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josh-j

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Re: The 2018/2019 freezing season
« Reply #350 on: October 15, 2018, 08:37:47 PM »
I don't really get cci gfs 2m anomalies. It doesn't seem to match EC and GFS models on meteociel at all. Yeah sure there are some positive Temp 850hPa anomalies on meteociel as well, but nothing dramatic, and there are even some negative fields on the map."

In case this helps anybody, anomalies both at 2m and at 850hpa can be viewed with the same colour scale at Tropical Tidbits:

https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=nhem&pkg=T2ma&runtime=2018101506&fh=198
(height level can be selected under Thermodynamics)

As the 2m temps there seem to match CCI, whatever the reason for the difference it probably isn't to do with CCI, rather the GFS (and/or reality). Which, of course, doesn't answer your question... but I find it so much easier to look at a two charts together when they have the same colour scale. :)

Sebastian Jones

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Re: The 2018/2019 freezing season
« Reply #351 on: October 15, 2018, 08:48:22 PM »
echoughton asks (presumably tongue in cheek): "But what does that mean for one of my top 15 favorite Alaska shows: Bering Sea Gold? They better be able to get out on the ice and mine, otherwise ratings will plummet!"
Norton Sound is a bay off the Bering Sea, so even when the Bering does not freeze, it, and other bays in the Bering, do freeze. The Iditarod will have to change its route to all overland if the Sound does not freeze....

bbr2314

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Re: The 2018/2019 freezing season
« Reply #352 on: October 15, 2018, 09:14:39 PM »
I don't really get cci gfs 2m anomalies.

Comparison, same date, same model (GFS 6z)
That is not the same date output...

be cause

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Re: The 2018/2019 freezing season
« Reply #353 on: October 15, 2018, 10:27:41 PM »
and meanwhile dmi80 continues to chart a novel course . Today was back to 11'C above mean on a par with the previous peak . b.c.
Conflict is the root of all evil , for being blind it does not see whom it attacks . Yet it always attacks the Son Of God , and the Son of God is you .

Niall Dollard

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Re: The 2018/2019 freezing season
« Reply #354 on: October 15, 2018, 10:30:18 PM »
I don't really get cci gfs 2m anomalies. It doesn't seem to match EC and GFS models on meteociel at all. Yeah sure there are some positive Temp 850hPa anomalies on meteociel as well, but nothing dramatic, and there are even some negative fields on the map.

But why should 2m anomalies match anomalies at 850 hPa level (which is approximately at an altitude of 1500m) ? Anomalies can be completely different for example when large anticyclones are at play and a strong inversion sets up at surface level.

With inversions you can have below normal 2m anomalies and above at 1500m the air can be well above normal.

Ice Shieldz

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Re: The 2018/2019 freezing season
« Reply #355 on: October 15, 2018, 11:17:15 PM »
Well it sure would be great if A-Team could come back with those amazing animations and descriptions of the ice flow. Especially given what's going on with all the export of multi-year ice.   ;)

miki

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Re: The 2018/2019 freezing season
« Reply #356 on: October 15, 2018, 11:20:34 PM »
Well it sure would be great if A-Team could come back with those amazing animations and descriptions of the ice flow. Especially given what's going on with all the export of multi-year ice.   ;)

Ditto  :)

Jim Hunt

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Re: The 2018/2019 freezing season
« Reply #357 on: October 15, 2018, 11:29:28 PM »
Well it sure would be great if A-Team could come back with those amazing animations

I wholeheartedly agree, but in the meantime here's an amazing animation courtesy of Suman Singha via:

http://GreatWhiteCon.info/2018/10/an-unusual-sea-ice-situation-north-of-greenland/

"The most revolutionary thing one can do always is to proclaim loudly what is happening" - Rosa Luxemburg

gerontocrat

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Re: The 2018/2019 freezing season
« Reply #358 on: October 16, 2018, 12:10:46 AM »

http://GreatWhiteCon.info/2018/10/an-unusual-sea-ice-situation-north-of-greenland/


I followed the link and then followed the link to CryoSat-2 via the Centre for Polar Observation and Monitoring: http://www.cpom.ucl.ac.uk/csopr/seaice.html

And what did I find? The Arctic divided into basins. The same as NSIDC uses? Partly yes, mostly no. See attached example - the Canadian Archipelago has swallowed part of the Beaufort.

Maybe very clever people will be able to translate data in the grids into NSIDC Seas and vice versa. But for amateurs like me it's a non-starter.

