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Tommy

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Re: The 2015 melting season
« Reply #2500 on: July 24, 2015, 09:33:17 PM »
These 2 recent articles about Greenland relate to Arctic.
Unless August gets cold, the whole Arctic ice-pack could be floating free, melting fast around the edges.
How does Greenland melt affect the Arctic?
Anyone?

Greenland's undercut glaciers melting faster than thought
http://phys.org/news/2015-07-greenland-undercut-glaciers-faster-thought.html

Greenland Experiences Sudden Onset of Melt Season
http://app3.scientificamerican.com/article/greenland-experiences-sudden-onset-of-melt-season/?mobileFormat=true
« Last Edit: July 26, 2015, 04:29:34 PM by Tommy »

Nick_Naylor

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Re: The 2015 melting season
« Reply #2501 on: July 24, 2015, 09:46:51 PM »
Nightvid, I'm not sure what is meant by "turning green," but there has been a stain on the surface north of Greenland extending to the West since this last clear view on the 16th, probably darkening and moving to the West a little since then.

Another thing that struck me about your image from today is that part of it has a blue cast, which is just a processing defect. This happens occasionally and interferes with visually interpreting the colors in the image as a whole. It usually goes away once the daily scan is complete.

Tor Bejnar

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Re: The 2015 melting season
« Reply #2502 on: July 24, 2015, 09:47:09 PM »
Chris,
Would some of the spring to early summer apparent delay be due to ice starting out well below freezing, so that much of the early heat is just warming the ice a bit?  I believe the changing buoy profiles show this.

It's hot in Florida, so when drinking ice water, I often fill the glass with ice, add water, gulp it down, then replenish the ice, add water, and drink it down again, all in quick succession.  I have a sense that the first filling with water seems to melt less ice than the 2nd filling.  I think this is because all the first glassful of ice was freezer cold, whereas half the second glassful of ice started out much closer to 32. (32? yeah, I'm an American.)
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Espen

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Re: The 2015 melting season
« Reply #2503 on: July 24, 2015, 09:47:51 PM »
As I see it at the moment. The Canadian Arctic Archipelago will be be more or less sea ice less sometimes in August, if any ice that will be drifting from above. The area will beat 2012!!!
Have a ice day!

Tommy

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Re: The 2015 melting season
« Reply #2504 on: July 24, 2015, 09:59:23 PM »
Quote
As I see it at the moment. The Canadian Arctic Archipelago will be be more or less sea ice less sometimes in August, if any ice that will be drifting from above. The area will beat 2012!!!
-- Espen

I agree.
There are so many factors coming together this year that were not there, or not as strong  in 2012. And multiple stronger factors, not just one or two.
And I suspect there will be much more of this open water on the Arctic Ocean showing up soon, as seen in the image on the right below (from screenshots I took from the intersection of the Arctic Ocean and the northern Canadian eastern coastal islands, near Greenland), but this water will open up all along the coastal region, and except maybe Northern Greenland.

Not much of the ice-pack will be left attached to any land within 2-3 weeks, except some crumbles bunching up here and there (barring a massive cyclone or something, crushing everything back in.)

Tommy.
« Last Edit: July 25, 2015, 06:08:53 AM by Tommy »

Neven

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Re: The 2015 melting season
« Reply #2505 on: July 24, 2015, 10:07:15 PM »
Repeating a comment from a new member here that was held up:

Chris:  This might be useful, not sure what the resolution is:

http://www.esrl.noaa.gov/psd/cgi-bin/db_search/DBSearch.pl?Dataset=NCEP+Reanalysis+Daily+Averages+Surface+Flux&Variable=Downward+solar+radiation+flux

from

http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.surfaceflux.html

The problem with such data is that Excel VBA cannot natively open netcdf. I have an Excel add on that can convert netcdf files to an Excel spreadsheet, however NCEP/NCAR have recently updated their format and that no longer works. Writing my own code to access netcdf 4 is a major project in itself.

