The 2015 melting season

[Nick_Naylor]

It's an interesting idea, but I question why latent heat, as opposed to sensible heat would prolong the life of the system? I'm probably just missing some part of your argument, but an explanation would help (me).

It looks to me like "latent" is here being used in the nontechnical sense, "existing but not yet developed or manifest; hidden; concealed."

That usage is reasonable, since the heat has been sequestered beneath the ice and is "latent". Using "latent" that way with "heat" specifically is hard to recommend though, because of the special meaning of the term in physics.

[jdallen]

It's an interesting idea, but I question why latent heat, as opposed to sensible heat would prolong the life of the system? I'm probably just missing some part of your argument, but an explanation would help (me).

It looks to me like "latent" is here being used in the nontechnical sense, "existing but not yet developed or manifest; hidden; concealed."

That usage is reasonable, since the heat has been sequestered beneath the ice and is "latent". Using "latent" that way with "heat" specifically is hard to recommend though, because of the special meaning of the term in physics.

Even so, the resulting temperature differential would still be quite low; only a degree C or two.  I don't think that's big enough to support a cyclone.  If it was, we'd be seeing them already, just with exposed ocean.

[Neven]

Open a separate topic! 

[budmantis]

Open a separate topic! 

You tell them, Tony Montana! "Meet my little friend"!!

Bud

[slow wing]

The storm from the Bering Strait has reached the Beaufort Sea and the Beaufort ice is taking a beating, particularly the Beaufort Arm.

The ice pack edge continues to retreat from the Laptev Sea.


Click on gif to see crossfade comparison between yesterday's and today's Arctic sea ice concentration maps from U. Bremen...

[oren]

Wow. Half of the loose detached stuff in the Beaufort gone in a day.

[Lord M Vader]

The cyclone seems to be bottoming out at 985 hpa. It seems like it will linger in the Beaufort area for 2-3 days more before weakening. This would have a great impact on the loose ice there. The question is whether it will be gone completely or not.

Meanwhile, the forecast calls for another small but quite intense cyclone to form in about 3-4 days just north of Svalbard is going to do some damage there if the forecast for it holds.

I think we should see some decent drops for the next 5 days but after that I think the drops will be much slower and only another 0,1-0,5 km² of ice will be lost until minimum. So far, August 2015 has seen a drop of 1,7 million km² of ice. This I think is the third biggest drop for August only trailing behind 2012 and 2008.

//LMV

[Neven]

Wow. Half of the loose detached stuff in the Beaufort gone in a day.

Yup, that's flash melting.

[BenB]

Over the past week, cracks have really developed and widened in the tongue of ice penetrating into the ESS, probably helped by the winds in recent days:

http://1.usa.gov/1NVWJZQ (21 August)
http://1.usa.gov/1NVWM87 (27 August)

It will be interesting to see whether this will speed up the melting process over the coming week, or whether we are too late for it to make a big difference.

[Neven]

I can't imagine a lot happening there, the ice looks so... together. But you never know.

Like LMV says, cyclone now at 985 hPa, which is pretty decent:

[Andreas T]

Over the past week, cracks have really developed and widened in the tongue of ice penetrating into the ESS, probably helped by the winds in recent days:

http://1.usa.gov/1NVWJZQ (21 August)
http://1.usa.gov/1NVWM87 (27 August)

It will be interesting to see whether this will speed up the melting process over the coming week, or whether we are too late for it to make a big difference.

these crack are I think, signs of refreeze. In July this ice was mobile without showing large cracks because it had already broken into smaller floes. Now these floes are sticking together with ice formed recently. When winds shift the ice it cracks again but these cracks open more easily than forming new cracks so movement produces this pattern of large chunks similar to what is seen in winter and early spring. This is seen at this time of year where surface temperatures drop.

[slow wing]

Concerning the state of the ice in the Beaufort Arm, ClimateReanalyser shows it is being tested right at the moment by winds up to ~20 m/s (~45 mph) - see figure below.