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bbr2314

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Re: The 2018/2019 freezing season
« Reply #359 on: October 16, 2018, 01:45:10 AM »
Foxe Basin is now freezing rapidly and the first new ice is appearing along Hudson Bay's western shore.



If the EURO / COPERNICUS are correct, Foxe Basin will be at fully covered in partial ice by 10/23-24, and that means it'll probably be at 90%+ grey ice by 10/30.

While Foxe Basin is certainly freezing early, I think the real surprise awaits in Hudson. There is a large area of cold "fresh" water in its northeast portion that is already approaching 0C. As Foxe Basin freezes solid, the refreeze is also going to begin along Southampton Island and the western shoreline. But once Foxe Basin is done entirely, I think there is going to be a very rapid surge of sea ice south, as it spreads S from Southamption + Coats Island into the "fresher" areas. It will take about a week for the ice to consolidate, but by 11/5, I think the HB refreeze will be at the stage Foxe Basin is currently, and by 11/15, it will be mostly done.

The below shots are from COPERNICUS, with 10/24 at top and 10/15 at bottom with bounding of +2C and -1.5C.

Dharma Rupa

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Re: The 2018/2019 freezing season
« Reply #360 on: October 16, 2018, 01:46:55 AM »
I followed the link and then followed the link to CryoSat-2 via the Centre for Polar Observation and Monitoring: http://www.cpom.ucl.ac.uk/csopr/seaice.html

And what did I find? The Arctic divided into basins. The same as NSIDC uses? Partly yes, mostly no. See attached example - the Canadian Archipelago has swallowed part of the Beaufort.

I guess that for the most part the sections make geophysical sense, but the name for that one certainly ought not be Canadian Archipelago.

colchonero

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Re: The 2018/2019 freezing season
« Reply #361 on: October 16, 2018, 02:46:44 AM »
I don't really get cci gfs 2m anomalies. It doesn't seem to match EC and GFS models on meteociel at all. Yeah sure there are some positive Temp 850hPa anomalies on meteociel as well, but nothing dramatic, and there are even some negative fields on the map.

But why should 2m anomalies match anomalies at 850 hPa level (which is approximately at an altitude of 1500m) ? Anomalies can be completely different for example when large anticyclones are at play and a strong inversion sets up at surface level.

With inversions you can have below normal 2m anomalies and above at 1500m the air can be well above normal.


In this case, they should. There is no strong wind, no additional moisture,  no inversion, not much precipitation, not much sunlight to warm lower altitudes so dramatically, no tight Isobars,  no big cyclones, no huge waves. Nothing that extraordinary, EXCEPT NO ICE.  Temperature will stay at or above 0C over open water, even if temp 850hPa drops to -20C, as long as there is no ice coverage.

Edit: In meteorology, there is always a reason, a cause, something is happening, and there is a consequence what will happen shortly after because of the things happening right now. Because of that we can make  forecasts for example for tomorrow. When something changes tomorrow you adjust your forecast for the upcoming days. You can't just say "oh they've decided not to match, just like that, for no reason"
I mean of course they don't have match exactly, but this is 15C+ difference over not insignificant period of time. And there is no event models are currently showing, that would cause that, except there is no ice.
« Last Edit: October 16, 2018, 03:04:46 AM by colchonero »

Aluminium

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Re: The 2018/2019 freezing season
« Reply #362 on: October 16, 2018, 08:54:16 AM »
October 11-15.

Sterks

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Re: The 2018/2019 freezing season
« Reply #363 on: October 16, 2018, 09:21:19 AM »
Looking at Wipneus regional graphs, it seems refreeze is very late in Laptev and in CAB (which from the map seems apparent the open waters are at Laptev sector and Atlantic front; maybe Chukchi).
Key region Beaufort, and CAA are actually very advanced in refreeze. ESS is not reaally late.
Laptev sea is shallow (mostly) and whether it is late or not matters less than if next year snows are heavy or not in adjacent region of Siberia.
The Atlantic front is at the mercy on how ocean currents work next years, and Chukchi is also at mercy of timing and strength of Bering inflow pulses.
So at the end of the day, all this late refreeze can be inconsequential to what happens next year.

GoSouthYoungins

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Re: The 2018/2019 freezing season
« Reply #364 on: October 16, 2018, 01:52:13 PM »
So at the end of the day, all this late refreeze can be inconsequential to what happens next year.

