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jdallen

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Re: The 2016 melting season
« Reply #4100 on: August 18, 2016, 04:51:28 PM »
slow wing, If you check the Barrow web cam it shows some drift ice moving in but no waves. The
Winddyty  site shows something else. OK it is a forecast for tomorrow but I think some calibration of these wave forecasts may be available ( at least a visual calibration ). If no waves appear tomorrow I would begin to doubt the accuracy of the Windyty arctic wave forecasts.  Web cam does show wet ,
muddy roads and water on a flat roof so it must have rained ?
If Winddyty *is* accurate, 96 hours out we will have large stretches north of 80 being subjected to 50KPH surface wind, and the remains of the Wrangel ice bridge being hit by 60+KPH.

It will be worthwhile to compare when we get there.
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RoxTheGeologist

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Re: The 2016 melting season
« Reply #4101 on: August 18, 2016, 05:37:02 PM »
1 degree of latitude, more in some points. That's 100 - 200 km.
Amazing he rotation is not felt in the Beaufort/Chukchi and Atlantic sectors. Amazing real melting rate.
However not so much in Laptev. Does Ekman pumping or other kinds of mixing/transport make heat and salinity available there, given the cold spring and summer, and that it is a shallow sea with purportedly not much input of heat and salinity from ocean currents?

That would be my hypothesis. From what I have read, the Atlantic water skirts the broad shallow continental shelf's on the eastern side of the Arctic; the sea is largely isolated from any mixing from the Pacific or Atlantic Oceans. Heating of Laptev is perhaps more down to sunlight than for any other part of the Arctic.

jdallen

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magnamentis

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Re: The 2016 melting season
« Reply #4103 on: August 18, 2016, 05:53:18 PM »
GFS model suggests temps at 850hp have dropped below -8 for much of the remaining ice pack.  Andrew Slater's 925hp temps have dropped a good way below 0, although not quite as far as I thought they might go.  Is the surface melt season all but over now?  And perhaps an early end to the bottom melt season later on?

without going into details, just check the various anomaly maps and you shall see that there is no widespread anomaly to the lower side. of course there are smaller spots with temporarily cooler and others with temporarily warmer than average temps but generally we are in the vicinity of the long term average, hence there is no reason to believe that the average temps will have an impact on either side, early or late minimum.

what is for sure is that the waters around are quite warmer than average which if anything is to predict it would be warmer conditions on sea level.

you can have a lock at the weather tab for o-buoy 14 and find an easy relation between surface temps and ice against no-ice envrionment. the moment the ice was mostly gone, temps remained hovering around zero while when the ice was still there temps dropped much lower overnight, this despite the fact that the weather is bad, windy and generally cooler than the sunny days from a few days ago. so water temps have a larger and more persistent impact than airtemps themselves. the entire western european climate is based on that fact ( gulf stream warm water's impact on general climate over a huge area with prevailing winds from ocean side ( north west to south east as the most frequent wind direction )

jplotinus

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Re: The 2016 melting season
« Reply #4104 on: August 18, 2016, 07:07:15 PM »
slow wing, If you check the Barrow web cam it shows some drift ice moving in but no waves. The
Winddyty  site shows something else. OK it is a forecast for tomorrow but I think some calibration of these wave forecasts may be available ( at least a visual calibration ). If no waves appear tomorrow I would begin to doubt the accuracy of the Windyty arctic wave forecasts.  Web cam does show wet ,
muddy roads and water on a flat roof so it must have rained ?

Barrow drift ice


Lord M Vader

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Re: The 2016 melting season
« Reply #4105 on: August 18, 2016, 07:10:01 PM »
Latest GFS 12z op forecast run still calls for another bomb cyclone at +150 hours bottoming out at 965 hpa. GFS also calls the cyclones MSLP to be below 975 hpa from +120 hours to +174 hours or about two days. Should make a huge damage if verified!

IMO, the next cyclone seems to be smaller in size but move over more fragile ice. It should also bring some warm air into the Arctic which our current Big Cyclone didn't. At the time when GFS is calling for a peak in the cyclone intensity, a high pressure dome will emerge over Beaufort Sea and perhaps make it to 1040 hpa.

And EVEN WORSE, the high pressure dome might be able to put a big dipole anomaly! As all this is quite far ahead we have to watch things closely!

Another thing of importance, which everyone here should care about, is given the fact that this melting season have been so cool and cloudy and we still are in the race for a second place makes me to wonder if we aren't very close to an Arctic where cyclonic summers are virually as bad as summers dominated by high pressures.

