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subgeometer

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Re: The 2018 melting season
« Reply #1200 on: June 12, 2018, 03:12:28 AM »
Nares Strait is also on the move - the last 2 days on Worldview

Pagophilus

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Re: The 2018 melting season
« Reply #1201 on: June 12, 2018, 03:27:05 AM »
Thanks for this.  The 2016 Slater map actually looks probable, which is not a bad thing in a probabilistic map. 

I think you are right about grid point location not being considered in the current maps.  Slater obviously did consider it, as you show, and one would think the current Slater model could easily either resume that practice, or include a new algorithm that at least factors in the latitude of a location, for example.  It seems to me that that would be relatively easy to do.

The difference in the Slater maps implies that there has been a change in methodology.  It is true that models, being models, are imperfect (I think to an excessive degree in the case of recent Slater maps), but one virtue of any model is that it can be used for comparison purposes with its own past results (like a thermometer that is three degrees 'off' the accepted value but that can still be used to accurately detect a 4C change in temperature).  That does not seem to be the case here, and I would think this must be troubling to researchers using the model in the long term. 

   

There is obviously something wrong with that Slater map.

In the original Slater model, the probabilities depend not only on the current sea ice concentration, but also on the location of the grid point.  For a grid point in Hudson Bay the probability is calculated in a different way than for a grid point in the Central Arctic.  Here is an example from a few years ago (2016, when Slater was still alive) to illustrate this:

« Last Edit: June 12, 2018, 05:32:37 AM by Pagophilus »

jdallen

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Re: The 2018 melting season
« Reply #1202 on: June 12, 2018, 04:17:42 AM »
Judging from the list below, seems like events are accelerating.

Rapid melt at the Gusinaya River delta in the East Siberian Sea.
An update now the weather is clearer. Jun3-11

There is currently 31C and sunny in Churchill. Whatever ice is left there is currently cooked and torched.

While our attention has been diverted towards the Russian side of the Arctic, warm air has crept in from the south over the CAA and CAB. <snippage>

Over 80% of remaining Hudson Bay ice is now showing blue.

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oren

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Re: The 2018 melting season
« Reply #1203 on: June 12, 2018, 07:50:20 AM »
To those wondering how come extent losses are so low when so much is happening around the arctic (besides the obvious explanation that when extent is low to begin with there is less easy ice that can be spectacularly lost), a look at Uni Bremen's Chukchi/Beaufort map gives an answer. The last 3 days show strong dispersion southward at the ice front. Wipneus' regional AMSR2 area charts help quantify the effect.
CLICK to animate.

Sterks

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Re: The 2018 melting season
« Reply #1204 on: June 12, 2018, 09:03:09 AM »
Yes, but what would be interesting to know now is the total area rate of decline and compactness. Not sure if Wipneus' area plot is up to date on the OP of the AMSR2 thread bc he mentions service has been discontinuous lately. But seems decline is about on par with recent years, now it may take the dive in the next days
« Last Edit: June 12, 2018, 09:08:55 AM by Sterks »

aperson

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Re: The 2018 melting season
« Reply #1205 on: June 12, 2018, 10:09:40 AM »
Terra / MODIS bands 7-2-1 make the warm air advection and insolation impacts clear as day. Attached are June 9-12 on the Siberian Arctic (click to play).

There appears to be advecting fog today due to high relative humidity and the strong inversion layer of 10C or more at the 925hPa level.

It looks like parts of the CAA will get to take the stage next while insolation continues to take its toll on the Laptev and East Siberian Seas.
« Last Edit: June 12, 2018, 10:19:40 AM by aperson »

Viggy

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Re: The 2018 melting season
« Reply #1206 on: June 12, 2018, 10:36:38 AM »
To those wondering how come extent losses are so low when so much is happening around the arctic (besides the obvious explanation that when extent is low to begin with there is less easy ice that can be spectacularly lost), a look at Uni Bremen's Chukchi/Beaufort map gives an answer. The last 3 days show strong dispersion southward at the ice front. Wipneus' regional AMSR2 area charts help quantify the effect.
CLICK to animate.

I'm imagining that the amount of energy to reverse the Beaufort Gyre (even locally) and the amount of heat generated as a result of it, must be quite enormous?