Incorrect.
big time oops

Jim Hunt

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Re: The 2018/2019 freezing season
« Reply #365 on: October 16, 2018, 03:27:14 PM »
And what did I find? The Arctic divided into basins. The same as NSIDC uses?

Not really! You can download the gridded data if you wish, and aggregate it any which way you choose:

http://www.cpom.ucl.ac.uk/csopr/data.html

You don't need to be "really clever", but I guess that's not necessarily right up the street of the average "amateur".
"The most revolutionary thing one can do always is to proclaim loudly what is happening" - Rosa Luxemburg

Sterks

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Re: The 2018/2019 freezing season
« Reply #366 on: October 16, 2018, 04:01:35 PM »
<snip A few ad hominems can be tossed around in the political and other threads, but in the primary threads such as this one, members are expected to shy away from pointless insults and instead post productive commentary. Thanks! ~~JP>
It is insulting to respond to a comment with a simple "incorrect". That's even shorter and emptier in intellect than Trump's "fake news" tuits.
So I wanted to respond displaying the same attitude of an ignorant. ;) Nothing else. Good luck with that member
« Last Edit: October 16, 2018, 07:45:30 PM by Sterks »

gerontocrat

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Re: The 2018/2019 freezing season
« Reply #367 on: October 16, 2018, 04:10:02 PM »
And what did I find? The Arctic divided into basins. The same as NSIDC uses?

Not really! You can download the gridded data if you wish, and aggregate it any which way you choose:

http://www.cpom.ucl.ac.uk/csopr/data.html

You don't need to be "really clever", but I guess that's not necessarily right up the street of the average "amateur".
Hullo Jim,

As Tommy Cooper said "Not Like That, Like That".
OK, so I got a gz file, extracted the .txt file using 7-zip, and can see the data.

1. As I don't have any GIS/mapping software, can you recommend a really really simple dumbo program (freebie would be good)?
2. I read somewhere that the NSIDC mask file has all the seas allocated by code for each grid element. I guess that it is possible to match the cryosat data to that mask to be able to generate summaries by NSIDC classification of the Arctic seas.
Where can  find a) the code book and b) the mask file ?

please, pretty please - I need some 'elp.

I will give it a go when I feel like making myself really confused and frustrated.

EDIT:-
I remembered an e-mail I got some time ago from NSIDC. So

- I found the code list (attached),
- I found the mask file - on GitHub.

So I am stuck - I don't know how to use GitHub. Installing it might kill my ancient laptop?
And the mask file does not have lat / long but the NSIDC overview tells me there are tools to do it  that I am totally unfamiliar with

A bridge too far I think, which is a shame. Adding the NSIDC sea code as an extra column in the cryosat-2 data would make it so easy to produce analyses by each sea and groups of seas to compare with area and extent data from the NSIDC excel files.
« Last Edit: October 16, 2018, 05:30:46 PM by gerontocrat »
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Jim Hunt

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Re: The 2018/2019 freezing season
« Reply #368 on: October 16, 2018, 05:28:08 PM »
please, pretty please - I need some 'elp.

I will give it a go when I feel like making myself really confused and frustrated.

Partly because I'm "a programmer" my approach would be to download the data in NetCDF format then view it in Panoply. Then perhaps follow Wipneus' Python programming tutorial. See the "Mapping Geocoded Data Sets" thread for more info:

https://forum.arctic-sea-ice.net/index.php/topic,1871.0.html

Be warned that I haven't actually tried to do any of that with the CS2 data!
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shendric

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Re: The 2018/2019 freezing season
« Reply #369 on: October 16, 2018, 06:02:14 PM »
Quote
A bridge too far I think, which is a shame. Adding the NSIDC sea code as an extra column in the cryosat-2 data would make it so easy to produce analyses by each sea and groups of seas to compare with area and extent data from the NSIDC excel files.

A modified NSDIC region mask (Baltic sea added) is included in the upcoming v2.1 of the AWI CryoSat-2 sea ice product for both the grids and the daily trajectory data sets.
Cheers, Stefan

Niall Dollard

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Re: The 2018/2019 freezing season
« Reply #370 on: October 16, 2018, 06:18:55 PM »
In this case, they should. There is no strong wind, no additional moisture,  no inversion, not much precipitation, not much sunlight to warm lower altitudes so dramatically, no tight Isobars,  no big cyclones, no huge waves. Nothing that extraordinary, EXCEPT NO ICE.  Temperature will stay at or above 0C over open water, even if temp 850hPa drops to -20C, as long as there is no ice coverage.