To access netcdf I would have to move onto something like R (or Python?) and I just don't have the time to learn a new language. Work pressures often make me think I need to stop blogging as it is, I have only managed to read about 15 new papers so far this year.
Hi Chris - Former lurker here, just signed up to post. A possible solution is Matlab or better yet the free version Octave, adding the netcdf toolbox: http://modb.oce.ulg.ac.be/mediawiki/index.php/NetCDF_toolbox_for_Octave

After installing the toolbox type at the Octave prompt the command "ver" to show the toolbox is installed, i.e. octave:1> ver
Should be easy to write out to a csv file from there. I found this on ResearchGate and will be trying it out soon myself, but on a linux box with libreoffice instead.
Cheers!
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ChrisReynolds

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Re: The 2015 melting season
« Reply #2506 on: July 24, 2015, 11:11:10 PM »
Thanks Guygee, I've saved a link to your post.

Neven

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Re: The 2015 melting season
« Reply #2507 on: July 24, 2015, 11:19:24 PM »
Forecast (both ECMWF and GFS) is still for 3-4 more days of this, high pressure moving to Siberia and then away, but perhaps high pressure building up again near the CAA and Beaufort coasts.

This freezing temps that GSF forecasts, however, right in the smashed up MYI zone, could stop the 2015 trend line dead in its tracks, I think:
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jai mitchell

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Re: The 2015 melting season
« Reply #2508 on: July 24, 2015, 11:20:41 PM »
chris,

there may be a solution found here:  http://www.unidata.ucar.edu/software/netcdf/software.html
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Neven

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Re: The 2015 melting season
« Reply #2509 on: July 24, 2015, 11:26:55 PM »
OTOH, 2012 had this (don't know if the maps are apple to apple though):
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Blaine

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Re: The 2015 melting season
« Reply #2510 on: July 24, 2015, 11:43:11 PM »


Chris: Actually, I'm suprised that the albedo effect isn't a lot larger than it is.  In order to get the net radiation, you need to subtract off the outgoing IR, which for a 0C blackbody is 315W/m^2.  Using 1120W/m^2 for full sun at the surface including some downwelling IR, maximum radiation at 90N is 445W/m^2.  Most of this incoming radiation is needed just to balance IR loss.  The difference gives maximum radiaitve melting of 3.3 cm ice per day.  The seasonal total is ~2m, with radiative melting ending around August 7.  Yes, this negelects reflection of surface-emitted IR, but it also neglects cloud and surface albedo, which should have a much larger effect.

For comparison 1 k km^3 per 5 days over the Arctic Ocean is around 1.43 cm per day, so peak blackbody melting at the pole exceeds peak PIOMAS melting over the Arctic Ocean by only around a factor of 2.4, which is smaller than I would have expected.  Melting by heat transport is obviously included in PIOMAS but not in the blackbody IR balance.

Jai:  That paramter is exactly zero for Antarctica in winter, so it appears to be shortwave radiative balance only.

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Re: The 2015 melting season
« Reply #2511 on: July 24, 2015, 11:47:46 PM »
Forecast (both ECMWF and GFS) is still for 3-4 more days of this, high pressure moving to Siberia and then away, but perhaps high pressure building up again near the CAA and Beaufort coasts.

This freezing temps that GSF forecasts, however, right in the smashed up MYI zone, could stop the 2015 trend line dead in its tracks, I think:

It might happen well what Jim showed of one of the buoys, a MYI layer down to 1 m thick, from top to bottom near 0C fresh water melting point, under a warmer pond, about to melt out, then weather changes, the saltier water pond cools down and/or freezes at -1.0C and the MYI is safe. Interruptus.
That was my free interpretation, it seems to me now though it could stop MYI melting
PS. Actually Crandles corrected my interpretation, I thought it was going to melt out anyway


The Ice Mass Balance buoy 2013F temperature profile has suddenly changed. It looks a bit like it's floating in a drill hole full of melt water, except this a "traditional" style IMB buoy with a separate thermistor string. Any thoughts?

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2015-imbs/#2013F-Temp

Bruce

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Re: The 2015 melting season
« Reply #2512 on: July 24, 2015, 11:50:02 PM »
chris,

there may be a solution found here:  http://www.unidata.ucar.edu/software/netcdf/software.html
Forgive me if I'm late to the party and this has been suggested, but GMT (The Generic Mapping Tools) work with NetCDF files and would let you convert grids to ASCII (as well as doing all sorts of other things). Pretty much every package manager I've encountered has pre-built GMT distributions so installation is trivial. And it's free. "Free" as in not-even-asking-you-to-donate free.

seaicesailor

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Re: The 2015 melting season
« Reply #2513 on: July 25, 2015, 12:30:44 AM »
Fact not to forget for August: open waters in Arctic are anomalously warm and Northern Hemiphere as a whole too, +0.59 C anomaly (Climate Reanalyzer)





Nightvid Cole

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Re: The 2015 melting season
« Reply #2514 on: July 25, 2015, 12:48:45 AM »
Forecast (both ECMWF and GFS) is still for 3-4 more days of this, high pressure moving to Siberia and then away, but perhaps high pressure building up again near the CAA and Beaufort coasts.

