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seaicesailor

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Re: The 2016 melting season
« Reply #1950 on: June 07, 2016, 12:34:26 AM »
Wherther that is hitting the nail on the head. I wonder to what point the weather patterns can really quench such a heat wave from just about everywhere in the NH since winter.
Jimbo Omega my impression is that when there are already open fronts that have been picking up sun heat (Beaufort) or convected from warm current (Svalbard) for a while, ice expansion over it is ice melting faster. There is no refreezing in the Atlantic side at this time, just ice drifting and eventually melting out.
The extent stall is probably laughs today tears tomorrow.

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Re: The 2016 melting season
« Reply #1951 on: June 07, 2016, 12:52:38 AM »
When talking about stalling extent or 'expansion' (dispersion would be better, but it looks as if the ice pack edge is expanding towards both Pacific and Atlantic), I do not mean to imply that everything has come to a full stop. On the contrary, I don't think that pushing ice out towards the Atlantic is good news at all for the ice (like sis says: laughs today, tears tomorrow).

Below Chris Reynolds' latest blog post I have just described my thoughts as they are right now with regards to this melting season and its record breaking prospects:

Quote
Thanks for a great post, Chris. Very stimulating. It was difficult to find something I disagree with, but here goes.

Quote
A new record is possible this year, but from my reading of all the data it is far from certain. With poor melt weather we could yet again see an increase in September volume on last year.

I believe it will take extremely poor melt weather for this year to end up above 2015 volume-wise. Why? Because there seems to be so much more heat in the system this year.

As for breaking the 2012 sea ice extent record, I'm agnostic just like you. There will definitely have to be periods you describe (sunny weather, high temps) for it to be possible, but here's a short list describing what factors each year has to bolster it's championship aspirations:

2012
- Exceptionally good melt weather the first half of June, perhaps the best there has ever been (in the record)
- Some more good melt weather during July
- Huge volume drops during May and June
- Very low compactness
- GAC during August

2015 (edit: I meant 2016, of course)
- Warmest winter on record
- Extremely early opening of Beaufort Sea where a lot of MYI is
- Even more MYI positioned right in front of Fram Strait, quite a bit of transport so far due to Beaufort Gyre
- Lowest snow cover on record for extended periods (Northern Hemisphere will be virtually snow-free - except for CAA and Greenland, of course - by next week, probably earliest on record)
- Lowest volume on record as of end of May
- Lowest volume outside of the CAB, where the ice is easier to melt
- A lot of thicker ice supposedly along the Siberian coast, that is under quite an intense heat wave as we speak (melt ponding, preconditioning)
- Compactness relatively low right now, due to melt ponding and dispersion into Atlantic and Beaufort Sea, possibly meaning more melting momentum during July and August
- Warm Atlantic (we don't know how warm, not enough real-time data)

So, anything is possible, but judging from this snapshot, the odds seem to be in 2016's favour, although its massive sea ice extent lead over 2012 is probably going to be slashed in the next 10 days.

It'll be exciting to see what happens after that. And hopefully not too depressing. Mixed feelings as always.
« Last Edit: June 07, 2016, 09:54:33 AM by Neven »
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bbr2314

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Re: The 2016 melting season
« Reply #1952 on: June 07, 2016, 12:56:49 AM »
The FRAM movement will result in a prolonged stall (as we had discussed previously and as I had mentioned would happen before the histrionics re: stall started).

Now HYCOM shows the next stage; after all the movement towards both the ATL and the PAC, there will be massive cracking developing right through the heart of the Arctic. So while extent may have temporarily stalled, this will yield to a major crash in area starting shortly. The pack is literally being ripped in half right now.


JimboOmega

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Re: The 2016 melting season
« Reply #1953 on: June 07, 2016, 01:14:37 AM »
The FRAM movement will result in a prolonged stall (as we had discussed previously and as I had mentioned would happen before the histrionics re: stall started).

Now HYCOM shows the next stage; after all the movement towards both the ATL and the PAC, there will be massive cracking developing right through the heart of the Arctic. So while extent may have temporarily stalled, this will yield to a major crash in area starting shortly. The pack is literally being ripped in half right now.
(image edited)

Assuming this image is indicative - is there precedent for the ice splitting in half so majorly like that?

I imagine that it's much too warm for the newly open water to refreeze, so... if it has happened, what does it mean based on analogue years?