The storm over the Arm is forecast by ClimateReanalyser to continue for around 3 days before the winds die away. Then we'll see if any of the Arm has survived it. Doubtful imo!

Such wind strengths are presumably not too unusual at this time of year, true or false?
But the ice this year seems to be too weak and thin, in at least some places, to be able to cope with these winds. It's fascinating and ominous at the same time!

[seaicesailor]

Concerning the state of the ice in the Beaufort Arm, ClimateReanalyser shows it is being tested right at the moment by winds up to ~20 m/s (~45 mph) - see figure below.

The storm over the Arm is forecast by ClimateReanalyser to continue for around 3 days before the winds die away. Then we'll see if any of the Arm has survived it. Doubtful imo!

Such wind strengths are presumably not too unusual at this time of year, true or false?
But the ice this year seems to be too weak and thin, in at least some places, to be able to cope with these winds. It's fascinating and ominous at the same time!

Storms this strong are not unusual as winter approaches (correct me if I am wrong), but the fact that this one is hitting over a huge area of open ocean is.

That's 40+ knots: a swell of waves 4 to 5 meters high and with 10 seconds of period (energy ~ height^2 x period).

See Jim Hunt post:

http://forum.arctic-sea-ice.net/index.php/topic,1149.msg61938.html#msg61938

EDIT: If you have had the luck of surfing in a swell this strong (which is not so strong for Atlantic or Pacific big swells), the waves coming with such period will make you roll under the wave out of control if you are an beginner (as I am). Ice floes are worse surfers than myself !

[Richard Rathbone]

I am not sure one should put so much theory and speculation into the DMI stuff. The answer will more likely be: Since the area got corrected upwards due to disappearance of melt ponds, DMI simply filled the gaps with the surrounding thickness, correcting its volume. It is practically impossible that volume is on the rise due to widespread bottom melt, which will last far into September. If a model can't deal with that it is faulty and not "indicating something".

I suspect HYCOM/CICE models have trouble dealing with that maybe because the ocean layer thicknesses in HYCOM can't reproduce the way near surface ocean heat is gathered in PIOMAS. Consequently their volume melt season ends earlier. As the graph shows, an early end is normal behaviour for that model. Heat that is warming the ocean in July and melting ice in September in PIOMAS, would go directly into melting ice in July in CICE rather than into HYCOM to be fed back in later months.

[Gonzo]

There's that correction.

http://polarportal.dk/en/havisen-i-arktis/nbsp/sea-ice-extent/

[Bruce Steele]

Seaicesailor, Waves in the Bering strait reached 9.5 ft at an 8 second period yesterday morning.
Conditions I would call steep waves but with that short a period I wouldn't call swell. If the Beaufort develops similar conditions it will do a lot of damage. A longer period wave would penetrate deeper into the water column and stir up more of the -.5 water that is currently residing there . 

http://www.ndbc.noaa.gov/station_page.php?station=48114

Microcat temperature at 6 meters is currently at -.4 for this buoy in the Beaufort. I think we have a lot of melt potential with these conditions.

http://www.whoi.edu/page.do?pid=139056

[F.Tnioli]

I am not sure one should put so much theory and speculation into the DMI stuff. The answer will more likely be: Since the area got corrected upwards due to disappearance of melt ponds, DMI simply filled the gaps with the surrounding thickness, correcting its volume. It is practically impossible that volume is on the rise due to widespread bottom melt, which will last far into September. If a model can't deal with that it is faulty and not "indicating something".

I suspect HYCOM/CICE models have trouble dealing with that maybe because the ocean layer thicknesses in HYCOM can't reproduce the way near surface ocean heat is gathered in PIOMAS. Consequently their volume melt season ends earlier. As the graph shows, an early end is normal behaviour for that model. Heat that is warming the ocean in July and melting ice in September in PIOMAS, would go directly into melting ice in July in CICE rather than into HYCOM to be fed back in later months.

That is excellent. Short, precise, essential. I am very grateful to you for this post, Richard!

P.S. If you by any chance will happen to visit federal science city of Reutov (which is where i live) in the future, then please remind me i wanna buy you a beer (or fruit juice if you're not into beer, or whatever else you'd prefer), ok?

