Arctic Sea Ice : Forum

Cryosphere => Arctic background => Topic started by: LRC1962 on April 08, 2015, 11:20:27 PM

Title: Importance of waves in the Arctic
Post by: LRC1962 on April 08, 2015, 11:20:27 PM
A few publications I have found regarding waves in the Arctic.
Wave heights in the 21st century Arctic Ocean simulated with a regional climate model (http://ifaran.ru/person/mokhov/publications/PDF/8_KhonMokhovPogarskiyEtal_GRL_2014.pdf)
Quote
In conclusion, we conducted an analysis of possible changes to the wind-wave climate in the Arctic Ocean in
the 21st century. This was done by means of a third-generation wave model and climate modeling under an
anthropogenic-forcing scenario. The outcomes demonstrate overall growth in wave height in the Arctic.
Concurrent with mean wave growth, models predict more frequent extreme waves in different areas of
the Ocean.
Estimates of ocean wave heights and attenuation in sea ice using the SAR wave mode on Sentinel-1A (http://onlinelibrary.wiley.com/doi/10.1002/2014GL062940/abstract)
Quote
Abstract
Swell evolution from the open ocean into sea ice is poorly understood, in particular the amplitude attenuation expected from scattering and dissipation. New synthetic aperture radar (SAR) data from Sentinel-1A wave mode reveal intriguing patterns of bright oscillating lines shaped like instant noodles. We investigate cases in which the oscillations are in the azimuth direction, around a straight line in the range direction. This observation is interpreted as the distortion by the SAR processing of crests from a first swell, due to the presence of a second swell. Since deviations from a straight line should be proportional to the orbital velocity toward the satellite, swell height can be estimated, from 1.5 to 5 m in the present case. The evolution of this 13 s period swell across the ice pack is consistent with an exponential attenuation on a length scale of 200 km.
Behind paywall.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on April 22, 2015, 11:06:57 AM
I missed this first time around  :-[

Some of my own researches into this intriguing subject, to me at least:

http://GreatWhiteCon.info/2015/03/sea-ice-and-swells-in-the-beaufort-sea-in-the-summer-of-2014/ (http://GreatWhiteCon.info/2015/03/sea-ice-and-swells-in-the-beaufort-sea-in-the-summer-of-2014/)

A recent article on the topic mentioned by ASLR (https://forum.arctic-sea-ice.net/index.php/topic,1149.msg50634.html#msg50634):

http://www.scientificamerican.com/article/giant-waves-quickly-destroy-arctic-ocean-ice-and-ecosystems1/ (http://www.scientificamerican.com/article/giant-waves-quickly-destroy-arctic-ocean-ice-and-ecosystems1/)

Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on April 22, 2015, 11:40:58 AM
Some additional references:

Sea ice floes dissipate the energy of steep ocean waves: http://arxiv.org/pdf/1502.06040 (http://arxiv.org/pdf/1502.06040)

On the 2012 record low Arctic sea ice cover: Combined impact of preconditioning and an August storm 2013 - http://onlinelibrary.wiley.com/doi/10.1002/grl.50349/full (http://onlinelibrary.wiley.com/doi/10.1002/grl.50349/full)

Storm-induced sea-ice breakup and the implications for ice extent: http://www.nature.com/articles/nature13262 (http://www.nature.com/articles/nature13262)

In Situ Measurements of an Energetic Wave Event in the Arctic Marginal Ice Zone: http://onlinelibrary.wiley.com/doi/10.1002/2015GL063063/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2015GL063063/abstract)

Swell and sea in the emerging Arctic Ocean - http://onlinelibrary.wiley.com/doi/10.1002/2014GL059983/epdf (http://onlinelibrary.wiley.com/doi/10.1002/2014GL059983/epdf)

Fracture of summer perennial sea ice by ocean swell as a result of Arctic storms: http://onlinelibrary.wiley.com/doi/10.1029/2011JC007221/abstract (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007221/abstract)

Waves in-ice observations made during the SIPEX II voyage of the Aurora Australis: http://dx.doi.org/10.4225/15/53266BEC9607F (http://dx.doi.org/10.4225/15/53266BEC9607F)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 22, 2015, 11:44:33 AM
An enquiry copied from the 2015 melting season thread (http://forum.arctic-sea-ice.net/index.php/topic,1149.msg54471.html#msg54471):

Quote
Pardon a newbie question. Will wave motion form if the ice is very broken and if so would that affect the meltdown?



Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 22, 2015, 11:49:23 AM
A picture of "a wave" in the Arctic, courtesy of ktonine and the following article:

Arctic Seas Surprisingly Alive in Winter (http://www.livescience.com/18741-arctic-seas-surprisingly-alive-winter.html)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.livescience.com%2Fimages%2Fi%2F000%2F024%2F877%2Fi02%2Farctic-winter-expedition-healy-ship-120228-02.jpg%3F1330543353&hash=75971d488ab84fe16b89f2b1659f05d1)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 22, 2015, 01:11:46 PM
It seems from a "debate" elsewhere that some people are labouring under the misapprehension that:

Quote
The only thing that happens in the basin is tides, which have a period(high to high) of about 12 hours.

and that:

Quote
You either have waves or you have ice.... you do not get both.

However, according to Asplin et al. (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007221/pdf).

Quote
Laser data collected during the helicopter EMI survey at station MYI indicated a swell period of 13.5 s, and a wavelength ranging from 200–300 m. Laser data were collected while the helicopter hovered over a large MY ice floe. These data were augmented with three-dimensional dynamic ship positioning data, which revealed approximate ship heave amplitude of 0.4 m, also with a period of 13.5 s. The swell caused the vast MY ice floe nearest the Amundsen to ride up one side of the swell and fracture as it crested the wave peak, creating smaller ice floes of width approximately one half of the wavelength of the swell. In a matter of minutes from the initial onset of swell propagation, all large MY ice floes in the region were fractured in this manner, yielding a new distribution of smaller MY ice floes ranging from 100–150 m in diameter

On 09 September 2009, we conducted a longitudinal helicopter EMI survey at 72.5 N, and determined the limit of the swell penetration into the pack ice at 72.526 N 134.51 W, a penetration of 350 km. Furthermore, the rotted FY ice margin was heavily fractured, with small floe sizes ranging from 20–50 m in diameter.

Whatever theory may predict regarding the interactions of sea ice and "waves", empirical evidence suggests that long period swells can in actual fact penetrate 100s of km into "pack ice".
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 22, 2015, 05:07:20 PM
A picture of "a wave" in the Arctic, courtesy of ktonine and the following article:

Arctic Seas Surprisingly Alive in Winter (http://www.livescience.com/18741-arctic-seas-surprisingly-alive-winter.html)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.livescience.com%2Fimages%2Fi%2F000%2F024%2F877%2Fi02%2Farctic-winter-expedition-healy-ship-120228-02.jpg%3F1330543353&hash=75971d488ab84fe16b89f2b1659f05d1)

You might want to double check the location for that picture.

http://arctic-winter-cruise.blogspot.com/2011/12/crashing-waves.html (http://arctic-winter-cruise.blogspot.com/2011/12/crashing-waves.html)

SO, there are big waves in the Bering Sea in December?

Sorry to interject science into the discussion. Here is a table of the relationship between wind speed and wave period and wavelength:

https://en.wikipedia.org/wiki/Swell_(ocean) (https://en.wikipedia.org/wiki/Swell_(ocean))

[hide]Conditions Necessary for a Fully Developed Sea at Given Wind Speeds, and the Parameters of the Resulting Waves
Wind Conditions   Wave Size
Wind Speed in One Direction   Fetch   Wind Duration   Average Height   Average Wavelength   Average Period and Speed
19 km/h (12 mph)   19 km (12 mi)   2 h   0.27 m (0.89 ft)   8.5 m (28 ft)   3.0 s, 2.8 m/s (9.3 ft/s)
37 km/h (23 mph)   139 km (86 mi)   10 h   1.5 m (4.9 ft)   33.8 m (111 ft)   5.7 s, 5.9 m/s (19.5 ft/s)
56 km/h (35 mph)   518 km (322 mi)   23 h   4.1 m (13 ft)   76.5 m (251 ft)   8.6 s, 8.9 m/s (29.2 ft/s)
74 km/h (46 mph)   1,313 km (816 mi)   42 h   8.5 m (28 ft)   136 m (446 ft)   11.4 s, 11.9 m/s (39.1 ft/s)
92 km/h (57 mph)   2,627 km (1,632 mi)   69 h   14.8 m (49 ft)   212.2 m (696 ft)   14.3 s, 14.8 m/s (48.7 ft/s)

