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Jim Hunt

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Re: The 2016 melting season
« Reply #3600 on: July 23, 2016, 05:13:26 PM »
This has data from beginning of june 2016, not real time either but more recent.

That IFREMER data is "weekly" rather than "monthly" though?
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Nick_Naylor

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Re: The 2016 melting season
« Reply #3601 on: July 23, 2016, 06:29:42 PM »
Most of the fast ice on Greenland's Northeast coast has let go. (needs a click)

seaicesailor

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Re: The 2016 melting season
« Reply #3602 on: July 23, 2016, 08:50:23 PM »
Both ECMWF and GFS show warm airmass entering into the Pacific side until Monday. Then a weak low dominates, although the Greenland High stays strong.
Both predict in one week something uncertain but peculiar anyway to me. The low would be dragging heat from America (aided by high over Greenland) and another low  from Asia simultaneously  (high over ESS). And a lot of heat!
Grain of salt.
« Last Edit: July 23, 2016, 09:11:21 PM by seaicesailor »

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Re: The 2016 melting season
« Reply #3603 on: July 23, 2016, 09:44:12 PM »
Not a joke after all

AmbiValent

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Re: The 2016 melting season
« Reply #3604 on: July 23, 2016, 09:47:40 PM »
If that comes to happen, would that also push the warm waters from the Kara into the Laptev?
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seaicesailor

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Re: The 2016 melting season
« Reply #3605 on: July 23, 2016, 10:10:09 PM »
If that comes to happen, would that also push the warm waters from the Kara into the Laptev?
I don't think that generally happens... but I don't really know.
I just wanted to show the short-lived but significant drift caused by the current high over the Pacific side. It is going to pass over that big region of polynya left by the storms  :-X

Shared Humanity

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Re: The 2016 melting season
« Reply #3606 on: July 23, 2016, 10:48:52 PM »
If that Ice drift map is correct we are going to see a lot of melt as ice gets pushed into the anomalously warm waters on the Atlantic side of the CAB. I've said this before but the Atlantic side of the CAB holds the key to this melt season. If that ice gets moving in a big way into the Barents and through the Fram we are going to see it get crushed.

jdallen

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Re: The 2016 melting season
« Reply #3607 on: July 23, 2016, 10:53:01 PM »
If that comes to happen, would that also push the warm waters from the Kara into the Laptev?

No, but it will push ice across warmer water along the Atlantic front 1700km worth of boundary with much more available heat.  We may get to see a test of one of my hypotheses.
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Re: The 2016 melting season
« Reply #3608 on: July 24, 2016, 12:23:52 AM »
This has data from beginning of june 2016, not real time either but more recent.

That IFREMER data is "weekly" rather than "monthly" though?
Weekly would be great as well, thanks Andreas.

My impression is that the amount of ice movement beginning with the storm in mid-June has been exceptional this year. I can't quantify that though.

icy voyeur

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Re: The 2016 melting season
« Reply #3609 on: July 24, 2016, 12:37:06 AM »
Not a joke after all

To my eyes, Fram export has been significantly increasing.
That figure scares me given the state of the ice. If that persists for a week or more, I worry we may be far closer to breaking a Sep record than it has seemed these last 6 weeks.  That's based on my assessment that the CAB is ahead of pace, mobile, and thus susceptible to be scattered towards peripheral seas as seems to have been in play lately. I hope we don't get a big storm in August to get the swells rocking.

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Re: The 2016 melting season
« Reply #3610 on: July 24, 2016, 01:19:18 AM »
Relatively clear skies north of Alaska, so I tacked on another 24 hours to the animation in post #3563.

July 19-22
http://feeder.gina.alaska.edu/search?utf8=✓&search%5Bsensors%5D%5B4%5D=1&search%5Bsensors%5D%5B3%5D=1&search%5Bfeeds%5D%5B5%5D=1&search%5Bstart%5D=&search%5Bend%5D=&commit=Search
Thank you Jay, the more frequent images shows more detail in the movement in the way that variations in speed during a day are shown. It also gives a better chance of seeing the ground between clouds. I am not clear what you mean by flow north east of Wrangel?
What stands out for me is the divergence of the ice in a large region further north towards the pole while near Wrangel there is a lot more ice than last year. The arrival of warm air shown by seaicesailor will test the strength of that.

pauldry600

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Re: The 2016 melting season
« Reply #3611 on: July 24, 2016, 01:42:04 AM »
Think arctic has a few surprises in store yet. This warm air is one and major storm still in late august september can never be ruled out.

In the British Isles where I live the sea used freeze over regularly in the 17 and 1800s in Winter , now it never does.