Neven

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Re: The 2016 melting season
« Reply #1954 on: June 07, 2016, 01:20:41 AM »
I imagine that it's much too warm for the newly open water to refreeze, so... if it has happened, what does it mean based on analogue years?

It means that the floes aren't going to move very far apart, unless some really big cyclones force them to. Floes in the ice pack tend to stick together. 2012 was the only year where really large portions of the pack separated themselves, forming sea ice islands that completely melted out.

But compactness will go down, and if ice floes are dispersed with clear skies above them, it could mean heavy melting later on. But I don't believe there will be very sunny skies over the Central Arctic for the time being, according to the forecast models.
« Last Edit: June 07, 2016, 01:27:23 AM by Neven »
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Re: The 2016 melting season
« Reply #1955 on: June 07, 2016, 01:42:23 AM »
werther writes:
Quote
MODIS today reveals some clear views and very interesting detail. Lots of small calvings (Amundsen Gulf etc)
Indeed the whole Amundsen turned blue 'over-night'. And then ever bluer the next day, June 6th. In the composite image, the arcuate piece has been moved directly upward to clear its fracturing counterpart of the 5th.

Once again, the breaks did not occur along old lines of refreezing and indeed seem unpredictable more than a few days in advance using satellite imagery to which we have access.

The image needs a click to display at its underlying resolution of 250 m.
« Last Edit: June 07, 2016, 03:35:29 AM by A-Team »

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Re: The 2016 melting season
« Reply #1956 on: June 07, 2016, 09:45:50 AM »
HYCOM shows extensive melting of the Beaufort Bastion...

meddoc

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Re: The 2016 melting season
« Reply #1957 on: June 07, 2016, 10:02:16 AM »
: meddoc  June 06, 2016, 06:27:02 PM
Regarding all that heat in the oceans (around 10e 22 Joules), I've already calculated that around
10e 16 Joules are required to melt an ice- mass of 25,000 km3 and at an average temperature of -10 C.


Calculate it again

Let's see trebuh

25.000.000 m3 x 917 kg/m3 x (10 C x 2100 J/kg x C + 334.000 J/kg) = 8,13 x 10e 15 J

« Last Edit: June 07, 2016, 10:48:16 AM by meddoc »

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Re: The 2016 melting season
« Reply #1958 on: June 07, 2016, 10:05:12 AM »
I think we should be keeping a close eye on Kara and Laptev over the next 2 days.

A pretty deep depression is currently developing over the Kara sea and will reach it's peak in about 24 hours, with surface air temps generally above 0C too





The ice over northern Kara and into Laptev looks quite fragmented and weak, leaving it easily open to attack from the storm.



I think there's a reasonable chance of sea ice in the southern Kara sea getting cut off from the rest of the pack soon.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Laurent

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Re: The 2016 melting season
« Reply #1959 on: June 07, 2016, 11:05:40 AM »
No wonder why the extent is kind of stalling compared to 2012, there is a huge melt all over the Arctic.
First the strength graph of hycom : http://www7320.nrlssc.navy.mil/hycomARC/navo/beaufortstrength_nowcast_anim30d.gif show that the ice is shattered nearly everywhere Beaufort, Chukchi, big part of central Arctic, Canadian Archipelago.

Off course I am picking the worst image and it is very volatile but just to have an idea.
Melting more important in the area 80° 170E

Thickness Forecast, not always true but good enough.
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif

Look in the Greenland sea area, something is brewing there, I don't find it normal, it looks as if the Atlantic wanted to take over the Fram from the Greenland side (hope that is just bullshit well i mean just winds and mecano elasticity of the ice).
« Last Edit: June 07, 2016, 11:34:12 AM by Laurent »

Adam Ash

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Re: The 2016 melting season
« Reply #1960 on: June 07, 2016, 11:47:34 AM »
Ummm.. in that last gif, it looks like the Beaufort Gyre is running in reverse - anti-clockwise!!  WTHeck?

Laurent

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Re: The 2016 melting season
« Reply #1961 on: June 07, 2016, 12:28:57 PM »
I thought it could be a mistake of mine making the gif... but no :
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif
Winds are prevailing over the beaufort Gyre.
http://www.weather-forecast.com/maps/Arctic?over=arrows&symbols=none&type=cloud

Considering winds in the Greenland sea, then that is a more reasonable point nethertheless I am still thinking the Atlantic is trying to get a grip on the other side.

