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Ice Shieldz

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Re: The 2017/2018 freezing season
« Reply #700 on: January 25, 2018, 12:10:58 PM »
Lincoln Sea Nares Export from 2017-12-24 to 2018-1-24. One tracked section of ice traveled approximately 115 miles (185km) in 31 days.  Furthest travel in one day was approximately 12 miles (19.3km).

Daniel B.

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Re: The 2017/2018 freezing season
« Reply #701 on: January 25, 2018, 03:49:36 PM »
At least if we do get more clouds it should reduce the impact of lost albedo from ice, right? (Although I've no idea of how the nkmbers stack up on this)

Yes, increased cloudiness will offset albedo losses due to decreased sea ice in the summer.  Which effect is greater is beyond my analysis.

romett1

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Re: The 2017/2018 freezing season
« Reply #702 on: January 25, 2018, 08:45:29 PM »
Temperatures north of 80 degree have gone up and it seems like they are staying at higher levels for the next 5 - 7 days. Image: http://ocean.dmi.dk/arctic/meant80n.uk.php

Niall Dollard

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Re: The 2017/2018 freezing season
« Reply #703 on: January 25, 2018, 09:28:58 PM »
Quote
Temperatures north of 80 degree have gone up and it seems like they are staying at higher levels for the next 5 - 7 days.

Looking at latest forecast for the N80 area shows a steady drop in temperatures and by Monday it will be a lot lower than currently (first image) as high pressure takes control


jdallen

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Re: The 2017/2018 freezing season
« Reply #704 on: January 25, 2018, 09:46:13 PM »
Temperatures north of 80 degree have gone up and it seems like they are staying at higher levels for the next 5 - 7 days. Image: http://ocean.dmi.dk/arctic/meant80n.uk.php
I wonder if this year's temperatures may be the mirror image of 2016/2017's - "coolish" early and warm late rather than warm early and "coolish" late.
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romett1

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Re: The 2017/2018 freezing season
« Reply #705 on: January 26, 2018, 09:13:24 AM »

Looking at latest forecast for the N80 area shows a steady drop in temperatures and by Monday it will be a lot lower than currently (first image) as high pressure takes control

Right, 7-day mean forecast lured me into a trap. Real "hotspot" is over ESS.


aperson

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Re: The 2017/2018 freezing season
« Reply #706 on: January 29, 2018, 12:00:00 AM »
GFS and ECWMF have been giving a signal for an unprecedentedly strong Arctic extratropical cyclone in the 10 day range. The signal is lost in ensemble blends due to variability, but control runs and a fair bit of ensemble members are showing this behavior.

It seems to be an effect of the extreme anticyclonic wavebreak over the Kamchatka peninsula that is currently developing, which I note is still being strengthened each gfs run and appears to be a case of dprog/dt due to lack of obs in the region.

I'll post more about it once Feb 1 rolls around and I get to validate my guess of NSIDC extent ~ 13.4 on Feb 1st from early in January.

Human Habitat Index

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Re: The 2017/2018 freezing season
« Reply #707 on: January 29, 2018, 01:04:26 AM »
aperson, I find your post very interesting, can you flesh it out a bit for a newbie and/or point me in the right direction so I can investigate myself.
There is a principle which is a bar against all information, which cannot fail to keep a man in everlasting ignorance. That principle is contempt prior to investigation. - Herbert Spencer

A-Team

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Re: The 2017/2018 freezing season
« Reply #708 on: January 29, 2018, 04:09:48 PM »
Quote
an unprecedentedly strong Arctic extratropical cyclone in the 10 day range.
That would set things in motion again but how? There's been minimal correlation between depicted near-surface GFS winds and ice feature displacements for the last couple of months. It would be feasible to morph Ascat images ten days out but better guidance is needed. (Actually it would work better to reconstruct the effective force of winds retrospectively: from observed ice movement.)

The movies below, which are too tall to display here synchronized at 676x1128 pixels, show a hiatus of about a week in mid-January but with some resumption of motion in the Beaufort's CAA floe stringer and Kara export tongue. The indexed color table, ICA2, is fairly effective at distinguishing MYI from FYI and so makes feature tracking easier.