In time could this happen in the arctic

A-Team

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Re: The 2016 melting season
« Reply #3612 on: July 24, 2016, 03:02:52 AM »
The images below look at the next five days of 'speed and drift' coarsely integrated over each km per day off Franz Josef which sums to roughly 76 km or 23 pixels of uneven advance across the polar front at the scale of AMSR2 3k.

Should this melt along the 1750 km front as the ice pack encounters above-freezing nullschool or hycom temperatures and salinities northward of the Barents sea, some 128,000 km2 of ice would melt. This needs to be revisited five days from now on July 28th as a reality check.
« Last Edit: July 24, 2016, 03:14:39 AM by A-Team »

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Re: The 2016 melting season
« Reply #3613 on: July 24, 2016, 07:11:41 AM »
East Siberian Sea;then and now, difference in less than two weeks(July 12 vs. July 23)
There are other areas of growth too, if you look closely





« Last Edit: July 24, 2016, 07:16:53 AM by Tigertown »

Rob Dekker

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Re: The 2016 melting season
« Reply #3614 on: July 24, 2016, 08:26:49 AM »
The images below look at the next five days of 'speed and drift' coarsely integrated over each km per day off Franz Josef which sums to roughly 76 km or 23 pixels of uneven advance across the polar front at the scale of AMSR2 3k.

Should this melt along the 1750 km front as the ice pack encounters above-freezing nullschool or hycom temperatures and salinities northward of the Barents sea, some 128,000 km2 of ice would melt. This needs to be revisited five days from now on July 28th as a reality check.

Nice assessment of the Atlantic front, A-team. If this comes about, we could see a 128,000/5=25k/day additional melt from the Atlantic front alone.

Looking at seaicesailor's HYCOM drift animation over the next couple of days :
http://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1493.0;attach=33280;image
I can't stop to wander what this "temporary miniature dipole" will do on the Pacific front.

With off-shore drift speeds of over 30cm/sec, over - what is it - 1000 km front ? that suggests some 25k/day compaction of the ESS ice alone, even disregarding any melt.

Combined with the Atlantic front melting, it looks like we are in for an interesting little ride the next couple of days....
« Last Edit: July 24, 2016, 09:47:49 AM by Rob Dekker »
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Rob Dekker

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Re: The 2016 melting season
« Reply #3615 on: July 24, 2016, 09:57:47 AM »
SW input becomes more like 320W/m2 under clear sky but we have to distribute that (after taking away reflected 37%) in the ice so the top surface does not gain much (melt power) from clear sky I think.
edit: this is supported by the low air temperatures at Obuoy14 under clear sky seen again today.

 It isn't easy to see how much surface melt occurs from Obuoy images, we have seen the AOFB drop to the lowered surface earlier. The 36cm you quote for IMB2015F is mostly snow, which although is probably quite dense from being drifted about will be less dense than ice. The 80cm is as Jim explains probably a narrow gap along the buoy body taking energy from melt water or higher absorption by the buoy.

Thank you for your additional notes on 2015F's melting profile, and the observations from obuoy14. Much appreciated. Although I don't see that your assessment comes to a better explanation of the observed bottom melt in 2015F.

About top-melt : Indeed I'm surprised how Obuoy14's melting ponds still freeze over, despite what you assess as 320 W/m^2 SW input, and the fact that it is close to (or inside) the melting zone. I remember quite a different scenario in other Obuoys in the melting zone from past years in July. Not sure what is going on there, and why air temperatures are so cold this year.
« Last Edit: July 24, 2016, 10:35:48 AM by Rob Dekker »
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seaicesailor

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Re: The 2016 melting season
« Reply #3616 on: July 24, 2016, 10:20:09 AM »
...
Should this melt along the 1750 km front as the ice pack encounters above-freezing nullschool or hycom temperatures and salinities northward of the Barents sea, some 128,000 km2 of ice would melt. This needs to be revisited five days from now on July 28th as a reality check.

Nice assessment of the Atlantic front, A-team. If this comes about, we could see a 128,000/5=25k/day additional melt from the Atlantic front alone.
...
With off-shore drift speeds of over 30cm/sec, over - what is it - 1000 km front ? that suggests some 25k/day compaction of the ESS ice alone, even disregarding any melt.

