The 2018 melting season

[Archimid]

There is volume loss in the CAB during June according to PIOMAS.

[A-Team]

The last 26 days of Ascat are shown below 'as is' and as multi-step enhanced. It is feasible to take the latter one step farther with AMSR2 masking of weather artifacts over open water though simultaneity of swath timing would be an issue.

On some days, a circularly widening wave pattern can be seen in the UR corner (white arrows, 2nd mp4), as if someone dropped a rock off the ice edge of the Chukchi. While standing wave patterns are commonly seen in Arctic cloud sets, the observed Ascat patterns have no counterpart in WorldView visible or infrared so these apparently are in the water.

Note in the LL corner, ice has been rotating in to the Mackenzie delta area from the 'Beaufort Gyre' region, then moving west up the Alaskan coast, meaning that a time series of AMSR2 concentration is not looking at the 'same' ice (as Oren noted up-forum).

In the LR corner, the Kara tongue extrusion is coming back into view. The record open water above Svalbard is only partly attributable to its dispersion, melt and export through SV-FJL-SZ. However the remnants may be next in line to melt (bringing open water to 84ºN), though AMSR2 is still seeing 100% concentration (3rd image) despite the re-whitening in Ascat.

It appears that the next open water in the Beaufort-Chukchi will not include ice off the central Alaskan coast which was entirely sourced by Amundsen Bay export. The main NW Passage is also headed for an early opening as seen in consistent blueing in AMSR2. June 27th of this year is not remarkable in the 2013-2017 context. (UH AMSR2 3.125 km for 2012 first becomes available on Aug 1st.)

The ImageJ enhancement steps used in 32-bit mode are global brightness/contrast, bicubic enlargement, local contrast, unsharp mask, and invert. False color visualizatiions are no longer useful as the correlation between ice age and Ascat roughness has largely been lost.

[Pagophilus]

aperson, I really liked your HYCOM SSS map -- it seems extremely useful to me, especially when tracking, as you do, the invasion of Atlantic waters into the Arctic.  One request and one question, which I hope you will forgive from a non-expert:
Could you please give the url for this map? (I could not track it down, I got to the NASA Aquarius site and could not get further)
And... how do they obtain Sea Surface Salinity values for the ice-covered areas of the Arctic?   (I assume that ice is largely freshwater, so....)  And further to that, this does not appear to be an anomaly, but an absolute value scale (units for this scale would be great too).

 

Here is HYCOM Sea Surface Salinity from 2014 - 2018 (July 1st used for 2014 as nearest reference date, click to animate). The major change we see this year is the Atlantification of the Barents sea. Regardless of how melting season progresses, my opinion is that this will affect freezing season next year greatly.

[FishOutofWater]

The sea surface salinity maps show the effects of melting ice in the melt season.  Therefore, they are not useful for determining where the Atlantic and Pacific waters are flowing into the Arctic in areas where ice is melting. Those maps should be interpreted very cautiously.

[Pagophilus]

Thank you, A-Team.  Great animations.  One thing that strikes me is something that has NOT changed much. 

The edge of the ice pack between north-east Greenland running out to Franz Josef Land has been virtually stationary over the past ten days or so.  This despite all warming in the Atlantic, the Atlantification in this area, the apparent strengthening of the North Atlantic Current branch around Svlabard, the increased salinity of the surface waters etc.  Nor, from your animations, does there seem to have been any great drift either direction happening in this area.  Are the floes just thick and stationary in this area, and slow to melt out?  Is the insolation so small at this high latitude that surface melting is also minimal?  Expert opinion appreciated!

PS Is this area of ice the Kara tongue -- and does that mean it was previously extruded from the Kara?

 

The last 26 days of Ascat are shown below 'as is' and as multi-step enhanced. It is feasible to take the latter one step farther with AMSR2 masking of weather artifacts over open water though simultaneity of swath timing would be an issue.

[johnm33]

Pagophilus https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/skill.html

[RoxTheGeologist]

Thank you, A-Team.  Great animations.  One thing that strikes me is something that has NOT changed much. 

The edge of the ice pack between north-east Greenland running out to Franz Josef Land has been virtually stationary over the past ten days or so.  This despite all warming in the Atlantic, the Atlantification in this area, the apparent strengthening of the North Atlantic Current branch around Svlabard, the increased salinity of the surface waters etc.  Nor, from your animations, does there seem to have been any great drift either direction happening in this area.  Are the floes just thick and stationary in this area, and slow to melt out?  Is the insolation so small at this high latitude that surface melting is also minimal?  Expert opinion appreciated!