Adam Ash

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Re: The 2016 melting season
« Reply #1962 on: June 07, 2016, 12:52:40 PM »
That all looks to be conspiring to arrange a mass exodus of everything from the CAA and eastern Beaufort straight over the pole to the North Atlantic cooking pot via the Barents instead of the usual dribble via Fram Straight.  Time will tell!

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Re: The 2016 melting season
« Reply #1963 on: June 07, 2016, 01:08:51 PM »
917 kg/m3

The density of ice at 0°, roughly, but if we're going to be pedantic about calculations here, you probably want to start with density at -10° if that's where things are beginning, which brings us to 919 kg/m3.

http://www.engineeringtoolbox.com/ice-thermal-properties-d_576.html

The more interesting density difference to me, though, is the huge difference in snow types.  I bet that's #!^@& to model and it may have dramatic impacts on the evolution of the season.  When I think "low winter power", that has implications for sea ice, but probably even stronger implications on land.

http://www.sengpielaudio.com/calculator-densityunits.htm

Fresh snow dry and light 30 – 50 kg/m³
Fresh snow weakly bound 50 – 100 kg/m³
Fresh snow strongly bound 100 – 200 kg/m³
Old snow dry 200 – 400 kg/m³
Old snow wet 300 – 500 kg/m³
Swimming snow 150 – 300 kg/m³
Firm snow (several years) 500 – 800 kg/m³
Ice 800 – 900 kg/m³
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Steven

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Re: The 2016 melting season
« Reply #1964 on: June 07, 2016, 01:11:12 PM »
Northern Hemisphere terrestrial snow cover extent for May 2016 was 4th lowest on record, according to Rutgers Global Snow Lab:

http://climate.rutgers.edu/snowcover






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Re: The 2016 melting season
« Reply #1965 on: June 07, 2016, 01:19:32 PM »
Northern Hemisphere terrestrial snow cover extent for May 2016 was 4th lowest on record, according to Rutgers Global Snow Lab:

Yes, which is why I found the snow density numbers to be so interesting.  I don't know that I've seen hemispheric snow mass or volume estimated before.  Is there a data series I'm missing that someone could refer me to?  PIOMAS for snow?

The area is obviously more important for albedo and reflectivity and thus more important in general.  However, the delta between 100 kg/m3 and 500 kg/m3 is not just huge in relative terms, but probably also huge in absolute terms, depending on just how much snow volume there is.

I bet there's enough volume to matter, but that's a SWAG.  I can't do math.  I just criticize others who can.  ::)
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Re: The 2016 melting season
« Reply #1966 on: June 07, 2016, 01:28:44 PM »
We thought those Pacific polynyas would be connected within a couple of days? The Arctic said NO.
Well, Bering bridge is a goner now, and Beaufort one - we _almost_ seen it go. I think, it would be better for the remaining ice if it would go, too. How exactly does it persist? With import of more ice from the north, basically, it looks to me. So it means less ice remaining up north - and more ice arriving to where it can melt easier. Lose/lose situation for the basin as a whole...
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Re: The 2016 melting season
« Reply #1967 on: June 07, 2016, 01:31:06 PM »
: meddoc  June 06, 2016, 06:27:02 PM
Regarding all that heat in the oceans (around 10e 22 Joules), I've already calculated that around
10e 16 Joules are required to melt an ice- mass of 25,000 km3 and at an average temperature of -10 C.


Calculate it again

Let's see trebuh

25.000.000 m3 x 917 kg/m3 x (10 C x 2100 J/kg x C + 334.000 J/kg) = 8,13 x 10e 15 J
Hm, excuse me, but 25.000 km3 = 25.000.000.000.000 m3, not 25.000.000. One km3 contains 1 billion m3. Not 1 thousand.
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Re: The 2016 melting season
« Reply #1968 on: June 07, 2016, 01:37:52 PM »
Thanks for the snow cover data, Steven. I can stop F5-ing that page now. PIOMAS updated too, so there will be a blog post on that later today, as soon as TypePad comes back to life.

Well, Bering bridge is a goner now, and Beaufort one - we _almost_ seen it go. I think, it would be better for the remaining ice if it would go, too. How exactly does it persist? With import of more ice from the north, basically, it looks to me. So it means less ice remaining up north - and more ice arriving to where it can melt easier. Lose/lose situation for the basin as a whole...

