Support the Arctic Sea Ice Forum and Blog

Author Topic: The 2017 melting season  (Read 691174 times)

greatdying2

  • ASIF Middle Class
  • Posts: 574
    • View Profile
Re: The 2017 melting season
« Reply #3950 on: August 27, 2017, 02:50:48 AM »
Nice, thanks for those A-Team.

I haven't posted any Bremen maps lately (slow ice and I've been busy), so here's an update: the last 30 days using the 5-day median filter, and the last 10 days using the last-under-90 filter.

As mentioned previously, several areas still look vulnerable in the few weeks remaining (before surface refreeze starts to dominate satellite imagery), including the remaining Beaufort tongue, the Laptev bite, and the area NE of Svalbard. Stay tuned...
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.

Thawing Thunder

  • ASIF Citizen
  • Posts: 156
    • View Profile
Re: The 2017 melting season
« Reply #3951 on: August 27, 2017, 01:40:16 PM »
Very nice and interesting. Thank you GD2!

greatdying2

  • ASIF Middle Class
  • Posts: 574
    • View Profile
Re: The 2017 melting season
« Reply #3952 on: August 28, 2017, 05:26:35 AM »
Welcome TT :)

Nice view of the Atlantic side today. Lots of foam...
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.

deconstruct

  • ASIF Lurker
  • Posts: 22
    • View Profile
Re: The 2017 melting season
« Reply #3953 on: August 28, 2017, 07:39:43 AM »
Model correction .... or the slippery slope?
The former I think.
Why would you assume anyone at NSIDC would correct any model? If they changed some model they a) would have published that and b) they would recalculate all previous data also, so a change of models would not start somewhere in between years, that just wouldn't make any sense. The point of those SIE numbers is, that you have a *consistent* record of SIE over multiple decades.

The NSIDC numbers are not here to show you some predefined goal, to which SIE should drop and someone is monitoring that and thinks "ice extent is a little slow this year, so just change something in the algorithm". NSIDC extent numbers just show you every day what the ice extent numbers are, calculated from the same satellite data using the same algorithm...

greatdying2

  • ASIF Middle Class
  • Posts: 574
    • View Profile
Re: The 2017 melting season
« Reply #3954 on: August 28, 2017, 09:00:11 AM »
Model correction .... or the slippery slope?
The former I think.
Why would you assume anyone at NSIDC would correct any model?

I don't think that's what he meant. I think he was wondering whether the wiggle in the line was just noise cancelling out, or if it reflected a real change in the rate of extent loss.
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.

VeliAlbertKallio

  • ASIF Citizen
  • Posts: 126
    • View Profile
    • Sea Research Society (SRS)
Re: The 2017 melting season
« Reply #3955 on: August 28, 2017, 05:15:20 PM »
"Why would you assume anyone at NSIDC would correct any model? If they changed some model they a) would have published that and b) they would recalculate all previous data also, so a change of models would not start somewhere in between years, that just wouldn't make any sense. The point of those SIE numbers is, that you have a *consistent* record of SIE over multiple decades."

This is the very point the Republican Party policy advisors made recommending for scrapping of F20 satellite as this would help Donald Trump and Congress to cite that the ice measurements are discontinuous, and thus provide inconsistent SIE numbers when once the opportunity rose as F17 failed and F19 too, with nothing to fill the data gap when F18 falters. To help further the cause of uncertainties and discontinuities, the government decided to scrap F20 to break the SIE series.  ;D


Model correction .... or the slippery slope?
The former I think.
Why would you assume anyone at NSIDC would correct any model? If they changed some model they a) would have published that and b) they would recalculate all previous data also, so a change of models would not start somewhere in between years, that just wouldn't make any sense. The point of those SIE numbers is, that you have a *consistent* record of SIE over multiple decades.