[seaicesailor]

Seaicesailor, Waves in the Bering strait reached 9.5 ft at an 8 second period yesterday morning.
Conditions I would call steep waves but with that short a period I wouldn't call swell. If the Beaufort develops similar conditions it will do a lot of damage. A longer period wave would penetrate deeper into the water column and stir up more of the -.5 water that is currently residing there . 

http://www.ndbc.noaa.gov/station_page.php?station=48114

Microcat temperature at 6 meters is currently at -.4 for this buoy in the Beaufort. I think we have a lot of melt potential with these conditions.

http://www.whoi.edu/page.do?pid=139056

Thanks for the precise data. Yet, if you see that map Jim posted, the predicted height was the lowest at the Bering strait, and much higher at Bering Sea and Chukchi Sea.

The storm is average compared to the storms in the North Atlantic (well, now not so average), but waves like these in the Arctic are very uncommon. I see this as self-evident since most of the time the ice does not give room for the wind to raise these waves except in large extents of open ocean. The open water right now is Beaufort + Chukchi, a longitudinal distance comparable to half the Mediterranean.

Another thing is that I would have thought 8 or 10 seconds of period (but for 4 -5 meter waves) can make a small 15 ft "sailor" really pitch down and up very badly. These are 30 to 40 knots in wide open sea!

EDIT. To avoid overposting, I attach current state of waves as predicted by model by using GFS 06Z update (NWS wavewatch III model, thanks Jim Hunt for that post). 4 -5 meter height, 10 - 11 seconds (!), 30 to 40 knots right now against Barrow coast (next thing I'll see watch the webcam). Obviouosly, nothing compared to those swells in the open Pacific, but we are not talking about typhoons either.

[jdallen]

Seaicesailor, Waves in the Bering strait reached 9.5 ft at an 8 second period yesterday morning.
Conditions I would call steep waves but with that short a period I wouldn't call swell. If the Beaufort develops similar conditions it will do a lot of damage. A longer period wave would penetrate deeper into the water column and stir up more of the -.5 water that is currently residing there . 

http://www.ndbc.noaa.gov/station_page.php?station=48114

Microcat temperature at 6 meters is currently at -.4 for this buoy in the Beaufort. I think we have a lot of melt potential with these conditions.

http://www.whoi.edu/page.do?pid=139056

Climate Reanalyzer shows the Chukchi, Beaufort and adjacent CAB and CAA just getting clobbered by that storm for the next 48 hours or so.

Then, as that dies down, a small storm almost as intense is predicted to pass north just East of Svalbard and slam into the weakest ice in the CAB, pulling +8C anomalous heat from the Barents with it.

Not likely to be a good week for the ice.

[gregb]

Speaking of clobbered. Look at the damage being done by the waves on the waterfront in Barrow.

[jdallen]

Speaking of clobbered. Look at the damage being done by the waves on the waterfront in Barrow.

That qualifies!

That's pretty extensive shoreline flooding, that is...

(Edit: unless I miss my guess, the Healy should be getting a serious wallop from this storm.)

[Bruce Steele]

Seaicesailor, Sorry for the double posting, I am tech challenged sometimes. I spent a lot of time at sea in fairly small boats ( < 36 ft. ). I have spent a lot of time looking at buoy data trying to decide whether any given day is a good one to challenge 40 miles of open waters here on the Northeastern coast of the Pacific. Anytime you have wave height exceeding wave period you have steep wave conditions. 9.5 ft. at 8 seconds makes for very difficult conditions and waves will pitch completely over the boat as the bow dips while the stern is pitched up. Nasty wet conditions that I would avoid if given any choice.  Thanks for the pictures of Barrow, illustrating what those conditions look like from land . Out at sea it gets scary and no place for a 15ft. sailboat!
 There were some discussions earlier this year on the potential for waves to impact the ice and we will soon see how far north the damage expands. The longer the period the deeper into the pack the waves will progress and the deeper into the water the mixing will pull up very warm( for the arctic ) water. Those -.4 waters are unprecedented in the buoy record for this time of year when looking back through the WHOI ITP buoy record.     

http://www.whoi.edu/page.do?pid=125976

This ITP buoy #53 documents conditions for the GAC in 2012 and comes as close as I can find for something comparable to ITP# 85 . For #85 it's hard to see the yellow in the upper right hand side of the T/S contours but the microcat is definitive.