In any way, when the next big El Niño emerge, which should be happening in about 15-20 years at most, I think we may reach a tipping point where an ice-free Arctic is unevitable no matter if we are shutting down all CO2-emissions.

BornFromTheVoid

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Re: The 2016 melting season
« Reply #4106 on: August 18, 2016, 07:29:41 PM »
Agreed, LMV. That forecast from about 96 hours on is as bad as it gets at this time of year. We'd see a huge amount of compression toward Fram and increase southward transport, as well as more warmth coming in from the Pacific. I wouldn't rule out challenging the 2012 August extent losses if that forecast came to fruition.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

be cause

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Re: The 2016 melting season
« Reply #4107 on: August 18, 2016, 07:40:57 PM »
it looks like storms have found a new playground . The one after next .. in @ 120 hours .. looks likely to wake a few of us to a new potential .. the Arctic autumn .
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 
 (phew)

jdallen

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Re: The 2016 melting season
« Reply #4108 on: August 18, 2016, 07:44:35 PM »
Agreed, LMV. That forecast from about 96 hours on is as bad as it gets at this time of year. We'd see a huge amount of compression toward Fram and increase southward transport, as well as more warmth coming in from the Pacific. I wouldn't rule out challenging the 2012 August extent losses if that forecast came to fruition.
I believe this is what BFTV and others of us are contemplating with no small amount of concern.

Add to the list... multi-meter waves in the Laptev bite and conditions which would likely utterly destroy any ice left near Wrangel Island when things are done.
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AbruptSLR

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Re: The 2016 melting season
« Reply #4109 on: August 18, 2016, 08:05:37 PM »
If the attached ECMWF for August 19 2016 holds-up we could be back down to a central pressure of 976 hPa by tomorrow:
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― Leon C. Megginson

be cause

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Re: The 2016 melting season
« Reply #4110 on: August 18, 2016, 08:11:45 PM »
 Neven .. just noticed that the term 'Arctic autumn' does not exist on wiki .. I have no computer skills .. anyone want to create the page ? The season is certainly creating itself as we watch !
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 
 (phew)

seaicesailor

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Re: The 2016 melting season
« Reply #4111 on: August 18, 2016, 08:22:07 PM »
If the attached ECMWF for August 19 2016 holds-up we could be back down to a central pressure of 976 hPa by tomorrow:
And it gets really tight on Saturday in a peculiar location. I mean... sheer curiosity on what this baby is gonna do.

Lord M Vader

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Re: The 2016 melting season
« Reply #4112 on: August 18, 2016, 08:41:55 PM »
Interestingly, ECMWF 12z op has backed from another bomb cyclone but instead have them splitted in two parts. Whether this run is an outlier or not remains to be seen.

The baby cyclone shouldn't do too much damage as it will encounter the area where the sea ice is thickest for now.

magnamentis

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Re: The 2016 melting season
« Reply #4113 on: August 18, 2016, 09:19:51 PM »
Interestingly, ECMWF 12z op has backed from another bomb cyclone but instead have them splitted in two parts. Whether this run is an outlier or not remains to be seen.

The baby cyclone shouldn't do too much damage as it will encounter the area where the sea ice is thickest for now.

i know how you mean it but still worth to mention that the most can be lost where the most is present :-)

in other words, i'd not be that sure about the stability of that ice, after all, many regions that look quite stable now, have been wide open a few months ago already, which tells us that given the right conditions there is no more safe heaven for the ice nowadays :-)

seaicesailor

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Re: The 2016 melting season
« Reply #4114 on: August 18, 2016, 09:25:48 PM »
Interestingly, ECMWF 12z op has backed from another bomb cyclone but instead have them splitted in two parts. Whether this run is an outlier or not remains to be seen.

The baby cyclone shouldn't do too much damage as it will encounter the area where the sea ice is thickest for now.
Sure, but precisely wanted to see among other things what happens to the ice within the CAA channels that is immobile in usual conditions. Not that is going to melt...

forkyfork

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Re: The 2016 melting season
« Reply #4115 on: August 18, 2016, 10:13:51 PM »
Interestingly, ECMWF 12z op has backed from another bomb cyclone but instead have them splitted in two parts. Whether this run is an outlier or not remains to be seen.

