The 2018 melting season

[El Cid]

I'm fucking blown away.

But how??

The Pacific side opened up very-very early and then nothing seemed to happen. BUT IT DID! It is not Atlantification, so let's call it PACIFICATION

[Frivolousz21]

The euro and gfs both clobber the CAA, BeAufort, chuchki and ESS the next 5 days.  And the Western CAB a bit.


Then they go reverse dipole with it being a high pressure grounded out of the NE ATL/Scandinavian furnace.

Fun indeed

[meddoc]

Yeah, still lot of Action in the Works.
The CAA also seems rather slushy on Arctic Explorer.
1,5 Months is still a LOT of Time to make Things exciting.
Only 1 or 2 Days of a GAC needed & we are in a whole new Territory.

[uniquorn]

Today's ecmwf wave and temperature from windy.

[Shared Humanity]

I'm fucking blown away.

But how??

Very interesting that you can see in this image the remnants of the thick ice flows that have been migrating from CAA into the Beaufort over the past year. Running along the Alaska coast, it is like the last line of defense for the entire Beaufort as the thin FYI ice north of this line melts out rapidly.

[magnamentis]

something along this line

https://forum.arctic-sea-ice.net/index.php/topic,382.msg118871.html#msg118871

https://forum.arctic-sea-ice.net/index.php/topic,2278.msg161665.html#msg161665

[uniquorn]

Very interesting that you can see in this image the remnants of the thick ice flows that have been migrating from CAA into the Beaufort over the past year. Running along the Alaska coast, it is like the last line of defense for the entire Beaufort as the thin FYI ice north of this line melts out rapidly.

I think that MYI ice string/arc lost it's integrity some time ago.
amsr2-uhh, jun10-jul27
edit:Added previous ascat animation. It looks like the MYI ice didn't drift that near to the Alaskan coast before it mostly melted out

[uniquorn]

Worldview, north of Greenland, clearest days close to jul27, 2012-2018

[Ned W]

Here is a comparison of 2015 to 2018, during the past three days (24-26 July),

How high is the 100% concentration bin for this year?

I don't have that data file with me (I'm away from home today) but it was quite high, suggesting to me that there is something slightly odd going on.  Maybe the algorithm that produces ice concentration from brightness temperature would assign some grid cells a concentration over 100%, and those are set to 100, resulting in a "spike" at that value?  But there were no 100% cells in the three-day average from 2015, just in the 2018 data set.  I'll post the exact numbers when I get a chance.

Or, if someone is interested, they can go here:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/geotiff/2018/07_Jul/

and download the concentration GeoTIFF files for the three days of 2018 (and 2015), and count the number of pixels with values of 1000 (the GeoTIFF concentration data are scaled by a factor of 10).

---------------------------------

Edited to add: 

OK, I found the numbers, here they are. 

For 2018, there was 398.75k km2 with an average concentration of 100% over the three-day window.  An additional 1266.25k km2 had a concentration of 90% to 99.9%.

For 2015, there were no grid cells that had an average concentration of 100%.  There was 510k km2 with a concentration of 90% to 99.9%.

Maps below of the 3-day averages.  Red = 100% concentration; orange = 90% to 99.9%.

2015:



2018:



I am wondering whether the difference is because the 2018 data are based on the NRT version of the CDR process, while the 2015 data are the final version of the CDR.  I probably ought to have a better understanding of that.

[Wherestheice]

The ice concentration on the Pacific side in 2018 looks in a much worse state than 2015. So I think what really matters here is what happens in the next month and a half. I think comparing previous years to this year doesn't do much except create something to talk about. 2018 has been a very odd year, going from a year where we thought the min. would be very high, to now much lower than we thought.

[Steven]

I am wondering whether the difference is because the 2018 data are based on the NRT version of the CDR process, while the 2015 data are the final version of the CDR.

Other datasets seem to confirm that at this moment there is a sharp contrast between the high-concentration ice in the Central Arctic versus the low-concentration ice on the Pacific side. 