The NSIDC numbers are not here to show you some predefined goal, to which SIE should drop and someone is monitoring that and thinks "ice extent is a little slow this year, so just change something in the algorithm". NSIDC extent numbers just show you every day what the ice extent numbers are, calculated from the same satellite data using the same algorithm...
« Last Edit: August 28, 2017, 05:43:31 PM by VeliAlbertKallio »

FishOutofWater

  • ASIF Citizen
  • Posts: 272
    • View Profile
Re: The 2017 melting season
« Reply #3956 on: August 28, 2017, 06:04:36 PM »
The destruction of the F20 satellite also hurt our ability to look inside of developing tropical storms and hurricanes. I need to write about it over at DK.

The destruction of the F20 satellite was an inexcusable attack not only on Arctic science but also on our ability to forecast storms like Harvey.

Yes, the destruction of this satellite will create confusion and uncertainty in the consistent long-term data set the NSIDC has developed, but it may also cost human lives.

greatdying2

  • ASIF Middle Class
  • Posts: 574
    • View Profile
Re: The 2017 melting season
« Reply #3957 on: August 28, 2017, 07:02:48 PM »
(Sorry for continuing OT...) Anyone who doubts anthropogenically driven climate change at this point doesn't care about even basic data, let alone nuances. Sooner or later (sooner, at the rate things are going), these people will be convinced not by data but by their own direct experience of the weather, and there's nothing the idiot politicians can do to hide that. "Fake weather?"  :o ;D 
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.

Jim Pettit

  • Global Moderator
  • ASIF Upper Class
  • *****
  • Posts: 1060
    • View Profile
Re: The 2017 melting season
« Reply #3958 on: August 28, 2017, 10:44:23 PM »
Guys, there are a number of other threads here for discussing politics, AGW, and the like. As we are nearing the annual minimum, it's especially important to keep this particular forum free of OT clutter. IOW: move along, please. Thanks!

Shared Humanity

  • ASIF Upper Class
  • Posts: 2152
    • View Profile
Re: The 2017 melting season
« Reply #3959 on: August 29, 2017, 05:16:57 AM »
Amen.

Andir

  • ASIF Lurker
  • Posts: 13
    • View Profile
Re: The 2017 melting season
« Reply #3960 on: August 29, 2017, 10:05:38 PM »
Arctic Sea Ice has a very small volume, but in relation big extent/area with this constellation the  minimum for extent will be later this season.
You are quite correct that the freezing season has not begun -- the best available evidence, which seems to be at the links below, shows net melt everywhere out through August 27th. It is better to wait on NSIDC's call than go charging off on divisive new forums out of synch with the scientific community.

I am skeptical that anyone here is running more sophisticated models than ESRL. Most people here are not running any model at all and indeed lack access to the necessary computing resources. It is usually better to defer to those with far greater skill sets -- unless you can specifically document problems with their products and link to your conflicting data.

@ A-Team, thanks for your answer. Im not a native speaker, but your answer sounds quite a little bit dominant or aggressive. I just had a question, if it is possible, that small volume and relatively big extent could end in a late minimum. This is just a feeling  without models, datas or publications. In your answer my question was gone. Dont know why.
Anyway, if questions are not  welcome, i am sorry.



Richard Rathbone

  • ASIF Citizen
  • Posts: 363
    • View Profile
Re: The 2017 melting season
« Reply #3961 on: August 30, 2017, 01:34:14 PM »
Arctic Sea Ice has a very small volume, but in relation big extent/area with this constellation the  minimum for extent will be later this season.

Anyway, if questions are not  welcome, i am sorry.


You need to use question marks "?" if you want something you write to be interpreted as a question. Word order matters too, you should start with the verb. You made a statement. You should write something like,

"Will the minimum extent be late this season because the ice has a small volume in relation to its area?",

to ask a question.