I'll attempt to answer that:
The edge of the pack is determined *largely* by the bathymetry (A-Team produced nice graphics to demonstrate this last year); The warmer Atlantic waters are much denser than the polar surface, that is freshened both by ice melting and by the large Arctic rivers. As soon as the Atlantic water hits the continental slope, it drops below the surface to form a layer at about 300m deep that circulates counter-clockwise around the Nansen Basin. The ice above is preserved by a cold, freshwater lens that covers much of the Arctic ocean.

This year is unusual in that the ice edge is over the abyssal plane north of Svalbard. It suggests that the warmer saline Atlantic is encroaching into the Arctic proper, and that, worryingly, the Pycnocline is breaking down locally. Thin, briny, first year ice that is becoming the norm in the Arctic is not as effective at preserving the pycnocline (less volume of saltier melt water) and may be contributing to the encroachment.

[Tor Bejnar]

... Could you please give the url for this map? ...

Aperson's map's link:  https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html

My browser claims "This site isn't secure", but I go there anyway. 

For similar maps of just the Beaufort Sea: https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/beaufort.html

[Pagophilus]

Wow.  That was fast.  Thank you kindly, johnm333, Rox and Tor Bejnar.  Rox, your concise explanation of the situation was eye-opening for me -- thanks for taking the time.

  Expert opinion appreciated!

I'll attempt to answer that:
The edge of the pack is determined *largely* by the bathymetry (A-Team produced nice graphics to demonstrate this last year); The warmer Atlantic waters are much denser than the polar surface, that is freshened both by ice melting and by the large Arctic rivers. As soon as the Atlantic water hits the continental slope, it drops below the surface to form a layer at about 300m deep that circulates counter-clockwise around the Nansen Basin. The ice above is preserved by a cold, freshwater lens that covers much of the Arctic ocean.

This year is unusual in that the ice edge is over the abyssal plane north of Svalbard. It suggests that the warmer saline Atlantic is encroaching into the Arctic proper, and that, worryingly, the Pycnocline is breaking down locally. Thin, briny, first year ice that is becoming the norm in the Arctic is not as effective at preserving the pycnocline (less volume of saltier melt water) and may be contributing to the encroachment.

[Pagophilus]

Hyperion, there may be something I am missing, but the "warm wet low-level winds" you cite blowing between Svalbard and Pole have been mostly between 0 C - 2 C, exceptionally around 3 C (source: nullschool).  Such winds are likely to carry low to very low amounts of water vapor.  This, combined with the low thermal gradients involved, seem to me to indicate that any wetting effect from these winds would not be a determining factor.  My understanding is that for surface melting, solar insolation and related albedo effects are paramount.  Would it not be more useful to track insolation than surface winds in this circumstance?

 

We have seen this week how several days of warm wet low level wind from the South made the pack between Svalbard and the pole look thicker on SMOS, when it most certainly was wetting the surface and melting it. Now a couple of days of northerlies in the area and the dispersion southwards gives the reverse:

[Hyperion]

The insulation is efficiently absorbed by the large water droplets in the fog, that evaporate some.  Then the vapour is rolled down onto the surface where the vapour condenses, releasing its energy, by wind waves that act like rollers on a beach. It was much warmer aloft. The near surface temperatures get pinned down by the energy being absorbed by melt and warming of exposed water. This is a very effective way of transferring insulation energy from a much larger area further south. Even a little moisture in the air means it takes a lot more energy to raise its temp by a given number of degrees than dry air of the same mass. Even without the phase change. The specific heat capacity of water is very high.

[uniquorn]

Where exactly was that buoy when bottom melting started?

According to hyperion's link to 2017B_clean.csv
date when bottom melt appeared to start
06/18/2017 00:00   86.64462   -2.7782   GPS

[Frivolousz21]

I said almost never.

That's one buoy showing almost no melt in June of last year. 

It also shows there was no snow cover.  Which isn't normal.

Please show evidence of the substantial slush pool over the CAB.

[Frivolousz21]

There is volume loss in the CAB during June according to PIOMAS.

That shows a nearly negligible amount of June volume loss.

[Archimid]

About as much as in September.