So, it takes 92 km/hr to make waves with a period greater than 13 seconds.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fapi.onlinelibrary.wiley.com%2Fasset%2Fv1%2Fdoi%2F10.1029%252F2009GL040676%2Fasset%2Fimage_n%252Fgrl26504-fig-0003.png%3Fl%3DCgg2pVVsCMw0MNOfhvJIPa%252BoTABc1x0uTf1i0A1ILbXZtPvfOkMImPATCRMNWyzvdVvqu6zQIGg%253D%26amp%3Bs%3D%252256e4f6653217492bba6d6fd08e2be9b0%2522%26amp%3Ba%3Dwol&hash=1faf90bf81cbad0552f627a11fbc7ccc)

http://onlinelibrary.wiley.com/doi/10.1029/2009GL040676/full (http://onlinelibrary.wiley.com/doi/10.1029/2009GL040676/full)

Here we see the attenuation of waves by ice. Waves with periods of 13 seconds attenuate by a factor of  1/1,000,000 in fifty kilometers. That means a ten meter wave would be a 0.01mm( 100 000 angstroms ) ripple at that distance. Do you really want to call 0.01 mm a wave?

Verg


Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 22, 2015, 05:34:41 PM
Quote
Whatever theory may predict regarding the interactions of sea ice and "waves", empirical evidence suggests that long period swells can in actual fact penetrate 100s of km into "pack ice".

Quote
Urban Dictionary: straw man
www.urbandictionary.com/define.php?term=straw+man (http://www.urbandictionary.com/define.php?term=straw+man)
Urban Dictionary
Top Definition. straw man. A logic fallacy involving the purposeful misrepresentation of an argument in order to strike it down. Beware of logic fallacies.

I make a statement about waves, you argue that my statements are false because I meant tides, swells and surges. No, I meant waves. And you have the audacity to use a picture misidentified as in the Arctic basin to bolster your argument. You also used observations in the sea of Okhotsk to refute a statement about the arctic basin. You use a singular event to refute an in general rule.

I ask you a direct question that would end a senseless semantic squabble, and you ignore it,

Jim Hunt,

Pardon a newbie question. Will wave motion form if the ice is very broken and if so would that affect the meltdown?

Welcome to ASIF

In general waves do not penetrate into the ice pack. Their effect is only on the periphery.

Verg :)

In what way does a remarkable observation of a surge in 2009 penetrating the arctic ice cap refute the assertion that "in general" this does not happen?

Quote
There are continuous reports of wave action 100's of km from the edge.

Does it support the assertion that there are "continuous reports" of such events? If you were grading a test, which of these statements would you grade as true, and which are false?

Verg

Please stop playing the troll.

Verg
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 22, 2015, 05:40:21 PM
Hi Vergent,

SO, there are big waves in the Bering Sea in December?

I refer you to the title of this thread. Is the Bering Sea in the Arctic?

Here we see the attenuation of waves by ice. Waves with periods of 13 seconds attenuate by a factor of  1/1,000,000 in fifty kilometers. That means a ten meter wave would be a 0.01mm( 100 000 angstroms ) ripple at that distance. Do you really want to call 0.01 mm a wave?

Are Asplin et al. telling porky pies (http://www.urbandictionary.com/define.php?term=porky+pies&defid=937755), or alternatively is the model used by Squire et al. lacking in some way?
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 22, 2015, 06:58:06 PM
Jim,

Quote
Are Asplin et al. telling porky pies, or alternatively is the model used by Squire et al. lacking in some way?

First let's look at 2009, and see if there are unusual conditions;

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F1gvBVNF.png&hash=e9b72fd63a7fd4e9f1a26ab0999afe54)

In 2009, while the CAB area loss was not that remarkable, but, the CAB area loss was all in one contiguous place. This expanse of exposed deep water creates the possibility for a long wavelength surge to develop within the CAB itself. What was needed was for a 92 km/h wind to blow for 69 hours. The coincidence of these two rare events created the exceedingly rare rare event recorded by Aspin et al. Edit; afterthought; the 2009 event could have been caused by a seiche type event in the ESS/Chukchi area.