To which I'd respond, "No, the details of the minimum extent are all about the weather and sensor noise. It might be a contributing factor to a very late minimum, but without the right weather, or the sensors missing some ice on a late day, it won't make a difference."

gerontocrat

  • ASIF Middle Class
  • Posts: 676
    • View Profile
Re: The 2017 melting season
« Reply #3962 on: August 30, 2017, 02:26:43 PM »
I am not often given to posting about the weather - I am able to get it all wrong on other threads.
But weather-forecast.com has a significant system coming into the Arctic from the North Atlantic over the coming days. Are the other weather forecasting systems coming up with something similar?
"Para a Causa do Povo a Luta Continua!"

iceman

  • ASIF Citizen
  • Posts: 261
    • View Profile
Re: The 2017 melting season
« Reply #3963 on: August 30, 2017, 02:43:07 PM »
Climate Reanalyzer shows something similar, with lots of rain and warmth on the Atlantic front.  But GFS has not been too reliable beyond forecast day 4-5.  Wait and see for another couple days.

Pavel

  • ASIF Citizen
  • Posts: 121
    • View Profile
Re: The 2017 melting season
« Reply #3964 on: August 30, 2017, 02:52:26 PM »
This atlantic low pressure system is similar to last year's fall and December cyclones. This could be start of a very mild fall and winter season in the Arctic

Archimid

  • ASIF Middle Class
  • Posts: 686
    • View Profile
Re: The 2017 melting season
« Reply #3965 on: August 30, 2017, 03:15:01 PM »
Cold spikes like the current one are not uncommon. The temperature will reach peak cold soon and then shoot back up.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

F.Tnioli

  • ASIF Middle Class
  • Posts: 587
    • View Profile
Re: The 2017 melting season
« Reply #3966 on: August 30, 2017, 04:40:24 PM »
Cold spikes like the current one are not uncommon. The temperature will reach peak cold soon and then shoot back up.
"Soon"? Likely, but not certainly. There is at least one solid model predicting that wouldn't be the case until some time 2040s (by no other than James Lovelock), and there are few major global factors which are powerful enough to halt rapid further temperature rise for (a few) decades, like changes in particulates produced by both man-made and reactive sources (forest fires, etc). And note the shape of that graph, too: looks like there is significant levelling since 2000s.

greatdying2

  • ASIF Middle Class
  • Posts: 574
    • View Profile
Re: The 2017 melting season
« Reply #3967 on: August 30, 2017, 07:26:53 PM »
At this time, The Arctic Sea Ice has a very small volume, but in relation big extent/area . Is my feeling right, that with this constellation the  minimum for extent will be more late this season.

Hi Andir. I think A-Team's response was not directed so much at you but in general -- many people seem to be jumping the gun somewhat in suggesting an end to the melting season. Yes, questions are very welcome. :)

In answer to your question, I think it does seem like a reasonable possibility.

(P.S. In answer to your other question, people often crop posts they are quoting when they only want to respond to one part of it.)
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.

Andir

  • ASIF Lurker
  • Posts: 13
    • View Profile
Re: The 2017 melting season
« Reply #3968 on: August 30, 2017, 07:39:20 PM »
@greatdying
Thank you for your explanations.
I was irritated
Now i am fine.

greatdying2

  • ASIF Middle Class
  • Posts: 574
    • View Profile
Re: The 2017 melting season
« Reply #3969 on: August 30, 2017, 08:10:10 PM »
But weather-forecast.com has a significant system coming into the Arctic from the North Atlantic over the coming days.

Yes, both ECMWF and GFS (both attached at day +4) forecast an Atlantic-side low starting in a few days and persisting for several days. If it comes to pass, this system may clear out the fairly large area of foam (see WorldView), maybe more than just the foam. Also, there is a small low forecast on the Russian side, which may give the Laptev bite (etc.) a little push.

Check out windy.com -- excellent, easy to interpret animations of both these models, updated several times a day. (To view the Arctic, switch to 3D view under Menu | Tools, which is that "3-bars" icon at the top-left of screen.)

@Andir, glad to hear it :)
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.

Shared Humanity

  • ASIF Upper Class
  • Posts: 2152
    • View Profile
Re: The 2017 melting season
« Reply #3970 on: August 30, 2017, 08:15:16 PM »
Would not take much for most of the ice in that image to disappear.

