, possibly in a record-setting way, which will likely delay refreezing well into October/November, echoing last year in an even worse way.

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Re: The 2017 melting season
« Reply #1625 on: May 30, 2017, 07:57:13 AM »
I guess, based on HYCOM ice thckness animation, that the MacKenzie delta has given way for a large melt pulse. As the ice is disappearing fast phase in the MacKenzie Bay and around it in the Beaufort.

Andreas T

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Re: The 2017 melting season
« Reply #1626 on: May 30, 2017, 10:12:22 AM »
I guess, based on HYCOM ice thckness animation, that the MacKenzie delta has given way for a large melt pulse. As the ice is disappearing fast phase in the MacKenzie Bay and around it in the Beaufort.
You better look at the worldview images https://go.nasa.gov/2ri0zKP
There is ice movement away from the coast, surface melt on landfast ice, an ice free McKenzie river and some recently formed ice melting away in the Beaufort. Not all opening water equates to ongoing melt. Open water absorbs sunlight and will melt ice because it is warming up now, but that takes a while to come together.

iceman

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Re: The 2017 melting season
« Reply #1627 on: May 30, 2017, 12:17:32 PM »
The probabilistic extent 50 days from now is in freefall..:
http://cires1.colorado.edu/~aslater/SEAICE/
The 50-day forecast has been too pessimistic for a while, in a model that is generally fairly accurate.  People have mentioned several reasons that help explain this discrepancy, and most appear to be at least partly reversing:
1) unusually large and persistent dispersion on Atlantic side (noted far upthread);

2) more cloud cover than expected;
     
The current state of high pressure in the CAB has not led to significant surface melt, as would have otherwise been expected.  This appears to be due to high levels of cloud cover.  The cloudcover appears to be a function of water vapor intrusion from the North American side in a classic 'negative PNA index' push at the 850 mb altitude.  This was the dominant system that operated on the arctic 2013/2014 melt seasons.  The PNA index has been negative but is projected to shift sharply to a strong positive in the forecast models.  This will combine with the forecast models of stronger high pressure in the CAB to greatly accelerate melt pond formation and precondition of ice loss through the rest of the melt season.
   ....
3) enough snow cover to retard ice melt;

The very heavy snowfall held out through May slowing the predicted May decline in the 50 day sea ice model. That snow is almost gone in north America now so I think the melt rates are going to start reflecting the model prediction soon. Siberia is warming up fast, but has more snow to melt. For predictive purposes it's probably better to smooth that curve out instead of predicting a cliff, in my opinion. But we all know how hard it is to predict the weather so let's not get overconfident in forecasts. No matter how we look at it, the forecast for the ice looks bad.
I would add:
4) lack of offshore winds that cause compaction;

   ....
With the state of the ice on that side and a series of lows in the Kara Sea blowing into the Barents and sucking warm moist air in, more and more open water will appear and start warming....
Reason 4) is something of a mixed bag.  Offshore winds open more water, generally at lower latitudes where the drop in albedo has greatest effect.  But they also tend to increase compaction, which will protect ice later in the season if it is driven toward the center of the pack.  (The current situation in Kara is a notable exception.)
     Net: I believe the model forecast for a sharp drop, and would expect it in less than 50 days if surface melt increases widely in the next week or two.

F.Tnioli

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Re: The 2017 melting season
« Reply #1628 on: May 30, 2017, 02:16:08 PM »
...
Reason 4) is something of a mixed bag.  Offshore winds open more water, generally at lower latitudes where the drop in albedo has greatest effect.  ...
All of your post seems to be true, to me, except i doubt this little bit about lower latitudes - for the time being. Here's why.

It is my understanding that in lower latitudes _this_ time of the year, there will be hours when the Sun is rather low over horizon (say some 5...10 degrees above it), "night hours daily" so to say. During those hours, sunlight will travel relatively great distance through the athmosphere, losing much of its energy before it reaches the surface.