The interest in the former is thick multi-year ice moving into a zone where it will melt for certain in early summer and in the latter for Fram export which may be dominated by ice formed in the Kara in late October 2017. (A refinement of FYI is needed ... perhaps age in months.)

As wind-driven ice flows past Ushakov Island (Остров Ушакова), too tall at 294 m for ice to flow over, a gap in the ice is formed on the downwind (lee) side. The ice soon seals up though as pressure eddies from the sides are unopposed.

On ASCAT scatterometer images, this results in a rough surface which images as white streamers. These are recognizable but not as noticeable on much higher resolution Sentinel-1AB imagery (next post).

Vize Island (Остров Визе), 140 km to the south, has the same effect though it is too small to show up as a standalone feature most days and considerably narrower projected across the direction of ice movement. Its highest point is 22 m and lacks an ice cap.

Together, the two streamers conveniently track the flow of the ice until all the Kara ice is exported (or melts out). Both islands had/have substantial research stations and over-wintering staff so possibly some dramatic footage can be located of ice piling up on the upwind (stoss) side.

This effect is not new nor is it restricted to ice flow (see wipneus' earlier Jan Mayen air flow images). It was very likely the basis for the island's prediction in 1924:

Quote
In 1924, oceanographer Vladimir Wiese studied the drift of Georgy Brusilov's ill-fated Russian ship Svyataya Anna when she was trapped on the pack ice of the Kara Sea. Vize detected an odd deviation of the path of the ship's drift caused by certain variations of the patterns of sea and ice currents. He deemed that the deviation was caused by the presence of an undiscovered island whose coordinates he was able to calculate with precision thanks to the availability of the successive positions of the St. Anna during its drift. The data of the drift had been supplied by navigator Valerian Albanov, one of the only two survivors of the St. Anna.

Finally, the island was discovered on 13 August 1930 by a Soviet expedition led by Otto Schmidt aboard the Icebreaker Sedov under Captain Vladimir Voronin. The island was named after Professor Vize of the Soviet Arctic Institute who was at the time aboard the Sedov and who was able to set foot on the island whose existence he had predicted. wiki
« Last Edit: January 30, 2018, 02:25:55 AM by A-Team »

A-Team

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Re: The 2017/2018 freezing season
« Reply #709 on: January 29, 2018, 05:54:33 PM »
The Sentinel-1AB radar tile from DTU/Saldo below shows the Kara ice intrusion and islands affecting its flow on 28 Jan 2018. (Schmidt Island, a western outlier of Severnaya Zemlya denoted s, has only a small role.) The streamers from Ushakov and Vize are indicated by Su and Sv respectively. Visible imagery won't be available any time soon at this latitude.

The UH SMOS ice thickness Geo2D for 27 Jan 2018 shows the islands clearly and, as expected, thin ice. However it does not pick up the level of streamer detail that we know must be there, probably because the Kara ice, though mostly new, is itself a matrix of different thickness floes with different histories.

The UH AMSR2 sea ice concentration does pick up the ice diversion around Ushakov for a few days around 03 Nov 2017 (slight slowing of animation; only Oct and Nov shown). However even the highest resolution January images do not show the Kara ice intrusion or its streamers (nor should they). Green shows 100% concentration, a class so abundant that it limits feature imaging.

Come summer melt season, it will be important to know the provenance of ice parcels, of which the Kara ice intrusion is but just one. ASCAT is doing the best at this for now but will be very affected by weather systems later. (It's rather worthless all year along the AK coast and Chukchi in from the Bering Sea.) Sentinel-1AB has a favorable orbital swath for this region but otherwise has incomplete and non-daily coverage.
« Last Edit: January 30, 2018, 02:56:17 AM by A-Team »

A-Team

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Re: The 2017/2018 freezing season
« Reply #710 on: January 30, 2018, 02:30:08 PM »
Quote
The search for intra-terrestrial intelligent life has largely been futile.
In my view, meteorology-driven 'coupled' models are dead wrong about the end stages of Arctic sea ice loss and disastrously optimistic on its timing, as are upper-bound trenders. Discussion of an ice-free Arctic is commonly avoided using undefined terms like 'seasonally' ice-free' or first ice-free 'summer', then qualified by a non-existent 'consensus' for a million sq km of ice still left in September. The kicker is invariably a picture of that last ice hugging the shores of the CAA.