Thawing Thunder

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Re: The 2018 melting season
« Reply #1207 on: June 12, 2018, 11:04:09 AM »
Quote from Uniquorn (image and text): An update now the weather is clearer. Jun3-11

Not only is the melt impressive but also the amount of warm water rushing north. Seems that this years's impressive snowcover is now reversing its effect ...
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Re: The 2018 melting season
« Reply #1208 on: June 12, 2018, 11:49:19 AM »
I'm imagining that the amount of energy to reverse the Beaufort Gyre (even locally) and the amount of heat generated as a result of it, must be quite enormous?

I think that's a surface effect where the ice is being blown against the prevailing current. I doubt that the underlying current has changed much. So its easy to see how quickly that  increase in extent could reverse if the window blows with the current.

However pushing the ice through the water should cause some extra melt underwater which may have show up later, although we won't notice it.
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meddoc

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Re: The 2018 melting season
« Reply #1209 on: June 12, 2018, 12:57:07 PM »
HYCOM Models seem to be backing off every second time I check them with regards to Cracking, Melt Ponds & Extent Loss.

Strange.

be cause

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Re: The 2018 melting season
« Reply #1210 on: June 12, 2018, 12:58:05 PM »
June 11th had the first visible open water above 89'N (@173'E) on worldview .. consequence of ice mobility .. cracks are appearing across the pole as they are in the Lincon Sea . I know a sq km or two of water is not statistically significant but it will be easier to see what is happening (including a re-freeze).

  the central pack still looks in pretty good shape with a good snow coat . Ice dispersing to the periphery could change things rapidly . Nares seems ready to open with the next Northerly and the Siberian heat just keeps coming .. b.c.
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Pagophilus

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Re: The 2018 melting season
« Reply #1211 on: June 12, 2018, 01:49:00 PM »
First signs of blue sea ice beginning to show in the ESS, in the Kolyma Gulf. 

Climate Reanalyzer indicates continued relatively clear, warm weather along this eastern portion of the Siberian Arctic coast.

Zoomed out image for context, then a close up, both images unaltered from today's Worldview.  The third image is that closeup with color saturation pushed +50 on Photoshop.

Pagophilus

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Re: The 2018 melting season
« Reply #1212 on: June 12, 2018, 03:26:48 PM »
Thank you -- I had not even considered this.  Adding to your post, I have brought across this very revealing graph by Gerontocrat of the Central Arctic Seas from the area and extent thread. To me, it confirms expert advice on this forum that area is a much better indicator of what is happening this time of year.  Since around June 7, Central Arctic Seas have actually gained extent, while area has dropped steeply.   And that area plot has got an ominously exponential feel to its decline.

I realize this sort of cross-pollination is duplication but given the number of posts about extent on this thread, I thought the graph might bring some comfort to the afflicted. 

To those wondering how come extent losses are so low when so much is happening around the arctic (besides the obvious explanation that when extent is low to begin with there is less easy ice that can be spectacularly lost), a look at Uni Bremen's Chukchi/Beaufort map gives an answer. The last 3 days show strong dispersion southward at the ice front. Wipneus' regional AMSR2 area charts help quantify the effect.
CLICK to animate.
« Last Edit: June 12, 2018, 03:35:12 PM by Pagophilus »

Pagophilus

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Re: The 2018 melting season
« Reply #1213 on: June 12, 2018, 03:59:24 PM »
Northern/Eastern Kara Sea relatively clear of clouds at last.  Contents can now be seen quite clearly, with much dark seawater between the floes in most of the sea. 

Slushy 'stringers' of melting ice extending from the pack can be seen at the northern margin (area A, second image).  And I believe the same sort of slushy 'stringers' can also be seen at area B on the map (third image) as ice melts in large volume into the Barents Sea.  At first I thought these might be clouds, but looking at the images over several days, they are persistent features.

All images Worldview, unaltered (apart from the red A and B lettering).

Tor Bejnar

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Re: The 2018 melting season
« Reply #1214 on: June 12, 2018, 04:02:12 PM »
Remember, SIA (sea ice area) does not count melt ponds as being 'ice covered sea'.  But as melt ponds are not ice free, SIA gives a false sense of ice loss during the melting season. 

(This is not to say that SIE (extent) doesn't have its own problems, as it can count actual ice-free areas between floes as being ice covered.) 

It would be interesting to see the SIA and SIE graphs for other years (like gerontocrat's graph posted above).  I suspect other years show the same divergence.