This also shows up in the SMOS images.  The left image below is for 27 July 2018, whereas the right image is for 27 July 2015.  (I removed the text "ice thickness" from the images below, because the SMOS images in summer don't show ice thickness but are also affected by surface wetness, sea ice concentration, temperature etc.)


 

[GoSouthYoungins]

Here is what I wrote on June 10th...

"triangle from north of greenland to north pole to 72 N on CAA is all that will be left of ice at minimum this year, most likely. New Record. By the solstice, there will be open water around the arctic everywhere except Greenland-CAA.  After that the edge will rapidly retreat and there will be flash outs. People who keep posting that it will be a "normal (2010-2017)" year are blowing my mind. I really don't get it how it will get warmer  for years on end in the ocean and the atmosphere but the ice is supposed to just chill..."

Look at the PIOMAS map. Go to worldview and checkout all the "10 foot thick ice" that is "mysteriously" flashing out and recalibrate your expectations. It's a great model, the most accurate one, but not better than visuals and common sense.

[Michael Hauber]

I think some of the change in ice conditions on the Pacific is due to changes in cloudiness/melt ponds etc.  Still some serious melt going on though.

[Ned W]

I am wondering whether the difference is because the 2018 data are based on the NRT version of the CDR process, while the 2015 data are the final version of the CDR.

Other datasets seem to confirm that at this moment there is a sharp contrast between the high-concentration ice in the Central Arctic versus the low-concentration ice on the Pacific side. 

This also shows up in the SMOS images.  The left image below is for 27 July 2018, whereas the right image is for 27 July 2015.  (I removed the text "ice thickness" from the images below, because the SMOS images in summer don't show ice thickness but are also affected by surface wetness, sea ice concentration, temperature etc.)


 

Steven, that's quite a contrast in the SMOS images.  But I'm still a bit curious about the extremely high number of grid cells in 2018 that are consistently reporting 100.0% concentration.

[uniquorn]

Steven, that's quite a contrast in the SMOS images.  But I'm still a bit curious about the extremely high number of grid cells in 2018 that are consistently reporting 100.0% concentration.

It could be weather/cloud related. There is similar interference on ascat and amsr2.

[bbr2314]

Latest COPERNICUS for 8/6 (concentration) and today, 7/29. The Laptev front is about to start gaining significant momentum. The ATL front also appears to be set to do the same (the forecast models show tremendous heat pouring into both regions but especially the ATL). This should prevent an early refreeze like 2017.

The bifurcation of the ESS shore ice is also imminently about to be complete. There will be nothing to stop the PAC from roaring further into the CAB at that point.

[bbr2314]

Today's image from Bremen shows the continued advance of the Pacific front into the CAB, though clouds are purpling some of the peripheral ice, the extremely rapid declines continue.

[slow wing]

Yes, the Beaufort Sea ice front facing the Alaskan north coastline is being pushed northwards. That's unsurprising, given the poor state of the ice there in recent days.

Otherwise a slight bounce-back, particularly in the ESS.

Adding today's false colour ice concentration map from U. Bremen, now 5 consecutive daily maps spanning 4 days and ending at 2018-07-28.

Click to animate...

[Aluminium]

July 24-28.

Greenland sea is also cleared. In total, difference between 24.07 and 28.07 is quite notable. About one third of ice is rapidly getting dark.

[Yuha]

Steven, that's quite a contrast in the SMOS images.  But I'm still a bit curious about the extremely high number of grid cells in 2018 that are consistently reporting 100.0% concentration.

It could be weather/cloud related. There is similar interference on ascat and amsr2.

I suspect it's melt ponds.
2015 had one of hottest and sunniest Julys on record and all of the ice may have been covered by melt ponds then. In contrast, July 2018 has been quite cool in central arctic.

[Steven]

I suspect it's melt ponds.
2015 had one of hottest and sunniest Julys on record and all of the ice may have been covered by melt ponds then. In contrast, July 2018 has been quite cool in central arctic.

Seems plausible.  Looking at Worldview, the ice surface in 2018 looks brighter than in previous years.  Moreover, I think weather models were showing new snowfall at high latitudes in the last few weeks (as opposed to the rainfall further south).