However, with climate change, the rare may become commonplace.

Verg

BTW, the source you cited for that picture identified it as;

Verge - THINK!  Here's the Healy in late fall in the Beaufort/Chukchi
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 22, 2015, 07:16:33 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FHlDRQXj.png&hash=1c798073f69c5abb0dac65b9f05e2bb5)
http://www.sci-news.com/othersciences/geophysics/science-extreme-waves-arctic-ocean-02084.html (http://www.sci-news.com/othersciences/geophysics/science-extreme-waves-arctic-ocean-02084.html)

Here is another remarkable event. But the 5m waves would have a period of 9 - 10s.

Verg
Title: Re: Importance of waves in the Arctic
Post by: Neven on June 22, 2015, 08:02:45 PM
Please stop playing the troll.

Jim Hunt isn't a troll, nor does he play one here. Don't even suggest it and stop being so aggressive, please.
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 22, 2015, 09:42:26 PM
Neven,

Sorry, I got frustrated because people kept telling me I was wrong, when I knew i was right. Here is proof:

A high-resolution hindcast of wind and waves for The North Sea,
The Norwegian Sea and The Barents Sea

arxiv.org/ftp/arxiv/papers/1111/1111.0770.pdf

Over an 11 year history(1991-2002), measured by quality controlled buoys, the maximum wave height was less than 13 meters(page 25). Only 2 surges with periods greater than 15 seconds were detected. They were 16 and 17 seconds(page 29). A 17 second period wave can penetrate the ice to 200 km, but it would be attenuated by a factor of 10,000 when it got there. A 12.5 meter high surge would be attenuated to 1.2 mm. We do not know if these surges even made it to the ice.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fapi.onlinelibrary.wiley.com%2Fasset%2Fv1%2Fdoi%2F10.1029%252F2009GL040676%2Fasset%2Fimage_n%252Fgrl26504-fig-0003.png%3Fl%3DCgg2pVVsCMw0MNOfhvJIPa%252BoTABc1x0uTf1i0A1ILbXZtPvfOkMImPATCRMNWyzvdVvqu6zQIGg%253D%26amp%3Bs%3D%252256e4f6653217492bba6d6fd08e2be9b0%2522%26amp%3Ba%3Dwol&hash=1faf90bf81cbad0552f627a11fbc7ccc)

Conclusion; While it is theoretically possible for surges to enter the Arctic Ice Cap, it is an exceedingly rare event and is dwarfed by other factors like tides and surface winds. It has been a negligible issue. Waves interact in the marginal ice field. It may become a significant issue when the CAB is more significantly exposed.

What happened in 2009? I do not know.

Verg

 Edit; I found a copy of the article where you can copy the graphs:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fonlinelibrary.wiley.com%2Fstore%2F10.1029%2F2010JC006402%2Fasset%2Fimage_n%2Fjgrc11793-fig-0009.png%3Fv%3D1%26amp%3Bt%3Dib8dwwrg%26amp%3Bs%3Dd9f5c717a2c6f3353a2f345f0e5dbe8aee3c562c&hash=929c3be1db5f44353205844b1b1aa55b) 

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fonlinelibrary.wiley.com%2Fstore%2F10.1029%2F2010JC006402%2Fasset%2Fimage_n%2Fjgrc11793-fig-0012.png%3Fv%3D1%26amp%3Bt%3Dib8e0372%26amp%3Bs%3Df189597d3d2bf8115d46861d77c1d7a407c5d32b&hash=4dc0d79f25627510a2b59f1047ffeb59)

Quote
Figure 12. Observed versus modeled ((top) WAM10 and (bottom) ERA-40) mean period, Tm (s), for the period 1991–2002. Only data from a subset of quality-controlled stations found in Figure 5 were used.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 22, 2015, 11:02:09 PM
Here is another remarkable event. But the 5m waves would have a period of 9 - 10s.

I know. I've blogged about it. See above:

http://forum.arctic-sea-ice.net/index.php/topic,1222.msg50645.html#msg50645 (http://forum.arctic-sea-ice.net/index.php/topic,1222.msg50645.html#msg50645)

FYI - This has happened for the second time now. A comment of yours (http://forum.arctic-sea-ice.net/index.php/topic,1222.msg54661.html#msg54661) was invisible to me when I posted one of mine (http://forum.arctic-sea-ice.net/index.php/topic,1222.msg54662.html#msg54662).
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 22, 2015, 11:03:50 PM
However, with climate change, the rare may become commonplace.