This freezing temps that GSF forecasts, however, right in the smashed up MYI zone, could stop the 2015 trend line dead in its tracks, I think:

I doubt it - it will nearly be August by the time those temps hit. It's "bottom melt" season, not "surface melt" season which extends from June through July.

Bottom melt dominates beginning from late July really, so slightly below freezing temps won't do anything to the melt. Bottom melt continues until the SST drops to near -1.7 C (or until the surface air is several degrees below freezing).

Nightvid Cole

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Re: The 2015 melting season
« Reply #2515 on: July 25, 2015, 01:23:28 AM »
Northern Sea Route is "open" based on ZMAW's map...


jdallen

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Re: The 2015 melting season
« Reply #2516 on: July 25, 2015, 01:35:58 AM »
Forecast (both ECMWF and GFS) is still for 3-4 more days of this, high pressure moving to Siberia and then away, but perhaps high pressure building up again near the CAA and Beaufort coasts.

This freezing temps that GSF forecasts, however, right in the smashed up MYI zone, could stop the 2015 trend line dead in its tracks, I think:

I doubt it - it will nearly be August by the time those temps hit. It's "bottom melt" season, not "surface melt" season which extends from June through July.

Bottom melt dominates beginning from late July really, so slightly below freezing temps won't do anything to the melt. Bottom melt continues until the SST drops to near -1.7 C (or until the surface air is several degrees below freezing).

Agree.  Insulation picked up by the water will still contribute to melt.  The temperature change is less an indication of melt stopping, and more an indication the heat sink provided by near zero water and ice at the surface is keeping up with the inputs. 

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Tommy

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Re: The 2015 melting season
« Reply #2517 on: July 25, 2015, 01:42:45 AM »
Check out the big waves...
(not waves I was just told. :-) Clouds. )
... in my GIF here, just 2 days, yesterday and today.
See the ice being shunted west in 24 hours.

Canadian coastline with Arctic Ocean near Greenland (not sure what that interface between northern coasts of the islands and the Arctic Ocean is called.? )
I just found out the name of that little island in the middle-left of the image -- Meighan Island and the big one on the right is Axel Heiberg Island



.
« Last Edit: July 25, 2015, 05:33:25 AM by Tommy »

slow wing

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Re: The 2015 melting season
« Reply #2518 on: July 25, 2015, 02:00:24 AM »
Surely they are clouds rather than waves. Check out your distance scale to find out how big those features are.

jdallen

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Re: The 2015 melting season
« Reply #2519 on: July 25, 2015, 02:24:49 AM »

Chris: Actually, I'm suprised that the albedo effect isn't a lot larger than it is.  In order to get the net radiation, you need to subtract off the outgoing IR, which for a 0C blackbody is 315W/m^2.  Using 1120W/m^2 for full sun at the surface including some downwelling IR, maximum radiation at 90N is 445W/m^2.  Most of this incoming radiation is needed just to balance IR loss.  The difference gives maximum radiaitve melting of 3.3 cm ice per day.  The seasonal total is ~2m, with radiative melting ending around August 7.  Yes, this negelects reflection of surface-emitted IR, but it also neglects cloud and surface albedo, which should have a much larger effect.

For comparison 1 k km^3 per 5 days over the Arctic Ocean is around 1.43 cm per day, so peak blackbody melting at the pole exceeds peak PIOMAS melting over the Arctic Ocean by only around a factor of 2.4, which is smaller than I would have expected.  Melting by heat transport is obviously included in PIOMAS but not in the blackbody IR balance.

Jai:  That paramter is exactly zero for Antarctica in winter, so it appears to be shortwave radiative balance only.

This seems a bit oversimplified, especially when you consider that without the existing GHG's, surface temperatures would be on the order of 32C colder than the current global average (14C).