[NeilT]

Trust me to be at work and not able to view when the storm comes ashore

I thought I'd have a quick check of the OBuoy camera's to see what's going on over them.

12 seems to have been pushed over, the winds are showing around 15m/s still.  10 has gone from re-freeze to open water and 11 was sitting on solid ice with the melt ponds freezing over.  Now it's in a mass of broken ice clearly melting from the bottom.

Well it's nice to know that the system didn't want us to have a boring slow finish to the season.

9 is in nice bright sunny weather.  Which probably explains that vanishing ice around the Fram.

[seaicesailor]

Seaicesailor, Sorry for the double posting, I am tech challenged sometimes. I spent a lot of time at sea in fairly small boats ( < 36 ft. ). I have spent a lot of time looking at buoy data trying to decide whether any given day is a good one to challenge 40 miles of open waters here on the Northeastern coast of the Pacific. Anytime you have wave height exceeding wave period you have steep wave conditions. 9.5 ft. at 8 seconds makes for very difficult conditions and waves will pitch completely over the boat as the bow dips while the stern is pitched up. Nasty wet conditions that I would avoid if given any choice.  Thanks for the pictures of Barrow, illustrating what those conditions look like from land . Out at sea it gets scary and no place for a 15ft. sailboat!
 There were some discussions earlier this year on the potential for waves to impact the ice and we will soon see how far north the damage expands. The longer the period the deeper into the pack the waves will progress and the deeper into the water the mixing will pull up very warm( for the arctic ) water. Those -.4 waters are unprecedented in the buoy record for this time of year when looking back through the WHOI ITP buoy record.     

http://www.whoi.edu/page.do?pid=125976

This ITP buoy #53 documents conditions for the GAC in 2012 and comes as close as I can find for something comparable to ITP# 85 . For #85 it's hard to see the yellow in the upper right hand side of the T/S contours but the microcat is definitive.

Thanks Bruce. I am sure you have more experience in navigation, don't let my nickname fool you! Also I was trying to visualize what small and not-so-small floes must be experiencing.

[magnamentis]

almost real time ice conditions as per now:





enjoy

[AbruptSLR]

Sigmetnow has just posted this in the SLR thread, showing that the pressure for the Arctic cyclone has now dropped down to 983 hPa:

[Jim Hunt]

Speaking of clobbered. Look at the damage being done by the waves on the waterfront in Barrow.

Quite so. Worse than a slightly later storm last year. See:

Sea Ice and Swells in the Beaufort Sea in the Summer of 2014

[jdallen]

Speaking of clobbered. Look at the damage being done by the waves on the waterfront in Barrow.

Quite so. Worse than a slightly later storm last year. See:

Sea Ice and Swells in the Beaufort Sea in the Summer of 2014

Seeing your picture, the surf this year has obviously blown completely through the shoreside surf protection, and completely cut off the isthmus to the right of the image. Some folks may be reconsidering the location of their homes.

[helorime]

Wild weather in Barrow indeed: https://www.adn.com/article/20150827/high-winds-causing-big-waves-flooding-barrow

[TerryM]

At the moment at 76N by 170W Nullschool is showing:
>3m waves, with an 8.3 sec. period
Temperatures of -1.5C SST & -1.1C air blowing from the Canadian side at 50 km/h


Assuming Bruce's sub-surfaces temperatures hold in this area I'd expect:


Wave action to be mixing the relatively cool surface water with the warmer, lower strata.
Coriolis effects to be driving this mixed water against and under whatever ice is further north.
Compaction and melting along that ice front.


Further south closer to where the cyclonic action is centered Ekman pumping will disperse surface water and the warm sub-surface water emerging will rapidly melt any ice still extant.