Mozi

  • ASIF Lurker
  • Posts: 13
    • View Profile
Re: The 2017 melting season
« Reply #3971 on: August 30, 2017, 09:30:42 PM »
The same as could have been (and was) said throughout this entire melting season... If all the ice can rely on going forward is the weather, before long luck will turn against it, whether this year or the next.

aperson

  • ASIF Lurker
  • Posts: 8
    • View Profile
Re: The 2017 melting season
« Reply #3972 on: August 30, 2017, 09:49:11 PM »
The current cyclone train extending from EPAC to the N. Atlantic reminds me a lot of the system that occurred in the winter to keep persistent high SSTs in the Atlantic side. Maybe more evidence of LP systems propagating into the Arctic on a more regular basis? It definitely makes me buy the model tracks

This winter: https://earth.nullschool.net/#2017/01/25/1800Z/wind/surface/level/orthographic=-63.23,34.74,331
Now: https://earth.nullschool.net/#current/wind/surface/level/orthographic=-63.23,34.74,331




Jim Hunt

  • ASIF Governor
  • Posts: 3302
    • View Profile
    • The Arctic sea ice Great White Con
Re: The 2017 melting season
« Reply #3973 on: August 30, 2017, 10:37:51 PM »
The current cyclone train extending from EPAC to the N. Atlantic reminds me a lot of the system that occurred in the winter to keep persistent high SSTs in the Atlantic side.

I'd been wondering aloud along similar lines in the heart of darkness. A fair way out, but:

Reality is merely an illusion, albeit a very persistent one - Albert Einstein

A-Team

  • ASIF Upper Class
  • Posts: 1878
    • View Profile
Re: The 2017 melting season
« Reply #3974 on: August 30, 2017, 10:38:32 PM »
Would not take much for most of the ice in that image to disappear
True, but not much action seen out to day 5 in either of our ice thickness and ice boundary predictions systems, ESRL and Hycom, though note the suggestion of CAA garlic press onset in the latter which could potentially break up what little remains of the very thickest ice.

Indeed very little happened by way of trend in the 13-29 Aug 17 time frame for UH AMSR2 sea ice concentration, which mostly wobbles between dispersion, compaction, and bulk ice pack displacement.
« Last Edit: August 30, 2017, 11:40:34 PM by A-Team »

PhysicsDoc

  • ASIF Lurker
  • Posts: 2
    • View Profile
Re: The 2017 melting season
« Reply #3975 on: August 30, 2017, 11:19:35 PM »
I am new to this forum but have been interested in artic sea ice trends for a while. I was removed from Guy McPhersons forum for cheekily pointing out that a blue ocean event was postponed for this season based on NSIDC ice extent data. I am as concerned as anyone about the future climate change has to offer but prefer to stick to data and physics as much as possible. I did not think my comments warranted banishment but so be it. I hope that does not happen here.
I did do a simple second order fit to the sea ice extent trends and the curve indicated a blue ocean around 2030 for what the extrapolation is worth (probably not much). I would be happy to share if anyone is interested.

liefde

  • ASIF Lurker
  • Posts: 20
  • ice melt will trump donald
    • View Profile
Re: The 2017 melting season
« Reply #3976 on: August 30, 2017, 11:59:16 PM »
Cold spikes like the current one are not uncommon. The temperature will reach peak cold soon and then shoot back up.
In fact, as of a week from now, starting around Wednesday, yet another +1.8C heat-anomalous period is predicted to further destroy remaining ice.

jdallen

  • ASIF Upper Class
  • Posts: 2434
    • View Profile
Re: The 2017 melting season
« Reply #3977 on: August 31, 2017, 03:45:56 AM »
Would not take much for most of the ice in that image to disappear
True, but not much action seen out to day 5 in either of our ice thickness and ice boundary predictions systems, ESRL and Hycom, though note the suggestion of CAA garlic press onset in the latter which could potentially break up what little remains of the very thickest ice.

Indeed very little happened by way of trend in the 13-29 Aug 17 time frame for UH AMSR2 sea ice concentration, which mostly wobbles between dispersion, compaction, and bulk ice pack displacement.
I expect it all got thinner however.