By contrast, at the North Pole in June and 1st half of July, the Sun will never be that low above the horizon, which will result in more W/m2 24/7 overall. While during "day hours daily" times, the difference between Pole and some lower latitudes in terms of how much W/m2 actually reaches the surface will be rather negligible. Given no cloud cover in all cases, of course. It's quite simple geometry, you see.

FishOutofWater

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Re: The 2017 melting season
« Reply #1629 on: May 30, 2017, 04:17:48 PM »
Jim, let me clarify the no cliff statement.  I said the 50 day curve should be smoothed out. I don't think the cliff 50 days out is going to happen that way because ice extent will begin dropping rapidly relative to last year well before 50 days out. I don't think the cliff in Slater's graph is going to happen that way.

Because there is so much thin ice dispersed around the Arctic some kind of cliff is possible but we don't know when it will happen.

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Re: The 2017 melting season
« Reply #1630 on: May 30, 2017, 05:05:40 PM »
The waters around FJL are opening back up again.

Neven

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Re: The 2017 melting season
« Reply #1631 on: May 30, 2017, 05:50:15 PM »
We also need to remember that the Slater graph is running on its own, given that Slater is no longer around to adjust/correct it where necessary.
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Lord M Vader

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Re: The 2017 melting season
« Reply #1632 on: May 30, 2017, 06:28:07 PM »
Neven: has anyone asked Zack Labe a.k.a Blizzard92 if he would be able to take over Andrew Slaters work? I think/believe that he would be a perfect choice for that task :)

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Re: The 2017 melting season
« Reply #1633 on: May 30, 2017, 06:50:56 PM »
@ FishOutofWater - Seems that the stability of the current wave 5 pattern you talked about is showing itself with the persistence of the low on the barents-kara side and the pole centered high. It'll be interesting to hear any more of your thoughts or forecasts on the matter.
« Last Edit: May 30, 2017, 06:58:12 PM by Ice Shieldz »

FishOutofWater

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Re: The 2017 melting season
« Reply #1634 on: May 31, 2017, 04:11:47 AM »
The CFS v2 model is showing the 5 wave pattern persisting in June but not July. There are peer reviewed papers of persistent weather patterns that found the 5 wave pattern caused heat waves, but I am not aware of any model having skill in forecasting the development of a persistent 5 wave pattern.

What's interesting is that there are signs of it developing now. Of course, I plan to study it the best I can from my laptop.

The physics of ocean/atmosphere couplings is way above my training and skills as a geochemist/geologist. However, there are ocean heat/atmospheric wave patterns that develop and evolve over months that may be predictable. El Niño and La Niña are the most well known persistent patterns but there are also patterns centered in the Atlantic.

Sea ice loss may be amplifying the patterns because heat in the Barents sea can amplify atmospheric ridges and intensify storms close to the pole.

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Re: The 2017 melting season
« Reply #1635 on: May 31, 2017, 05:21:57 AM »
Bright colors everywhere. I believe the opening of the CAA is only a couple weeks out now.

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Re: The 2017 melting season
« Reply #1636 on: May 31, 2017, 08:10:46 AM »
Warm surface air to start invading the CAA and the Chukchi Sea tomorrow and get progressively warmer over the next few days. Greenland will see warm air over land at 1000 mb in a few days. It's about to get real.

Lord M Vader

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Re: The 2017 melting season
« Reply #1637 on: May 31, 2017, 08:53:45 AM »
Yes, and it's also looks like the ECMWF 00z run wants to develop a loe pressure over the CAB in 4-9 days.. That might halt the worst damage, just like last year depending on whether that's temporarily or a more persistent pattern shift.... Beaufort, Laptev, Kara and CAA should however take a big hit from the latest forecast. But the most important thing for the final outcome this season is the weather in the CAB!