I think your estimate of outbound Black Body radiation at the top of the atmosphere is high by about 70W/M2, but I lack the math right now to work it out.

EDIT:  Found this NASA graphic, which might be instructive.
« Last Edit: July 25, 2015, 02:39:00 AM by jdallen »
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Tommy

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Re: The 2015 melting season
« Reply #2520 on: July 25, 2015, 02:41:47 AM »
Quote
slow wing
Surely they are clouds rather than waves. Check out your distance scale to find out how big those features are.

Lol ! Yes. Clouds.
Still a cool movement of ice.
Would love to try kayaking up in that coastal shear one day (with a guide, not too far from a town, a town with a pub. )




« Last Edit: July 25, 2015, 02:50:21 AM by Tommy »

greatdying2

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Re: The 2015 melting season
« Reply #2521 on: July 25, 2015, 02:53:53 AM »
About to pass 2014...
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

greatdying2

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Re: The 2015 melting season
« Reply #2522 on: July 25, 2015, 03:04:53 AM »
And just in the Basin, still diverging from 2014 & 2013, and even a bit below 2012 for now, except NSIDC area. Jaxa area is noteworthy.


The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

Blaine

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Re: The 2015 melting season
« Reply #2523 on: July 25, 2015, 03:18:53 AM »
Yes, jdallen, reflection of ~22% of outgoing longwave sounds quite reasonable, but I'm not sure how that contradicts what I said unless you're assuming a total albedo (cloud+surface) under 0.22 which sounds quite low to me.  Yes, the blackbody assumption is a considerable oversimplification, but we're still rapidly running out of positive radiative balance this time of year.

Tommy

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The Great Shear.
« Reply #2524 on: July 25, 2015, 05:36:43 AM »
The big shear off the continent from July 4 to today.
Gif video grab I made today.
You have to ignore the jumping clouds, to focus on the ice shearing off the whole Canadian coast.

http://satwagraphics.com/testing/arctic_shearing.gif
.

greatdying2

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Re: The 2015 melting season
« Reply #2525 on: July 25, 2015, 05:49:19 AM »
Yesterday (July 23) was a clear day over Beaufort, so the Bremen map reflected the true sea ice concentration there and in the adjacent area of the CAB. And this reality is a huge area with 50% concentration, with just a few remaining relatively small patches at high density (MYI remnants?) and about the same amount of holes at 0%.

So, is most of this ice doomed?
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

ChrisReynolds

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Re: The 2015 melting season
« Reply #2526 on: July 25, 2015, 07:31:40 AM »
chris,

there may be a solution found here:  http://www.unidata.ucar.edu/software/netcdf/software.html

I've been there already Jai, I have Panoply. Thanks.

Blizzard_of_Oz

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Re: The 2015 melting season
« Reply #2527 on: July 25, 2015, 09:06:28 AM »
Lots of interesting discussion here, but also a fair bit of confusion so let's try and clear that up.

Radiation Balance:

(1) Rnet = ((1-a) * SWD) + LWD - LWU

  • a = albedo (in this case, pertinant to shortwave radiation only - lets say 0.2-4.0 micrometers). a * SWD = upward solar radiation.
  • SWD = shortwave radiation, downwards. A function of location and time and atmospheric constituent e.g. water vapor, aerosols, and importantly, clouds
  • LWD = longwave radiation, downwards; a function of atmospheric temperature and radiators like water vapor, clouds, CO2 etc. which determine atmospheric emissivity.
  • LWU = longwave radiation, upwards; function of surface "skin" (i.e. radiant) temperature and surface emissivity

All terms are in units of Watts per meter squared.
Net radiation can be computed for any "surface" whether that be the ice/ocean/land surface or the top of atmosphere (though I have couched things in terms of an ice surface). A black body has an emissivity of 1.0. Snow often considered close to a blackbody. The atmosphere is grey body (i.e. emissivity below 1.0) - see PDF of lecture notes below.
Be careful to consider your spatial and temporal frame of reference when talking about such quantities - are you talking about a particular hour, month, year or decade; are you talking about a point at the pole, the region north of 65N or the entire planet?