Comparison of the weekly MODIS composites for 2018 (left) versus 2015 (right).

   

JAXA AMSR2 also suggests that surface melting has been relatively weak in the past few weeks (image from Wipneus):

[Neven]

Looking at Worldview, the ice surface in 2018 looks brighter than in previous years.

Expect those brighter colours to dim. This high pressure over the Siberian side and part of the CAB is spelling trouble, especially if it lasts beyond this forecast (and then gets followed by a GAC?):

[bbr2314]

Looking at Worldview, the ice surface in 2018 looks brighter than in previous years.

Expect those brighter colours to dim. This high pressure over the Siberian side and part of the CAB is spelling trouble, especially if it lasts beyond this forecast (and then gets followed by a GAC?):

You know a GAC is around the corner with all the heat accumulating in the NATL, Laptev, and Pacific front. I would suspect it will center over the western periphery of the CAB, in an attempt to equalize the leads opening across the entire Pac front / the residual heat behind it. I suspect this is why 2012's occurred where it did, although it did ride in on a Siberian heat / smoke blast which is probably the secondary factor re: where it occurs.

This year, the Siberian smoke train is well and active, we just need a bit more instability in the western areas now melting out / +Arctic oceanic heat. It probably won't take more than another two weeks to get to that point.

In the meantime, the output you posted / what's being shown by the ECMWF in the short and medium range is simply catastrophic for the remaining ice. The reaction by the ATL front will be especially interesting to watch as it has slowly and steadily been losing thickness / perhaps this is the event that causes it to "poof" like what has now happened to the west.

[pearscot]

Is there a possibility that the pack gets cut in half? I really don't think such an action would be viable due to compaction, as well as the gyre, but in a broader sense such an event would increase the entirety's surface area.

Nonetheless, the continual degradation gets worse, when I thought the cloudiness indicated a welcome and needed temporary stall.

[bbr2314]

Is there a possibility that the pack gets cut in half? I really don't think such an action would be viable due to compaction, as well as the gyre, but in a broader sense such an event would increase the entirety's surface area.

Nonetheless, the continual degradation gets worse, when I thought the cloudiness indicated a welcome and needed temporary stall.

Not exactly in half, but the shore ice in the ESS has shown no willingness to move alongside the PAC front as it normally does. I suspect a portion will remain shorefast and survive the summer. The ensuing gradient(s) will be larger than normal and likely foster even more cyclonic activity deeper into the CAB as the "arm" that normally buffers retreat is either non-existent or stuck to Russia this year.

[Frivolousz21]

The NEATL is exploding in near surface oceanic heat.

This will happen all the way to the ice edge as the weather progresses.

If this forecast holds its not overstating it that the laptev region could be crippled all the way towards 85N.

Ice thickness about 1M or less even this late can vanish under a moisture laden WAA + Warm sst + sun.




Man the models are showing incredible heat and moisture coming at the arctic from Eurasia and the NE ATL.

Its more then I recall ever seeing.

[bbr2314]

I wonder if the Mediterranean is acting as an amplifier for the heat / etc in Europe. It does not freeze over in winter and therefore heat can accumulate much more readily year-over-year under +GHG forcing. The Mediterranean heat situation could partially explain why ridging has become so persistent to its north and why we've seen the SSTA maps evolve as they have this year (of course, the NE NATL has also been aided by the heat pulses derived from +GHG forcing over North America, which leaves residual + anomalies off the Eastern seaboard that end up transported N of Europe as well).

[bbr2314]

The latest COPERNICUS is horrible for both the ATL and Laptev fronts by 8/7. Wow. At this image frame, anything under yellow has a week to melt out entirely. 2012 here we come?

[pearscot]

I wonder if the Mediterranean is acting as an amplifier for the heat / etc in Europe. It does not freeze over in winter and therefore heat can accumulate much more readily year-over-year under +GHG forcing. The Mediterranean heat situation could partially explain why ridging has become so persistent to its north and why we've seen the SSTA maps evolve as they have this year (of course, the NE NATL has also been aided by the heat pulses derived from +GHG forcing over North America, which leaves residual + anomalies off the Eastern seaboard that end up transported N of Europe as well).