Combined with the Atlantic front melting, it looks like we are in for an interesting little ride the next couple of days....
This is a bad July week. Add to the picture the ESS "bite" that has been advancing quietly thanks to the state of the ice after the storms.
This whole week is going to be hell in CAA as well.
Saturday then may end up with very warm air intrusions.
« Last Edit: July 24, 2016, 10:45:47 AM by seaicesailor »

seaicesailor

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Re: The 2016 melting season
« Reply #3617 on: July 24, 2016, 10:28:10 AM »
Update to
http://forum.arctic-sea-ice.net/index.php/topic,1493.msg84472.html#msg84472
Curious to see what happens on Saturday 12Z, I post the updated GFS 850 mb air temperature prediction when it shows something interesting (this one does).
For the moment both GFS and EC have shifted the predicted quadri-pole in a way that worsens the WAA from America and mitigates the one from Asia.

seaicesailor

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Re: The 2016 melting season
« Reply #3618 on: July 24, 2016, 10:45:05 AM »
East Siberian Sea;then and now, difference in less than two weeks(July 12 vs. July 23)
There are other areas of growth too, if you look closely
The Laptev tongue is merging with the ESS bite.
The image also shows SSTs under CAA ice! I understand if the NOAA used sensor is infrared, the ice is perfectly opaque to it...

Andreas T

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Re: The 2016 melting season
« Reply #3619 on: July 24, 2016, 11:08:48 AM »
IR can not tell the difference between ice and water and sees the surface (including cloud ). Water temperatures are below ice temperatures in places so, unless there is some mask for ice from microwave sensors, temperature charts are a poor guide to where ice is covering the water.

JayW

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Re: The 2016 melting season
« Reply #3620 on: July 24, 2016, 02:24:40 PM »

Thank you Jay, the more frequent images shows more detail in the movement in the way that variations in speed during a day are shown. It also gives a better chance of seeing the ground between clouds. I am not clear what you mean by flow north east of Wrangel?
What stands out for me is the divergence of the ice in a large region further north towards the pole while near Wrangel there is a lot more ice than last year. The arrival of warm air shown by seaicesailor will test the strength of that.

Edit: bad gif, sorry, had to tidy it up.

It's my pleasure, I added another 24 hours. 104 hours total. The skies were pretty cooperative again.  First second attachment.

Hopefully my observations aren't too out there. :)

Actually, that divergent zone was the area I meant to describe, but did so poorly.  I added a second first attachment, it's the same gif, just zoomed into the area of interest.

As you mention, the "undulating" or perhaps "swaying" motion (just trying to find the right words to describe it) can be seen.  I attribute that motion largely to the winds.  But within that divergent zone, there apart to be little "swirls" perhaps eddies.  I'm not sure these can be explained by the wind, and ocean currents might be a better explanation for these. 

One thing I wonder, does the divergent allow these currents to develop?  Or are they quasi-stationary, and exist under the ice, only to be seen when the ice breaks up sufficiently?

One of my favorite things to look at is where the smallest pieces of ice, and especially the brash ice, interact with the eddies.  And how the swirls resemble fractals. 

Unfortunately, some resolution has to be sacrificed in order to post the animations, especially as the length grows.  I have the luxury of watching a slightly "prettier" animation than the forum gets to see.

http://feeder.gina.alaska.edu/search?utf8=✓&search%5Bsensors%5D%5B4%5D=1&search%5Bsensors%5D%5B3%5D=1&search%5Bfeeds%5D%5B5%5D=1&search%5Bstart%5D=&search%5Bend%5D=&commit=Search
« Last Edit: July 24, 2016, 02:30:54 PM by JayW »
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iceman

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Re: The 2016 melting season
« Reply #3621 on: July 24, 2016, 04:43:40 PM »
The images below look at the next five days of 'speed and drift' coarsely integrated over each km per day off Franz Josef which sums to roughly 76 km or 23 pixels of uneven advance across the polar front at the scale of AMSR2 3k.

Should this melt along the 1750 km front as the ice pack encounters above-freezing nullschool or hycom temperatures and salinities northward of the Barents sea, some 128,000 km2 of ice would melt. This needs to be revisited five days from now on July 28th as a reality check.
Nice assessment of the Atlantic front, A-team. If this comes about, we could see a 128,000/5=25k/day additional melt from the Atlantic front alone.
   ....

Indeed, very effective way of displaying the images.
I would expect melt rate to lag ice movement substantially: maybe only half the calculated amount over the 5-day interval (though with continued melt for a while afterwards).

seaicesailor

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Re: The 2016 melting season
« Reply #3622 on: July 24, 2016, 05:13:24 PM »

Thank you Jay, the more frequent images shows more detail in the movement in the way that variations in speed during a day are shown. It also gives a better chance of seeing the ground between clouds. I am not clear what you mean by flow north east of Wrangel?
What stands out for me is the divergence of the ice in a large region further north towards the pole while near Wrangel there is a lot more ice than last year. The arrival of warm air shown by seaicesailor will test the strength of that.