FYI:  from NSIDC:
Quote
Total ice-covered area is defined as the area of each pixel with at least 15 percent ice concentration multiplied by the ice fraction in the pixel (0.15 to 1.00). Total ice extent is computed by summing the number of pixels with at least 15 percent ice concentration multiplied by the area per pixel, thus the entire area of any pixel with at least 15 percent ice concentration is considered to contribute to the total ice extent.

This 'problem' sometimes makes me want to quit my job, damn the carbon output, and go up to the Arctic to see for myself.  I'd recommend someone do some research on just how off the two measures are by studying several actual pixel's worth (or nine) of area.
« Last Edit: June 12, 2018, 04:19:05 PM by Tor Bejnar »
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uniquorn

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Re: The 2018 melting season
« Reply #1215 on: June 12, 2018, 04:16:42 PM »
Not only is the melt impressive but also the amount of warm water rushing north. Seems that this years's impressive snowcover is now reversing its effect ...
There's little evidence of river water freezing at the mouths of the rivers yet.
Kolyma and Gusinay rivers jun9-11. There is some light cloud so the temperature image should only be taken as a rough guide.

Worldview Terra/Modis true color (scaled only)
VIIRS Brightness Temperature (Band15,day) light blue~-1C, yellow~6C

gerontocrat

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Re: The 2018 melting season
« Reply #1216 on: June 12, 2018, 04:42:47 PM »
Remember, SIA (sea ice area) does not count melt ponds as being 'ice covered sea'.  But as melt ponds are not ice free, SIA gives a false sense of ice loss during the melting season. 
Hullo Tor,

How much area does one pixel cover ?
The bigger the area, the bigger the melt pond required to be excluded from the area total?
Or does the algorithm work in a different way ?

Best regards,

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ReverendMilkbone

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Re: The 2018 melting season
« Reply #1217 on: June 12, 2018, 05:44:18 PM »
Hello all, this thread has been linked to other forums around the web, can someone here give a layman's explanation of what has been happening over the last 10-15 days? 

Sure doesn't sound good, I am just not up to speed with a lot of these terms.  Is it looking like an ice free Arctic this year?

oren

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Re: The 2018 melting season
« Reply #1218 on: June 12, 2018, 05:54:02 PM »
Remember, SIA (sea ice area) does not count melt ponds as being 'ice covered sea'.  But as melt ponds are not ice free, SIA gives a false sense of ice loss during the melting season. 
How much area does one pixel cover ?
The bigger the area, the bigger the melt pond required to be excluded from the area total?
Or does the algorithm work in a different way ?
(Warning - Wipneus is 1000 times more qualified to explain this, but let me try)
Each NSIDC grid cell is a huge 25x25 km. You can see the grid "pixels" by enabling sea ice concentration in Worldview. Scrolling this through consecutive days and toggling the ice concentration overlay can teach a lot about the meaning of the data vs. the white/blue/tendril ice you can actually see.
Worldview with sea ice concentration enabled

The size of each specific melt pond doesn't matter. What matters is the total concentration of ice vs. water as sensed by the satellite. When ice concentration drops below 15%, area and extent for that pixel are no longer counted. When ice concentration is above 15%, extent is counted as 100% of that pixel area, while area is counted as the concentration% of that pixel area. Hope this helps.

gerontocrat

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Re: The 2018 melting season
« Reply #1219 on: June 12, 2018, 06:00:23 PM »
Hullo Oren,

Thanks for the explanation.

So melt ponds can exaggerate area loss,

but on the other hand,

Melt ponds also mean (especially now at maximum insolation) that the likelihood of the ice melting out is increased substantially?


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oren

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Re: The 2018 melting season
« Reply #1220 on: June 12, 2018, 06:22:12 PM »
Yes, and yes.
Some more interesting artifacts - sometimes ice winks out, especially during a storm (rain, waves), only to come back the next day when it becomes drier. And sometimes when melt ponds become so deep that they drain through the bottom, apparent area goes up.
There's also the coastal ice that is really there but is filtered out due to the NSIDC mask, or persistently remains on their extent even after it's long gone.
In general, I think NSIDC is much more vulnerable to such shenanigans, due to its less advanced algorithm and very large grid size. And AMSR2 on the (nominally) 3.125km grid is naturally the best, especially with the "home-brew" filters added by Wipneus to remove some of the effects of clouds/water vapor among other things.
I recommend to all to read the first post on the home-brew thread for a bit more background.
« Last Edit: June 12, 2018, 06:27:54 PM by oren »