That's a very viable theory. At the end of the day the Mediterranean is a battery and it is gaining heat which will be transferred elsewhere. And, to your point, it has been substantially above average this entire year. I don't and won't claim to know the exchange rates between the Mediterranean and the Atlantic, but it occurs nonetheless. I still think we are a year out for an el nino, but when it does hit I think it will be as strong as the last one.

[bbr2314]

Welp, the 18z GFS puts a 576DM+ heat ridge over the CAB / Laptev...

[Frivolousz21]

Yes I'm cherry picking but the gfs after the initial thrust of heat reforms a Siberian positive dipole.


This would be a perfect storm of events to cripple the laptev/CAB Atlantic front and finish the ESS off.

[uniquorn]

Bring back Hyperion, we need the full monte.

Today's ecmwf wave and temperature from windy

[jdallen]

Yes I'm cherry picking but the gfs after the initial thrust of heat reforms a Siberian positive dipole.


This would be a perfect storm of events to cripple the laptev/CAB Atlantic front and finish the ESS off.

Just the high pressure by itself *without* a dipole is bad enough.  Between bottom melt and Insolation that's enough melt potential to strip 4-8CM/day off of existing ice, much of which is under 1M thick at the moment.

As I said earlier, based on what happened in the Kara, without optimal melt conditions, I'd expect the Chukchi to be ice-free, and very large swaths of the Beaufort, ESS and Laptev to be gone by the 3rd week of August.

[FredBear]

I wonder if the Mediterranean is acting as an amplifier for the heat / etc in Europe. It does not freeze over in winter and therefore heat can accumulate much more readily year-over-year under +GHG forcing. The Mediterranean heat situation could partially explain why ridging has become so persistent to its north and why we've seen the SSTA maps evolve as they have this year (of course, the NE NATL has also been aided by the heat pulses derived from +GHG forcing over North America, which leaves residual + anomalies off the Eastern seaboard that end up transported N of Europe as well).

That's a very viable theory. At the end of the day the Mediterranean is a battery and it is gaining heat which will be transferred elsewhere. And, to your point, it has been substantially above average this entire year. I don't and won't claim to know the exchange rates between the Mediterranean and the Atlantic, but it occurs nonetheless. I still think we are a year out for an el nino, but when it does hit I think it will be as strong as the last one.

The Med has a surface current inflow from the Atlantic, any heat gain is lost by evaporation, radiation, etc. There is an outflow to the Atlantic of warmer saltier water but any heat in that goes out at depth and will not affect the surface in the northern hemisphere?

[Glenn Tamblyn]

FredBear is correct.

Surface flow for the Mediterranean is into the Med, not out.
Net flow for the entire Med is into it. The balance is lost to evaporation.

There is a flow out along the sea floor out through the Straits of Gibraltar of quite saline water. This becomes part of the intermediate depth waters of the Atlantic ~1500 meters down. There are complex internal flows within the Atlantic. But not impacting surface currents.

[slow wing]

Adding today's false colour ice concentration map from U. Bremen, now 6 consecutive daily maps spanning 5 days and ending at 2018-07-29.

Click to animate...

[Neven]

All of the yellow/green is turning pink/purple again, but we've seen enough to know which ice is likely to be gone come September. But it will take some time to melt out though.

[uniquorn]

Update on the Mclure Strait.
AMSR2-UHH jul15-29 and Worldview jul28(clearest recent day)

[bbr2314]

I wonder if the Mediterranean is acting as an amplifier for the heat / etc in Europe. It does not freeze over in winter and therefore heat can accumulate much more readily year-over-year under +GHG forcing. The Mediterranean heat situation could partially explain why ridging has become so persistent to its north and why we've seen the SSTA maps evolve as they have this year (of course, the NE NATL has also been aided by the heat pulses derived from +GHG forcing over North America, which leaves residual + anomalies off the Eastern seaboard that end up transported N of Europe as well).