Right now, I'm watching the eastern seaboard of North America as I think the first of what will become a regular series of tropical depressions will start sweeping NE to eventually descend on the Barentsz, taking in train massive amounts of moisture.

At some point, the remains of Harvey will emerge from the Mississippi/Ohio watershed and similarly start a more rapid northeasterly trajectory.

If the Cyclone Cannon starts up, that will push the minimum out, possibly quite a ways, as the heat they carry will slow loss to atmosphere and permit more bottom melt.

If it does not, then we may see an "early" start to the refreeze, which may still be bad news, as it will tend to trap more of this season's heat.

Regardless,  anything beyond 2nd year ice will be at historically low levels, and none of it particularly robust, even as it puts a lid on the arctic.
This space for Rent.

aperson

  • ASIF Lurker
  • Posts: 8
    • View Profile
Re: The 2017 melting season
« Reply #3978 on: August 31, 2017, 06:39:20 AM »
Edit: Wrong thread.
« Last Edit: August 31, 2017, 06:49:14 AM by aperson »

jai mitchell

  • ASIF Upper Class
  • Posts: 1748
    • View Profile
Re: The 2017 melting season
« Reply #3979 on: August 31, 2017, 06:47:20 AM »
Between the cyclone train that is being generated from EPAC toward the pole and the amount of upwelling that was done by Harvey (and more storms this season at this rate), I'm starting to wonder if the levee on our convection budget just breached. Maybe this is the wording we should be using to explain to people how climate change and a runway greenhouse effect work?

Upwelling from Harvey: https://twitter.com/SoonerTom/status/903089795345338376
Cyclone train from equator toward pole: https://twitter.com/ZLabe/status/903083907653935105

aperson,

the thread you are looking for to post this is here:  http://forum.arctic-sea-ice.net/index.php/topic,2148.msg127394/topicseen.html#msg127394
Haiku of Past Futures
My "burning embers"
are not tri-color bar graphs
+3C today

Tigertown

  • ASIF Upper Class
  • Posts: 1628
    • View Profile
Re: The 2017 melting season
« Reply #3980 on: August 31, 2017, 09:34:44 AM »
There has been definite deterioration over the last few days. Aug. 27th-30th.
A lot of darkening in the image before appearing blue on the 30th.
CLICK IMAGE Zoom
« Last Edit: August 31, 2017, 09:40:14 AM by Tigertown »

A-Team

  • ASIF Upper Class
  • Posts: 1878
    • View Profile
Re: The 2017 melting season
« Reply #3981 on: August 31, 2017, 01:02:00 PM »
I expect it all got thinner however.
Right, there is net melt everywhere through Sept 4th. As far as we know, the freezing season has not started. There'll be some overlap in a few weeks though.

prefer to stick to data and physics as much as possible
There's a quite remarkable new daily forecast resource from the physical science division of the Earth Science Research Laboratory at NOAA/CIRES. The radiation balance is probably the most interesting of these products from a physics standpoint as we enter the fall.

It's better to work with the maps of surface properties than integral summary products which lose geospatial distribution, notably the peripheral dominance of most processes. For working with the netCDF data files (.nc), the main choice out there is Panoply as matlab is unaffordable.

It looks to me like RASM-ESRL has made a very substantial improvement on snow cover and depth  (3rd animation, GFS on right), a topic that has largely eluded us factually despite often being invoked here to explain the melt season.

https://www.esrl.noaa.gov/psd/forecasts/seaice/
ftp://ftp1.esrl.noaa.gov/RASM-ESRL/ModelOutput archives
https://www.giss.nasa.gov/tools/panoply/
« Last Edit: August 31, 2017, 02:02:41 PM by A-Team »

Sterks

  • ASIF Citizen
  • Posts: 149
  • Member # 1000
    • View Profile
Re: The 2017 melting season
« Reply #3982 on: August 31, 2017, 03:02:11 PM »
Right, there is net melt everywhere through Sept 4th. As far as we know, the freezing season has not started. There'll be some overlap in a few weeks though.
Right. So who's we?
In my opinion, the ESRL graphs show as many symptoms of continued melting as already overlapping symptoms of refreezing in very extensive areas of the Arctic. These snows shown above come accompanied of temperatures below -3ºC, sometimes below -6ºC, also shown in the same web page. Snow is made of frozen water, and with these temperatures, it may remain frozen, as far as I know.
Some locations near the Beaufort "appendix" show SSTs close to -2C, and some early signs of expansion (not dispersion) of the pack, coexisting with other areas where the water heat excess is melting the ice in a matter of days.