We can agree on something then!
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 22, 2015, 11:13:40 PM
What happened in 2009? I do not know.

Here's what happened once again (always assuming you agree that Asplin et al. aren't telling porky pies):

Quote
A swell period of 13.5 s, and a wavelength ranging from 200–300 m. Approximate ship heave amplitude of 0.4 m, also with a period of 13.5 s.

Here's where it happened once again (at the point marked "MYI" on the map):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fforum.arctic-sea-ice.net%2Findex.php%3Faction%3Ddlattach%3Btopic%3D1149.0%3Battach%3D17344%3Bimage&hash=958d1d2e9b33b4463a965b82f56af613)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 22, 2015, 11:22:12 PM
You have the audacity to use a picture misidentified as in the Arctic basin to bolster your argument.

No I didn't. I posted an interesting picture of a wave in the Arctic (and an interesting link) in a topic about waves in the Arctic. Thanks for your interesting link.

I ask you a direct question that would end a senseless semantic squabble, and you ignore it,

You ignored a set of increasingly heavy hints to pursue "a senseless semantic squabble" somewhere else.

Please stop playing the troll.

I echo what Neven said.
Title: Re: Importance of waves in the Arctic
Post by: Michael Hauber on June 23, 2015, 12:16:57 AM
Neven,

Sorry, I got frustrated because people kept telling me I was wrong, when I knew i was right. Here is proof:

A high-resolution hindcast of wind and waves for The North Sea,
The Norwegian Sea and The Barents Sea

arxiv.org/ftp/arxiv/papers/1111/1111.0770.pdf

Over an 11 year history(1991-2002), measured by quality controlled buoys, the maximum wave height was less than 13 meters(page 25). Only 2 surges with periods greater than 15 seconds were detected. They were 16 and 17 seconds(page 29). A 17 second period wave can penetrate the ice to 200 km, but it would be attenuated by a factor of 10,000 when it got there. A 12.5 meter high surge would be attenuated to 1.2 mm. We do not know if these surges even made it to the ice.

It was not two surges, but two measurements of mean period (as the label on the diagram indicates) that were measured greater than 15 seconds.  I note from these tables that significant numbers of measurements of mean period > 10 seconds were made.  A distribution (http://www.dtic.mil/dtic/tr/fulltext/u2/a227040.pdf) (see page 34) of periods shows that non-negligible numbers of waves have periods of 2.5 x the mean period.  So we have a small but significant number of times were the mean period is 10s, and each time this happens, a small percentage of waves will have periods as high as 25 s.  Looking at the attenuation diagrams you provided, such waves can penetrate for 1600 km, maintaining 10% of their original height.
Title: Re: Importance of waves in the Arctic
Post by: Michael Hauber on June 23, 2015, 12:18:32 AM

First let's look at 2009, and see if there are unusual conditions;

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F1gvBVNF.png&hash=e9b72fd63a7fd4e9f1a26ab0999afe54)

In 2009, while the CAB area loss was not that remarkable, but, the CAB area loss was all in one contiguous place.

As was the case in 2007, 2008, 2010, 2011, 2012, but not really in 2013 or 2014.
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 23, 2015, 02:49:09 AM
Neven,

Sorry, I got frustrated because people kept telling me I was wrong, when I knew i was right. Here is proof:

A high-resolution hindcast of wind and waves for The North Sea,
The Norwegian Sea and The Barents Sea

arxiv.org/ftp/arxiv/papers/1111/1111.0770.pdf

Over an 11 year history(1991-2002), measured by quality controlled buoys, the maximum wave height was less than 13 meters(page 25). Only 2 surges with periods greater than 15 seconds were detected. They were 16 and 17 seconds(page 29). A 17 second period wave can penetrate the ice to 200 km, but it would be attenuated by a factor of 10,000 when it got there. A 12.5 meter high surge would be attenuated to 1.2 mm. We do not know if these surges even made it to the ice.