Not sure where this conversation is going - but I do agree with your last point. Lack of ice has a huge effect on 2m surface temperatures (and anomalies). Some central parts of the Laptev and Chukchi have no sea ice within 300 to 400km. Any air advected from cold sources of the CAB or other area will have warmed considerably over the relatively warm arctic ocean and won't be much below the temperature of the SST. In times past (which the anomalies are based on) these same parts could be well expected to be ice covered by now and easily attaining temperatures of -20 C. So it's easy to see how parts of the Arctic Ocean that are not ice covered can accrue such large +ve anomalies at the 2m level.

In the case above then it is possible to see how you could have cold air aloft (near normal 850 hPa temps) and warm surface conditions. The opposite also frequently happens in the Arctic (very warm 850hPa with only modest warming at the surface). A case in point being the end of November last year over the top of Ellesmere. The 850 hPa temps rose to temperatures above zero on 24/11/17 some 20 C above normal as warm air migrated north from Baffin on the west side of a a strong Greenland anticyclone. Meanwhile at surface level these warm anomalies did not transfer to such an extent with a Tmax there of -15 C. Anomaly of +10 C.

Point being that anomalies at 1500m will be frequently different to anomalies at the surface because of the different states at the surface (Ice cover/no ice cover, deep snow/no snow etc). 

litesong

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Re: The 2018/2019 freezing season
« Reply #371 on: October 16, 2018, 06:42:20 PM »
Appears that some of the Ice Sheet cold has slipped into the seas northeast of Greenland. Despite down slope warming, the flow of atmospheric cold remains sub-average.....
After some of the cold moved off the Greenland Ice Sheet to the northeast, a warm front replaced it on the eastern half of the Ice Sheet.
With the High Arctic temperatures now fluttering up & down, due first to half of Greenland Ice Sheet atmosphere at sub-average temperatures, flowing into the Seas northeast of Greenland & a portion then flowing to the NP. Second, a warm front replaced the cold on the eastern half of the Greenland Ice Sheet. Third, that very temporary warmth has mostly been pushed off the Ice Sheet, &  flows into the High Arctic, supporting warm temperatures there. Fourth, looking at the Greenland Ice Sheet again, cold envelopes it, pumped from the vast cold atmosphere that has over-taken all of mid-Canada, the middle of the U.S. & even into northern Mexico.
https://climatereanalyzer.org/wx/DailySummary/#t2anom 
« Last Edit: October 17, 2018, 12:36:54 AM by litesong »

FishOutofWater

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Re: The 2018/2019 freezing season
« Reply #372 on: October 16, 2018, 07:13:03 PM »
The open water, especially water that's above 0C tends to increase atmospheric water vapor levels which reduces outgoing longwave radiation. It also increases atmospheric instability and leads to storms being a bit stronger. When combined with warmer than normal waters in the far north Atlantic and Pacific it can also lead to stronger blocking high pressure areas and more blocking.

The block on the dateline going up into the Arctic on the 30 day 500mb anomaly map is stunning.
« Last Edit: October 16, 2018, 07:57:23 PM by FishOutofWater »

Jim Hunt

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Re: The 2018/2019 freezing season
« Reply #373 on: October 16, 2018, 08:00:40 PM »
A modified NSDIC region mask (Baltic sea added) is included in the upcoming v2.1 of the AWI CryoSat-2 sea ice product for both the grids and the daily trajectory data sets.

Thanks very much for that most interesting information Stefan.

Have you fixed the 2.1 release date yet by any chance?
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gerontocrat

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Re: The 2018/2019 freezing season
« Reply #374 on: October 16, 2018, 08:06:45 PM »
Quote
A bridge too far I think, which is a shame. Adding the NSIDC sea code as an extra column in the cryosat-2 data would make it so easy to produce analyses by each sea and groups of seas to compare with area and extent data from the NSIDC excel files.

A modified NSDIC region mask (Baltic sea added) is included in the upcoming v2.1 of the AWI CryoSat-2 sea ice product for both the grids and the daily trajectory data sets.
Cheers, Stefan
Shendric -that is the best news I have heard in ages. Just think - cryosat-2 data according to NSIDC regions. All we need now is a few years data, say until 2025, but patience is a virtue.
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uniquorn

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Re: The 2018/2019 freezing season
« Reply #375 on: October 16, 2018, 08:59:12 PM »
amsr2-uhh and ascat oct7-15.
CAA and Fram export continue. Open water remains north of Severnaya Zemlya for the time being.