A-Team

  • ASIF Upper Class
  • Posts: 1878
    • View Profile
Re: The 2017 melting season
« Reply #3983 on: August 31, 2017, 04:11:24 PM »
Right. So who's we?  In my opinion
You should write the chief scientist there and tell them of the big mistake in their model.

oren

  • ASIF Upper Class
  • Posts: 1571
    • View Profile
Re: The 2017 melting season
« Reply #3984 on: August 31, 2017, 05:57:51 PM »
A. Snow does not constitute refreezing, even though it may somewhat affect area readings.
B. -2 and even -6 deg temps do not generally freeze seawater, though they refreeze meltponds (again affecting area readings).

Archimid

  • ASIF Middle Class
  • Posts: 686
    • View Profile
Re: The 2017 melting season
« Reply #3985 on: August 31, 2017, 06:54:07 PM »
What a cliffhanger season. ;D ;D
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Sterks

  • ASIF Citizen
  • Posts: 149
  • Member # 1000
    • View Profile
Re: The 2017 melting season
« Reply #3986 on: August 31, 2017, 07:29:47 PM »
Right. So who's we?  In my opinion
You should write the chief scientist there and tell them of the big mistake in their model.
No, I don't find anything essentially mistaken in their model, don't misunderstand my words.
Let's not make a ball effect of misunderstandings. I don't agree with some of what you said, not with what the maps indicate. You being whatever collectivity or an individual. Ok? That's all.

Sterks

  • ASIF Citizen
  • Posts: 149
  • Member # 1000
    • View Profile
Re: The 2017 melting season
« Reply #3987 on: August 31, 2017, 07:41:40 PM »
A. Snow does not constitute refreezing, even though it may somewhat affect area readings.
B. -2 and even -6 deg temps do not generally freeze seawater, though they refreeze meltponds (again affecting area readings).
I get it. I just say, I thought I saw a significant cooling in the ESRL forecast for a vast region of the pack, comprising not only North of 80N but also the pacific-side edge, and it looked more agreeable with freezing than melting, that's all. I understand bottom melt will continue at places, but if cold temperatures dominate, even that can abate earlier than expected... Or coexist with ocean surface freezing, briefly

Daniel B.

  • ASIF Citizen
  • Posts: 125
    • View Profile
Re: The 2017 melting season
« Reply #3988 on: August 31, 2017, 08:55:47 PM »
I am new to this forum but have been interested in artic sea ice trends for a while. I was removed from Guy McPhersons forum for cheekily pointing out that a blue ocean event was postponed for this season based on NSIDC ice extent data. I am as concerned as anyone about the future climate change has to offer but prefer to stick to data and physics as much as possible. I did not think my comments warranted banishment but so be it. I hope that does not happen here.
I did do a simple second order fit to the sea ice extent trends and the curve indicated a blue ocean around 2030 for what the extrapolation is worth (probably not much). I would be happy to share if anyone is interested.
and recede rapidly, depending largely on the temperatures in the North Atlantic (the Pacific is a

I would hesitate to use a simple second order fit.  The reasoning is that the Arctic ice will expand much smaller concern, due to the narrow straight).  It has difficulty expanding indefinitely, due to the open waters.  Similarly, the ice will recede rapidly, until it reaches the confines of Greenland and the Canadian archipelago.  The curve will more closer resemble an S-shape, with slower melting at the onset and ending, and much faster in the middle.  Granted, everything is speculation until it happens, but the data is tending to agree with this fit.