Archimid

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Re: The 2018 melting season
« Reply #1221 on: June 12, 2018, 06:32:57 PM »
In my understanding melt ponds thin the ice from above but not all the ice that melts is lost. Melted water is lost through holes in the ice,  but fresh water tends to freeze in the holes stopping the water loss. That water can then refreeze when it's cloudy and the surrounding ice is cold enough.
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Lord M Vader

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Re: The 2018 melting season
« Reply #1222 on: June 12, 2018, 06:47:53 PM »
As we are getting closer to the solstice it seems, at this moment, more and more likely that the the sea ice in ESS, Chukchi, Laptev, Barents and Kara Sea will take a major damage this season. OTOH, it looks like the sea ice in Beaufort, CAA and the adjacent areas north of Greenland will be spared this season.

This idea is based upon the GFS monthly forecast that hints of a more cyclonic weather pattern over the North American side while high pressure will remain in charge over the Siberian side.

Another factor is that the Arctic Oscillation has been mostly in its positive phase since 2013. In fact, the AO index hasn't been below -1 since fall 2015 (you can see the time series from 1950 to present day at ). Sooner or later we'll see more -AO dominate the weather in Arctic but right now I don't see such a switch to come.
Of course, a swing to -AO in July with a high pressure over the North American side would make potentially catastrophic damage to the sea ice as the ice thickness in this area is thinner than normal. Most of us remember the big high pressure in July 2015 that compensated for the lack of melting momentum by June.

//LMV

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Re: The 2018 melting season
« Reply #1223 on: June 12, 2018, 07:29:46 PM »
... Nasa came to a different conclusion in the case of the smaller Mackenzie River in 2012 ... after an ice dam gave way, Aqua infrared showed phenomenal near-surface warming of an area ~ 500 km x 500 km. (In the case of either suspended sediment or algal bloom, heat from sunlight is captured higher up in the water column than it would have been otherwise.) ...
Never thought about the Mackenzie ice dams (which develop to some extent every year, I recall reading) being part of the 2012 'perfect storm'.

... they're not talking about normal year-on-year river flow, dammed or not. 

They're talking about a one-off pulse of 9,500 km^3 of fresh water from partial drainage of Lake Agassiz - a relic of the Ice Age approximately the size of the Black Sea.  Yes, that'll have an effect on Arctic ice.  It's not remotely relevant to year-on-year observations of sea ice melt.

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Re: The 2018 melting season
« Reply #1224 on: June 12, 2018, 07:42:46 PM »
The Gulfstream peak velocity has cracked 7kmph. This is near 2 kmph faster than I've been able to find back to 2014 on null school charts. And a strong coherent lunge to the north is visible off Newfoundland.
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Re: The 2018 melting season
« Reply #1225 on: June 12, 2018, 08:24:17 PM »


... they're not talking about normal year-on-year river flow, dammed or not. 

They're talking about a one-off pulse of 9,500 km^3 of fresh water from partial drainage of Lake Agassiz - a relic of the Ice Age approximately the size of the Black Sea.  Yes, that'll have an effect on Arctic ice.  It's not remotely relevant to year-on-year observations of sea ice melt.
A-Team also quoted from 2012 an area 500 by 500 km affected
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Re: The 2018 melting season
« Reply #1226 on: June 12, 2018, 08:32:50 PM »
This event is teaching me that warm air advection and a subsequent stable temperature inversion layer are what's important to drive melt. It gives you a 1-2 punch of higher temperatures and suppressed convection to increase insolation. See: https://en.wikipedia.org/wiki/Convective_inhibition

When tracking these cyclones, I would say that the outflow and WAA are more important to follow than the cyclone track itself.

I also think we're about 2 more days away from a sustained extent cliff. ECMWF and GFS both show sustained sunny and warm conditions over the East Siberian and Laptev seas with significant melt-ponding reaching significantly into the central basin.

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Re: The 2018 melting season
« Reply #1227 on: June 12, 2018, 08:49:07 PM »
As we are getting closer to the solstice it seems, at this moment, more and more likely that the the sea ice in ESS, Chukchi, Laptev, Barents and Kara Sea will take a major damage this season. OTOH, it looks like the sea ice in Beaufort, CAA and the adjacent areas north of Greenland will be spared this season.

This idea is based upon the GFS monthly forecast that hints of a more cyclonic weather pattern over the North American side while high pressure will remain in charge over the Siberian side.