However that isn't a physically stable state, any more than a pencil thrown out the window coming to rest on its point. We can look forward instead to what is called a stochastic excursional ratchet.

The 156 day mp4 below shows how that would work. Note that with the main ice pack gone, what is the physical mechanism confining last ice to the CAA: the ice is not landfast (grounded), it lifts off poleward with a southern breeze, and ratchets out in prodigous volume through the Beaufort, McClure, Martin, Peary, Nares, and Fram. It won't be coming back either because waves across long fetches of open water will irrevocably mix incoming warm portal water.

romett1

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Re: The 2017/2018 freezing season
« Reply #711 on: January 30, 2018, 03:40:56 PM »
Seems like more open water over Bering Sea (Worldview Jan 29 vs Jan 28).

gerontocrat

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Re: The 2017/2018 freezing season
« Reply #712 on: January 30, 2018, 04:56:49 PM »
Discussion of an ice-free Arctic is commonly avoided using undefined terms like 'seasonally' ice-free' or first ice-free 'summer', then qualified by a non-existent 'consensus' for a million sq km of ice still left in September. The kicker is invariably a picture of that last ice hugging the shores of the CAA.

The 156 day mp4 below shows how that would work. Note that with the main ice pack gone, what is the physical mechanism confining last ice to the CAA: the ice is not landfast (grounded), it lifts off poleward with a southern breeze, and ratchets out in prodigous volume through the Beaufort, McClure, Martin, Peary, Nares, and Fram. It won't be coming back either because waves across long fetches of open water will irrevocably mix incoming warm portal water.

Super duper A-Team.

The guys doing these models need to see your animations to properly understand that sea-ice is not static, and build the Arctic (and Antarctic ) movement into their models.

I am happy to admit that it is mainly from your postings that I have fully realised that even in the depths of winter the sea-ice is not a solid lump - rather the reverse. (Sea-ice drift in winter in the Antarctic is also often spectacular)
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dnem

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Re: The 2017/2018 freezing season
« Reply #713 on: January 30, 2018, 06:08:57 PM »
Quote
The search for intra-terrestrial intelligent life has largely been futile.
In my view, meteorology-driven 'coupled' models are dead wrong about the end stages of Arctic sea ice loss and disastrously optimistic on its timing

Would you hazard a guess on the likely timing?

meddoc

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Re: The 2017/2018 freezing season
« Reply #714 on: January 30, 2018, 07:05:03 PM »

Would you hazard a guess on the likely timing?

Well, I guess the Nuclear Weapons Modernization Timelines are a pretty good Indicator:
China: 2019- 21
Russia: 2020
India: 2020- 21

magnamentis

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Re: The 2017/2018 freezing season
« Reply #715 on: January 30, 2018, 07:43:15 PM »
Seems like more open water over Bering Sea (Worldview Jan 29 vs Jan 28).

while i agree i assume you are aware that the most part is clouds while indeed the shape below is showing less ice. just wanted to make sure that first glance does not mislead anyone (blue against gray is not ice against ice free ) sorry if that was clear but i had to take a close look to be sure what's showing ;)
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romett1

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Re: The 2017/2018 freezing season
« Reply #716 on: January 30, 2018, 08:02:16 PM »
Seems like more open water over Bering Sea (Worldview Jan 29 vs Jan 28).

while i agree i assume you are aware that the most part is clouds while indeed the shape below is showing less ice. just wanted to make sure that first glance does not mislead anyone (blue against gray is not ice against ice free ) sorry if that was clear but i had to take a close look to be sure what's showing ;)

On the first image there are clouds, but ice edge has moved some 10 - 20 km. Looking at temperature forecasts over Bering and Chukchi I guess there is no significant freezing there soon.