Today's ecmwf waves from windy.
« Last Edit: October 16, 2018, 09:04:50 PM by uniquorn »

GoSouthYoungins

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Re: The 2018/2019 freezing season
« Reply #376 on: October 16, 2018, 11:18:45 PM »
<snip A few ad hominems can be tossed around in the political and other threads, but in the primary threads such as this one, members are expected to shy away from pointless insults and instead post productive commentary. Thanks! ~~JP>
It is insulting to respond to a comment with a simple "incorrect". That's even shorter and emptier in intellect than Trump's "fake news" tuits.
So I wanted to respond displaying the same attitude of an ignorant. ;) Nothing else. Good luck with that member

You basically said that it doesn't matter if there is or isn't ice. That's insulting to the whole premise of this forum, and runs counter to everything ever said on this thread (and is pretty ignorant). "Incorrect" seemed sufficient. Otherwise I'd have to just repeat everything already posted on this thread about the effects of the lack of ice and the implications for the future.

I think if you are going to make as bold of a claim as you did, you need to provide more of an explanation than the Laptev is shallow and the Atlantic has variable currents. I'm totally open to different ideas...even if they prove wrong the discussion of possibilities is always good. But flippantly saying it doesn't matter if there is open ocean instead of ice is not a theory.
« Last Edit: October 16, 2018, 11:41:39 PM by GoSouthYoungins »
big time oops

GoSouthYoungins

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Re: The 2018/2019 freezing season
« Reply #377 on: October 16, 2018, 11:40:04 PM »
I think we can make a pretty good guesstimate already for how the freezing season will pan out:

The Laptev Sea freeze will be several weeks delayed. This may be countered (not in effect, but in extent measurements) by an early freeze in the Hudson Bay.

The Chukchi Sea will likely be the real story (which will probably lead into Bering Sea anomalies as well). The delays will probably be record setting.

ESS, Beaufort, and CAA will probably be quicker to freeze than in recent years.

Barents and Kara have non-impressive SST anomalies but currently the ice edge is very far away. Likely nothing too interesting.

The other seas may change weather patterns but I don't think have a direct or predictable effect on the arctic, so I don't really care.

Agree, disagree?
big time oops

uniquorn

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Re: The 2018/2019 freezing season
« Reply #378 on: October 17, 2018, 12:09:37 AM »
Key region CAB is late freezing this year.
All three island groups on the Atlantic front are still ice free, exposing a very long Atlantic front. Much of the Atlantic ice edge is probably still affected by warmer salty water this year. As is the Chukchi sea.
So, at the end of each day, this might be quite consequential to what happens this year.

amsr2-uhh(from2013) and ascat extent from 2010-2018
hycom sea surface salinity (0m) sep24-oct23 (forecast) (click to run)
« Last Edit: October 17, 2018, 12:15:49 AM by uniquorn »

shendric

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Re: The 2018/2019 freezing season
« Reply #379 on: October 17, 2018, 09:01:03 AM »

Thanks very much for that most interesting information Stefan.

Have you fixed the 2.1 release date yet by any chance?

It will be released in the next days, definitely before the end of next week. I can post the anouncement here in the forum as well.
Stefan

Niall Dollard

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Re: The 2018/2019 freezing season
« Reply #380 on: October 17, 2018, 10:22:17 AM »

Agree, disagree?

I agree with that  summation.

Only comment i would  make is that maybe,if synoptic weather patterns play ball with an anticyclonic block to the northern Chukchi, that it might not be a record breaking late freeze up in the Chukchi. 
The Beaufort seems to be advancing well and if there was persistent easterlies this would gradually cool down the very high Chukchi SSTs. There is a long way to go though, admittedly.
Of course Chukchi may still be bombarded with warm southerlies , like last winter, so will wait and see.

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Re: The 2018/2019 freezing season
« Reply #381 on: October 17, 2018, 10:28:38 AM »
Interesting study from MIT shows a change in the rotational speed of the Beaufort Gyre due to loss of ice in that area. This seems to affect many of the parameters associated with ice drift, salinity , AMOC etc.
Perhaps other more learned Forum members might like to discuss the repercussions .....

http://news.mit.edu/2018/arctic-ice-sets-speed-ocean-current-1017

Sterks

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Re: The 2018/2019 freezing season
« Reply #382 on: October 17, 2018, 04:22:45 PM »
Interesting study from MIT shows a change in the rotational speed of the Beaufort Gyre due to loss of ice in that area. This seems to affect many of the parameters associated with ice drift, salinity , AMOC etc.
Perhaps other more learned Forum members might like to discuss the repercussions .....

http://news.mit.edu/2018/arctic-ice-sets-speed-ocean-current-1017

I have read here just about the opposite, and from people like A-Team. That the Gyre is losing strength due to more cyclonic weather of late years and because thicker ice used to help better in transferring the anticyclonic motion of airmasses to the ocean in Winter and Spring . So go figure...