The heavy cloud / mist cover is letting very little heat escape and the long fetch (earlier today from near the Mackenzie Delta, now from as far west as Ellesmere Island), will allow waves to build (and strata to mix) wherever ice sheets are not encountered.


I think we'll find lots of open ocean should the skies ever clear. Late season storms seem to tear ice up more than at other times.
Terry

[greatdying2]

EDIT. To avoid overposting, I attach current state of waves as predicted by model by using GFS 06Z update (NWS wavewatch III model, thanks Jim Hunt for that post). 4 -5 meter height, 10 - 11 seconds (!), 30 to 40 knots right now against Barrow coast (next thing I'll see watch the webcam). Obviouosly, nothing compared to those swells in the open Pacific, but we are not talking about typhoons either.

Jeebus, the houses in those webcam grabs look like they're in the water. Certainly suggests that this is not a common occurrence. The shed of that house on the right will be lucky to survive. And is that a telephone pole?!?

P.S. Ditto all the other more recent comments. Should have read further before posting, but it was so exciting! (Except that I feel sorry for the families in those homes...)

[Csnavywx]

Lots of convective showers blowing through on that webcam as cold air aloft runs over that relatively warm, open ocean water. Definitely doesn't look like something you should see at that latitude.

[greatdying2]

The definition of "shore up"?

[slow wing]

Drama on the Pacific side of the Arctic Ocean as flash melting from the storm strips away much of the remaining ice cover from the peripheral seas.

Meanwhile, the ice edge at the Laptev Sea continues to speed inwards towards the Pole.

The ice pack is suddenly looking a whole lot smaller!

Click on the gif to crossfade between the U. Bremen ice concentration maps for the past 3 days...

[Adam Ash]

The definition of "shore up"?

Poor souls!  I suspect the supervisor of the front end loader work is a bloke called Canute!  Good luck, but I don't like your chances!

Looks like the spit between the Isatkoak Lagoon and the sea along Eben Hopson Street could go very easily if the storm persists, together with the power poles...

http://seaice.alaska.edu/gi/observatories/barrow_webcam

[slow wing]

I just checked with Nullschool and one amazing aspect of the ice retreat from the Laptev is that the wind isn't even blowing towards the Pole and it hasn't been for at least the past two days - more in a Westerly direction - i.e. towards the Atlantic.

So the ice edge retreat is not being driven by compacting winds! Is it just bottom melt as the ice is pushed sideways?!
(EDIT: now looking around nervously for OldLeatherNeck, who might be telling me the edge is being pushed towards pole by Coriolis force. I checked at least the sign of the force and that actually makes sense.)

And if there is so much heat under the ice then this could go on for a while as well!  Notably, none of the recent U. Bremen maps have been showing full concentration in that region beyond about 5 degrees from the Pole, particularly on the Atlantic side. WorldView confirms the weakness in more detail, showing 'pinholes' (up to ~km scale) and larger tears.

On top of that, there is a storm predicted in that region in a couple of days from now!


Where will the ice edge end up this year in the direction going from the Pole to the Laptev Sea?

[epiphyte]

I know it's blowing my own trumpet - but...

Poof.

[Neven]

Poof, peek-a-boo, flash melting...

I've put up a summary on the ASIB, also discussing the consequences for MYI: Arm's race (and a storm)

[plinius]

I just checked with Nullschool and one amazing aspect of the ice retreat from the Laptev is that the wind isn't even blowing towards the Pole and it hasn't been for at least the past two days - more in a Westerly direction - i.e. towards the Atlantic.

So the ice edge retreat is not being driven by compacting winds! Is it just bottom melt as the ice is pushed sideways?!
(EDIT: now looking around nervously for OldLeatherNeck, who might be telling me the edge is being pushed towards pole by Coriolis force. I checked at least the sign of the force and that actually makes sense.)

And if there is so much heat under the ice then this could go on for a while as well!  Notably, none of the recent U. Bremen maps have been showing full concentration in that region beyond about 5 degrees from the Pole, particularly on the Atlantic side. WorldView confirms the weakness in more detail, showing 'pinholes' (up to ~km scale) and larger tears.