//LMV

Yes, having half the Arctic consistently sunny and warm and the other half consistently cooler and cloudy is really interesting. I don't remember anything similar since I've started reading this forum in 2015. Like LMV says, this could save half the ice. Half a bullet dodged I guess?

I wonder how much damage large cyclones later on in the season could do though? If they disperse the ice from the cloudy sector into the warmed up salty open water, it could trigger extra melt later on. That would be a second bullet to dodge.

aperson

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Re: The 2018 melting season
« Reply #1228 on: June 12, 2018, 09:04:20 PM »
Euro and GFS are both showing a significant negative dipole anomaly in the 4d window. Positive and Negative DA are both bad, the difference is which side gets the high pressure and which direction wind flows across the Arctic.

The second image is Fig. 7 from https://journals.ametsoc.org/doi/10.1175/JCLI3619.1

"Fig. 7. Composites of SLP anomalies: (a) the positive phase, (b) the negative phase, and (c) differences between (a) and (b). The blue and yellow areas in (c) represent differences exceeding the 0.05 and 0.01 significance levels, respectively. Contour interval: 1 hPa."

ArcticMelt1

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Re: The 2018 melting season
« Reply #1229 on: June 12, 2018, 09:22:15 PM »
Today, on the island of Kotelny, the record high maximum temperature (+11.4С) is up to June 19 (records from 1936).

oren

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Re: The 2018 melting season
« Reply #1230 on: June 12, 2018, 09:38:14 PM »
Temps on the Laptev shore, in Tiksi, remain seriously warm. It's a miracle the fast ice is even still there, with such temps sustained for days on end and the wind blowing north.
And now ESS shore temps, in Pevek, have joined the high club. If this also becomes sustained results will soon follow.

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Re: The 2018 melting season
« Reply #1231 on: June 12, 2018, 10:53:32 PM »
If this is real we might have a serious problem. I've gone over two months up till late July looking at this area in 2017, and it all looks like this six July example. There appears to be a broad powerful surge coming from the Atlantic and flooding east along the Russian coast.
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Re: The 2018 melting season
« Reply #1232 on: June 12, 2018, 11:04:22 PM »
I consistently see so much disparity between what RTG-SST reports and what LW IR temperatures show that I wouldn't pay too much attention to transient features from it without cross-validating with another source.

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Re: The 2018 melting season
« Reply #1233 on: June 13, 2018, 12:15:24 AM »
Post from a new member that I had to release:

Hello all, this thread has been linked to other forums around the web, can someone here give a layman's explanation of what has been happening over the last 10-15 days? 

Sure doesn't sound good, I am just not up to speed with a lot of these terms.  Is it looking like an ice free Arctic this year?
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Re: The 2018 melting season
« Reply #1234 on: June 13, 2018, 12:28:21 AM »
Is it looking like an ice free Arctic this year?
No chance of an ice-free Arctic for at least 20 years.

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Re: The 2018 melting season
« Reply #1235 on: June 13, 2018, 12:30:19 AM »
Because area is dropping faster than extent, compactness (which is area divided by extent) has also started to go down. It will probably go down some more due to the dispersion and melt ponding (this gets picked up for area, not or much less so for extent), but still has some way to go to come near the lower years:
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Pagophilus

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Re: The 2018 melting season
« Reply #1236 on: June 13, 2018, 12:51:30 AM »
On June 12 2014 the AMSR2 showed a strongly similar pattern of ice distribution to the present one.  Obviously there are differences, the most significant perhaps being the current open ocean north and east of Svalbard.  The future is always uncertain, but below is an image of June 12 2014, July 12 2014 and August 12 2014, to show how it worked out that year.  (Very similar to your predictions for this one, Lord V.)

We can perhaps expect worse, because this June 12 we start with 600,000 km2 less ice extent.   


As we are getting closer to the solstice it seems, at this moment, more and more likely that the the sea ice in ESS, Chukchi, Laptev, Barents and Kara Sea will take a major damage this season. OTOH, it looks like the sea ice in Beaufort, CAA and the adjacent areas north of Greenland will be spared this season.

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Re: The 2018 melting season
« Reply #1237 on: June 13, 2018, 01:21:18 AM »
Quote
No chance of an ice-free Arctic for at least 20 years.

That is false. There is a very low chance this year, increasing  every year that gets warmer and the weather more extreme. Saying there is no chance it will happen before 2037 is simply not true.

