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Author Topic: Importance of waves in the Arctic  (Read 41045 times)

Tigertown

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Re: Importance of waves in the Arctic
« Reply #100 on: October 10, 2016, 06:07:19 AM »
Some of this may have overlapping info, but it helped alleviate my ignorance of the subject
and may help others. It's more in regard to the Beaufort Sea, but is very educational on this subject.

https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/52133/HutchingsJenniferCEOASNear-InertialInternal.pdf?sequence=1

johnm33

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Re: Importance of waves in the Arctic
« Reply #101 on: October 10, 2016, 11:53:03 AM »
A recent study about solitary waves
http://phys.org/news/2016-10-year-old-puzzle-tied-enigmatic-lone.html
and from Tigertowns link
"Of particular concern is the recent reduction of sea ice in the Arctic Ocean and the lengthening of the ice-free season ( Stroeve et al. 2012). The rapid loss and diminishing extent of multiyear ice and increase in younger ice suggest a thinner, weaker ice pack ( Comiso et al. 2008). The persistence of near-inertial oscillations in the Beaufort Sea during freeze up and melt suggests that an increase in weaker, younger ice may cause a widespread increase in near-inertial energy. Large-scale changes in ice concentrations and strength may lead to longer decay times and longer ice-free seasons, conditions that are favorable for increased near-inertial internal wave gen-eration and internal wave–induced mixing in the Arctic"
I think I'm seeing the effects of internal waves passing through the forming ice pack, their signature being low numbers of parallel lines. Largely caused by the movement of ice, most notably when the ice sheers away from the CAA or rapidly moves over the ridges. For instance

changed the animated gif for a date relevent snapshot
« Last Edit: November 06, 2016, 08:01:15 PM by johnm33 »

johnm33

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Re: Importance of waves in the Arctic
« Reply #102 on: October 29, 2016, 12:21:41 PM »
With this much ice on the move I expect a large wave system to arrive at the shelf of the CAA, by Banks/PPI, possibly big enough to break the thick ice free.

Will the ice arriving at the NSI persit or is enough heat being transported there by atlantic waters to melt it?

johnm33

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Re: Importance of waves in the Arctic
« Reply #103 on: November 07, 2016, 01:14:18 AM »
Completely different wind patterns.

Good news is the ice seems to be thickening suppressing the waves except at the periphery

Already lots of Atlantic waters pouring in by Laptev where the ice still looks vulnerable


So if this http://cci-reanalyzer.org/DailySummary/#T2 happens as predicted we should see some melt/thinning between NSI and the pole and some action at the 'focal' point of the arc of the continental rise in Beaufort

Maybe that's already happening

So with what looks like an abrupt halt to the inflow from the Pacific and a massive amount of movement of the ice towards Canadas north shore I'm expecting some fairly big disruption to the deeper layers, I just have no idea where it will show.

johnm33

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Re: Importance of waves in the Arctic
« Reply #104 on: November 21, 2016, 11:37:17 AM »
timallard posted this over at Area and Extent, 5Min on waves in the Beaufort.
https://www.youtube.com/watch?v=tDmM5zsxd4E

Jim Hunt

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Re: Importance of waves in the Arctic
« Reply #105 on: November 21, 2016, 12:05:38 PM »
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Jim Hunt

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neXtWIM: Waves in a next-generation sea ice model
« Reply #106 on: November 24, 2016, 10:40:02 AM »
I've just stumbled across an overview of the Nansen Environmental and Remote Sensing Center's neXtWIM project:

With increasing temperatures worldwide, the Arctic is experiencing rapid and drastic changes in sea ice conditions, with innumerable consequences for the environment and human activities. In particular, the sea ice extent has experienced several record lows in the last decade, producing more open water in the Arctic ocean, and consequently more waves. At the same time many industries such as tourism, shipping and the oil and gas industry are seeking to take advantage of the reduced ice cover to expand their operations. While there are some economic benefits to this trend, there are also increased chances for accidents.

NeXtWIM aims to provide a forecast system based on an extremely realistic sea ice model, which will provide key information about ice edge location, wave heights, and floe sizes to operators in or near the Marginal Ice Zone - the area at the boundary between the sea ice and the ocean where large waves and small, broken pieces of ice can be extremely hazardous.