The baby cyclone shouldn't do too much damage as it will encounter the area where the sea ice is thickest for now.
any individual op model is going to be erratic after about day 5. refer to the ensembles for guidance. that being said, the euro ensemble is showing a very ugly pattern through day 10



« Last Edit: August 18, 2016, 10:26:14 PM by forkyfork »

AbruptSLR

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Re: The 2016 melting season
« Reply #4116 on: August 18, 2016, 10:37:25 PM »
The attached 12z ECMWF sequence for Aug 21, 22, 23 & 24, shows the split low-center pattern that LMV cited, & shows that the central pressure gets down to 974 hPa on the 23rd.
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JimboOmega

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Re: The 2016 melting season
« Reply #4117 on: August 18, 2016, 11:12:49 PM »
Given the visibly broken appearance of the sea ice, I wonder how much compaction will take a vertical character.

That is, rather than just shoving dispersed blocks of ice together, will it shove them over and under each other?  Such a thing definitely happens in general as ice is forming in the winter (as in at pressure ridges).  Still, this would be a very different mechanic that we might get to watch with this huge and long lasting cyclone!

werther

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Re: The 2016 melting season
« Reply #4118 on: August 18, 2016, 11:40:00 PM »
Wipneus elsewhere on the Forum: "..Area continues dropping so fast that is approaching 2012 again.."

While I'm following all of this without much urge to keep commenting until it's all done, I still collect MODIS tiles in my CAD every few days.
Tonight, I'm waiting for the last complete tiles in and around the CAA and Beaufort. With those, it is possible to make a comparison. From what I see (or not, as the cyclone has covered up a lot of the pack in the Greenland sector), I feel free to refer to Wipneus' remark above.

Before I go on, I'll take some time to complete the CAD image.

Ninebelowzero

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Re: The 2016 melting season
« Reply #4119 on: August 18, 2016, 11:53:55 PM »
Patch of open water within 20 miles of the pole on Worldview current image?

forkyfork

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Re: The 2016 melting season
« Reply #4120 on: August 19, 2016, 12:42:14 AM »
the 12z euro ensemble mean is in and it's continued bad news for the ice. GAC pattern leading to a dipole

http://www.tropicaltidbits.com/analysis/models/?model=ecmwf-ens&region=nhem&pkg=mslpa&runtime=2016081812&fh=0&xpos=0&ypos=200

press play
« Last Edit: August 19, 2016, 12:56:21 AM by forkyfork »

seaicesailor

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Re: The 2016 melting season
« Reply #4121 on: August 19, 2016, 12:57:22 AM »
the 12z euro ensemble mean is in and it's continued bad news for the ice. strong GAC leading to a dipole

http://www.tropicaltidbits.com/analysis/models/?model=ecmwf-ens&region=nhem&pkg=mslpa&runtime=2016081812&fh=0&xpos=0&ypos=200

press play
With my short experience, it surprises me how tight is the averaged prediction of the cyclone for day 5. Even when the minimum shows 983 hPa, count with the typical smearing effect when we average solutions with lower minimums, but falling at different locations. The deviations shown at wetterzentrale and ecmwf.int are not so large as in other 120h forecasts especially for a strong storm. And the weather pattern is pretty sharp. I know this is a futile exercise given that we are about to know but just learning here. Feel free to correct me if I'm wrong.

Neven

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Re: The 2016 melting season
« Reply #4122 on: August 19, 2016, 01:33:43 AM »
2016 Arctic cyclone, update 2 is up. And here's a bonus, CAJAX compactness is lowest on record (for the date), which means there's a lot of compaction potential:
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werther

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Re: The 2016 melting season
« Reply #4123 on: August 19, 2016, 01:56:29 AM »
Most of the missing tiles are in now. I've fit them in.

Structure and quality of this ice pack is not like it used to be. Even compared to '12. Yes, NBZ, there's a 20 km2 polynia 35 km from the Pole. Part of a growing zone where the loose floes are getting torn apart ever further. Reaching to the Atlantic Front from the back side.

If there's any mesh-shaped structure left, it should be under the thick cloud cover between Ellesmere, Greenland and the Pole. But where the clouds are thinner, there's indication of lots of holes and wide leads.
Around the centre of the cyclone, some 300 km NW of Axel Heiberg Island, sweeps of visibility between the rushing cloudbelts reveal many holes of open water, 5-10 km2. This is in a sector that used to be firmly structured MYI.
It is now almost as mobile as the rest, its just the concentration that keeps up an image of a pack as UniBremen shows.