This year the uncertainties are the early opening of the Bering, a thin CAB, no ice North of Svalbard and the ever present warmer planet.
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Re: The 2018 melting season
« Reply #1238 on: June 13, 2018, 01:47:06 AM »
Quote
No chance of an ice-free Arctic for at least 20 years.

That is false. There is a very low chance this year, increasing  every year that gets warmer and the weather more extreme. Saying there is no chance it will happen before 2037 is simply not true.

This year the uncertainties are the early opening of the Bering, a thin CAB, no ice North of Svalbard and the ever present warmer planet.

Agreed. A statement like that is very ignorant of how the Arctic has and will continue to behave.
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Re: The 2018 melting season
« Reply #1239 on: June 13, 2018, 01:47:28 AM »
Welcome, Reverend.  I will attempt a summary, at the certain risk of exposing my ignorance to my far more knowledgeable peers on this forum.  Below is an NSIDC map of the Arctic.  You should get familiar the names of the seas and adjacent land masses... you are going to need them. If you really want to learn, get stuck into this forum -- the participants are knowledgeable, principled, open and generously tolerant of newbies like myself.  Now for the summary (gulp).

The year's melting started with an unusually quick retreat of the ice on the Pacific Side in the Bering Sea, and then into part of the Chukchi Sea.  Ongoing year on year invasion of warmer Atlantic waters has resulted in a substantial and alarming retreat of the ice on the Atlantic side, producing open ocean well to the north of the island of Svalbard. 

Over the past 10-15 days there has been a lot of melting on the Siberian side of the Arctic because it has been so warm and sunny there.  The Laptev Sea in particular has suffered, the north/eastern Kara sea is following suit, and the East Siberian Sea may be next to go.  A fierce and short-lived storm in early June pounded the ice on the Atlantic side.  The overall results of that storm are still unclear. 

There is no particular sign of a catastrophic melt of Arctic ice taking place, but the ice, by almost all measures (volume, extent, area) is lower than any point prior to 2012, and second lowest since 1979 in extent at present.  You can expect the Arctic minimum sea ice extent to go down over the next decade or two, with some considerable year-to-year variations.  When exactly there will be an 'ice-free Arctic' is uncertain, and indeed we would have to define 'ice-free' first.   That is not to say there is little cause for concern -- there is massive cause for concern.  Positive feedback loops may kick in strongly and accelerate the melting processes, and the ongoing loss of the Arctic summer ice has profound implications for our warming world.


 
Post from a new member that I had to release:

Hello all, this thread has been linked to other forums around the web, can someone here give a layman's explanation of what has been happening over the last 10-15 days? 

Sure doesn't sound good, I am just not up to speed with a lot of these terms.  Is it looking like an ice free Arctic this year?

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Re: The 2018 melting season
« Reply #1240 on: June 13, 2018, 01:47:36 AM »
Quote
No chance of an ice-free Arctic for at least 20 years.

That is false. There is a very low chance this year, increasing  every year that gets warmer and the weather more extreme. Saying there is no chance it will happen before 2037 is simply not true.

This year the uncertainties are the early opening of the Bering, a thin CAB, no ice North of Svalbard and the ever present warmer planet.

Thank you, seems like it is only a couple years away..

(ends in 2016)



Plus a chart I check everyday;

http://ocean.dmi.dk/arctic/meant80n.uk.php

Looks like we are just now going above freezing north of 80 deg.

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Re: The 2018 melting season
« Reply #1241 on: June 13, 2018, 02:29:24 AM »
Well done Pagophilus.

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Re: The 2018 melting season
« Reply #1242 on: June 13, 2018, 02:53:24 AM »
Well done Pagophilus.

Thank you, oren.         (P. blushes happily, doffs cap, steps back into the ranks)

And may I add an IR image of the Siberian side from Worldview to the record?  The skies are largely clear right now and so therefore is the overall picture for IR and related wavelength radiation.  The area from the Kara to the Laptev is as warm as we might fear, and the Kara looks as if it might be getting the worst of it, on this image.  Warmer readings at bottom right in the Kara may be from clouds, however. 

South Kara sea and ESS look more coolly resistant, but ESS seems to be edging towards melting. Again, on this image. 