Of course, both antagonistic effects end up with catastrophic consequences.
This makes me lose a bit of confidence, then I forget it and I trust scientists again.

gerontocrat

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Re: The 2018/2019 freezing season
« Reply #383 on: October 17, 2018, 04:50:19 PM »
Interesting study from MIT shows a change in the rotational speed of the Beaufort Gyre due to loss of ice in that area. This seems to affect many of the parameters associated with ice drift, salinity , AMOC etc.
Perhaps other more learned Forum members might like to discuss the repercussions .....

http://news.mit.edu/2018/arctic-ice-sets-speed-ocean-current-1017

I have read here just about the opposite, and from people like A-Team. That the Gyre is losing strength due to more cyclonic weather of late years and because thicker ice used to help better in transferring the anticyclonic motion of airmasses to the ocean in Winter and Spring . So go figure...

Of course, both antagonistic effects end up with catastrophic consequences.
This makes me lose a bit of confidence, then I forget it and I trust scientists again.
Both can be happening at the same time.

Like late refreeze tends to reduce time available for ice thickening but late refreeze allows ocean heat to escape more allowing faster stronger refreeze.

So which influence will prevail, or will a completely new environment emerge with completely new wind and ocean currents?

'Ware scientists who only look at one thing that is going on and dismiss all others. This is uncharted territory with very little data about what is going on down there under the surface.

Anyway - "that is my opinion and it belongs to me".
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Dharma Rupa

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Re: The 2018/2019 freezing season
« Reply #384 on: October 17, 2018, 05:08:55 PM »
'Ware scientists who only look at one thing that is going on and dismiss all others. This is uncharted territory with very little data about what is going on down there under the surface.

Anyway - "that is my opinion and it belongs to me".

I'm more inclined to be wary of scientists who make pronouncements when there is no possibility of performing an experiment.  In fact, I'm more inclined to call them prognosticators than scientists, and I include cosmologists in that category.

All it would take is an "it appears" or an "it seems likely" here and there and I'd be willing to call them scientists.


FishOutofWater

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Re: The 2018/2019 freezing season
« Reply #385 on: October 17, 2018, 06:06:44 PM »
That paper is saying what A-Team and I have been saying for some time. There are a number of papers about the increase in the fresh water content of the Beaufort gyre from 2000 - 2015. We know that the gyre has spun up with the decline of multiyear sea ice and we know why. This paper quantifies it and models it.

What A-Team and I have been saying is that there is now evidence of weakening of the gyre in response to increased storminess over the past several years. The release of fresh water from the gyre is one of the causes of the cold SST anomaly in the Greenland and Labrador seas.

gerontocrat

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Re: The 2018/2019 freezing season
« Reply #386 on: October 17, 2018, 08:19:19 PM »
That paper is saying what A-Team and I have been saying for some time. There are a number of papers about the increase in the fresh water content of the Beaufort gyre from 2000 - 2015. We know that the gyre has spun up with the decline of multiyear sea ice and we know why. This paper quantifies it and models it.

What A-Team and I have been saying is that there is now evidence of weakening of the gyre in response to increased storminess over the past several years. The release of fresh water from the gyre is one of the causes of the cold SST anomaly in the Greenland and Labrador seas.
Trouble is the paper is subscriber only, so people like me have no idea if the paper gives any idea of
- what additional quantities of fresh cold water were sucked into the gyre during the period of spinning up,
- how much water is now escaping,
- any idea of how much impact that will have on the movement of warm and cold water into and out of the Arctic
- and from that any idea of the impact on Arctic Sea Ice and regional climates.

If this change is happening now what impact could there be on the 2018-19 freezing season?
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magnamentis

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Re: The 2018/2019 freezing season
« Reply #387 on: October 17, 2018, 08:51:00 PM »
Key region CAB is late freezing this year.

how do you mean "key-region" ?

to my understanding the CAB is the region that is anyways ice covered and the bigger part of it all year round, hence i don't really understand how this can be a key-region when talking about refreeze. if you mean "core-region" i get it, else i need enlightenment please.