It doesn't matter where the heart of the cyclone goes. It hurts everywhere.

The pack is just a thread away from a first icefree minimum. I'm not comforted by the numbers. Extent, Area, Volume fall short of informing the real state of what's left of the sea ice cover.

RoxTheGeologist

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Re: The 2016 melting season
« Reply #4124 on: August 19, 2016, 02:24:53 AM »
Arctic sea ice is preserved through the summer by salinity. Fresh cold melt water from the ice enhances the stability of the pycnocline, and prevents the Arctic surface waters from mixing with the warmer saltier water from the Pacific and Atlantic that form the layer beneath it.

http://onlinelibrary.wiley.com/doi/10.1029/2009JC005660/full

However, the Atlantic Waters are entering the Arctic warmer than they have ever been.
https://www.researchgate.net/profile/Katrine_Husum/publication/49791240_Enhanced_modern_heat_transfer_to_the_Arctic_by_warm_Atlantic_Water/links/0c96052dbcae5d9150000000.pdf

And there is an increased incidence of Arctic cyclones linked to climate change
http://www.wiley.com/WileyCDA/PressRelease/pressReleaseId-110301.html

I think that is what we are seeing with the current extensive melting; a large storm mixing warm deep water from below the ice. It's not only the edges of the ice that will be susceptible to melting, the warmer water underlies the surface over much of the CAB. Without the protection of a cohesive ice pack, there is, perhaps, little to prevent it.

JayW

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Re: The 2016 melting season
« Reply #4125 on: August 19, 2016, 03:00:16 AM »
August 14-18.  Wrangel island, as always, in the lower left corner.

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Dundee

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Re: The 2016 melting season
« Reply #4126 on: August 19, 2016, 03:07:40 AM »

. . . Without the protection of a cohesive ice pack, there is, perhaps, little to prevent it.

In my formative years, spent on U.S. submarines, the Marginal Ice Zone, or MIZ, was that part of the ocean where there was ice, but which was affected by waves (this was  even a qualification test question, believe it or not). This is crucial to a submarine - under the pack proper, layers are relatively stable. The density of water and thus the submarine's trim is strongly a function of depth, not radically a function of horizontal movement. In the MIZ things are mixed up by wave action and navigating by submarine near ice is much more "interesting".

This is also crucial to the ice. In the MIZ the cap over deep, warm, saline water is broken, with predictable results.

As years go by and this year in particular (I note at least one source showing 50% concentration at the Pole) the storms are getting stronger, the ice is getting thinner, and the MIZ makes up a bigger and bigger fraction of the remaining ice. My NSIDC poll prediction was 4.47, if nothing weird happens, with the caveat that bad ice years are occurring more often than the normal distribution suggests.

Weird seems to have arrived, and would anyone care to guess what fraction of today's pack is NOT currently affected by wave action? The good news is, I don't have to drive a submarine underneath any of it. The bad news is that far, far more of the Arctic than when I drove submarines is safer to navigate because there is no ice to avoid.
« Last Edit: August 19, 2016, 03:23:28 AM by Dundee »

Watching_from_Canberra

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Re: The 2016 melting season
« Reply #4127 on: August 19, 2016, 04:08:20 AM »
Fascinating insight!

Juan C. García

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Re: The 2016 melting season
« Reply #4128 on: August 19, 2016, 04:12:12 AM »
The Bremen update has been published.
In a way, it is incredible that half of the area north of 85N, has 75% concentration or less ... and a cyclone is coming again!

Edit: Hope that they are melt ponds...
« Last Edit: August 19, 2016, 04:19:58 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

jdallen

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Re: The 2016 melting season
« Reply #4129 on: August 19, 2016, 04:23:46 AM »
The Bremen update has been published.
In a way, it is incredible that half of the area north of 85N, has 75% concentration or less ... and a cyclone is coming again!

Edit: Hope that they are melt ponds...
Even more than that, I'm looking at the pack being torn in three; the section towards Wrangel is already stripped off. 

On the Atlantic side, the ice between the pole and Franz Josef islands is only 200KM from splitting off the ice on the Laptev side from the main pack.