[Pagophilus]

Hyperion, my main point was that solar insolation is a much more important thing to track than surface winds of this nature.   I appreciate your argument regarding fog below, but do we have any sound evidence of such widespread, persistent fogs over the past month or so?  In addition, this area north of Greenland has been pretty cloudy, and that generally inhibits surface melting, and it also inhibits solar energy reaching any such surface fogs. 

I am curious as to whether others think the mechanism you describe is likely to be a significant one for Arctic ice.  If it is, we should consider it carefully.   

The insulation is efficiently absorbed by the large water droplets in the fog, that evaporate some.  Then the vapour is rolled down onto the surface where the vapour condenses, releasing its energy, by wind waves that act like rollers on a beach. It was much warmer aloft. The near surface temperatures get pinned down by the energy being absorbed by melt and warming of exposed water. This is a very effective way of transferring insulation energy from a much larger area further south. Even a little moisture in the air means it takes a lot more energy to raise its temp by a given number of degrees than dry air of the same mass. Even without the phase change. The specific heat capacity of water is very high.

[Michael Hauber]

I'm a bit late to the friv bashing session.  But I'll add that if the ice isn't freezing, it is melting.  The ocean below is always warm enough to melt the ice, and freezing only happens when the air above is far enough below 0 to more than balance out the slow addition of energy from below.  I would say that there is never any freezing happening in June, and that the ice north of 80N is basically always melting in June, but that the melting except possibly in rare circumstances (and near the Atlantic edge around Svalbaard) is too small to matter.

[uniquorn]

edited from 2017B_clean.csv

Date                          Latitude    Longitude Ice Thickness (m)
06/01/2017 00:00   86.91893   -0.40262           1.9
06/30/2017 20:00   85.48884   3.60228            1.76

Definitely not wanting to bash anyone, just posting buoy data.

[Pagophilus]

The Chukchi and Beaufort are getting that hollow, blue-grey look that comes of too many hard nights days out.   

Both Worldview images are slightly tweaked for contrast.  I realize the Atlantic side is largely cloaked in cloud right now, so in the second image, at top middle the remaining (cloud free) Laptev fast ice can be referenced for a rough color comparison. 

Maybe both these seas might melt out faster than some of us expect?

I also have a nagging feeling the first Worldview image must have been doctored - have the British Isles ever been completely free of cloud?

[Pagophilus]

I know that it is overwhelmingly likely that you are correct, Michael, but I have a novice's question to ask.  If the Arctic ice is fresh, then its melting point is 0 C, I presume.  If the ocean water below is saltwater, then it can be up to -1.8 C, which means that it is then colder than the melting point of freshwater ice.  So in this simplistic formulation, the ice should not melt -- it should even form during these conditions at the bottom of the ice, even without a lot of heat being sucked way at the interface between the ice and the atmosphere.  Now, I suspect that salinity/entropy has got something to say here, but what exact physical principle is at work?  Is it ultimately entropy -- that the salt ions and water molecules will tend to become as mixed as possible?  And/or is it that the ice has a lot harder time growing when salt ions are present?  Or... (I often discover something I never thought of...)   

I'm a bit late to the friv bashing session.  But I'll add that if the ice isn't freezing, it is melting.  The ocean below is always warm enough to melt the ice, and freezing only happens when the air above is far enough below 0 to more than balance out the slow addition of energy from below.  I would say that there is never any freezing happening in June, and that the ice north of 80N is basically always melting in June, but that the melting except possibly in rare circumstances (and near the Atlantic edge around Svalbaard) is too small to matter.

[Michael Hauber]

I know that it is overwhelmingly likely that you are correct, Michael, but I have a novice's question to ask.  If the Arctic ice is fresh, then its melting point is 0 C, I presume.  If the ocean water below is saltwater, then it can be up to -1.8 C, which means that it is then colder than the melting point of freshwater ice.  So in this simplistic formulation, the ice should not melt -- it should even form during these conditions at the bottom of the ice, even without a lot of heat being sucked way at the interface between the ice and the atmosphere.  Now, I suspect that salinity/entropy has got something to say here, but what exact physical principle is at work?  Is it ultimately entropy -- that the salt ions and water molecules will tend to become as mixed as possible?  And/or is it that the ice has a lot harder time growing when salt ions are present?  Or... (I often discover something I never thought of...)   

I hadn't thought about that angle.  The salty water below would not freeze and neither would the ice melt.  It is the multi-year ice that is fresh and the first year ice is much saltier, and there is a good amount of first year ice north of 80N. 