magnamentis

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Re: The 2017/2018 freezing season
« Reply #717 on: January 30, 2018, 08:11:10 PM »
yeah that's about what i was saying, it has moved but having a quick glance one could get the blue to gray impression. all good, thanks.
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jdallen

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Re: The 2017/2018 freezing season
« Reply #718 on: January 30, 2018, 11:02:50 PM »
Seems like more open water over Bering Sea (Worldview Jan 29 vs Jan 28).
Most of that Bering extent looks like slash, and probably barely able to keep up with the bottom melt from water that's 2-3C, combined with steadily increasing heat uptake from insolation.  It won't have a chance to thicken, and will vanish quickly once the net heat exchange becomes positive rather than negative.
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Tigertown

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Re: The 2017/2018 freezing season
« Reply #719 on: January 30, 2018, 11:44:11 PM »
A bad winter as far as thickening of the Arctic sea ice, according to data from the Sentinel satellites.
Click Image to compare January 30th, 2015 through 2018

Michael Hauber

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Re: The 2017/2018 freezing season
« Reply #720 on: January 31, 2018, 03:57:19 AM »

However that isn't a physically stable state, any more than a pencil thrown out the window coming to rest on its point. We can look forward instead to what is called a stochastic excursional ratchet.


The ice there does not need to be stable.  It just needs to take longer for it to flow or melt away than the summer melt season lasts.

Climate change:  Prepare for the worst, hope for the best, expect the middle.

Michael Hauber

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Re: The 2017/2018 freezing season
« Reply #721 on: January 31, 2018, 04:01:58 AM »

The guys doing these models need to see your animations to properly understand that sea-ice is not static, and build the Arctic (and Antarctic ) movement into their models.


The sea ice models already have ice movement built into their models. 

Good rule of science - if an amateur, even a gifted one, discovers something, there is a high chance it has already been discovered by the experts, and careful checking should be done before claiming that the experts are not already aware.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

Shared Humanity

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Re: The 2017/2018 freezing season
« Reply #722 on: January 31, 2018, 04:45:14 AM »
The Garlic Press is operating in the dead of winter!!!

Lord M Vader

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Re: The 2017/2018 freezing season
« Reply #723 on: January 31, 2018, 08:51:32 AM »
Should mean a huge compacting and a big widening of the Atlantic sector. The latter one should refreeze and regain all eventually losses. Had this been in March, April, May or June however it should have been devastating for the ice.

Neven

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Re: The 2017/2018 freezing season
« Reply #724 on: January 31, 2018, 09:57:40 AM »
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration of said movement.  ;)
Compare, compare, compare

gerontocrat

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Re: The 2017/2018 freezing season
« Reply #725 on: January 31, 2018, 11:11:29 AM »

The guys doing these models need to see your animations to properly understand that sea-ice is not static, and build the Arctic (and Antarctic ) movement into their models.


The sea ice models already have ice movement built into their models. 

Good rule of science - if an amateur, even a gifted one, discovers something, there is a high chance it has already been discovered by the experts, and careful checking should be done before claiming that the experts are not already aware.
If so, then are you also saying that A-Team was wrong in saying that the ice north of Greenland and the CA will not persist in the way the NASA model predicts ? (A-Team says, I think, that NASA does not take (sufficient) account of that that ice is not land fast and if bounded by open ocean to the north would be sent north by southerly winds, then be destroyed by wave action / ocean melt / ocean currents, and would not reform)
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Gray-Wolf

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Re: The 2017/2018 freezing season
« Reply #726 on: January 31, 2018, 01:28:22 PM »

The guys doing these models need to see your animations to properly understand that sea-ice is not static, and build the Arctic (and Antarctic ) movement into their models.


The sea ice models already have ice movement built into their models. 