If the winds won't do it, I guess temps will, starting next week (see actual temp forecast for next week below). Will the ice blockade be gone by mid-June? That would still be 2-3 weeks earlier than in 2009 and 2011.
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Re: The 2016 melting season
« Reply #1969 on: June 07, 2016, 01:39:36 PM »
My bad, so add six zeroes. Then it's :

8,13 x 10e 21 Joules.

Which is only 1 magnitude less- 1/10 of the Heat stored in the Oceans.

So, I'm a bit more relaxed now, but still, much of this Heat is carried to the 2 Poles.

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Re: The 2016 melting season
« Reply #1970 on: June 07, 2016, 02:09:13 PM »
scrolling down to the bottom of this page:
http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/
Quote
Perspective: Ice Loss and Energy

It takes energy to melt sea ice. How much energy? The energy required to melt the 16,400 Km3 of ice that are lost every year (1979-2010 average) from April to September as part of the natural annual cycle is about 5 x 1021 Joules. For comparison, the U.S. Energy consumption for 2009 (www.eia.gov/totalenergy) was about 1 x 1020 J. So it takes about the 50 times the annual U.S. energy consumption to melt this much ice every year. This energy comes from the change in the distribution of solar radiation as the earth rotates around the sun.

To melt the additional 280 km3 of sea ice, the amount we have have been losing on an annual basis based on PIOMAS calculations, it takes roughly 8.6 x 1019 J or 86% of U.S. energy consumption.

However, when spread over the area  covered by Arctic sea ice, the additional energy required to melt this much sea ice is actually quite small. It corresponds to about 0.4 Wm-2 . That’s like leaving a very small and dim flashlight bulb continuously burning on every square meter of ice. Tracking down such a small difference in energy is very difficult, and underscores why we need to look at longer time series and consider the uncertainties in our measurements and calculations.

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Re: The 2016 melting season
« Reply #1971 on: June 07, 2016, 02:20:52 PM »
weather conditions in coronation gulf (is this right?) look like optimal preconditioning  followed by energy input:

F.Tnioli

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Re: The 2016 melting season
« Reply #1972 on: June 07, 2016, 03:40:47 PM »
...
Thickness Forecast, not always true but good enough.

...
When i look at this, i think: that WHOLE TON of bottom melt, around some regions between ~72 and ~86 degrees latitude, and longitude-wise all the way +-90 degrees from 180E.

I even got this wild idea: if there is some near-0 water under the ice, and it starts to melt it from the bottom, and some under-ice current exists at the location, then sort of "under-ice river" would form: whereever the current is most intensive, intensity of melt would be higher (as more near-0 water comes through, melting more ice), and so along such "under-ice river flow", the ice would get thinner than to the sides of the "river", forming a bit wider "opening" under-ice for the water to flow through, and so more water flows through, and the process then self-amplificating - very very slowly, but still.

And later as ice compacts mechanically, those "passages" under the ice would disappear from time to time. Can this explain some few of those "colored lines" we see popping up in so many places on that animation, i wonder.
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Re: The 2016 melting season
« Reply #1973 on: June 07, 2016, 03:50:30 PM »
Here is the Beaufort Gyre from May 25th up to June 7th. It is not counter-rotating yet despite winds favoring that at GFS nullschool; both translational and rotational motion are jittery and depend somewhat on which floe is being tracked. Note the expansive dispersion in the lower Gyre in the last few frames (two-frame animation at bottom: blue is later date June 7th).

Someone asked how these are made. The issues are variable thickness clouds and weak floe contrast. After capturing the dates at a size slightly larger than needed, a round of adaptive contrast (ImageJ --> CLAHE set to 64 blocksize, 175 slope) and four rounds of auto B&C contrast compression on the grayscaled images, a cropping frame is found that holds the floes in view over the 14 days and the image resized to fit forum constraints on pixel dimensions and overall file size.

A 'before' is attached for the first frame of 25 May 16. It's not feasible to totally remove cloud cover but floe tracking (recognizability) and floe monitoring (collisions and disintegration) can be markedly improved.

Given all the Modis-based products we use on these forums, I just have to wonder how many of them just go with the raw image as provided on WorldView. ie could readily be improved. NASA could easily add a scripted enhanced layer option but they won't because the targeted scientific audience is largely pre-photoshop and fixated with literal imagery even when making no real use of sensor brightness or color.