Looking through some MODIS images, channel 3-6-7 shows quite a lot of red in the high Arctic at the end of June in 2007,2008, 2010, 2011, 2012, so some substantial surface melt.

Current conditions - its almost a tale of two Arctics.  The Pacific side has some significant ice dispersal deep in the Beaufort, and plenty of red suggesting surface melt.  From Greenland towards Laptev there is quite an area of solid looking ice that is still supporting a crack/lead pattern instead of separating out into individual floes, and little reddening/surface melt.  I'd say the Pacific side is well on the way to a major meltout, and the Atlantic side will hold up quite well, suggesting that an extreme outcome in either direction is less likely than normal this year.

[slow wing]

... If the ocean water below is saltwater, then it can be up to -1.8 C, which means that it is then colder than the melting point of freshwater ice. ...

Isn't this a simple sign mistake? Instead, the ocean water can be down to -1.8 C. It can be warmer than that.

At the interface, the ice is always at the same temperature as the sea water just below it as they are in thermal contact. So both are anywhere between 0 and -1.8 C.

In winter the ice is cooled from above until the bulk ice gets colder than the ocean water at the interface and then progressively freezing it - bottom freezing - that's how the ice gets thicker.


In summer the ice is heated from above. Once all the ice is above the temperature of the interface (getting progressively cooler going from the surface to the water interface, though all between 0 and -1.8 C) then bottom melting will start due to the salt ions in the liquid water compromising the ice lattice structure at the interface - bottom melting - making the ice thinner.


This interface melting will start at some temperature between 0 and -1.8 C, depending on how saline the ocean water is at the interface.

[Brigantine]

In the Beaufort Gyre salinity is currently more like 28 PSU so the freezing point is ~-1.6C.

In the middle layers of the ice, you can get brine channels enlarging slightly (via a small amount of ice melt), when the temperature increases from -20C to -19C.
(As the brine channels enlarge, the salinity drops quickly, and the melting point rises to the current ice temperature.)

[Pagophilus]

Thank you all.  It makes more sense now, esp. with slow wing's explanation.  It seems that first year/young ice is a very complex issue.   And yes, I meant down to -1.8 C.  Will try to remember my number line in future. 

... If the ocean water below is saltwater, then it can be up to -1.8 C, which means that it is then colder than the melting point of freshwater ice. ...

Isn't this a simple sign mistake? Instead, the ocean water can be down to -1.8 C. It can be warmer than that.

At the interface, the ice is always at the same temperature as the sea water just below it as they are in thermal contact. So both are anywhere between 0 and -1.8 C.

In winter the ice is cooled from above until the bulk ice gets colder than the ocean water at the interface and then progressively freezing it - bottom freezing - that's how the ice gets thicker.


In summer the ice is heated from above. Once all the ice is above the temperature of the interface (getting progressively cooler going from the surface to the water interface, though all between 0 and -1.8 C) then bottom melting will start due to the salt ions in the liquid water compromising the ice lattice structure at the interface - bottom melting - making the ice thinner.


This interface melting will start at some temperature between 0 and -1.8 C, depending on how saline the ocean water is at the interface.

[Kate]

The Chukchi and Beaufort are getting that hollow, blue-grey look that comes of too many hard nights days out.   



I also have a nagging feeling the first Worldview image must have been doctored - have the British Isles ever been completely free of cloud?

What a strange thing to add to an otherwise good post

[Pagophilus]

The Chukchi and Beaufort are getting that hollow, blue-grey look that comes of too many hard nights days out.   

I also have a nagging feeling the first Worldview image must have been doctored - have the British Isles ever been completely free of cloud?

What a strange thing to add to an otherwise good post

Ah, yes, attempts at humor -- sorry about that, they keep creeping in, no matter how hard I try to resist. Would it help to say that the line was crafted in the spirit of Flanders and Swann's song: 'The English Weather'? 

No, I thought not.  But please listen to the song sometime -- it is rather funny.

[Aluminium]

June 24-28.

[Rob Dekker]

I also have a nagging feeling the first Worldview image must have been doctored - have the British Isles ever been completely free of cloud?

What a strange thing to add to an otherwise good post

Ah, yes, attempts at humor -- sorry about that, they keep creeping in, no matter how hard I try to resist. Would it help to say that the line was crafted in the spirit of Flanders and Swann's song: 'The English Weather'? 