Good rule of science - if an amateur, even a gifted one, discovers something, there is a high chance it has already been discovered by the experts, and careful checking should be done before claiming that the experts are not already aware.
If so, then are you also saying that A-Team was wrong in saying that the ice north of Greenland and the CA will not persist in the way the NASA model predicts ? (A-Team says, I think, that NASA does not take (sufficient) account of that that ice is not land fast and if bounded by open ocean to the north would be sent north by southerly winds, then be destroyed by wave action / ocean melt / ocean currents, and would not reform)
Did we not see a great thickness of ice melt out ,in situ, to the north of Greenland in August 2012?
I feel combinations of hostile conditions surrounding this rump ice , coupled with drift/wind forcing will see this ice lost without any changes needed once we turn blue Ocean over late summer in the basin?
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gerontocrat

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Re: The 2017/2018 freezing season
« Reply #727 on: January 31, 2018, 03:10:39 PM »
Image from Weather-forecast.com below. If it happens (Sunday to Tuesday) there will be some mobility in the ice?
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A-Team

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Re: The 2017/2018 freezing season
« Reply #728 on: January 31, 2018, 03:18:02 PM »
The mp4 below shows 138 days of Arctic Ocean ice movement from the fall minimum to mid-winter for the last six years (15 Sept to 30 Jan for 2012-13 through 2017-18). Keeping years synchronized allows the same date to be displayed for all six years simultaneously. (Using sequential display, it would be very difficult to compare say Dec 1st for the six years as the frames would be widely separated.)

The year 2014-15 (lower left corner) displays an uncanny resemblance to the current year, at least so far. Both the Kara intrusion and the Beaufort stringer are rather good matches in timing. Presumably synoptic weather patterns and winds were similar. The Beaufort-Chukchi circulation of CAA floes is also seen in 2015-16 (right panel, middle).

TransPolar drift ... what the heck was that, an ice circulation notion from the 80's? Long gone, but still shown in 2018 journals.

Two earlier winters are available as well. I have all eight years butted up going at 1.5 full size (which for Ascat is 1.5*348 x 340 pixels) but there is really no way of posting that on the forum (or viewing on a phone). Again, ImageJ freeware is the best way to go because of how mouse-over is treated on animations.
« Last Edit: January 31, 2018, 03:34:10 PM by A-Team »

numerobis

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Re: The 2017/2018 freezing season
« Reply #729 on: January 31, 2018, 03:31:26 PM »
GFS and ECWMF have been giving a signal for an unprecedentedly strong Arctic extratropical cyclone in the 10 day range. The signal is lost in ensemble blends due to variability, but control runs and a fair bit of ensemble members are showing this behavior.

In today's ECMWF I'm seeing a low pressure system building over Greenland about now (rather than the high that usually figures there), then heading to the pole on Sunday around 960 hPa and on to the Beaufort by Wednesday next week.

Is 960 hPa unprecedented? In Iqaluit we've had a few storms blow by at 970 hPa, about one a month this fall/winter.

RoxTheGeologist

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Re: The 2017/2018 freezing season
« Reply #730 on: January 31, 2018, 04:46:43 PM »
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration of said movement.  ;)

How did you derive that answer, Neven?

bhenson

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Re: The 2017/2018 freezing season
« Reply #731 on: January 31, 2018, 04:59:14 PM »
GFS and ECWMF have been giving a signal for an unprecedentedly strong Arctic extratropical cyclone in the 10 day range. The signal is lost in ensemble blends due to variability, but control runs and a fair bit of ensemble members are showing this behavior.

In today's ECMWF I'm seeing a low pressure system building over Greenland about now (rather than the high that usually figures there), then heading to the pole on Sunday around 960 hPa and on to the Beaufort by Wednesday next wee

Is 960 hPa unprecedented? In Iqaluit we've had a few storms blow by at 970 hPa, about one a month this fall/winter.

The 0Z and 06Z Wed GFS runs are stronger than the ECMWF, producing a low in the 949-953mb range north of Greenland on Feb. 5-6. Note the slug of mild air (above 0°C) being drawn toward the North Pole.

numerobis

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Re: The 2017/2018 freezing season
« Reply #732 on: January 31, 2018, 07:19:24 PM »
Indeed, ECMWF shows it getting above-freezing north of Svalbard.

gerontocrat

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Re: The 2017/2018 freezing season
« Reply #733 on: January 31, 2018, 07:26:55 PM »
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration of said movement.  ;)

How did you derive that answer, Neven?