As you mention, the "undulating" or perhaps "swaying" motion (just trying to find the right words to describe it) can be seen.  I attribute that motion largely to the winds.  But within that divergent zone, there apart to be little "swirls" perhaps eddies.  I'm not sure these can be explained by the wind, and ocean currents might be a better explanation for these. 

One thing I wonder, does the divergent allow these currents to develop?  Or are they quasi-stationary, and exist under the ice, only to be seen when the ice breaks up sufficiently?

One of my favorite things to look at is where the smallest pieces of ice, and especially the brash ice, interact with the eddies.  And how the swirls resemble fractals. 

Jay, the eddies may happen because of the particular bathymetry of the Chukchi sea. There are "obstacles" in this shallow sea that create very particular flow structures and currents, maybe that explains the turbulence at the right side of the Wrangel Island in the pictures.
As for the waving of the open waters, I think it is due to the winds that first are trying to disperse the ice (because they are caused by a low pressure system over the area), later trying to compact them (because they are associated to high pressure system over the area). But just my 2c.

Quantum

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Re: The 2016 melting season
« Reply #3623 on: July 24, 2016, 06:54:05 PM »
Just for reference, the dates that the NW passage (southern and northern routes) and the northern route open for the last few years. I always think this is an interesting bit of information.

Reference for the NW passage routes above. Note in some cases the routes may close again, these are the approx dates they first opened.

2012
Southern NW route: August 9th
Middle NW route: July 31st
Northern NW route: August 27th
Northern route: August 4th

2013
Southern NW route: August 22nd
Middle NW route: Does not open
Northern NW route: Does not open
Northern route: August 29th

2014
Southern NW route: August 30th
Middle NW route: Questionably around September 14th
Northern NW route: Does not open
Northern route: August 7th

2015
Southern NW route: August 13th (taking a ridiculous maze like path around the ice though)
Middle NW route: September 8th
Northern NW route: September 8th
Northern route: July 31st

Andreas T

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Re: The 2016 melting season
« Reply #3624 on: July 24, 2016, 07:11:53 PM »
Jay W, looking at this animation produced by an ocean model the same swaying motion appears. I have a hunch that this is due to the pressure fluctuations the passing weather systems bring but I don't know whether the change in height in the ocean surface is enough to shunt water masses on that scale. The model animation does illustrate the complexities of ocean flows and the fact that rotation is a necessary feature in a flow which can not move water anywhere without making space for that water to move into.
Another place where that sloshing motion shows is in the buoy tracks such as http://obuoy.datatransport.org/monitor#overview/gpstracks zoom in on the top left and remove unwanted older tracks on the right.
apart from the larger scale irregular swaying, there are smaller scale tidal movements which show as a kind of corkscrew pattern

Andreas T

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Re: The 2016 melting season
« Reply #3625 on: July 24, 2016, 08:00:25 PM »
SW input becomes more like 320W/m2 under clear sky but we have to distribute that (after taking away reflected 37%) in the ice so the top surface does not gain much (melt power) from clear sky I think.
edit: this is supported by the low air temperatures at Obuoy14 under clear sky seen again today.

...

...

About top-melt : Indeed I'm surprised how Obuoy14's melting ponds still freeze over, despite what you assess as 320 W/m^2 SW input, and the fact that it is close to (or inside) the melting zone. I remember quite a different scenario in other Obuoys in the melting zone from past years in July. Not sure what is going on there, and why air temperatures are so cold this year.
sorry,I should have expressed more clearly that I meant 320 - (0.37 x 320) as input into meltponded ice ice and ocean. My point is that maybe half or more of this could go to bottom melt, then the surface looses 70W/m2 to IR radiation and some to cold air from open sea water / evaporation ? As ballpark figures it looks reasonable I think. Especially when around Obuoy14 albedo is probably higher than 0.37 after freezing of ponds during low sun angles and irradiance will be below July average now.
Have a look at the Obuoy10 video, I think it illustrates (better if there would not be a missing bit in summer 2015) that once surface melt has opened the ice for SW it is bottom melt which finishes off the floes even when the surface is getting fresh snow. In 2014 that opening was too brief and the floe survived almost at the same latitude.