The up coming winds may produce that result.
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Tigertown

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Re: The 2016 melting season
« Reply #4130 on: August 19, 2016, 05:29:45 AM »
That would make bbr "Justified" like Raylan Givens

Another big drop today in SIE. We will go sub 5M tommorow and I do not see any way whatsoever that we won't soon go under 4M. After that,the game's up for grabs the last couple of weeks. I think that I read somewhere that area is around 3.25 km2, so a little compaction could go a long way before it's over....
« Last Edit: August 19, 2016, 05:39:37 AM by Tigertown »
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epiphyte

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Re: The 2016 melting season
« Reply #4131 on: August 19, 2016, 06:56:44 AM »

. . . Without the protection of a cohesive ice pack, there is, perhaps, little to prevent it.

In my formative years, spent on U.S. submarines, the Marginal Ice Zone, or MIZ, was that part of the ocean where there was ice, but which was affected by waves (this was  even a qualification test question, believe it or not). This is crucial to a submarine - under the pack proper, layers are relatively stable. The density of water and thus the submarine's trim is strongly a function of depth, not radically a function of horizontal movement. In the MIZ things are mixed up by wave action and navigating by submarine near ice is much more "interesting".

This is also crucial to the ice. In the MIZ the cap over deep, warm, saline water is broken, with predictable results.

As years go by and this year in particular (I note at least one source showing 50% concentration at the Pole) the storms are getting stronger, the ice is getting thinner, and the MIZ makes up a bigger and bigger fraction of the remaining ice. My NSIDC poll prediction was 4.47, if nothing weird happens, with the caveat that bad ice years are occurring more often than the normal distribution suggests.

Weird seems to have arrived, and would anyone care to guess what fraction of today's pack is NOT currently affected by wave action? The good news is, I don't have to drive a submarine underneath any of it. The bad news is that far, far more of the Arctic than when I drove submarines is safer to navigate because there is no ice to avoid.

Not entirely unfamiliar with submarines myself, but have never spent time on one on patrol, let alone the arctic. But as for the waves... well, quite. Once the stratification is broken, the 3-D picture becomes nothing less than chaotic - and given that the surface layer is normally the coldest, things can only go downhill from there...

6roucho

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Re: The 2016 melting season
« Reply #4132 on: August 19, 2016, 07:38:37 AM »
That would make bbr "Justified" like Raylan Givens
Indeed. I think everyone agreed that in the event of a GAC2016 the ice was either toast or nearly toasted, but the precise form of a bifurcation (or trifurcation) would be excellent prescience.

6roucho

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Re: The 2016 melting season
« Reply #4133 on: August 19, 2016, 09:20:35 AM »
"We have created an ocean where there was once an ice sheet. It is man’s first major achievement in re-shaping the face of the planet."

https://www.theguardian.com/commentisfree/2016/aug/18/ice-scientists-arctic-ice-disappearing-reduce-emissions-peter-wadhams

Although the article conflates ice-free with no ice at all.

seaicesailor

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Re: The 2016 melting season
« Reply #4134 on: August 19, 2016, 10:13:45 AM »
The "baby" is going to reinitiate strong transport toward the Atlantic ending in... 10 days?

I wonder if this small core from today till Sunday can qualify as a so-called "Arctic hurricane" or polar low, winds at +30 knot, deep and extremely compact, decaying shortly (but temporarily).
https://en.m.wikipedia.org/wiki/Polar_low

Paladiea

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Re: The 2016 melting season
« Reply #4135 on: August 19, 2016, 10:37:29 AM »
Wow with all this ocean rotation going on, may I suggest an alternate name for this phenomenon; The Maelstrom. :)
The most enjoyable way to think about heat transfer through radiation is to picture a Star Wars laser battle, where every atom and molecule is constantly firing at every other atom and molecule.

werther

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Re: The 2016 melting season
« Reply #4136 on: August 19, 2016, 11:03:26 AM »
These are illustrations taken from yesterday’s CAD MODIS file.

First, what used to be the ‘safe pack’ N of the CAA. The sign of safety used to be the well structured ‘mesh-pattern’ of leads and floes. The rhomboid/trapezium shaped floes used to have a median surface of about a 1000 km2 at the end of winter and usually a SE-NW line-up. These properties lasted all through summer in a large part of the CAB. Until 2012. Since then, the ‘safe pack’ diminued in size, down to 1.8 and even 1.2 Mkm2. And its’structure decomposed as the trapezoid floes got to median sizes of less then 100 km2.

Yesterday this was the situation:


What’s left of a ‘safe pack’ is around 1Mkm2 in size. It has hardly any structure.