Perhaps as ice gets thinner (which it is) and prone to breaks and cracks etc (which it is) then it becomes more responsive to wind, waves and ocean currents? (But I am sure all the models take that into account(?))
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josh-j

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Re: The 2017/2018 freezing season
« Reply #734 on: January 31, 2018, 07:47:53 PM »
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration of said movement.  ;)

How did you derive that answer, Neven?

I would humbly suggest that Neven's answer is derived from the paper he linked to. :)

gerontocrat

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Re: The 2017/2018 freezing season
« Reply #735 on: January 31, 2018, 07:51:32 PM »
AbruptSLR posted this link to mashable.com on weird weather

https://mashable.com/2018/01/30/wild-arctic-weather-siberia-temperatures-warm-100-degrees[/#otlLGP0kZgqR

I have put it here because of this quote

Quote
Meanwhile, the unusually high temperatures over Siberia will slide northeastward, toward Alaska and the Pacific side of the Arctic. Once there, it may impede the buildup of winter ice cover, which has been hovering at or near all-time lows for this time of year.

Some computer model simulations sweep an unusually warm air masses across a broad swath of the Arctic Ocean during the next 2 weeks, from the Atlantic and Pacific sides of the Far North. These warm pulses could ensure that Arctic sea ice sets another record low winter maximum.
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Michael Hauber

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Re: The 2017/2018 freezing season
« Reply #736 on: February 01, 2018, 01:27:07 AM »
The sea ice models already have ice movement built into their models. 

But perhaps not the acceleration of said movement.  ;)

A 2011 paper, based on AR4 models.  The AR5 models have a faster ice loss, so the issue pointed to in the paper may (or may not) already be fixed.
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epiphyte

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Re: The 2017/2018 freezing season
« Reply #737 on: February 01, 2018, 05:37:13 AM »
We can look forward instead to what is called a stochastic excursional ratchet.

@A-Team... Just to clarify for those of us running along next to the train, here. You're implying that it's irreversible?


jdallen

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Re: The 2017/2018 freezing season
« Reply #738 on: February 01, 2018, 07:42:15 AM »
We can look forward instead to what is called a stochastic excursional ratchet.

@A-Team... Just to clarify for those of us running along next to the train, here. You're implying that it's irreversible?
It is irreversible, short of finding a way to reduce total system enthalpy.

Total heat in the system increases each year.  That sets a floor below which the system can't fall.  That floor means that the 20-22,000KM2 MAX SIE we saw 40-50 years ago is impossible, even with the coldest possible refreeze.  Heck, I doubt we could get past 16,000KM2...
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echoughton

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Re: The 2017/2018 freezing season
« Reply #739 on: February 01, 2018, 12:30:12 PM »
I just went to weatherbell.com and checked the current radar. Mild in the Chukchi but still vast areas of minus 20-50 over what has been a very cold winter in most of Siberia. Canada to the pole is at or below normal and DMI daily spike has come down to almost normal. That reanylyzer above is smokin some shit.

A-Team

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Re: The 2017/2018 freezing season
« Reply #740 on: February 01, 2018, 12:53:32 PM »
Here are 138 days of all eight years simultaneously, all that is available at the ASCAT archive. Earlier years are shown in smaller sizes; 2017-18 is repeated in the lower right corner. A few features are marked up in the initial gif. The mp4 runs from the fall minimum of Sept 15th to 30 Jan.

https://cloudconvert.com/avi-to-mp4 free online with video editing options

Technical note: Surprisingly easy to make, considering it reduces 1104 separate days of images of size 1170 x 1170 (or 1,511,265,600 pixels) to something quite manageable.

In the larger scientific perspective, data is not the same as information. Given massive modern collection schemes, distilling data to information becomes imperative.