« Last Edit: June 13, 2018, 05:16:44 AM by Pagophilus »

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Re: The 2018 melting season
« Reply #1243 on: June 13, 2018, 03:38:43 AM »
Rev.Milkbone,
I just watched Paul's first viedo.  Do recognize his "2020 or sooner" forecast of less than 1,000,000 sq. km. of Arctic Sea Ice (ASI) ("ice free") is his guess. 

He discounted the Gompertz curve showing ice free in 2025 (+/-), saying there was nothing that could cause that curve.  However, much discussion on the threads of this forum (ASI blog = ASIB) this winter was about how much snow may have been falling on the ice due to the extra water vapor in the air and what consequences this would have, and we've been watching winter storms drop snow (because it is cold).  (Historically, it is understood that not much snow fell over the 'desert' Arctic Ocean.)  Fresh snow has a very high albedo (reflects 95% of solar radiation) so might delay ice melt once the sun rises.  Thick snow may 'hide' melt ponds delaying their absorbing most of the solar radiation.  These would be positive feedbacks (positive here being 'good for the ice').   But snow may have negative feedbacks as well:  clouds (especially low clouds) in the winter will reduce heat loss to space (Paul showed how recent winters have been rather warmer than it used to be).  Snow is a great insulator, so if it falls on the ice when ice is thin, it would cause less ice to grow during the winter.  Countering this, if there is lots of snow on thin ice, the ice will be weighed down and sea water will mix with the bottom snow and freeze...  Anyway, you can see that trying to figure out the consequences of a new phenomenon in the Arctic (snow) is not straight forward, but that there are both positive and negative consequences for the ice. 

Chris Reynolds used to post 'really good stuff' in this forum.  One of the things he kept bringing to our attention were positive feedbacks that we hadn't recognized.  Thinking about Paul's video, he showed a graph that showed how third, fourth and fifth year ice was a smaller percentage of the ASI coverage in recent years than it used to be.  He did not point out that the 'thinning' of these curves sort of stopped a few years ago.  (Is this chance? Or is is due to Arctic realities [a positive feedback] we don't yet understand?) 

Even as the average person on these threads is rather pessimistic about the survival of summertime ASI, only a handful think 'ice free'dom will arrive this year or next. Nonetheless, a first 'blue ocean event' in 2025 or 2050 (as some of Wipneus's graphs project) is not good news for humanity!  I'm among the more pessimistic here, and I thought, back in 2012, an ice free Arctic would happen by 2019. Although I think it could happen next year, I won't be surprised if it doesn't happened in seven.

Just one more watcher, educated in earth sciences, but a neophyte when it comes to most aspects of ASI.
Arctic ice is healthy for children and other living things.

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Re: The 2018 melting season
« Reply #1244 on: June 13, 2018, 04:08:09 AM »
I consistently see so much disparity between what RTG-SST reports and what LW IR temperatures show that I wouldn't pay too much attention to transient features from it without cross-validating with another source.

No SERIOUSLY, I am NOT referring to SST, but the current that is heading east at a consistant speed in a band hundreds of km out from the coast. The speed being about five times that of the peak speeds usually measured here. And its usually all eddies and not much else along this coast. I don't know what null school bases its current maps on. But if this has been going on for months and very odd ssta distribution in the Atlantic suggests that it may well have, this is a major mode change with as some rough calculations suggest to me, a million to over 20 million tonnes per second of Atlantic water flowing along the Russian coast. The sudden thinning of that huge swath of ice eastward along the ESAS over the last week may have not just been about the weather, but the mixing of the fresh surface with a warm tongue of Atlantic water intruding underneath over the shallow shelf. There has been hints posted  earlier on this thread that this had started to happen with the increase in salinity at, was it 30m? depth in a connecting finger between the Atlantic and Pacific sides. This could be a rapid and complete atlantification of the whole Arctic basin in progress.
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Re: The 2018 melting season
« Reply #1245 on: June 13, 2018, 05:09:38 AM »
Terra / MODIS Bands 7-2-1 imagery from June 10th to 13th of the East Siberian Sea (ESS) coastline (click to animate. It may load slowly but I think it's instructive to see what sustained insolation and above freezing temperatures due to ice).

I recommend using this band over visible imagery since it makes melt pond intensity much clearer, and it separates clouds from snow better in the melt season since fewer clouds are composed of ice droplets. From the description:

Quote
Liquid water on the ground appears very dark since it absorbs in the red and the SWIR. Sediments in water appear dark blue. Ice and snow appear as bright turquoise. Clouds comprised of small water droplets scatter light equally in both the visible and the SWIR and will appear white. These clouds are usually lower to the ground and warmer. High and cold clouds are comprised of ice crystals and will appear turquoise.