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Re: The 2017 melting season
« Reply #1638 on: May 31, 2017, 12:19:50 PM »
The Canadian Arpegio (or however you spell it) is notoriously difficult to break down so it may not all go but this will surely test it to the limit

Tigertown

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Re: The 2017 melting season
« Reply #1639 on: May 31, 2017, 01:52:05 PM »
I think the opening of the CAA may be more important than it initially appears to be. It's kind of like opening a pressure relief valve of sorts. It seems to me, with my limited experience, to change the dynamics within the CAB.
                                                                                                                             
pauldry600
Quote
The Canadian Arpegio (or however you spell it) is notoriously difficult to break down so it may not all go but this will surely test it to the limit
It don't have to all go, as in melt. If enough gets weakened and broken up, the rest will eventually just flush out. Remember that at the end of last melt season, smaller floes were moving through until the end and got frozen together. I don't suspect the bonds between these to be any stronger than elsewhere. Also, wave activity has been infiltrating some of the channels, despite the dampening effect of the ice.
« Last Edit: May 31, 2017, 02:04:38 PM by Tigertown »

iceman

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Re: The 2017 melting season
« Reply #1640 on: May 31, 2017, 02:05:47 PM »
   ....
It is my understanding that in lower latitudes _this_ time of the year, there will be hours when the Sun is rather low over horizon (say some 5...10 degrees above it), "night hours daily" so to say. During those hours, sunlight will travel relatively great distance through the athmosphere, losing much of its energy before it reaches the surface.

By contrast, at the North Pole in June and 1st half of July, the Sun will never be that low above the horizon, which will result in more W/m2 24/7 overall. While during "day hours daily" times, the difference between Pole and some lower latitudes in terms of how much W/m2 actually reaches the surface will be rather negligible. Given no cloud cover in all cases, of course. It's quite simple geometry, you see.

Maybe we are using "lower latitudes" in different senses.  I meant low relative to the Arctic, as in Chukchi or southern Beaufort.  The sun is fairly high in the sky there now - approx. forty degrees ascension at noon.
     You're right that the poles potentially receive the most insolation around the solstice.  This chart is for top-of-atmosphere iirc; I haven't seen comparable figures for ground level that would account for angle of incidence, atmospheric thickness, etc.

Tigertown

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Re: The 2017 melting season
« Reply #1641 on: May 31, 2017, 02:55:24 PM »
The open water in the Chukchi area has been taking on insolation, without doubt.
The SST's have risen and will continue to do so.(Top image)
Also, the water below the surface based on 5 meters down has warmed. (bottom image)

 

Random_Weather

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Re: The 2017 melting season
« Reply #1642 on: May 31, 2017, 03:16:14 PM »
@ Iceman (Insolation between 80-90N)


https://climexp.knmi.nl/data/ifresco6_ssi_-179.5-179.5E_80-90N_n__yr.txt

Fresco SSI is using a cloud fraction algorithm

FishOutofWater

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Re: The 2017 melting season
« Reply #1643 on: May 31, 2017, 04:47:57 PM »
Low pressure is appearing in the central arctic in both the ECMFW and GFS models but the pattern is less than ideal for sea ice because there's heat over the Kara and Barents seas as well as the CAA. The forecasts give us some hope that we won't see a worst case scenario this summer.

The GFS has been particularly poor at prognosticating lately and no model has done well more than 5 days out so Arctic forecasts are subject to change without notice. The problem we face this June is that the jet stream is pretty strong but also very wavy. The waves are carrying heat into the Arctic and sending the cold down in the troughs over the Urals and central north America. The net result is excess heat in the Arctic. In the summer of 2013, when the jet stream collapsed around the Arctic ocean shores, it kept the cold air over the ocean and the heat over the continents. We are seeing the opposite so far this year.

Thanks again to Levi Cowan at tropicaltidbits.com for the images.