(The red line marks this 1Mkim2 area. The green line is the margin of low concentration ice in August '15)

As I wrote in August ’13: “…In it’s original form, the pack is/was meshed into trapezium shaped areas, averaging about 1000 km2, by stress leads. They start to widen as the pack gets more mobile, prone to, FI, tides. The ridging on their sides gets weaker, starts filling the leads with debris. Mechanical forces fracturize this further and eventually starts decomposing the large trapezia into smaller floes, following the secondary cracks that were already present. What happens is not just melting but structural weakening…”

Tonight I wrote: “…a growing zone where the loose floes are getting torn apart ever further. Reaching to the Atlantic Front from the back side…”:


A part of the band of floes N of Frantsa Yosefa/Severnaya Zemlya.

It’s what was also picked up by JDAllen. This is no cohesive pack. There’s just a 137 km stretch of loose floes between open water stretches. It could easily open up given the right conditions.
« Last Edit: August 20, 2016, 09:31:09 AM by werther »

Glenn Tamblyn

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Re: The 2016 melting season
« Reply #4137 on: August 19, 2016, 11:16:47 AM »
Looking at the latest Bremen concentration map, a wild thought strikes me. If the ESS bite continues to expand and all that mid concentration ice near the pole really gets hammered, might we have:

- A year that only comes close to matching 2012 for area/extent
- Several large remnant 'islands' below Wrangel and the Laptev
- And an essentially ice-free pole for a short period.

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Re: The 2016 melting season
« Reply #4138 on: August 19, 2016, 11:45:24 AM »
The Bremen update has been published.
In a way, it is incredible that half of the area north of 85N, has 75% concentration or less ... and a cyclone is coming again!

Edit: Hope that they are melt ponds...

Looking at the latest 48 hour AVHRR loop, my uneducated opinion is that there is ice diverging, and we are seeing open water between floes.  But I can't be sure that explains it all, it could be a combination of the two.  Impossible to tell from this imagery, but at least some open water is responsible.  I'll let others decide the magnitude of each.

http://weather.gc.ca/satellite/satellite_anim_e.html?sat=hrpt&area=dfo&type=nir
« Last Edit: August 19, 2016, 01:07:19 PM by JayW »
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iceman

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Re: The 2016 melting season
« Reply #4139 on: August 19, 2016, 01:27:32 PM »
Just an animation of before and after the storm. The rotation in the pack is really noticeable for just 3 days.

Not only cyclone-driven rotation, but the lows themselves are tracing loops around the Arctic basin.  Kind of brings to mind a gigantic eggbeater stirring in an outsize bowl.

Rubikscube

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Re: The 2016 melting season
« Reply #4140 on: August 19, 2016, 01:51:32 PM »
Amazing. Now can the SIA crash be sustained on a slightly weaker storm alone, with no help from 925 hPa temps? The next 2-3 days will be really interesting in that regard. It doesn't look like we're going to get a new 953 pHa storm (that's a pretty sick forecast), but instead it looks like a dipole may be on the horizon, which could be just as devastating.

Jim Hunt

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Re: The 2016 melting season
« Reply #4141 on: August 19, 2016, 02:04:22 PM »
A closeup of Wipneus' high resolution AMSR2 area data:



A similar drop tomorrow will take us below the 2015 minimum.
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Re: The 2016 melting season
« Reply #4142 on: August 19, 2016, 02:17:37 PM »
On our very own ASIG page, the CAB area is now at an all time low for this date:


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Re: The 2016 melting season
« Reply #4143 on: August 19, 2016, 02:27:25 PM »
Amazing. Now can the SIA crash be sustained on a slightly weaker storm alone, with no help from 925 hPa temps? The next 2-3 days will be really interesting in that regard. It doesn't look like we're going to get a new 953 pHa storm (that's a pretty sick forecast), but instead it looks like a dipole may be on the horizon, which could be just as devastating.

From what I can see, these systems are associated with a warm front as in mid latitudes. May not this lead to an increase of the temperature up to 750 m or even 1500 m (2500-5000 feet) ?. 925 hPa or 850 hPa is not as high altitude.
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BornFromTheVoid

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Re: The 2016 melting season
« Reply #4144 on: August 19, 2016, 02:44:45 PM »
On our very own ASIG page, the CAB area is now at an all time low for this date:

While being a very different measure and not ideal for year to year comparisons, MASIE shows close to the opposite.



But does have the overall extent as lowest on record.