Some reference material by Martin Wild at ETH:
https://www1.ethz.ch/iac/edu/courses/master/modules/radiation_and_climate_change/download/Lecture5_2014


Surface energy balance: e.g. for a given ice-atmosphere interface surface:

(2) Rnet = H + E + G

  • H = Sensible heat flux; function of temperature gradient from air to surface, wind speed, stability of atmosphere (+ve towards atmo)
  • E = Latent heat flux to the atmosphere; often thought of as evaporation+sublimation; function of vapor gradient from air to surface, wind speed, stability of atmo (+ve towards atmo)
  • G = flux into the surface. For ice during the melt season, G can be decomposed into a melt flux (which is also a latent flux, though different from E) and a conductive (or diffusive) flux that warms the underlying ice (a function of subsurface temperature & diffusivity properties; the flux that causes the buoy temperature profiles to change). This term will be negative when ice is growing. (+ve into the surface)

Surface radiant temperature (Trad) features in each term of (2). Hence, expand each term and solve for Trad (given all the required inputs/states of SWD, LWD, Tair, humidity, precip, wind, pressure and subsurface temperature). All terms in (2) are in units of Watts per meter squared and the sign convention is given. There are other subtle items such as sub-surface penetration of solar radiation etc. but we'll not go into that.

There is an energy balance at the base of the ice (the ice-ocean interface) but the terms will be of different importance or magnitude and involve a different fluid (sea water) as well as salinity dynamics. Throw a volume between these two energy balances and whacko!, you have yourself a (highly, highly simplified) thermodynamic sea ice model. Now make it all move around properly and you have a neanderthal CICE.


Other item:  Latent heat of fusion (J/kg) compared to heat capacity of (sea) ice (J/kg/K).
L(fusion) : 335000 Joules will melt 1kg of pure ice that is at 0C
Specific heat of pure ice at 0C is 2093 J/kg/K.
So if we removed the same amount of energy from the 1kg 0C ice as would be used to melt it (and it was a completely closed system and the heat capacity did not change with temperature), the ice would now be approx. -160 C. Phase change of H2O involves lots of energy! - vaporization even more so.
Of course, salinity will play a (non-linear) role in these thermodynamic quantities in sea ice, as will temperature - just google it if you want to see the curves.

Old question: I don't know who is using CICE5 for operational forecasting. If I was running an operational system of that sort I'd probably wait until the model has had a good thrashing in the academic community before I switched over from an earlier version.

ChrisReynolds

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Re: The 2015 melting season
« Reply #2528 on: July 25, 2015, 09:31:03 AM »
I'll have to get back to Blaine, JD Allen and Blizzard later, got to dash.

oren

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Re: The 2015 melting season
« Reply #2529 on: July 25, 2015, 10:06:03 AM »
Maybe a good idea to transfer all the energy/radiation discussions into a new thread?

Neven

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Re: The 2015 melting season
« Reply #2530 on: July 25, 2015, 10:54:49 AM »
Yes, please. I've looked for an existing thread, and maybe this one is suitable: OLR in the Arctic. Otherwise, open a new thread, someone. All of this will be lost, never to be found again, as this is the thread with the most pages on the forum.
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Re: The 2015 melting season
« Reply #2531 on: July 25, 2015, 11:09:05 AM »
IMB buoy 2013F is supposedly somewhere near O-Buoy 10, which recently started transmitting pictures again. Here's what the ice in the area (77.43 N, 144.55 W) looks like this morning:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/summer-2015-images/#OBuoy10

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Jim Hunt

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Re: The 2015 melting season
« Reply #2532 on: July 25, 2015, 11:23:23 AM »
Old question: I don't know who is using CICE5 for operational forecasting. If I was running an operational system of that sort I'd probably wait until the model has had a good thrashing in the academic community before I switched over from an earlier version.

Thanks Andrew. Fairy Nuff, but how long does such "a good thrashing" take?

http://forum.arctic-sea-ice.net/index.php/topic,108.msg52498/topicseen.html#msg52498 
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slow wing

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Re: The 2015 melting season
« Reply #2533 on: July 25, 2015, 12:45:32 PM »
Looking at the latest EOSDIS images, we were already aware of the incursion at ~140E inside the 80 degrees N circle. But the ice in the picture is dark directly below it and sloping away to the right as one  scans downwards.

Is this the thin ice we've seen in the ice maps from models and is this confirmation it is in bad shape?

It will be interesting to see how it evolves.