To do this, NeXtWIM will incorporate wave-ice interactions into the next generation sea ice model, neXtSIM. This sea ice model is currently being developed at the Nansen Environmental and Remote Sensing Center (NERSC), and has at its core the highly accurate elasto-brittle sea ice rheology. This platform will be the first of its kind worldwide, giving NERSC, Bergen and Norway generally a leading role in Arctic science.
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johnm33

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Re: Importance of waves in the Arctic
« Reply #107 on: November 26, 2016, 10:07:48 PM »
14min. on waves, probably already posted elsewhere but I've forgotten who posted it.  https://www.youtube.com/watch?v=UOm2t3QMR6k
Looking at Nullschool it's pretty clear that over most of the arctic proper air temps. are low enough to cause rapid freezing, but the ocean where it shows through is still above -1.8, not by much, but almost everywhere, this suggests to me that we still have some serious mixing going on and associated bottom melt. Taking a look at http://marine.copernicus.eu/services-portfolio/access-to-products/ , the first product, add to cart then veiw, +top right to opt North polar, then switch datasets to daily mean, [what is sigma theta?] choose sea ice area fraction variable,+ top left to zoom, then the cine icon bottom left for animation menu. I chose 11-01 til 12-01 and 2 frames a second. It should look like this before the animation.

There may be other/better explanations but I'm seeing the effect of wind on broken ice shifting huge volumes around, disturbing the deeper waters causing them to slough around in the basins on the Canadian side, then bounce back generating numbers of internal waves in the process, lifting the thick ice free of the CAA, probably send a pulse of warmer water through the archipelago.
edit Maybe the permalink will work for you, for me the animator just turns things grey.
http://cmems-view.cls.fr/ViewService/?permalinking=true&bgmap=Blue%20Marble%20North%20Polar&dataset=http://nrtcmems.mercator-ocean.fr/thredds/wms/global-analysis-forecast-phy-001-024&numColorBands=20&logScale=false&bbox=-1410644.53125,-480468.75,5410644.53125,4480468.75&abovemaxcolor=0x000000&belowmincolor=0x000000&nodatacolor=null&layer=siconc&time=2016-11-26T12%253A00%253A00.000Z&palette=rainbow&style=boxfill&scaleRange=0,1.0000153&displayScaleRange=0,1.0000153&opacity=1&record_id=eec7a997-c57e-4dfa-9194-4c72154f5cc5&dataset_id=daily%20mean%20fields%20from%20Global%20Ocean%20Physics%20Analysis%20and%20Forecast%20updated%20Daily
« Last Edit: November 26, 2016, 11:00:41 PM by johnm33 »

Jim Hunt

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Re: Importance of waves in the Arctic
« Reply #108 on: December 12, 2016, 01:49:57 PM »
A special edition of the intriguingly titled open-access journal "Elementa: Science of the Anthropocene ":

https://home.elementascience.org/special-features/marginal-ice-zone-processes-in-the-summertime-arctic/

Articles include:

Air-sea interactions in the marginal ice zone

Modeling the seasonal evolution of the Arctic sea ice floe size distribution

Scaling observations of surface waves in the Beaufort Sea

From the latter:

Currently, wave forecasts in ice by Wave-Watch 3 (WW3) simply scale inputs by the ice concentration. We have shown how the treatment of wind input can be improved in partial ice cover using the ice concentration, where wave energy is a function of open water distance between floes. However, it is clear that the physics of short, distance-limited waves in ice will not be described solely by the ice concentration. Physically accurate wave models will need to consider the interaction of waves and ice for wave scattering and regeneration. Additionally, the open water distance for wave generation in partial ice depends on the geometry of floes and floe size distribution. Efforts are currently being made to obtain better floe size distribution estimates from satellite images, which will serve to improve our understanding of wave generation in fractional ice cover.
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Jim Hunt

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Re: Importance of waves in the Arctic
« Reply #109 on: December 14, 2016, 03:28:27 PM »
With a hat tip to DavidR:



Plus some big waves in the North Atlantic:

http://public.wmo.int/en/media/press-release/19-meter-wave-sets-new-record-highest-significant-wave-height-measured-buoy

A World Meteorological Organization expert committee has established a new world record wave height of 19 meters (62.3 feet) measured by a buoy in the North Atlantic.

The wave was recorded by an automated buoy at 0600 UTC on 4 February 2013 in the North Atlantic ocean between Iceland and the United Kingdom (approximately 59° N, 11° W). It followed the passage of a very strong cold front, which produced winds of up to 43.8 knots (50.4 miles per hour) over the area.

The previous record of 18.275 meters (59.96 feet) was measured on 8 December 2007, also in the North Atlantic.