I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Nightvid Cole

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Re: The 2016 melting season
« Reply #4145 on: August 19, 2016, 03:06:15 PM »
On our very own ASIG page, the CAB area is now at an all time low for this date:

While being a very different measure and not ideal for year to year comparisons, MASIE shows close to the opposite.



But does have the overall extent as lowest on record.



Any ideas why the discrepancy?

Tor Bejnar

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Re: The 2016 melting season
« Reply #4146 on: August 19, 2016, 03:42:32 PM »
Further to Nightvid's ASIG CAB area graph, the CAB extent graph shows 200 km^2 more than 2012 on this date (yesterday).  Very low area and relatively high extent makes for very low concentration.
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Re: The 2016 melting season
« Reply #4147 on: August 19, 2016, 04:09:59 PM »
Just wondering about cyclones:

They usually form over the sea and dissipate once they make landfall, right? I assume in previous years these cyclones were not as devastating or long lasting to the more solid Arctic ice. And with there being less solid ice to act as a dampener, they are less likely to expire as quickly?

Is it possible that in 10/15 years, once most of the remaining ice is gone, these cyclones will be a more or less permanent fixture over the summer months?
(quoting from other thread)
   ....  The research on the 2012 GAC states that an upper level vortex is key to the generation and longevity of major Arctic cyclones.  Looking at 250hp winds there has been a strong vortex in play, and has been for a while.  However whether the low pressure generated this upper vortex, or the upper generated the surface low I'm not sure.  Looking at the CMC forecast (only model I found with 250hp winds for Arctic) what stands out to me is that the jetstream through the European and west Russian region is quite weak, and a lot of the jetstream wind is diverted into a branch that passes through the Barents/Kara/Laptev sea region.  My guess is that this diversion may be playing a key role in what is predicted to be the rapid development of a low pressure system over that general region.  ....
This sounds like a good insight.  Lower-level winds are picking up considerable warmth and moisture from Barents and Kara, which seems to contribute to the re-intensification of the central low.

There is a huge difference between the major 2 types of cyclones: the tropical cyclones and the mid-latitude cyclones. The latter is what is formed in arctic.
The difference is form where they derive their power(energy).

 In the tropical cyclones(called hurricanes in the Atlantic or typhoons in the Pacific mainly) the energy is being derived from the condensation of moist air(latent heat), i.e ultimately from warm waters. The tropical cyclones have warm cores and have no fronts.

In the mid-latitude cyclones(like in the arctic and mid latitudes) the energy is being derived from the horizontal temperature gradient in the atmosphere and not from the sea. They are also cold core systems and "carry" fronts with them. Their movement and intensification is lead mainly from above, from upper level lows and ultimately from the jet stream.
 And while the surface they touch, plays a role on their development, so there is a difference if they pass through sea or solid land, i think it's the friciton that plays the main role that they more easily intensify over sea than land. Of course warmer waters mean more moisture so more instability so more severe thunderstorms for example, but this is a different thing from intensification. Perhaps warm waters contribute a lot to the intensification of surface cyclones also, but i'm not aware of anything like this in the literature(perhaps someone can point me to any such research).

 About the topic of Arctic ice melt: i'm no expert whatsoever, not even close but seing the above pictures for ice concentration for today and comparing them with previous years(leap- no leap years etc is irrelevant obviously) i'm in awe of where our climate is heading.  :'(
18 august:


taken from here:
http://iup.physik.uni-bremen.de:8084/amsredata/asi_daygrid_swath/l1a/n6250/
http://www.iup.uni-bremen.de:8084/amsr2data/asi_daygrid_swath/n6250/


I have to ask: How much percentage of the destruction(of the minimum in september) is carried to the next summer? I mean does a huge minimum mean anything for the next melt season or a relatively good/cold winter can replace the loss easily?


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Re: The 2016 melting season
« Reply #4148 on: August 19, 2016, 05:13:44 PM »

Edit: Hope that they are melt ponds...

definitely not melt ponds, fragmentation it is and melt ponds are already over freezing now as has been seen with the ponds close to buoy 14 before the attack from below made it all vanish within a few hours which is exactly what we shall see in at least 3 more large places soon. be prepared :D

F.Tnioli

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Re: The 2016 melting season
« Reply #4149 on: August 19, 2016, 05:19:51 PM »
...
Any ideas why the discrepancy?
Isn't it obvious? He compares _extent_ numbers to _area_ numbers. Like if it's same thing. It's not. And it's not. ;)
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