It was not two surges, but two measurements of mean period (as the label on the diagram indicates) that were measured greater than 15 seconds.  I note from these tables that significant numbers of measurements of mean period > 10 seconds were made.  A distribution (http://www.dtic.mil/dtic/tr/fulltext/u2/a227040.pdf) (see page 34) of periods shows that non-negligible numbers of waves have periods of 2.5 x the mean period.  So we have a small but significant number of times were the mean period is 10s, and each time this happens, a small percentage of waves will have periods as high as 25 s.  Looking at the attenuation diagrams you provided, such waves can penetrate for 1600 km, maintaining 10% of their original height.

Michael,

Thank you for this. 25 second surges seem impossible in the shallow northern waters. This dataset includes Iceland, Ireland, and England. A narrower data set near the marginal ice zone is needed.

I found a surf report site for Svalbard:

http://www.surf-forecast.com/maps/Svalbard/significant-wave-height/150 (http://www.surf-forecast.com/maps/Svalbard/significant-wave-height/150)

Now they seem to peak out at 6 ft, which, is a mean and follows the relationship you suggest would indicate peak wave height of around 15 ft. Less than 5 meters. Too small to enter the basin.

There also is a global animation:

http://www.surf-forecast.com/weather_maps/Global-Pacific (http://www.surf-forecast.com/weather_maps/Global-Pacific)

It's scale is in wave energy. It appears that wave energy is attenuated by a factor of 5 as it passes through the window between England and Iceland. It also shows how deep wave intrusion under the antarctic ice is continuous.

Again thanks for putting me straight about that data.

Verg
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 23, 2015, 11:02:20 AM
So we have a small but significant number of times were the mean period is 10s, and each time this happens, a small percentage of waves will have periods as high as 25 s.  Looking at the attenuation diagrams you provided, such waves can penetrate for 1600 km, maintaining 10% of their original height.

Quite so, but nevertheless Asplin et al. report a 0.4 meter 13.5 second swell 250 km from the ice edge on September 6th 2009, with the effects of said swell visible from a helicopter for a further 100 km.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 23, 2015, 11:15:45 AM
I found a surf report site for Svalbard

If you were a surfer you would look at the period forecast before the wave height. Here's one from my friendly local neighbourhood surf forecasting site:

http://magicseaweed.com/World-Surf-Chart/64/?chartType=PERPW (http://magicseaweed.com/World-Surf-Chart/64/?chartType=PERPW)

Here's one I prepared earlier for the Arctic basin on September 6th 2009:

Title: Re: Importance of waves in the Arctic
Post by: A-Team on June 23, 2015, 06:39:17 PM
Quote
Quite so, but nevertheless Asplin et al. report a 0.4 meter 13.5 second swell 250 km from the ice edge on September 6th 2009, with the effects of said swell visible from a helicopter for a further 100 km.
That bears repeating.

This was an extraordinarily well-documented event -- by before and after video, by helicopter EMI, by laser altimetry, by ship's instrumentation of heave, pitch and roll, by ice coring, by ice salinity measurement, by floe size and thickness distributions, by ship's crew, by scientific staff who were about to disembark onto by the MYI just prior to its collapse, by further swells observed 3 days following, etc etc -- that was published in a major peer-reviewed geophysics journal.

There is nothing that special about the Siberian cyclonic lows with central pressures of 990 mb and 986 mb; the only thing special is a monitoring icebreaker happened to be out there in the ice in the condition it was in on Sept 2012.

The article remains utterly uncontroversial within the scientific community with 39 articles citing the 2012 paper. One of those is a follow-up article by the same authors (bad url at www.bio.gc.ca/ (http://www.bio.gc.ca/) but available through ResearchGate).

Quote
The results of Radarsat-2 imagery analysis show that a flexural fracture event which occurred in the Beaufort Sea region on 06 September 2009 affected ~40,000 km2. Open water fractional area in the area affected initially decreased from 3.7% to 2.7%, but later increased to ~20% following wind-forced divergence of the ice pack.