As Neven recently stated : "Jokes are dangerous in serious discussions (and need plenty of emoticons or 'this is a joke' signs)."

This is especially true since ClimateGate when climate science deniers accused the official records of being "doctored".

So that is kind of a sensitive item among the science oriented people here on this forum.

[Frivolousz21]

The 00Z is quite interesting.

Definitely would be a game changer

[aperson]

The 00Z is quite interesting.

Definitely would be a game changer

There's definitely an opportunity for a real 1030+ hPa dome instead of the weenie ones that keep showing up. Models are in pretty major disarray regarding how they handle the tropospheric polar vortex even as early as t=96 though. Small changes in modeled potential vorticity are going to result in big differences in terms of how strong the dome is and how much warm air is advected.

00z GFS vs ECMWF provided below to show the spread in modeling at t=144. I think there's agreement that areas will see high pressure ridges up to 1030hPa, but I think there's a lot of uncertainty as to whether we get a cloud-free dome and where it sets up if it does (Beaufort vs Chukchi)

[oren]

June 24-28.

Thanks.
Interesting developments all around - the Chukchi warm water reared itd head and attacked the ice all around, I guess the winds shifted. Laptev polynia resumed its growth. And Fram export seems to have picked up. All signs of a melting season still not given up.
Poor Pagophilus - I got the joke immediately, but an icon could have helped clarify   

[psymmo7]

Yes - poor Pagophilus.

It's a shame that the meaning of words has become so debased by "deniers" of various kinds that humor must take a back seat.

The Flanders and Swann song Pagophilus refers to is  actually called "A song of the weather", but Britons will recognisae it as referring to "their" weather.

It can be heard here:

[cesium62]

Interesting developments all around - the Chukchi warm water reared itd head and attacked the ice all around, I guess the winds shifted. Laptev polynia resumed its growth. And Fram export seems to have picked up. All signs of a melting season still not given up.

The Slater Probabilistic Prediction today looks like a Nuke went off on the Greenland half of the CAB.  It's currently predicting extent below the September minimum of 2013 and 2014, but in the middle of August of 2018.  No doubt the glitch will be gone tomorrow...

[Hyperion]

Fascinating myself watching what these steam hose southerly, and meltwater flushing northerly low altitude winds have been doing to the Sea surface temperature anomalies. It really is a washing machine on the Atlantic Front. Last ten days with today's winds frozen before it loops. What will today's SSTA look like tomorrow?...

[Richard Rathbone]

Interesting developments all around - the Chukchi warm water reared itd head and attacked the ice all around, I guess the winds shifted. Laptev polynia resumed its growth. And Fram export seems to have picked up. All signs of a melting season still not given up.

The Slater Probabilistic Prediction today looks like a Nuke went off on the Greenland half of the CAB.  It's currently predicting extent below the September minimum of 2013 and 2014, but in the middle of August of 2018.  No doubt the glitch will be gone tomorrow...

NSIDC data is compromised due to satellite testing at the moment http://nsidc.org/arcticseaicenews/

Products that depend on it, such as the Slater projection, will also be compromised. The 27th is obviously badly wrong in several swaths, and 28th-29th are also at risk as are July 9-12th.

[Pagophilus]

Thank you, psymmo and oren for your sympathies.  I have perked up considerably now that you have actually posted the Flanders and Swann song on this illustrious forum.   I had been resisting the use of emoticons, but I now know the time has come to give in.  As to the song, my favorite verse is "In July, the sun is hot.  Is it shining?  No, it's not."  Really the question we face ourselves in this coming month in the Arctic.

Oh, and ...   



Later addition:  I should add, on a more serious note, that your point is taken too, Rob D.  I also need to remember that this is an international forum, which is wonderful, but it also means that we all have different baselines for humor or cultural references, myself included.  So, yeah ... emoticons...

 

Yes - poor Pagophilus.

It's a shame that the meaning of words has become so debased by "deniers" of various kinds that humor must take a back seat.

[Pagophilus]

Interesting developments all around - the Chukchi warm water reared itd head and attacked the ice all around, I guess the winds shifted. Laptev polynia resumed its growth. And Fram export seems to have picked up. All signs of a melting season still not given up.

Adding to that, the north Kara Sea hangs by a thread, and we appear to be edging closer to the open water in the Kara and Laptev Seas uniting, which seems significant to me.  There is a larger than normal amount of ice in the Hudson Bay and the south Kara Sea that is highly likely to melt out in the next month, and that provides some built-in 'catch-up' for area and extent losses.