Andreas T

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Re: The 2015 melting season
« Reply #2534 on: July 25, 2015, 02:26:55 PM »
Yes, please. I've looked for an existing thread, and maybe this one is suitable: OLR in the Arctic. Otherwise, open a new thread, someone. All of this will be lost, never to be found again, as this is the thread with the most pages on the forum.
I have copied some posts by quoting them in the OLR thread, but could that be moved into "cryosphere" / background so it isn't as much out of view?
or open a new topic there

iceman

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Re: The Great Shear.
« Reply #2535 on: July 25, 2015, 03:07:36 PM »
The big shear off the continent from July 4 to today.
   ....

Pretty impressive, and winds in the coming week look to push the ice edge further away from its MYI redoubt.

Nightvid Cole

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Re: The 2015 melting season
« Reply #2536 on: July 25, 2015, 03:11:57 PM »
Yes, please. I've looked for an existing thread, and maybe this one is suitable: OLR in the Arctic. Otherwise, open a new thread, someone. All of this will be lost, never to be found again, as this is the thread with the most pages on the forum.

Atmospheric OLR stuff can go to that thread, and anything about absorption/reflection/emission by ice can go to my arctic sea ice optics thread...

Nightvid Cole

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Re: The 2015 melting season
« Reply #2537 on: July 25, 2015, 03:15:10 PM »
Yesterday (July 23) was a clear day over Beaufort, so the Bremen map reflected the true sea ice concentration there and in the adjacent area of the CAB. And this reality is a huge area with 50% concentration, with just a few remaining relatively small patches at high density (MYI remnants?) and about the same amount of holes at 0%.

So, is most of this ice doomed?

Yes. The concentration is now below 50% over much of that region. There's already more water than ice surface, and it is still July.

iceman

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Re: The 2015 melting season
« Reply #2538 on: July 25, 2015, 03:29:25 PM »
Yesterday (July 23) was a clear day over Beaufort, so the Bremen map reflected the true sea ice concentration there and in the adjacent area of the CAB. And this reality is a huge area with 50% concentration, with just a few remaining relatively small patches at high density (MYI remnants?) and about the same amount of holes at 0%.

So, is most of this ice doomed?

Yes. The concentration is now below 50% over much of that region. There's already more water than ice surface, and it is still July.

I think not: both area and extent are currently higher than in 2014, when Beaufort didn't come close to melting out.  Granted that the slowdown starting next week is unlikely to be as pronounced or prolonged as in 2014, and concentration is unusually low.
     The dynamic is noteworthy, though - a lot of those high-concentration MYI patches will become stranded in open water before the minimum.  Don't think I've seen that phenomenon before on this scale.

Tommy

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Re: The 2015 melting season
« Reply #2539 on: July 25, 2015, 03:35:12 PM »

Is volume plummeting?
« Last Edit: July 25, 2015, 05:09:35 PM by Tommy »

Tommy

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Re: The 2015 melting season
« Reply #2540 on: July 25, 2015, 03:42:20 PM »
Question for anyone.

1. Now that all that thickest ice has dislodged from the coast, where will it go?
Or will it just float back in to the coast in a couple of weeks?

2. Does red represent the oldest ice. or just the most bunched up, piling up over a few years?


From July 24 - thickness and volume tab.
http://polarportal.dk/en/havisen-i-arktis/nbsp/sea-ice-extent/



Neven

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Re: The 2015 melting season
« Reply #2541 on: July 25, 2015, 03:53:51 PM »
1. Now that all that thickest ice has dislodged from the coast, where will it go?
Or will it just float back in to the coast in a couple of weeks?

Yes.

Quote
2. Does red represent the oldest ice. or just the most bunched up, piling up over a few years?

Probably both.
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Peter Ellis

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Re: The 2015 melting season
« Reply #2542 on: July 25, 2015, 04:25:17 PM »
     The dynamic is noteworthy, though - a lot of those high-concentration MYI patches will become stranded in open water before the minimum.  Don't think I've seen that phenomenon before on this scale.
Closest looks to be 2006, where an "arm" of older ice in the Beaufort managed to hang on right to the end of the melt season despite melt-out of newer ice nearer the Pole.
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=09&fd=15&fy=2006&sm=09&sd=06&sy=2006

Neven

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Re: The 2015 melting season
« Reply #2543 on: July 25, 2015, 05:14:46 PM »
Both ECMWF and GFS have taken another step towards a reformation of high pressure on the American side of the Arctic, now with a cyclone on the other side as well. In other words, a classic dipole. But as it's more than 9 days away, I'm not posting any images (you can check them for yourself on Wetterzentrale or elsewhere).