Andreas T

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Re: The 2016 melting season
« Reply #3626 on: July 24, 2016, 09:14:10 PM »
Its not good manners to post three times in a row, I won't do it again (soon ;))
To go with seaicesailors map of currents I did a IR visible composite (to help identify clouds) of the Chukchi showing warm water along the Alaskan coast. This is mostly water warmed by runoff from land and shallow waters which have been ice free early, I dont think it came all the way through the Bering strait this quickly. But the effect of the current moving it towards the ice is clear I think.
On the Siberian side the effect of the remnants of thick ice we discussed earlier in the season are clear.
 There is also a patch of colder water in the centre. Whether that relates to bathymetry or is a coincidental allignment I won't try to guess.
worldview link http://go.nasa.gov/2al5tyF

seaicesailor

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Re: The 2016 melting season
« Reply #3627 on: July 24, 2016, 11:18:55 PM »
Yet another low that travels the same corridor as usual in 2016. This one however will drag the heat from North America, starting as early as 3 days from now. Apart from the usual mess it will cause on the floes.
We should paint the tracks of this season's lows, how tight most would fall along the same lane.

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Re: The 2016 melting season
« Reply #3628 on: July 25, 2016, 12:30:27 AM »
Just for reference, the dates that the NW passage (southern and northern routes) and the northern route open for the last few years. I always think this is an interesting bit of information.

Reference for the NW passage routes above. Note in some cases the routes may close again, these are the approx dates they first opened.

2012
Southern NW route: August 9th
Middle NW route: July 31st
Northern NW route: August 27th
Northern route: August 4th

2013
Southern NW route: August 22nd
Middle NW route: Does not open
Northern NW route: Does not open
Northern route: August 29th

2014
Southern NW route: August 30th
Middle NW route: Questionably around September 14th
Northern NW route: Does not open
Northern route: August 7th

2015
Southern NW route: August 13th (taking a ridiculous maze like path around the ice though)
Middle NW route: September 8th
Northern NW route: September 8th
Northern route: July 31st

Very nice, Quantum! Where did you get it from, if I may ask?
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Quantum

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Re: The 2016 melting season
« Reply #3629 on: July 25, 2016, 01:32:49 AM »
Just for reference, the dates that the NW passage (southern and northern routes) and the northern route open for the last few years. I always think this is an interesting bit of information.

Reference for the NW passage routes above. Note in some cases the routes may close again, these are the approx dates they first opened.

2012
Southern NW route: August 9th
Middle NW route: July 31st
Northern NW route: August 27th
Northern route: August 4th

2013
Southern NW route: August 22nd
Middle NW route: Does not open
Northern NW route: Does not open
Northern route: August 29th

2014
Southern NW route: August 30th
Middle NW route: Questionably around September 14th
Northern NW route: Does not open
Northern route: August 7th

2015
Southern NW route: August 13th (taking a ridiculous maze like path around the ice though)
Middle NW route: September 8th
Northern NW route: September 8th
Northern route: July 31st

Very nice, Quantum! Where did you get it from, if I may ask?
I went through all the AMSR2 maps and then used the world view satellite data to narrow it down when cloud wasn't covering the area. Its the best approximation I can do, so the dates may not be perfect.

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Re: The 2016 melting season
« Reply #3630 on: July 25, 2016, 01:44:14 AM »
I went through all the AMSR2 maps and then used the world view satellite data to narrow it down when cloud wasn't covering the area. Its the best approximation I can do, so the dates may not be perfect.

It may not be perfect, but it is.  :)

It's something that has been on my to-do list for years (I believe there's a paper out there somewhere as well), but I have a long to-do list.  ;)
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Re: The 2016 melting season
« Reply #3631 on: July 25, 2016, 02:07:20 AM »
Yet another low that travels the same corridor as usual in 2016. This one however will drag the heat from North America, starting as early as 3 days from now. Apart from the usual mess it will cause on the floes.
We should paint the tracks of this season's lows, how tight most would fall along the same lane.

A while back I speculated this may relate to tropical activity, and Rosby waves transmitting instability towards the poles and eastwards resulting in matching peaks in polar low pressure activity near Siberia and south of Australia eg upper level map.  The tropical activity is influence by a combination of ENSO and Indian Ocean influences.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

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Re: The 2016 melting season
« Reply #3632 on: July 25, 2016, 05:37:43 AM »
SIE just dropped over 77k km2 to drop the new total under 7 million. Nares is about to give and many places in main pack are loosening up more. If nothing happens to recompact soon,
I think more mobility will mean bigger losses.

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Re: The 2016 melting season
« Reply #3633 on: July 25, 2016, 07:55:50 AM »
Regarding the fast ice in North East Greenland. I have watched this for a number of years. I would point out that there appears to be a geologic feature a bit off the coast, something like a geologic ridge under water, that supports persistent, perennial ice. Essentially 'fast ice' but not exactly. (this is indicated by the relatively thick ice a bit off the coast).

This year, the melt in NE Greenland appears to be occurring somewhat early. It will be quite interesting to observe how it progresses up there.