The set-up is here: http://go.nasa.gov/1PDyAwL; a bit of Banks Island and Prince Patrick are showing that provide locational context.
« Last Edit: June 07, 2016, 05:02:43 PM by A-Team »

Neven

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Re: The 2016 melting season
« Reply #1974 on: June 07, 2016, 04:19:30 PM »
Very nice, A-Team.
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Re: The 2016 melting season
« Reply #1975 on: June 07, 2016, 05:51:36 PM »
It is heading to some nice warm temperatures in Kugluktuk later this week, highs of 17C, currently 5C and raining:

http://weather.gc.ca/city/pages/nu-16_metric_e.html


Yet in Timmins Ontario, expecting wet snow tonight :(

http://weather.gc.ca/city/pages/on-127_metric_e.html
and so it goes

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Re: The 2016 melting season
« Reply #1976 on: June 07, 2016, 05:56:23 PM »
Very nice, A-Team.
Definitely.  In addition to the dispersion starting in the last frames, its also pretty obvious that the larger floes and many of the smaller ones are breaking up further. 

Still a very long way from the 100M diameter where side melt starts to become a factor, but opening up more open water in the interior of the pack and making more likely that mechanical factors in flow will bring up more water - and heat - from depth.
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Re: The 2016 melting season
« Reply #1977 on: June 07, 2016, 06:20:50 PM »
I follow this site very closely, and I'm very interested in the IJIS data. Can somebody help me to understand why the size of the pack is currently stalled out? I understand this season was off to an aggressive start, but I don't understand what is currently going on. After looking at the images posted, it does look like there is bottom melt going on since the ice thickness continues to decrease across all areas, by why is it not shrinking for the moment? Do you guys think there is still substantial melt going on, but the pack is being spread out so that its extent is roughly the same? I can't quite wrap my head around the processes at play that would cause such an event to occur. Perhaps it has been quite cold the stall is real; I don't know.
pls!

bbr2314

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Re: The 2016 melting season
« Reply #1978 on: June 07, 2016, 06:30:37 PM »
There are about 500 posts describing why it has stalled if you want to go back and read any of the past few pages....

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Re: The 2016 melting season
« Reply #1979 on: June 07, 2016, 06:32:44 PM »
Do you guys think there is still substantial melt going on, but the pack is being spread out so that its extent is roughly the same?

Physics and meteorology would strongly suggest melt is continuing or accelerating, which by default leaves increased dispersion of the leading edges of the ice pack as the most probable explanation.

With  some work, the gridded sea ice concentration data available from some agencies could be used to check this hypothesis, but more than likely it will be a short-lived phenomenon as ice continues to melt out.

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Re: The 2016 melting season
« Reply #1980 on: June 07, 2016, 06:39:08 PM »
There are about 500 posts describing why it has stalled if you want to go back and read any of the past few pages....
When someone has already admitted they don't understand the previous explanations, suggesting they go back and read them again is obnoxious and foolish.

I'd far sooner have honest newbie questions than this kind of snarky crap.

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Re: The 2016 melting season
« Reply #1981 on: June 07, 2016, 06:41:02 PM »
There are about 500 posts describing why it has stalled if you want to go back and read any of the past few pages....

I have read through the last few pages...there is so much going on so my apologies for asking a question in this thread.

From what I've seen it appears as though the ice is being set up for some substantial drops once the weather favors more melt. Even Barrow, AK hit 46F yesterday. Well, I'll go back to lurking, I don't feel like getting yelled at.
pls!

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Re: The 2016 melting season
« Reply #1982 on: June 07, 2016, 06:56:30 PM »
Ummm.. in that last gif, it looks like the Beaufort Gyre is running in reverse - anti-clockwise!!  WTHeck?

If you look at the Barrow radar map you'll see that off-shore broken up ice is moving by from the west, the inshore ice at Nunavaq just broke off.  I don't think the Barrow ice will last much longer.

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Re: The 2016 melting season
« Reply #1983 on: June 07, 2016, 07:07:28 PM »
... Do you guys think there is still substantial melt going on, but the pack is being spread out so that its extent is roughly the same? ...
We do indeed. See, when ice fragments enough, some wave and wind actions often disperse pieces over greater area than initial "one big solid piece" occupied.