A more detailed analysis courtesy of Magic Seaweed:

http://magicseaweed.com/news/massive-atlantic-wave-doesnt-set-record/9799/
« Last Edit: December 16, 2016, 01:00:19 AM by Jim Hunt »
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Jim Hunt

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Re: Importance of waves in the Arctic
« Reply #110 on: December 16, 2016, 12:53:34 AM »
During the Fall 2016 AGU conference in San Francisco it was finally revealed when the June 2015 “waves in ice” event experienced by the R/V Lance occurred.

More at:
http://GreatWhiteCon.info/2015/07/rv-lance-encounters-another-energetic-wave-event-in-the-arctic/#comment-216687
« Last Edit: December 16, 2016, 01:26:03 AM by Jim Hunt »
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johnm33

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Re: Importance of waves in the Arctic
« Reply #111 on: December 16, 2016, 12:57:03 PM »
I had to take a look, animated this from 10-22 to see what it looked like

from here http://marine.copernicus.eu/services-portfolio/access-to-products/ first product, basket/veiw there's now a -90sec tutorial below, or select dataset/variable /date then just click on icon bottom left for options.

Tor Bejnar

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Re: Importance of waves in the Arctic
« Reply #112 on: January 12, 2017, 02:40:27 PM »
I came across this abstract:  Wind waves in arctic seas by Gemmrich, Johannes und Rogers, Erick und Thomson, Jim und Lehner, Susanne und Pleskachevsky, Andrey (2015)
The reduction of the sea ice coverage during the boreal summer will lead to an increased importance of wind waves for the dynamic processes of the Arctic Seas. Larger ice free areas lead to longer fetch and thus longer and higher sea state. Wind waves will enhance upper-ocean mixing, may affect the breakup of ice sheets, and will likely lead to increased coastal erosion. ...

Just what I've been hearing on this thread!
Arctic ice is healthy for children and other living things.

Jim Hunt

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Re: Importance of waves in the Arctic
« Reply #113 on: January 24, 2017, 04:25:32 PM »
With a hat tip to Cate, more from Thomson et al. on the Autumn 2015 voyage of R/V Sikuliaq:

https://eos.org/project-updates/the-balance-of-ice-waves-and-winds-in-the-arctic-autumn

We have an enormous set of air, ice, and ocean measurements to analyze, both from the ship and from numerous autonomous platforms employed during the field campaign. The 2015 autumn ice recovery demonstrated the highly interactive nature of ice, wave, atmospheric, and oceanic processes. The winds and waves modulate this ice recovery, which influences, in turn, the interactions between the atmosphere and ocean.

This strongly coupled problem is clearly a massive challenge for the models we use to forecast the ice, waves, ocean, and atmosphere. These interactions cannot be implemented in computational codes before we understand them empirically or, better yet, the underlying physical principles are understood.
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Cate

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Re: Importance of waves in the Arctic
« Reply #114 on: January 25, 2017, 12:14:49 AM »
Jim, thank you for putting me in the right place. :D

Jim Hunt

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Re: Importance of waves in the Arctic
« Reply #115 on: March 26, 2017, 10:12:22 AM »
A couple of papers from Pierre Rampal et al.:

neXtSIM: a new Lagrangian sea ice model

and currently under discussion:

Wave-ice interactions in the neXtSIM sea-ice model

The amount of attenuation that waves in ice experience is the main factor in determining the amount of momentum transferred to the ice. However, definitive confirmation of any particular physical models for this is still lacking.
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DrTskoul

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Re: Importance of waves in the Arctic
« Reply #116 on: March 26, 2017, 12:49:39 PM »
A couple of papers from Pierre Rampal et al.:

neXtSIM: a new Lagrangian sea ice model

and currently under discussion:

Wave-ice interactions in the neXtSIM sea-ice model

The amount of attenuation that waves in ice experience is the main factor in determining the amount of momentum transferred to the ice. However, definitive confirmation of any particular physical models for this is still lacking.



Neat. Thanks Jim.
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Jim Hunt

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Re: Importance of waves in the Arctic
« Reply #117 on: April 29, 2017, 12:29:03 AM »
Possibly paywalled, but according to The Economist:

The quickest way to break the ice is by submarine. Russian researchers investigate new ways to make waves...

Dr Kozin’s original research was on ways to permit naval submarines to surface safely and quickly through ice, the previous method having been simply to rise until contact was made with the ice sheet and then increase buoyancy until the ice cracked. That, though, is slow and can damage the boat. Dr Kozin found that the bow wave from a submarine travelling close to the surface pushes the ice sheet upwards, making flexural gravity waves in it, which cause it to break up.