Rob Dekker

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Re: The 2016 melting season
« Reply #3634 on: July 25, 2016, 08:13:47 AM »
SW input becomes more like 320W/m2 under clear sky but we have to distribute that (after taking away reflected 37%) in the ice so the top surface does not gain much (melt power) from clear sky I think.
edit: this is supported by the low air temperatures at Obuoy14 under clear sky seen again today.

...

...

About top-melt : Indeed I'm surprised how Obuoy14's melting ponds still freeze over, despite what you assess as 320 W/m^2 SW input, and the fact that it is close to (or inside) the melting zone. I remember quite a different scenario in other Obuoys in the melting zone from past years in July. Not sure what is going on there, and why air temperatures are so cold this year.
sorry,I should have expressed more clearly that I meant 320 - (0.37 x 320) as input into meltponded ice ice and ocean. My point is that maybe half or more of this could go to bottom melt, then the surface looses 70W/m2 to IR radiation and some to cold air from open sea water / evaporation ? As ballpark figures it looks reasonable I think. Especially when around Obuoy14 albedo is probably higher than 0.37 after freezing of ponds during low sun angles and irradiance will be below July average now.

Thanks Andreas. This triggered something which I think may be important :
If Insolation is 320 W/m^2 and IR imbalance is -70 W/m^2 then any surface that has an albedo of  0.8 (1 - 70/320) or higher will actually COOL the air above it.

Now, in the Beaufort, we just had that storm from last week which (I think it was seaicesailor that asserted that) deposited some fresh snow over the entire area.

Some of that fresh snow is visible on the Obuoy14 camera and also on the Healy's web cam.

Of course, nearby water has a very low albedo, and thus will absorb more heat than it emits, for a long time to come (at least until September), and will cause bottom-melt on the ice flows around it.
But for top-melt, if this fresh snow cover has an albedo of over 0.8 then it might just explain why the melting ponds on the Obuoy14 flow is freezing over (at least on the edges).

Even more general : The storm from last week must have increased the albedo of the ice floes in the entire Beaufort/Chukchi/ESS area, and may have halted top-melt to the point where even isolated melting ponds freeze over due to the surrounding high-albedo snow cover.

I think there is something to that, and it suggests that the effects of a cold storm like the one from last week significantly alters the top-melt situation (and thus its "melting momentum") for long after it is gone. Although bottom-melt due to nearby open ocean water will continue virtually unimpeded.
« Last Edit: July 25, 2016, 08:52:58 AM by Rob Dekker »
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Andreas T

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Re: The 2016 melting season
« Reply #3635 on: July 25, 2016, 12:21:44 PM »
Regarding the fast ice in North East Greenland. I have watched this for a number of years. I would point out that there appears to be a geologic feature a bit off the coast, something like a geologic ridge under water, that supports persistent, perennial ice. Essentially 'fast ice' but not exactly. (this is indicated by the relatively thick ice a bit off the coast).

This year, the melt in NE Greenland appears to be occurring somewhat early. It will be quite interesting to observe how it progresses up there.
The Zachariae Isstrom thread is worth looking through from the start and has accumulated lots of background information (much of it provided by Espen) over the last 3 years e.g.
http://forum.arctic-sea-ice.net/index.php/topic,400.msg10519.html#msg10519

Sidd has collected bathymetry too http://membrane.com/sidd/greenland-2013/Zachtrough
I remember Espen posting about a small island which anchors the piece of ice which always remained in place off the coast when most of the ice around it was moving, but can't find it right now.
edit some how messed up the links, sorry
There is another thread from late autumn 2013 which mentions that island, Tobias Oer
http://forum.arctic-sea-ice.net/index.php/topic,633.msg16551.html#msg16551
« Last Edit: July 25, 2016, 08:26:56 PM by Andreas T »

JayW

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Re: The 2016 melting season
« Reply #3636 on: July 25, 2016, 12:23:10 PM »
I think I got too ambitious.  Here's one month, June 24-July 23, 2016.  I tried using just one frame per day, but wasn't really pleased with the outcome.  Instead I opted for two frames per day.  I also tried to get as much "real estate" in the shot as possible.  It ended up being like 60mb.  I finally got it down to a size where it could be posted.

Hope it's satisfactory.
http://feeder.gina.alaska.edu/search?commit=Search&search%5Bend%5D=&search%5Bfeeds%5D%5B5%5D=1&search%5Bsensors%5D%5B3%5D=1&search%5Bsensors%5D%5B4%5D=1&search%5Bstart%5D=&utf8=
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pauldry600

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Re: The 2016 melting season
« Reply #3637 on: July 26, 2016, 12:24:10 AM »
Looking at Uni Bremen ice seems to have taken a curious shape of an arrow pointing to the Southeast.