EDIT: it's also the reagion that is mostly around or below -20C (not always but mostly and in big parts) hence, same question, how can a region that is most stable providing a similar to same condition each year be key to freezing process. i don't say insignificant, but IMO not key.

FishOutofWater

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Re: The 2018/2019 freezing season
« Reply #388 on: October 17, 2018, 09:13:02 PM »
The Beaufort gyre is where the fresh water is stored. The Beaufort gyre does not have a constant pole of rotation - it moves about depending on the winds and other factors. If they gave an actual link to the paper one of us could probably pull it up. Instead, they give us their science writer's PR and no link to the source. Google and google scholar didn't quickly pull it up. The link may be on an author's web pages.

Anyway, it's pretty clear that they modelled the fresh water build up we already know about from other reports and web pages. It's only in the past few years that some of that fresh water has been released.

FishOutofWater

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Re: The 2018/2019 freezing season
« Reply #389 on: October 17, 2018, 09:25:13 PM »
Note that there was evidence of strong deep convection in the Labrador and Greenland seas last year in late winter but the anomalous vortex around Greenland and the stormy polar July caused larger than normal amounts of water to flow out of the Arctic, freshening the top 1000m of the Labrador sea. On the other side of the Arctic, sea surface height gradients and southerly winds have driven warm Pacific water into the Chukchi, replacing the fresh water. This should slow down the freezing season in the Chukchi this winter and slow the onset of deep convection in the Labrador sea.

And note the Mercator 10 day projection in the middle. The profile is much saltier than the profile 10 days earlier. It looks like I have found a problem with the forecast model. Don't use it for anything until the forecast is consistent with the past and present Mercator model output.
« Last Edit: October 17, 2018, 09:32:39 PM by FishOutofWater »

vox_mundi

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Re: The 2018/2019 freezing season
« Reply #390 on: October 17, 2018, 09:31:35 PM »
The Ice‐Ocean governor: ice‐ocean stress feedback limits Beaufort Gyre spin up 
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL080171

https://doi.org/10.1029/2018GL080171


Abstract
The Beaufort Gyre is a key circulation system of the Arctic Ocean and its main reservoir of freshwater. Freshwater storage and release affects Arctic sea‐ice cover, as well as North Atlantic and global climate. We describe a mechanism that is fundamental to the dynamics of the Gyre, namely the “ice‐ocean stress governor”. Wind blows over the ice and the ice drags the ocean. But as the gyre spins up, currents catch the ice up and turn off the surface stress. This governor sets the basic properties of the gyre, such as its depth, freshwater content, and strength. Analytical and numerical modeling is employed to contrast the equilibration processes in an ice‐covered versus ice‐free gyre. We argue that as the Arctic warms, reduced sea‐ice extent and more mobile ice will result in a deeper and faster Beaufort Gyre, accumulating more freshwater that will be released by Ekman upwelling or baroclinic instability.

Plain Language Summary
The Beaufort Gyre, located north of Alaska and Canada, is a key circulation system of the Arctic Ocean. Changes in its depth and circulation influence the evolution of the Arctic sea ice cover, the North Atlantic circulation and the global climate. The gyre is driven by persistent, ice‐mediated, winds, accumulating surface fresh water towards the center, deepening the gyre and spinning up its currents.We describe a mechanism, dubbed here the "ice‐ocean governor", in which the interaction of surface currents with the ice regulates the depth of the Beaufort Gyre: the spinning up of the gyre reduces the relative speed between the ocean and the ice, and hence the fresh water accumulation. This competes with, and we argue is more important than, the release of fresh water by flow instability which moves water from the center towards the periphery.In the current climate the depth and speed of the Beaufort Gyre is mainly set by the governor, but this may change in a warming world where reduced ice cover will render the ice‐ocean governor less effective. The resulting deeper, swifter gyre will likely exhibit more variability in its fresh water storage and flow speeds.
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gerontocrat

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Re: The 2018/2019 freezing season
« Reply #391 on: October 17, 2018, 09:37:07 PM »
If they gave an actual link to the paper one of us could probably pull it up. Instead, they give us their science writer's PR and no link to the source.