But personally i think it's something else being major factor here. The "extent" total number includes regions with as low as 30% ice concentration (in some systems - even as low as 15%), you can see how this can compensate for loss of ice due to melt because of the above paragraph. Some areas "slush" into larger extent, others "ice covered" in extent-sense areas - shrink as ice melts away completely, and when there is much former and not too much latter, extent numbers can stall for a while.

Check "ice area" numbers if you can. They tell a bit better story, overall. Still far from perfect, of course. Volume numbers are IMHO the best if one wants to know "how much melt is going on", but sadly those are hardest to get, larger uncertainty, and way less sources, especially near-realtime.

The opposite thing is noted too, with varying scale, every melt season: i.e. when big areas of "low concentration" extent happen to "cross minimum allowable concentration to be counted as ice extent", - then we see extent numbers dropping multi-hundred thousands square kilometers per day without correspondedly intensive real physical melt going on. Usually that's a thing for way later in a melt season to happen.

Basically both sorts are mostly quirks of the calculation method called "sea ice extent" rather than real physical processes, i think.
To everyone: before posting in a melting season topic, please be sure to know contents of this moderator's post: https://forum.arctic-sea-ice.net/index.php/topic,3017.msg261893.html#msg261893 . Thanks!

CraigsIsland

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Re: The 2016 melting season
« Reply #1984 on: June 07, 2016, 07:41:52 PM »
There are about 500 posts describing why it has stalled if you want to go back and read any of the past few pages....

I have read through the last few pages...there is so much going on so my apologies for asking a question in this thread.

From what I've seen it appears as though the ice is being set up for some substantial drops once the weather favors more melt. Even Barrow, AK hit 46F yesterday. Well, I'll go back to lurking, I don't feel like getting yelled at.

No worries - explore the other bits of the forum, there may be a more relevant thread than this beast of a thread.

Welcome fellow lurkers!

seaicesailor

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Re: The 2016 melting season
« Reply #1985 on: June 07, 2016, 08:01:35 PM »
I follow this site very closely, and I'm very interested in the IJIS data. Can somebody help me to understand why the size of the pack is currently stalled out? I understand this season was off to an aggressive start, but I don't understand what is currently going on. After looking at the images posted, it does look like there is bottom melt going on since the ice thickness continues to decrease across all areas, by why is it not shrinking for the moment? Do you guys think there is still substantial melt going on, but the pack is being spread out so that its extent is roughly the same? I can't quite wrap my head around the processes at play that would cause such an event to occur. Perhaps it has been quite cold the stall is real; I don't know.

Ice is dragged around by winds and it just happens that diverging winds are strongly pushing ice toward the Atlantic Ocean and weakly pushing Beaufort ice toward the coast. The two main open fronts.
A lot of melt going on, see AMSR2 thread in particular. It is hitting precisely where there is no open water so extent does not go down suddenly, but melting starts on the surface.
As for bottom melt I dont think it is really happening in Central Arctic because temperatures have to be sustained over freezing for a few days, see buoy 2015F where it was bottom-freezing until a couple of weeks, and bottom melt did not start yet (apparently surface melting did not either).

http://imb.erdc.dren.mil/2015F.htm

Beaufort sea is also relatively cold but there is a lot of open water.
That thing from the thickness map of HYCOM is not bottom melt, but the predicted effect of a low pressure system. The thickness prediction of this model is totally unreliable though. The low will mess up a bit (mechanically break and separate ice). But volcano wont be erupting under the ice.
Edit: although if the storm is strong or persistent enough, it can literally make a hole on the ice cap... is that coming?
« Last Edit: June 07, 2016, 08:14:46 PM by seaicesailor »

JayW

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Re: The 2016 melting season
« Reply #1986 on: June 07, 2016, 08:32:34 PM »
Run to run consistency hasn't been great, so take with salt.

ECMWF spins up quite the cyclone at hour 120
http://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=nhem&pkg=z500_mslp&runtime=2016060712&fh=144&xpos=0&ypos=129
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seaicesailor

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Re: The 2016 melting season
« Reply #1987 on: June 07, 2016, 08:36:06 PM »
Well... that can make a hole lol

woodstea

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Re: The 2016 melting season
« Reply #1988 on: June 07, 2016, 09:42:46 PM »
I follow this site very closely, and I'm very interested in the IJIS data. Can somebody help me to understand why the size of the pack is currently stalled out? I understand this season was off to an aggressive start, but I don't understand what is currently going on. After looking at the images posted, it does look like there is bottom melt going on since the ice thickness continues to decrease across all areas, by why is it not shrinking for the moment? Do you guys think there is still substantial melt going on, but the pack is being spread out so that its extent is roughly the same? I can't quite wrap my head around the processes at play that would cause such an event to occur. Perhaps it has been quite cold the stall is real; I don't know.