http://www.nature.com/nclimate/journal/v6/n9/full/nclimate3041.html

oren

  • ASIF Upper Class
  • Posts: 1571
    • View Profile
Re: The 2017 melting season
« Reply #3989 on: August 31, 2017, 09:04:57 PM »
I am new to this forum but have been interested in artic sea ice trends for a while.
I prefer to stick to data and physics as much as possible.
Welcome, PhysicsDoc with the right approach.

magnamentis

  • ASIF Upper Class
  • Posts: 1229
    • View Profile
    • Nexpaq Modular ARA iOS Software Mobile Computing Phones Philosophy Ethics Numerology Mikrocirkulation Vaskular Therapie Gesundheit Blut Gesundheit Schmerzen Multipelsklerose Diabetes Immunsystem Fibromyalgie
Re: The 2017 melting season
« Reply #3990 on: August 31, 2017, 09:46:52 PM »
Right. So who's we?  In my opinion
You should write the chief scientist there and tell them of the big mistake in their model.
No, I don't find anything essentially mistaken in their model, don't misunderstand my words.
Let's not make a ball effect of misunderstandings. I don't agree with some of what you said, not with what the maps indicate. You being whatever collectivity or an individual. Ok? That's all.

probably an individual sharing his views with others or even a majority, at least i see things similarly and if bottom melt is a reality (which of course it is) is still think we could be in for a surprise, similar to what happend in beaufort recently 25% gone in no time.  as i mentioned earlier, i expect a very late in the season effect of bottom melt to the final result of this season due to generally thin and fragmented ice, not even talking about a storm an wave action which could happen almost any time during the next few weeks that are still well within the average period of melting.
http://magnamentis.com
Knowledge, Understanding & Insight Are Among The Best Sources For Personal Freedom & Vitality !

Tigertown

  • ASIF Upper Class
  • Posts: 1628
    • View Profile
Re: The 2017 melting season
« Reply #3991 on: September 01, 2017, 05:51:00 AM »
Whatever the cause may be, there is melting near Svalbard.

Michael Hauber

  • ASIF Middle Class
  • Posts: 664
    • View Profile
Re: The 2017 melting season
« Reply #3992 on: September 01, 2017, 06:10:41 AM »
Right. So who's we?  In my opinion
You should write the chief scientist there and tell them of the big mistake in their model.

It would only take a very small mistake in their model to allow for some freezing in some locations, although it seems obvious to me that melt still dominates the Arctic. 

There was a report in the 2017 freezing season season thread (reply #40) suggesting that even at 80N fresher patches of surface sea water were starting to freeze (or do they mean patches of fresh water on the boat?) and some floes had accumulated a couple inches of snow.  Perhaps bottom melt would be more than any surface freezing still though.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

PhysicsDoc

  • ASIF Lurker
  • Posts: 2
    • View Profile
Re: The 2017 melting season
« Reply #3993 on: September 01, 2017, 09:39:51 AM »
Thanks Daniel B. for the link I will check it out.

gerontocrat

  • ASIF Middle Class
  • Posts: 676
    • View Profile
Re: The 2017 melting season
« Reply #3994 on: September 01, 2017, 02:05:42 PM »
To state the obvious, air temperatures in the central Arctic are declining rapidly, and sea temperatures presumably much more slowly. So the melting vs freezing is a matter of the competing forces of temps above and temps below 1.8 degrees celsius. So I started to think about numbers concerning heat storage capacity and thermal conductivity (I think it was A-Team that woke my brain up).

ENERGY STORAGE CAPACITY
The specific heat of seawater is about 3.9 times that of air per unit of MASS.
1 cubic metre of seawater weighs about 1,000 kg
1 bar (sea level) air has a density of approximately 1.225 kg/m3.
                  
Therefore as a store of heat one cubic metre of seawater has the capacity of nearly 3,200 cubic metres of air.

THERMAL CONDUCTIVITY is a measure of the ability to transfer heat.
Water is 24 times better at it than air. (Apparently salinity does not change this significantly).
Ice is 91 times better at it than air.