F.Tnioli

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Re: The 2017 melting season
« Reply #1644 on: May 31, 2017, 04:53:05 PM »
Speaking of Canada, R.S. posted a map of forecasted fire hazards in Alberta (Canada) yesterday. The map says more than half of Alberta is either "very high" or "extreme" fire danger - northern half, at that. With "extreme" being a big part of that half-Alberta landmass:



They had to evacuate some towns there in 2016, and now they go for record heat - again. There were mentions earlier in this topic about "gray" state of lots of ASI, caused by soot and such.

If i get it right, right now winds in and around Alberta will have soot from fires to circle around and much within Alberta itself, naturally decreasing alberdo further, resulting in even more fires. At some point winds will change, and lots of black carbon may end up going somewhere else.

What i don't know - is where lots of that soot will go if we'll have that 5-wave pattern firmly establsihed in June. Any ideas?

F.Tnioli

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Re: The 2017 melting season
« Reply #1645 on: May 31, 2017, 05:01:38 PM »
...
Maybe we are using "lower latitudes" in different senses.  I meant low relative to the Arctic, as in Chukchi or southern Beaufort.  The sun is fairly high in the sky there now - approx. forty degrees ascension at noon.
     You're right that the poles potentially receive the most insolation around the solstice.  This chart is for top-of-atmosphere iirc; I haven't seen comparable figures for ground level that would account for angle of incidence, atmospheric thickness, etc.
I think we understand it the same. As for "Sun is fairly high in the sky at lower latitudes idea" - this is, like you said yourself, at _noon_. At local midnight, it is correspondedly "fairly low" there. And it's "high enough to let most W/m2 to reach the surface" at times like local 6AM and 6PM. So, the total picture "daily" is like "some ~18 hours of full and almost-full W/m2 hitting the surface", while the remaining ~6 hours is like "much of sunlight does not reach the surface". That's for "lower latitudes".

At the Pole, though, the Sun is like "high enough to let most W/m2 to reach the surface" 24/7 now and for the next ~1.5 months, so that's all 24 hours daily. Which is why if Pole gets wet, albedo drop effect there will be way more important than same effect at "lower latitudes", i think. You can interpolate the rest for places "in between", of course.


Retron

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Re: The 2017 melting season
« Reply #1646 on: May 31, 2017, 06:28:51 PM »
Looks like the crack has almost made it across the whole of the north of Greenland... the odds on it reaching the Atlantic side in the next day or two must be short!


jai mitchell

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Re: The 2017 melting season
« Reply #1647 on: May 31, 2017, 07:21:09 PM »
I haven't seen comparable figures for ground level that would account for angle of incidence, atmospheric thickness, etc.

not significant effects.  Clouds, yes, angle and thickness, not much.  Incident received radiation at the pole is significantly more on June 21 than at the equator.
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gregcharles

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Re: The 2017 melting season
« Reply #1648 on: May 31, 2017, 08:01:19 PM »
The Canadian Arpegio (or however you spell it) ...

It's Canadian Arpeggio, assuming you mean the notes "C, E♭, G♭, A" played as a sequence. Canadians loves them some diminished sevenths! 

 :P

(Canadian Arctic Archipelago. CAA is the easiest way to spell it.)

seaicesailor

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Re: The 2017 melting season
« Reply #1649 on: May 31, 2017, 08:11:17 PM »
The ACNFS drift forecast. Actually the first frame corresponds to almost 20h ago. A lot of action that shows today in the sat images.
The "peeling-off" of Kara sea is going to continue for a couple of days I am afraid. Then things get pretty quiet, except for Beaufort sea where "blow wind blow" (as the blues says, now that we get musical) from inland well into June.
Speaking of Beaufort sea and of blues, I did not see so much blue there so early since 2012 (I mean, scrolling back in Worldview).
And continuing with music, I recommend some Bach to some depressed members if family & friends don't help, Bach has some stuff that shows the reality (or illusion) humans are not that bad.
Well avoid the violin partitas if depressed
Cheers