In this series of images we can sea rapid snowpack retreat and melt pond formation. I am surprised at the change in albedo over 4 days.

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Re: The 2018 melting season
« Reply #1246 on: June 13, 2018, 05:10:46 AM »
Blue meltponds have appeared on the ESS fast ice over the past couple of days

The silt plume of this lesser river, compared to the Lena(the Pegtymel I believe) entering in the Eastern ESS is visible at least 30km out the sea despite having having only broken a channel through the shore ice. The nutrients in the silt must play a part in algal blooming as well as the immediate effect on albedo, warmth and salinity

2 images from june 13

edit: that silt has been pouring under the coastal ice for a week at least, and the plume can be seen pushed along the coast, with the siltiest area in today's frame only the most recent flow, which must be heading to its peak - I replaced the still with a gif of the last 6 days, The river has been flowing/plume developing longer than that but it was too cloudy to see the water clearly
« Last Edit: June 13, 2018, 05:59:58 AM by subgeometer »

Pagophilus

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Re: The 2018 melting season
« Reply #1247 on: June 13, 2018, 05:15:27 AM »
Thanks for this.   It summarized and clarified a lot for me.


However, much discussion on the threads of this forum (ASI blog = ASIB) this winter was about how much snow may have been falling on the ice due to the extra water vapor in the air and what consequences this would have, and we've been watching winter storms drop snow (because it is cold).  (Historically, it is understood that not much snow fell over the 'desert' Arctic Ocean.)  Fresh snow has a very high albedo (reflects 95% of solar radiation) so might delay ice melt once the sun rises.  Thick snow may 'hide' melt ponds delaying their absorbing most of the solar radiation.  These would be positive feedbacks (positive here being 'good for the ice').   But snow may have negative feedbacks as well:  clouds (especially low clouds) in the winter will reduce heat loss to space (Paul showed how recent winters have been rather warmer than it used to be).  Snow is a great insulator, so if it falls on the ice when ice is thin, it would cause less ice to grow during the winter.  Countering this, if there is lots of snow on thin ice, the ice will be weighed down and sea water will mix with the bottom snow and freeze...  Anyway, you can see that trying to figure out the consequences of a new phenomenon in the Arctic (snow) is not straight forward, but that there are both positive and negative consequences for the ice.

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Re: The 2018 melting season
« Reply #1248 on: June 13, 2018, 05:18:24 AM »
The weather models continue to show a favorable pattern overall after day 5-6 for the Arctic at whole in terms of ice retention.


Tho the Russian side is still looking warm.




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Re: The 2018 melting season
« Reply #1249 on: June 13, 2018, 05:53:42 AM »
Hyperion, I checked out the recent developments on SMOS Bremen in response to your post, and I went from quiet complacency to a fit of the heebie-jeebies.  Now I'm calmer, but I think your comments deserve serious consideration.

I have posted the set of SMOS images below for June 2, 6, 9 and 11.  I realize the SMOS can be temperamental, but there does seem to be a progression in the results.  Or is it that SMOS is just being weird?  (I notice a random instant flare-up of SMOS 'thin ice' in the CAA on the June 11 image, which seems massively improbable.)  Or is something else going on, like surface melting, to cause this pattern? Or, heaven forbid, are you right?  Comments, anyone, who knows more about this? 


No SERIOUSLY, I am NOT referring to SST, but the current that is heading east at a consistant speed in a band hundreds of km out from the coast. The speed being about five times that of the peak speeds usually measured here. And its usually all eddies and not much else along this coast. I don't know what null school bases its current maps on. But if this has been going on for months and very odd ssta distribution in the Atlantic suggests that it may well have, this is a major mode change with as some rough calculations suggest to me, a million to over 20 million tonnes per second of Atlantic water flowing along the Russian coast. The sudden thinning of that huge swath of ice eastward along the ESAS over the last week may have not just been about the weather, but the mixing of the fresh surface with a warm tongue of Atlantic water intruding underneath over the shallow shelf. There has been hints posted  earlier on this thread that this had started to happen with the increase in salinity at, was it 30m? depth in a connecting finger between the Atlantic and Pacific sides. This could be a rapid and complete atlantification of the whole Arctic basin in progress.
« Last Edit: June 13, 2018, 06:49:47 AM by Pagophilus »