Climate Reanalyzer predicts that the high that is currently over that delicate-looking Beaufort-Chukchi area, exposing it to constant insolation, is going to hang around for another 5 days or so. Larger weather issues I leave to the experts...     

[Richard Rathbone]

Climate change = a song about the British weather 60 years ago can be used to refer to the Arctic today

[Pagophilus]

I have to ask, and I hope you don't mind briefly explaining, friv or aperson, what it is you as experts see here.  I get that there are zones of high pressure all around the Arctic right now, and it seems there is a low pressure zone trapped right in the middle.  Your comments seem to indicate that there is a risk of a high pressure zone/dome building up over the CAB area.  Is that correct?  And if so, why would this develop?  I would appreciate learning...

The 00Z is quite interesting.
Definitely would be a game changer

There's definitely an opportunity for a real 1030+ hPa dome instead of the weenie ones that keep showing up.

[Daniel B.]

Yes - poor Pagophilus.

It's a shame that the meaning of words has become so debased by "deniers" of various kinds that humor must take a back seat.

Yes, unfortunately too many are so thin-skinned that any potential negativism can be considered an attack on their person, and they demand repercussions.  People are too afraid to say anything that might be misconstrued, that sensitivity is winning out over accuracy, and subjectivism over objectivity.

[RikW]

Interesting developments all around - the Chukchi warm water reared itd head and attacked the ice all around, I guess the winds shifted. Laptev polynia resumed its growth. And Fram export seems to have picked up. All signs of a melting season still not given up.

The Slater Probabilistic Prediction today looks like a Nuke went off on the Greenland half of the CAB.  It's currently predicting extent below the September minimum of 2013 and 2014, but in the middle of August of 2018.  No doubt the glitch will be gone tomorrow...

It shows the same weird pattern as this picture:

The current NSIDC values are in all likeliness wrong , drop in area -750k. See also the delta map for the mess.

I expect a correction or withdrawal of the data.

[FishOutofWater]

The major stratospheric warming in February caused intense polar subsidence. The jet stream then pushed out like it was an El Niño. It brought on a very cold stormy, snowy spring in the NE N America and brought on storms that moved from the N Atlantic into the Arctic. There is not good evidence yet of a shift to high pressure over the pole. It will likely be a pretty good year for sea ice despite the very thin ice visible in many areas on Worldview. When low pressure systems lift up air that's been cooled by ice water the low to mid level air column is going to be cold.

[bbr2314]

The major stratospheric warming in February caused intense polar subsidence. The jet stream then pushed out like it was an El Niño. It brought on a very cold stormy, snowy spring in the NE N America and brought on storms that moved from the N Atlantic into the Arctic. There is not good evidence yet of a shift to high pressure over the pole. It will likely be a pretty good year for sea ice despite the very thin ice visible in many areas on Worldview. When low pressure systems lift up air that's been cooled by ice water the low to mid level air column is going to be cold.

The only problem with your thesis is that the "ice water" cooled air is ending up in Africa instead of the Arctic...

In fact I would suggest that it is aiding advection of Saharan airmasses N into / over Europe and is directly responsible for the record-worst ATL front this year. Again, the ATL front is record worst, so I do not see how your argument ^ supports "retention" when we are already seeing the exact opposite occur.

[RoxTheGeologist]

I'm a bit late to the friv bashing session.  But I'll add that if the ice isn't freezing, it is melting.  The ocean below is always warm enough to melt the ice, and freezing only happens when the air above is far enough below 0 to more than balance out the slow addition of energy from below.  I would say that there is never any freezing happening in June, and that the ice north of 80N is basically always melting in June, but that the melting except possibly in rare circumstances (and near the Atlantic edge around Svalbaard) is too small to matter.

The cold surface mixed layer extended down to around 50-100 m in the Arctic, and basically insulated the ice from any bottom melt going on. the cold mixed layer would be more dense than the deeper warmer water, but it's supported by the halocline. The two don't mix. there is enough heat in the Atlantic waters to melt all the ice, but the heat doesn't get to the surface.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.834.7019&rep=rep1&type=pdf

[FishOutofWater]

The weather has been cold, cloudy and stormy on the Canadian side of the Arctic for the past 30 days. That's why that part of the Arctic looks white on satellite imagery now while it looked blue in Late June in 2012. The satellite photo shows sea ice melt ponds on the Canadian side of the Arctic ocean north of 80ºN on 20June 2012.