Still, a bit more than yesterday, and three more days of widespread high pressure left to go.
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Neven

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Re: The 2015 melting season
« Reply #2544 on: July 25, 2015, 05:25:46 PM »
Okay, I'll post one image because it's such a gorgeous dipole, but it's 10 days out, so the forecast is bound to change:
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Nightvid Cole

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Re: The 2015 melting season
« Reply #2545 on: July 25, 2015, 05:55:58 PM »
Yesterday (July 23) was a clear day over Beaufort, so the Bremen map reflected the true sea ice concentration there and in the adjacent area of the CAB. And this reality is a huge area with 50% concentration, with just a few remaining relatively small patches at high density (MYI remnants?) and about the same amount of holes at 0%.

So, is most of this ice doomed?

Yes. The concentration is now below 50% over much of that region. There's already more water than ice surface, and it is still July.

I think not: both area and extent are currently higher than in 2014, when Beaufort didn't come close to melting out.  Granted that the slowdown starting next week is unlikely to be as pronounced or prolonged as in 2014, and concentration is unusually low.
     The dynamic is noteworthy, though - a lot of those high-concentration MYI patches will become stranded in open water before the minimum.  Don't think I've seen that phenomenon before on this scale.

Can you find a single example of <50% concentration ice as of July 23/24 of a given year surviving the season? I think not.

Extent and area tell you that there's a lot of slush, sure, but a lot of slush is still just slush.

Shared Humanity

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Re: The 2015 melting season
« Reply #2546 on: July 25, 2015, 05:56:49 PM »
Okay, I'll post one image because it's such a gorgeous dipole, but it's 10 days out, so the forecast is bound to change:

It would be really cool if the pressure gradient on that high was steeper.

Neven

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Re: The 2015 melting season
« Reply #2547 on: July 25, 2015, 06:19:24 PM »
You're not easily satisfied, SH!  ;D
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seaicesailor

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Re: The 2015 melting season
« Reply #2548 on: July 25, 2015, 06:40:26 PM »
     The dynamic is noteworthy, though - a lot of those high-concentration MYI patches will become stranded in open water before the minimum.  Don't think I've seen that phenomenon before on this scale.
Closest looks to be 2006, where an "arm" of older ice in the Beaufort managed to hang on right to the end of the melt season despite melt-out of newer ice nearer the Pole.
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=09&fd=15&fy=2006&sm=09&sd=06&sy=2006
As much as I dont know whether MYI in Beaufort will survive or not, this 2006 example tells me 2015 chances are priori much higher for total melt out
Right image is 7/22/2015

Tommy

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Re: The 2015 melting season
« Reply #2549 on: July 25, 2015, 06:40:53 PM »
Can anyone show me a pic/image from a previous year where that ice has dislodged completely from that area along the Canadian islands?

I made this GIF which ranges through Aug, July, mid-Sept., for 2007, 2012, 2013, and finally, yesterday.

I can't find any image that shows that big white gap.

Because this is Thickness, then that gap obviously has more ice in it than shows here, but I can't find any that show any gap anything like that, and the same is true on satellite photos from those and other years I looked at, even by the lowest extent of seasons, and the gap does not show for ice extent for all those years either. If no white or even purple shows up at that point in previous years on a thickness map, would suggest there was never a significant gap there before - an actual gap in ice, because any thinning there in previous years still had some pretty thick ice on it, joined to the Fjords.
The lowest I can find was a tiny blip of 1m ice, nearest to the Beaufort Sea, in early Sept. 2012, No white, and a just tiny blip of thin ice compared to this.

Therefore, are we in uncharted territory for that area?
Even in lean years there was thick ice on the ocean joined to thick ice in the Fjords of that area.

I'm probably missing something.

Below the gif is Satellite from July 23 this year.
I colored open Ocean water in red around that gap area. As you can see it extends far eastwards towards Lincoln Sea, and that does not show up like that on any other Satellite photos from previous years that I have seen?
Any answers?

http://satwagraphics.com/2017_2008-_2012.gif

« Last Edit: July 25, 2015, 07:08:25 PM by Tommy »