Methinks the oceans have it for the moment, despite the greater mobility of air. And one is not just talking about sea surface temperatures. In the articles and discussions on Harvey it became apparent that a major source of energy was that the Gulf waters were well above average temperatures at considerable depth. Is it the same in the Arctic and the North Atlantic / North Pacific ?
"Para a Causa do Povo a Luta Continua!"

Pavel

  • ASIF Citizen
  • Posts: 121
    • View Profile
Re: The 2017 melting season
« Reply #3995 on: September 01, 2017, 02:22:37 PM »
The weather conditions still warm enough to continue melting futhermore in September. (The pics below will update). There's not so much open water north of 80 latitude. The ice should continue to retreat on the edges and most likely the minimum extent should occur relatively late in September



Often Distant

  • ASIF Lurker
  • Posts: 11
    • View Profile
Re: The 2017 melting season
« Reply #3996 on: September 01, 2017, 03:03:32 PM »
More ice on the move off northern Greenland.

oren

  • ASIF Upper Class
  • Posts: 1571
    • View Profile
Re: The 2017 melting season
« Reply #3997 on: September 01, 2017, 03:18:49 PM »
The weather conditions still warm enough to continue melting futhermore in September. (The pics below will update). There's not so much open water north of 80 latitude. The ice should continue to retreat on the edges and most likely the minimum extent should occur relatively late in September
I think the opposite.  All that slushy ice between the ESS and the pole will be easy to refreeze should the low temps come, as the water around it have not had a chance to mix. I think the balance of probability is more towards an early refeeze before Sept 15th, rather than a late one.

A-Team

  • ASIF Upper Class
  • Posts: 1878
    • View Profile
Re: The 2017 melting season
« Reply #3998 on: September 01, 2017, 05:59:51 PM »
The first two animations below look at the Beaufort-Chukchi; a recent tweet put them at near-record extent. Of course the boundaries of these two seas are somewhat arbitrary in that they do not correspond to bathymetery, currents, inflows from the Bering Sea or anything else physical. https://www.weather.gov/afc/ice

There are definitely learning curves in re-projecting these massive daily comprehensive ESRL forecasts into maps in standardized Arctic projection with interactive palettes. Another issue in making comparisons is that many of our favorite products provide only a final map, not the netCDF data file used to make the map.

The key thing to using Panoply is setting all the preferences before even opening an .nc file. I will load a 14 screen animation of preferences with recommended settings after things settle down. Panoply is not matlab but it can still make some very respectable animated maps (not shown!).

Panoply cannot export gif animations, only mp4 movies not accepted by forum software. However, like the crucial gimp tool 'Slice', Panoply can export all the individual frames as .png or .jpg which gimp can layer up from there as the usual small-sized differenced gifs.

The two lower animations look at whether, in correcting AMSR2 for passing weather using previous days, ESRL ice motion can be taken into account. That is, the ice pack might move quite a bit between day n-1 and day n. This time of year, there's not much bulk coherent motion as the driving wind varies with location meaning ridging, rafting, compression and dispersion do as well. So one approach is to mask high motion regions, not allowing cloud-free areas of day n-1 to correct cloudy areas of day n there, if you catch my drift.

The whole-Arctic animation is made with a 3-day geometric mean, rather than harmonic or arithmetic means or medians or multi-day overlay minimum or other rules. The idea with all these variations is to overweight earlier days at a given pixel if it is bluer than a newer day on the (somewhat shaky) assumption that cloudy weather on later days make  pixels whiter (concentration higher).

Animations get out of order, below, because even 'legal' ones (well within forum bounds) can fail to load, or rather the forum just loads a single gif frame. This then requires multiple rounds of deleting the failed attachments and reloading them. Those that load properly on early rounds then rise to the top of the stack, out of sequence.
« Last Edit: September 01, 2017, 07:28:24 PM by A-Team »

ktonine

  • ASIF Citizen
  • Posts: 363
    • View Profile
Re: The 2017 melting season
« Reply #3999 on: September 01, 2017, 06:54:32 PM »
A-Team, it can't be said often enough - THANKS!