That's a very viable theory. At the end of the day the Mediterranean is a battery and it is gaining heat which will be transferred elsewhere. And, to your point, it has been substantially above average this entire year. I don't and won't claim to know the exchange rates between the Mediterranean and the Atlantic, but it occurs nonetheless. I still think we are a year out for an el nino, but when it does hit I think it will be as strong as the last one.

The Med has a surface current inflow from the Atlantic, any heat gain is lost by evaporation, radiation, etc. There is an outflow to the Atlantic of warmer saltier water but any heat in that goes out at depth and will not affect the surface in the northern hemisphere?

Exactly, evaporation and radiation = +500MB ridging overhead... I was not talking about the water itself getting to the Arctic, just its heat.

[bluesky]

I am wondering whether the difference is because the 2018 data are based on the NRT version of the CDR process, while the 2015 data are the final version of the CDR.

Other datasets seem to confirm that at this moment there is a sharp contrast between the high-concentration ice in the Central Arctic versus the low-concentration ice on the Pacific side. 

This also shows up in the SMOS images



.  The left image below is for 27 July 2018, whereas the right image is for 27 July 2015.  (I removed the text "ice thickness" from the images below, because the SMOS images in summer don't show ice thickness but are also affected by surface wetness, sea ice concentration, temperature etc.)


 

Steven, that's quite a contrast in the SMOS images.  But I'm still a bit curious about the extremely high number of grid cells in 2018 that are consistently reporting 100.0% concentration.

Seeing the large extent of sea ice with 100% or close to 100% concentration in Central Arctic, I just wonder whether there is a bipolar sea saw that may happen in August and whether that could suddenly deplete ice extent and ice area with a prolonged transpolar drift through Fram Strait (sorry maybe the answer is in the ECMWF forecast, but just asking). Also, beside the seemingly low extent of pools of water versus previous years, seemingly due to relatively cold average temperature, just wondering whether the transpolar drift has not been as high as the previous years.

[gerontocrat]

From the attached image my speculations are:-

- will the Greenland Sea completely melt out?
- when will the Russian Arctic Sea Ice Route be fully open (a bit more ESS and Laptev melt required?)

[uniquorn]

With warm winds forecast from the Greenland sea/Svalbard, here is a worldview animation of north of Greenland/Fram Strait, jul10-30

[binntho]

Seeing uniqorns animation above made me wonder (again) if the lack of Fram export is due to the ice not moving in the right direction, or because the ice melts out before reaching the Fram Strait.

The latter seems to be happening along the front from the North-East corner of Greenland and way past Svalbard.

[uniquorn]

I wouldn't be surprised if the pack drifted and melted away from the N Greenland coast this week, hopefully temporarily.
edit: added Ascat, north of Greenland mar21-jul30

[Aluminium]

Northern Sea Route probably will be open this or next week, I think. Only two small parts need to melt or push out. In Severnaya Zemlya (or Northern Land) ice of the Shokalsky Strait looks the more vulnerable than the Vilkitsky Strait. In the East Siberian Sea latest EOSDIS shows clearly water band north of Ayon Island.

[oren]

I wouldn't be surprised if the pack drifted and melted away from the N Greenland coast this week, hopefully temporarily.
edit: added Ascat, north of Greenland mar21-jul30

Thanks for the animation. It seems some kind of export towards the Fram has been going on for most of these months, Judging by the movement behind the front. But recently the ice has been melting so quickly that there is very little left actually crossing the "export" threshold.

[Viggy]

July 30 AMSR2 data still coming in on Earthview but Beaufort is absolutely getting smashed right now.

Attached a gif showing the region from July 28-30

(Click to play)

[gerontocrat]

July 30 AMSR2 data still coming in on Earthview but Beaufort is absolutely getting smashed right now.

I clicked - Cor! Should show up on NSIDC area data ( 5 day average means not all at once).

[Neven]

I've just posted a pre-PIOMAS update prelude on the ASIB with lots of compare, compare, compare.

[miki]

I've just posted a pre-PIOMAS update prelude on the ASIB with lots of compare, compare, compare.

Thanks, Neven. Dense, complete and compare-ready.