Is this a clue to our destiny this melt season?

Nightvid Cole

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Re: The 2016 melting season
« Reply #3638 on: July 26, 2016, 01:51:00 AM »
For some reason, Environment Canada's cloud free mosaic seems stuck on the week ending July 4. I looked at the ECMWF's forecast for the next 10 days and it shows that low just bouncing around the arctic, so it will likely be overcast for much of the time over most of the central Arctic. I badly wish we could get a few clear days to see what shape the ice is in on MODIS. :(

Nick_Naylor

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Re: The 2016 melting season
« Reply #3639 on: July 26, 2016, 03:21:18 AM »
Is this a clue to our destiny this melt season?

Absolutely, and it's meaning will make itself known to us in the coming weeks.

ghoti

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Re: The 2016 melting season
« Reply #3640 on: July 26, 2016, 06:11:23 AM »
I think I'm seeing Radarsat mosaics from July 15-18th tonight...

For example:
http://ice-glaces.ec.gc.ca/cgi-bin/getprod.pl?prodid=IPYMMR1EA&wrap=1&lang=en

Is that working now for you?

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Re: The 2016 melting season
« Reply #3641 on: July 26, 2016, 09:50:41 AM »
Weather forecasts predict warmth entering from North America first Alaska then from CAA during a whole week. The forecasts both ECMWF and GFS for Sat are pretty much the same as 3 days ago, warmth entering from Asia too.
Then they predict a massive, huge inflow of warm air from Alaska and Pacific that is beyond unreliable.
All in all a bad week, this low is dragging a lot of heat, it may look different at first glance.

binntho

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Re: The 2016 melting season
« Reply #3642 on: July 26, 2016, 10:18:20 AM »
The Arctic in turmoil. 31st July 00Z on Nullschool
« Last Edit: July 26, 2016, 12:33:39 PM by binntho »
because a thing is eloquently expressed it should not be taken to be as necessarily true
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seaicesailor

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Re: The 2016 melting season
« Reply #3643 on: July 26, 2016, 12:07:46 PM »
The Arctic in turmoil. 31st August 00Z on Nullschool
You mean July 31?
The image shows South winds strong in CAA, Laptev, ESS, weak in Chukchi. Export to Barentz.

This week could see also ice export to Barentz's CAB sector.

binntho

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Re: The 2016 melting season
« Reply #3644 on: July 26, 2016, 12:34:47 PM »
The Arctic in turmoil. 31st August 00Z on Nullschool
You mean July 31?
Absolutely! Thanks for pointing this out, I've edited to the correct date.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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Jim Hunt

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Re: The 2016 melting season
« Reply #3645 on: July 26, 2016, 12:56:32 PM »
The low pressure area currently hovering over the Northern Sea Route seems to have bottomed out at 988 hPa:
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slow wing

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Re: The 2016 melting season
« Reply #3646 on: July 26, 2016, 01:48:00 PM »
Yep, Jim, the ECMWF forecast has 988 hPa as the lowest.

However, the low above it is ready to follow it down this year's 'storm alley' - from the Siberian side down to the Beaufort Sea. That next one is currently predicted to bottom out in 120h, at 981 hPa in the Laptev Sea, then to hold to 986 hPa at 192h, by then in the Beaufort and CAB.

There is a lot of ridging throughout the animation - i.e. closely spaced isobar lines - which will correspond to windiness.

The lows ridge against several highs, with the strongest one - over Greenland - predicted to top out in 96h at 1040 hPa.

Hopefully I can attach the gif that is made with Tropical Tidbits' handy built in gifmaker. Site:
http://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=nhem&pkg=z500_mslp&runtime=2016072600&fh=12&xpos=0&ypos=0

UPDATE: I can't get it to run (how about you?). It may be too big. Will just leave it as people can instead click on the site link to run the animation.
« Last Edit: July 26, 2016, 01:59:17 PM by slow wing »

A-Team

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Re: The 2016 melting season
« Reply #3647 on: July 26, 2016, 02:44:59 PM »
In #3612, the next five days of Hycom 'speed and drift' -- as anticipated by seaicesailor, SharedH and jdallen -- should have reversed the northward track of the polar front above Svalbard and Franz Josef by now. Indeed that seems to be the case so far three days in (1st animation).

The polar front this year aligns remarkably well with the plunge line of continental shelf bathymetry, which could be seasonal coincidence or more interestingly a consequence of the ongoing 'Atlantification' trend in the Barents Sea, followed by increasing ice pack melt from warmer saltier Atlantic Waters cascading down the shelf into their-density-appropriate depth in the Nansen Trough along with return water mixing.