BINGO! Found it

Googled " Beaufort Gyre Governor " and got - http://oceans.mit.edu/JohnMarshall/wp-content/uploads/2018/02/meneghello2018governor.pdf

I am supposed to be doing my personal admin but.....
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FishOutofWater

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Re: The 2018/2019 freezing season
« Reply #392 on: October 17, 2018, 09:50:53 PM »
Thanks for the link. This is a model study to test the hypothesis that sea ice acts as a governor to the Beaufort gyre. Here's the introductory statement to what they did:

To  explore  the  governor  mechanism  and  test  our  theoretical  model,  we  analyze  the
response of an idealized gyre under two different limit-case scenarios:  i) an ice-driven gyre
(α=1 in equation 1, in which forcing depends purely on gradients ofτ=τi) and

 ii) an ice free, wind-driven gyre (α=0, in which forcing depends purely on gradients of τ=τa).

We conclude with a discussion of the implications of the governor for the Arctic Ocean’s
circulation and its fresh water content.


The implications of this study are quite significant. Without the sea ice governor, the Beaufort gyre will go through sudden expansions and contractions. Large pulses of fresh water will be released to the Labrador sea causing sudden disruptions of the meridional overturning circulation (MOC). This will destabilize NH winter weather patterns causing swings from warm to cold over periods that haven't yet been determined, perhaps decadal or less.
« Last Edit: October 17, 2018, 10:00:31 PM by FishOutofWater »

Brigantine

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Re: The 2018/2019 freezing season
« Reply #393 on: October 17, 2018, 11:23:36 PM »
And note the Mercator 10 day projection in the middle. The profile is much saltier than the profile 10 days earlier. It looks like I have found a problem with the forecast model.

It's not the model, it's just the scale. Darker colours representing the same salinities. Mercator is like that.

gerontocrat

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Re: The 2018/2019 freezing season
« Reply #394 on: October 17, 2018, 11:27:02 PM »
Hullo again FishOutofWater.

Do you remember this recent paper ?
Is there a connection with the Beaufort Gyre Governor discussion?

OCEANOGRAPHY Copyright © 2018

Warming of the interior Arctic Ocean linked to sea ice
losses at the basin margins

Mary-Louise Timmermans1*, John Toole2, Richard Krishfield2
Quote
Arctic Ocean measurements reveal a near doubling of ocean heat content relative to the freezing temperature in the Beaufort Gyre halocline over the past three decades (1987–2017). This warming is linked to anomalous solar heating of surface waters in the northern Chukchi Sea, a main entryway for halocline waters to join the interior Beaufort Gyre. Summer solar heat absorption by the surface waters has increased fivefold over the same time period, chiefly because of reduced sea ice coverage. It is shown that the solar heating, considered together with subduction rates of surface water in this region, is sufficient to account for the observed halocline
warming. Heat absorption at the basin margins and its subsequent accumulation in the ocean interior, therefore, have consequences for Beaufort Gyre sea ice beyond the summer season.
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FishOutofWater

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Re: The 2018/2019 freezing season
« Reply #395 on: October 17, 2018, 11:38:10 PM »
I think that some of the heated water discussed in that recent paper ends up in the Pacific water layer of the Beaufort gyre. It would be below the meltwater layer and above the Atlantic water layer.

Yes, those papers are related in more than just the authorship.

As to the darker color on the Mercator x-section, I tried to use the fixed scale that keeps the same color for the same temperature & salinity. It looks like that didn't happen with the image for the forecast.

I absolutely hate scales that change over time because I'm generally trying to see change over time.

uniquorn

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Re: The 2018/2019 freezing season
« Reply #396 on: October 17, 2018, 11:44:13 PM »
Key region CAB is late freezing this year.
how do you mean "key-region" ?<snippage>
Sorry about that, I was using Sterks terminology ;)
wipneus-regional-arctic-sea-ice-extent-oct16

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Re: The 2018/2019 freezing season
« Reply #397 on: October 17, 2018, 11:48:01 PM »
Thick ice making its way down the Mclure Strait. Polar view 0ct15.

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Re: The 2018/2019 freezing season
« Reply #398 on: October 17, 2018, 11:54:40 PM »
Thick ice making its way down the Mclure Strait.
I think all this MYI will make the northern CAA a laggard in summer 2019, as it was this year.

magnamentis

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Re: The 2018/2019 freezing season
« Reply #399 on: October 18, 2018, 01:00:22 AM »
Thick ice making its way down the Mclure Strait.
I think all this MYI will make the northern CAA a laggard in summer 2019, as it was this year.

that and not too far out there will be no or little replacement MYI and that's the latest when we gonna be in for another step down the ladder, could be before, depending on weather conditions but latest when most of the MYI has gone south one or another way.