I think it might help to think about what you mean by "the size of the pack". Watching the sea ice extent numbers daily, it's easy to forget SIE is just an abstraction, not the actual amount of sea ice out there in the real world. The extent will go up and down as winds pull ice apart and push it together, even if the amount of ice is exactly the same. It's not terribly meaningful -- at least on its own -- over a short time frame.

I agree with seaicesailor that it appears a lot of surface melt is happening to thick ice. Up to a certain point that won't register in the extent number, but it could be setting the stage for a series of massive drops later on. Or not. Time will tell...

Lord M Vader

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Re: The 2016 melting season
« Reply #1989 on: June 07, 2016, 09:44:58 PM »
GFS ensemble supports the idea of a rather naughty cyclone in the Arctic basin. And ECMWF 00z ensemble also had a fairly naughty cyclone so I thinkthe forecast is fairly trustworthy. The question is how bad this would be for the ice and in what form the precipitation will come. If snow it's good for the ice,if rain well not so good...

In any case, as the forecast calls for a more or less neutral AO I think we won't see a new record low this year. And I think my original guess for 3,7-3,9 Mn km2at minimum might have been too optimistic. From now it might be more reasonable to believe that the minimum would end up somewhere in the range 3,9-4,7 Mn km2 unless more HP-dominated weather will set in by the end of June and July. In addition, more WAA is also needed.

Best, LMV

Laurent

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Re: The 2016 melting season
« Reply #1990 on: June 07, 2016, 09:57:01 PM »
Pearscot do we have answered your question ?
You may reply in stupid questions thread, it is not about stupid questions but about things that are obvious (seem to) for people reading this forum for a long time.
http://forum.arctic-sea-ice.net/index.php/topic,143.msg78353.html#msg78353

A-Team

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Re: The 2016 melting season
« Reply #1991 on: June 07, 2016, 10:02:39 PM »
Quote
Run to run consistency of ECMWF hasn't been great 120 hrs
Being very forward directed here, we don't spend nearly enough time going back and seeing what actually transpired, both in actual weather and effect on the floes.

Below the  ECMWF image 3 posts back is enlarged, with Banks Island (barely locatable on their 1950's vintage map) in pink. This event is well west of the Beaufort Gyre.

Stepping through GFS forecast 3 hours at a time for the same period over at nullschool, there is a similar but weaker predicted cyclone that would act towards reversing the direction of gyration. (There's little difference using Sfc or 850 relative to 1000 height, not shown.)

Sigmetnow

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Re: The 2016 melting season
« Reply #1992 on: June 07, 2016, 10:05:05 PM »
Time lapse of dwindling old arctic sea ice, updated to March 2016.
https://www.youtube.com/embed/-lachmN5YO4
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Neven

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Re: The 2016 melting season
« Reply #1993 on: June 07, 2016, 10:10:26 PM »
Well, I'll go back to lurking, I don't feel like getting yelled at.

There was no yelling, just some snark, don't worry about it.

And yes, you were right, JAXA SIE is most probably stalling because like seaicesailor said: diverging winds are strongly pushing ice toward the Atlantic Ocean and weakly pushing Beaufort ice toward the coast. I made two animations yesterday showing just this (previous page).
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RoxTheGeologist

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Re: The 2016 melting season
« Reply #1994 on: June 07, 2016, 10:34:59 PM »
Over on the Atlantic side the icecookiemonster can't keep up either. Up to now, we had spectacular ice edge retreat on both sides of the Arctic. Now we have expansion on both sides of the Arctic, causing sea ice extent to stall completely. What an awesome place.

It does seem to me that there has been more melting in 2016 than the previous two years between Svalbard and Franz Josef lands (perusing worldview). Isn't CAB ice being spread out and pushed over warmer Atlantic water? From my Negroni making experience, this is going to melt the ice a lot faster than not mixing, despite the extent increasing. What surprises is that there isn't a coincidental area loss. Will that take a few days to show up?