A couple of oceanography papers address this cascading, which is not uniform along the polar front but associated primarily with the St Anna Trough bathymetry; the second animation shows some maps from a 2007 presentation of V Ivanov and P Golovin who write:

Quote
Cascading is a specific type of buoyancy driven current, in which dense water formed by cooling, evaporation or freezing in the surface layer over the continental shelf descends down the continental slope to a greater depth.

The general concept of cascading (shelf/slope convection) was formulated by Fritjof Nansen (1906). He was also the first to make direct measurements of cascading over the Rockall Bank in the North Atlantic Ocean (Nansen, 1913).

In the Arctic Ocean cascading is normally fed by salty/denser water, which forms over the shallow shelf areas inside the openings in the ice cover in winter. These openings, known as polynyas, are created by favorable wind which cracks fast ice and moves it offshore. Vertical heat flux from the ocean to the atmosphere in polynyas has the scale of hundreds of watts per square meter, which is about two orders of magnitude higher than the vertical flux through the surrounding fast and pack ice
.
As a result of this huge vertical heat flux water in polynyas rapidly freezes up forming frazil and surface ice. The brine, which is released during this process admixes to the water making the water column inside polynya saltier/denser than the surrounding water.

This denser water starts moving off shelf, cascading down slope under the influence of gravity force and then is deflected to the right (along the slope) by the Coriolis forcing. Various types of instability affect the dense water flow. The major one is baroclinic instability, which causes meandering and eddy formation.

In the stratified Arctic Ocean descending dense water does not normally reach the base of the slope. At the depth, where the density in the water ‘plume’ equalizes the density of the ambient water, the plume detaches of slope intruding into the water column. This depth is often referred as the ‘equilibrium density level’. http://research.iarc.uaf.edu/DWC_Laptev/introduction.php 2007
Quote
Atlantic water flow into the Arctic Ocean through the St. Anna Trough in the northern Kara Sea: The Atlantic Water flow from the Barents and Kara seas to the Arctic Ocean through the St. Anna Trough (SAT) is conditioned by interaction between Fram Strait branch water circulating in the SAT and Barents Sea branch water—both of Atlantic origin.

A distinct vertical density front over the SAT eastern slope deeper than ~50 m is attributed to the outflow of Barents Sea branch water to the Arctic Ocean. In turn, the Barents Sea branch water flow to the Arctic Ocean is conditioned by two water masses defined by relative low and high fractions of the Atlantic Water. They are also traceable in the Nansen Basin downstream of the SAT entrance.

A persistent northward current was recorded in the subsurface layer along the SAT eastern slope with a mean velocity of 18 cm/s at 134–218 m and 23 cm/s at 376–468 m. Observations and modeling suggest that the SAT flow has a significant density-driven component. It is therefore expected to respond to changes in the cross-trough density gradient conditioned by interaction between the Fram Strait and Barents Sea branches. Further modeling efforts are necessary to investigate hydrodynamic instability and eddy generation caused by the interaction between the SAT flow and the Arctic Ocean Fram Strait branch water boundary current.
http://eprints.soton.ac.uk/379601/ I Dmitrenko 2015
Quote
Current research on the West Spitsbergen Current focuses in on two areas: heat content and methane gas release. Atlantic Water core temperature associated with the WSC has increased by almost 1 °C in recent year; AW core temperature decrease moving cyclonically around the Arctic. This means that heat is being lost to the surrounding water.

As the temperature of AW water is increased, even more heat will be lost to the surrounding water as the WSC moves around under the Arctic Ocean. If the heat flux out of the Atlantic Water core in the WSC is vertically upward then that would lead to warming of the Arctic Surface Water and the melting of more Arctic Sea Ice. https://en.wikipedia.org/wiki/West_Spitsbergen_Current
« Last Edit: July 27, 2016, 12:37:01 AM by A-Team »

A-Team

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Re: The 2016 melting season
« Reply #3648 on: July 26, 2016, 03:00:22 PM »
Quote
UPDATE: I can't get it to run (how about you?). It may be too big
It can't run, as only the first frame of the animation was captured/uploaded, though the Tropical Tidbits link works fine (but for how long?) and is nicely done. 700x700 pixels is the maximal size that will run here without a click.
« Last Edit: July 26, 2016, 03:05:42 PM by A-Team »

slow wing

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Re: The 2016 melting season
« Reply #3649 on: July 26, 2016, 03:06:22 PM »
Thanks A-Team, very kind of you to tidy up the gif.  :D