It takes quite a bit of experimentation with codecs vs forum software to get the movie playing properly as they are both somewhat black boxes. (As a gif, it would take 65 MB, far too big.) The 696 pixel width displays at greater than 700 pxl forum width, apparently because video resolutions of 420, 720, 1080 are the default options. Try 'reloading' a couple of times if your browser is only displaying an empty controller initially. Or download the file and view on your local movie player.
« Last Edit: February 01, 2018, 04:54:35 PM by A-Team »

FishOutofWater

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Re: The 2017/2018 freezing season
« Reply #741 on: February 01, 2018, 07:53:02 PM »
No, it hasn't been a very cold winter in *most* of Siberia. In one part of eastern Siberia it has been very cold. We have also been cold in part of eastern North America. However, the western sides of the continents have been very warm as has been the sector of Alaska and Siberia near the dateline.

Dateline blocking has been very strong this winter and it has penetrated into the Arctic.


uniquorn

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Re: The 2017/2018 freezing season
« Reply #742 on: February 01, 2018, 08:18:15 PM »
Lincoln Sea Nares. More fast ice letting go?

Shared Humanity

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Re: The 2017/2018 freezing season
« Reply #743 on: February 02, 2018, 03:44:15 AM »
Lincoln Sea Nares. More fast ice letting go?

And it is February and Nares has not stopped flowing. Maybe open through the entire winter?

jdallen

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Re: The 2017/2018 freezing season
« Reply #744 on: February 02, 2018, 04:38:27 AM »
Lincoln Sea Nares. More fast ice letting go?

And it is February and Nares has not stopped flowing. Maybe open through the entire winter?
That in itself is not unusual.  The Nares has been open all winter several times over the last couple of decades, if I recall correctly.

It is more critical now because of how much less MYI we have left, which is preferentially what is being sucked through the strait.
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bairgon

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Re: The 2017/2018 freezing season
« Reply #745 on: February 02, 2018, 12:16:24 PM »
Lincoln Sea Nares. More fast ice letting go?

Actually, as can be seen in the gif in the message below, all the ice there was fairly mobile recently. Appears to have stopped on 30th Jan, and started forming an outer "bridge" between Ellesmere and Greenland. However, as you point out this is decaying rapidly.

Lincoln Sea Nares Export from 2017-12-24 to 2018-1-24. One tracked section of ice traveled approximately 115 miles (185km) in 31 days.  Furthest travel in one day was approximately 12 miles (19.3km).

meddoc

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Re: The 2017/2018 freezing season
« Reply #746 on: February 02, 2018, 02:00:25 PM »
Just to make Things worse, there is a Polar Vortex Collapse forecasted in 3 days.

Seems like the Cold has had enough over Siberia & now ducking into Greenland' Cover.


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Re: The 2017/2018 freezing season
« Reply #747 on: February 02, 2018, 04:58:01 PM »
The question is, how will Monday's storm system affect the ice pack? We've been looking at that over at the Nares Strait forum, cross-posted images below, expecting extensive radial shearing as well as translation and compression towards the NH side.

Mobility along the CAA over the last eight years is also shown there; while we expect it to be greater today (for a given wind forcing) with weaker thinner ice, that is not so easy to show. Daily ice motion vectors are compiled at several places (or we could do it ourselves with SIFT etc) but how wind reanalyses translate to actual momentum transfer depend on many other factors such as ridges and keels, leads and concentration, current position of the ice pack relative to boundary conditions (eg islands) and so forth that don't match up for year-on-year same-date comparisons.





« Last Edit: February 02, 2018, 05:04:40 PM by A-Team »

Niall Dollard

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Re: The 2017/2018 freezing season
« Reply #748 on: February 02, 2018, 08:35:44 PM »
The models this evening are indicating that the main storm centre will track up the Fram Strait late Sunday/Monday and then grind to a halt somewhere between the Pole and Severnaya Zemlya on Tuesday and slowly fill.

The models also show a significant storm surge on its eastern flank. A sig wave height of 10m in the open water just north of Svalbard will create some battering to the ice.

Going on this track, it looks like the worst of the damage will be between Svalbard, Franz Josef and on to Severnaya Zemlya. (but the north coast of Greenland will receive strong westerlies also).

Thomas Barlow

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Re: The 2017/2018 freezing season
« Reply #749 on: February 02, 2018, 09:58:07 PM »