DavidR

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Re: The 2016 melting season
« Reply #1995 on: June 07, 2016, 11:00:27 PM »
What surprises is that there isn't a coincidental area loss. Will that take a few days to show up?
Area loss for June so far is right on average,( 411K vs 412K) and well ahead of 2012, which has over 600K km^2 more area. So its showing reasonable melt  for this time of the year. I agree the stall is a lot about extent being blown into  warm water.
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JimboOmega

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Re: The 2016 melting season
« Reply #1996 on: June 07, 2016, 11:06:08 PM »

It does seem to me that there has been more melting in 2016 than the previous two years between Svalbard and Franz Josef lands (perusing worldview). Isn't CAB ice being spread out and pushed over warmer Atlantic water? From my Negroni making experience, this is going to melt the ice a lot faster than not mixing, despite the extent increasing. What surprises is that there isn't a coincidental area loss. Will that take a few days to show up?

I am also curious what we "expect" to happen with this current spreading reality. Is the ice actually just getting smooshed thinner? Will cracks and leads develop through the middle of the pack?  Will that allow significant insolation enhancement?

Anyway, on Friday I was shocked when I saw what I was subsequently informed were melt ponds over the ESS in the ASMR2 imagery. That seems to have become mostly a static feature, at least according to ASMR2 over the course of the last few days.  Even though the heat has remained "on" in that area....  Bad, increased absorption of solar heat, etc. But it's not the least bit clear to me when/where that "bad" actually has an impact. Maybe it stays like that until July?

I've read a few people saying that the current extent growth/plateau is a long term "bad" thing for the ice, but I haven't seen a time range attached to it.  Or what exactly happens when the longer term "bad" impact is realized.

So... curious what we can expect in the next week or so, especially from those who have watched this a lot closer than I in recent years.
« Last Edit: June 07, 2016, 11:31:29 PM by JimboOmega »

woodstea

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Re: The 2016 melting season
« Reply #1997 on: June 07, 2016, 11:31:25 PM »
Anyway, on Friday I was shocked when I saw what I was subsequently informed were melt ponds over the ESS in the ASMR2 imagery. That seems to have become mostly a static feature, at least according to ASMR2 over the course of the last few days.  Even though the heat has remained "on" in that area....  Bad, increased absorption of solar heat, etc. But it's not the least bit clear to me when/where that "bad" actually has an impact. Maybe it stays like that until July?

Every morning the first thing I do when I get on the computer is have a look at Worldview to see if any of that expanse of bluish ice in and around the ESS has started to collapse. I've been amazed at the color changes over such a wide area and the persistence of clear skies there. Surely the whole thing is about to dissolve! Not yet, though.

My conclusion is that the ice there is thicker than I imagined it. The HYCOM thickness graphs show this, but I think it's just difficult for me here in Kansas City to visualize 2+ meter ice.

pauldry600

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Re: The 2016 melting season
« Reply #1998 on: June 07, 2016, 11:35:37 PM »
Im no expert but

Id say a week of slow melt and then normal Summer slide meaning 2012 and this year will be neck and neck.

Sea Ice thats melting now is more robust than whats so far gone. I left a jug of ice out in 72F today and it took a lot longer to melt than I thought.

Andreas T

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Re: The 2016 melting season
« Reply #1999 on: June 08, 2016, 12:19:10 AM »
Anyway, on Friday I was shocked when I saw what I was subsequently informed were melt ponds over the ESS in the ASMR2 imagery. That seems to have become mostly a static feature, at least according to ASMR2 over the course of the last few days.  Even though the heat has remained "on" in that area....  Bad, increased absorption of solar heat, etc. But it's not the least bit clear to me when/where that "bad" actually has an impact. Maybe it stays like that until July?

Every morning the first thing I do when I get on the computer is have a look at Worldview to see if any of that expanse of bluish ice in and around the ESS has started to collapse. I've been amazed at the color changes over such a wide area and the persistence of clear skies there. Surely the whole thing is about to dissolve! Not yet, though.

My conclusion is that the ice there is thicker than I imagined it. The HYCOM thickness graphs show this, but I think it's just difficult for me here in Kansas City to visualize 2+ meter ice.
Have a look through this thread http://forum.arctic-sea-ice.net/index.php/topic,890.50.html
I started it a couple of years ago especially to record what is happening there to be able to find and compare later.
20 days from start of surface melt to complete break up is what other recent years managed and they had several bouts of 20oC temperatures in that period too.