[Dharma Rupa]

The two don't mix. there is enough heat in the Atlantic waters to melt all the ice, but the heat doesn't get to the surface.

Um...Hasn't gotten.  It is my expectation that eventually it will get there, and that we will only know that after the fact.

[FishOutofWater]

The fresh water layer has broken down over the past year in the CAA. Ice and fresh water flowed into the Labrador sea and saltier water replaced it. Large channels like the Nares (which is starting to flow again) have northerly salty flows on the east side and southerly fresh flows on the west side.

Note that I show images from 1 year apart. That makes for an apples to apples comparison that doesn't have confusion caused by seasonal melting differences.

Mercator's 30m salinity maps are most helpful. The Mercator temperature maps are unhelpful at 30 and 100m because they don't have the level of detail needed to see subtle changes between negative 1 and negative 2 Celsius.

Note also that for the past year the salty Atlantic water intruded into the central Arctic very close to the north pole at a depth of 30m. The Atlantic side of the pole inside 80ºN does not have a protective fresh water layer above 300m any more.

[Pagophilus]

Thanks, Fish.  Looks like huge stuff to me -- it is scary to think of moving towards a world where warm, salty Atlantic water makes more and more contact with the Arctic ice.  I did not get the full impact of what you were writing about until I put the 2017 and 2018 images side by side, so forgive me if this seems too nitpicky, but I am reposting relevant sections of your images in that format here.  The CAA/Nares development looks serious.  Is the apparent 2018 'joining of the bridge' between the saline waters of the Atlantic and Pacific (if that is real) also of significance?   And one central question... is this below-ice information observed, or is it modeled, or is it modeled with interpolations from some observations?     

The fresh water layer has broken down over the past year in the CAA. Ice and fresh water flowed into the Labrador sea and saltier water replaced it. Large channels like the Nares (which is starting to flow again) have northerly salty flows on the east side and southerly fresh flows on the west side.

Note that I show images from 1 year apart. That makes for an apples to apples comparison that doesn't have confusion caused by seasonal melting differences.

Mercator's 30m salinity maps are most helpful. The Mercator temperature maps are unhelpful at 30 and 100m because they don't have the level of detail needed to see subtle changes between negative 1 and negative 2 Celsius.

Note also that for the past year the salty Atlantic water intruded into the central Arctic very close to the north pole at a depth of 30m. The Atlantic side of the pole inside 80ºN does not have a protective fresh water layer above 300m any more.

[michael sweet]

It appears that both of the ice arches in the Nares Strait have broken today.  The upper arch is collapsing and the lower arch has two very long cracks.

Sorry, I don't know how to post images.  I used Arctic.io explorer with the data set for 6/29. 

[bbr2314]

Thanks, Fish.  Looks like huge stuff to me -- it is scary to think of moving towards a world where warm, salty Atlantic water makes more and more contact with the Arctic ice.  I did not get the full impact of what you were writing about until I put the 2017 and 2018 images side by side, so forgive me if this seems too nitpicky, but I am reposting relevant sections of your images in that format here.  The CAA/Nares development looks serious.  Is the apparent 2018 'joining of the bridge' between the saline waters of the Atlantic and Pacific (if that is real) also of significance?   And one central question... is this below-ice information observed, or is it modeled, or is it modeled with interpolations from some observations?     

The fresh water layer has broken down over the past year in the CAA. Ice and fresh water flowed into the Labrador sea and saltier water replaced it. Large channels like the Nares (which is starting to flow again) have northerly salty flows on the east side and southerly fresh flows on the west side.

Note that I show images from 1 year apart. That makes for an apples to apples comparison that doesn't have confusion caused by seasonal melting differences.

Mercator's 30m salinity maps are most helpful. The Mercator temperature maps are unhelpful at 30 and 100m because they don't have the level of detail needed to see subtle changes between negative 1 and negative 2 Celsius.

Note also that for the past year the salty Atlantic water intruded into the central Arctic very close to the north pole at a depth of 30m. The Atlantic side of the pole inside 80ºN does not have a protective fresh water layer above 300m any more.

I would think the most serious change is in fact the joining of ATL / PAC water in the High Arctic. It looks like it will ensure the thick ESS ice is cleaved from the main pack within the next two weeks or so. This will leave the CAB without its "arm" and make it exceedingly vulnerable into August / September.