Follow-up studies by Dr Kozin and his pupil, Vitaliy Zemlyak, who is now at the Sholem-Aleichem Priamursky State University in Birobidzhan, indicate that a submarine travelling 30 metres below the ice can break a sheet one metre thick. At 20 metres it could break ice two metres thick. And it can do it quickly. Comparable data are not available for Arktika, but America’s heavy icebreaker, Polar Star, can break a channel through two-metre ice at a rate of three knots. A submarine could force such a passage ten times as fast.


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

gerontocrat

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Re: Importance of waves in the Arctic
« Reply #118 on: April 29, 2017, 11:04:05 AM »
Possibly paywalled, but according to The Economist:

The quickest way to break the ice is by submarine. Russian researchers investigate new ways to make waves...

Dr Kozin’s original research was on ways to permit naval submarines to surface safely and quickly through ice, the previous method having been simply to rise until contact was made with the ice sheet and then increase buoyancy until the ice cracked. That, though, is slow and can damage the boat. Dr Kozin found that the bow wave from a submarine travelling close to the surface pushes the ice sheet upwards, making flexural gravity waves in it, which cause it to break up.

Follow-up studies by Dr Kozin and his pupil, Vitaliy Zemlyak, who is now at the Sholem-Aleichem Priamursky State University in Birobidzhan, indicate that a submarine travelling 30 metres below the ice can break a sheet one metre thick. At 20 metres it could break ice two metres thick. And it can do it quickly. Comparable data are not available for Arktika, but America’s heavy icebreaker, Polar Star, can break a channel through two-metre ice at a rate of three knots. A submarine could force such a passage ten times as fast.



Pods of the Orca do that to knock seals off ice floes. The ice floe either breaks up or turns turtle. Nature first !

Shared Humanity

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Re: Importance of waves in the Arctic
« Reply #119 on: April 29, 2017, 06:24:07 PM »
Possibly paywalled, but according to The Economist:

The quickest way to break the ice is by submarine. Russian researchers investigate new ways to make waves...

Dr Kozin’s original research was on ways to permit naval submarines to surface safely and quickly through ice, the previous method having been simply to rise until contact was made with the ice sheet and then increase buoyancy until the ice cracked. That, though, is slow and can damage the boat. Dr Kozin found that the bow wave from a submarine travelling close to the surface pushes the ice sheet upwards, making flexural gravity waves in it, which cause it to break up.

Follow-up studies by Dr Kozin and his pupil, Vitaliy Zemlyak, who is now at the Sholem-Aleichem Priamursky State University in Birobidzhan, indicate that a submarine travelling 30 metres below the ice can break a sheet one metre thick. At 20 metres it could break ice two metres thick. And it can do it quickly. Comparable data are not available for Arktika, but America’s heavy icebreaker, Polar Star, can break a channel through two-metre ice at a rate of three knots. A submarine could force such a passage ten times as fast.



Pods of the Orca do that to knock seals off ice floes. The ice floe either breaks up or turns turtle. Nature first !


That is so cool!

Shared Humanity

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Re: Importance of waves in the Arctic
« Reply #120 on: April 29, 2017, 06:26:58 PM »
I would just like to say that this topic, "Importance of waves in the Arctic" is one of the most important topics on this entire blog due to the preponderance of FYI and vast, newly open waters.

johnm33

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Re: Importance of waves in the Arctic
« Reply #121 on: May 19, 2017, 11:41:49 AM »
Subgeometers post 1531 on the melt season thread:-
"RE cracks, I was looking around 83N on Pacific side for a strip that Bremen showed as low concentration a couple of days ago and there are fairly regular parallel cracks in 2 directions. In Gimp's levels I pulled in the black point to accentuate the cracks. I've include the same area and date for last year, with the same processing. It shows a lot of cracking around the opening in the Beaufort, but less further into the basin

Looks interesting alongside  Jai's image of cracks aligned to directions of motion and stresses in Lincoln Sea. I've no idea if the 'periodicity' is significant(perhaps the pack is being stretched as much as squeezed these days?) but it does suggest a pack that will be more easily dispersed"
When I see these long more or less parallel cracks I always think of internal waves

So I took a look at beaufort https://www7320.nrlssc.navy.mil/hycomARC/beaufort.html

* 85.3694_-149.4939_to_81.4305_-127.7995__16May2017.jpg
To me it looks like huge disturbances taking place at depth.

johnm33

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Re: Importance of waves in the Arctic
« Reply #122 on: July 17, 2017, 10:24:49 AM »
Look above for animation, it seems that the wave complex's peak around the new/full moon dates,[24+9] and melt follows . This may be coincidence/happenstance or may indicate a new fact of life for arctic ice. It's worth taking a look at the other animations too. https://www7320.nrlssc.navy.mil/hycomARC/beaufort.html