On top of that, there is a storm predicted in that region in a couple of days from now!


Where will the ice edge end up this year in the direction going from the Pole to the Laptev Sea?

@slow wing: If you assume a nicely circular icesheet and blow a wind exactly parallel to the ice edge in a clockwise direction, then you have a very strongly compacting regime - think of the Ekman spiral! In addition this drives more water from the ice-free regions under the ice - another factor that moves the edge.
Very unlikely that the pole is reached from either edge this year.

[slow wing]

Yep, that makes sense from first principles if I'm understanding this correctly.

The water and the ice floating on it are rotating anti-clockwise with the Earth. The rotation lifts the water surface up above the water level at the North Pole. (Compare with a whirlpool or water rotating in a pot - it's lower at the centre of rotation.) A wind blowing clockwise slows the water and ice down but it is still at the same height above the Pole so it flows inwards.


Yep, I'm guessing the closest encroachment this melt season of the ice pack edge from the North Pole on the Atlantic side will be around 5 degrees.

[seaicesailor]

Yep, that makes sense from first principles if I'm understanding this correctly.

The water and the ice floating on it are rotating anti-clockwise with the Earth. The rotation lifts the water surface up above the water level at the North Pole. (Compare with a whirlpool or water rotating in a pot - it's lower at the centre of rotation.) A wind blowing clockwise slows the water and ice down but it is still at the same height above the Pole so it flows inwards.


Yep, I'm guessing the closest encroachment this melt season of the ice pack edge from the North Pole on the Atlantic side will be around 5 degrees.

https://forum.arctic-sea-ice.net/index.php/topic,1344.0.html

See some references at the first post about wind-driven drift, Coriolis effect, and subsequent Ekman pumping.
This is a recurring off-topic issue so we better stop it now :--)

edit: sorry for the tone. :--(

[slow wing]

Thanks for the link. Yes, I should take that plunge... 

[Gonzo]

slow wing

So the ice edge retreat is not being driven by compacting winds! Is it just bottom melt as the ice is pushed sideways?!

There will be bottom melt, and it is a metre thick or less by the look of it, but it I doubt it could reach the pole, because of the spin around the pole and the closer proximity of Greenland and CAA to the pole (than say Russia is)  grabbing the ice, and bunching up on that side, but it could open up all the way from Laptev to Atlantic if the season is longer than usual.

[skanky]

We might see a couple century's the next 3 days.

Boom.

[DavidR]

We might see a couple century's the next 3 days.

Boom.

NSIDC dropped 177 K yesterday, that's the third biggest decline since August 1st this year and the 7th biggest decline after Aug 1st  in the last  10 years.
But hey there's another three weeks of melt to  go who knows where will end up.

[deep octopus]

With yesterday's drop, the one-day extent seems to be virtually tied with 2007 (+17,000 km²) and 2011 (+9,000 km²). That was quick. Yesterday's drop also crashed well below the minima of 2013 and 2014. The ice is starting to look rather tiny on the maps.

[LRC1962]

As Neven points out in his post, waves are going to be the issue. Will they compact the ice and push it all together or will the waves be pushed under the ice and flash melt it into slush? IMO either is possible and we will not get an answer until it is over.

[seaicesailor]

(somebody correct me if I am wrong) the latest GFS no longer predicts a central cyclone. That would have been a "halt".
Now, I would not expect but a gradual decline of extent until mid September.

What the 12Z GFS and 00Z ECWMF do predict within the next five days is warm air from America extending into the Pacific side of the Arctic. No refreezing there in sight.
Then there is this very cold spell from Greenland into the Atlantic side.
Small storms all around.
No, it aint finished.

[meddoc]

It long ain't over...
3 more cyclones in the Pacific developing, too.
As "Winter is coming" we could see a ramp- up of Arctic Amplification, especially with that Monster El Niño.
Preconditioning 2016...

[seaicesailor]

After the storm, come some warmth.