Energy available for lateral melting was assessed by estimating the change in energy entrainment from longwave and shortwave radiation in the mixed-layer of the ocean following flexural fracture. 11.54 MJ · m-2 of additional energy for lateral melting of ice floes was identified in affected areas. The impact of this process in future Arctic sea ice melt seasons was assessed using estimations of earlier occurrences of fracture during the melt season, and is discussed in context with ocean heat fluxes, atmospheric mixing of the ocean mixed layer, and declining sea ice cover. We conclude that this process is an important positive feedback to Arctic sea ice loss

Another relevant citing article describes 4 m swell in pack ice SE of Svalbard/N of Hopen Island in early May 2010. The March 2015 paper is paywalled but Dr. Collins sent a pdf within 10 minutes. This has a very nice review of Arctic wave literature and wave physics of the witnessed event, another hair-raising story of researchers about to go off-ship. Here the main instrumentation was shipboard GPS with vertical position accuracy of 0.05 m. Recommended read.
Quote
These are the largest known waves recorded in the Arctic with substantial ice cover present, and we expect the measurement of large-wave events to occur more frequently in the future due to the fetch wave-ice fetch feedback loop.
http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=1049&context=oceanwaves (http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=1049&context=oceanwaves)
http://onlinelibrary.wiley.com/doi/10.1002/2015GL063063/abstract (http://onlinelibrary.wiley.com/doi/10.1002/2015GL063063/abstract)

See also "Swell and sea in the emerging Arctic Ocean", a mooring study by J Thomson and WE Rogers Geophys Res Lett http://onlinelibrary.wiley.com/doi/10.1002/2014GL059983/pdf (http://onlinelibrary.wiley.com/doi/10.1002/2014GL059983/pdf) (free full):

Quote
Wave observations were collected using a 600 kHz Nortek Acoustic Wave and Current (AWAC) sensor deployed on a subsurface mooring at 75 ◦ N, 150 ◦ W as part of the Beaufort Gyre Exploration Project. The AWAC was mounted at the top (50 m below the surface) of the 3000 m mooring, looking up to the surface. The AWAC uses sonar pings to determine the distance from the instrument to the sea surface, and this dis- tance is recorded at 1 Hz for 1024 s at the beginning of each hour. These records are processed using a fast Fourier transform to determine the wave energy spectra, as well as the significant wave height (defined as 4 times the square root of the variance in sea surface elevation at frequencies 0.05–0.6 Hz), or the ice draft when ice is present.

We show that the increased open water of 2012 allowed waves to develop beyond pure wind seas and evolve into swells. The swells remain tied to the available fetch, however, because fetch is a proxy for the basin size in which the wave evolution occurs. Thus, both sea and swell depend on the open water fetch in the Arctic, because the swell is regionally driven. This suggests that further reductions in seasonal ice cover in the future will result in larger waves, which in turn provide a mechanism to break up sea ice and accelerate ice retreat.

In summary, I find it quite inappropriate, bordering on rudeness, to continuing challenging -- without any observational basis or consideration of readily available subsequent on-topic papers -- the original authors' summary of waves in ice being an unsuspected and trending feedback mechanism furthering loss of Arctic sea ice.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 23, 2015, 07:36:16 PM
Thanks for the ResearchGate tip A-Team. Whilst there I noticed that one of LRC's original ("behind paywall") articles is available:

Estimates of ocean wave heights and attenuation in sea ice using the SAR wave mode on Sentinel-1A (https://www.researchgate.net/publication/272791320)

Quote
Over the last 30 years, the dramatic reduction in ice cover and thickness in the Arctic is opening larger ocean expanses for wave development. Understanding how the waves influence the breaking of ice in floes, and how sea ice attenuates surface gravity waves, are essential improvements for Earth system models at high latitudes. The representation of sea ice in commonly used numerical wave models is still fairly crude, often based on a partial blocking of wave energy. Wave transformation in sea ice combines a change in phase speed, scattering by ice floes and changes in ice thickness, and dissipation. Recent refinements taking into account both scattering by ice floes and friction below the ice have been introduced by Doble and Bidlot [2013]. However the functional form of parametrizations and the magnitude of the coefficients are still very uncertain due to the paucity of wave measurements in ice-covered waters.



 
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 25, 2015, 12:31:57 PM
Everyone,

Please read this so we can be speaking the same language;

http://www.stormsurf.com/page2/tutorials/wavebasics.shtml (http://www.stormsurf.com/page2/tutorials/wavebasics.shtml)

Verg
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 26, 2015, 11:16:40 AM
Please read this so we can be speaking the same language;

Verg,

I'm afraid that once again I fail to comprehend the point you are endeavouring to make. I pointed interested readers (possibly even big wave surfers!) at that same page in my own article on the topic. Aren't you and I already speaking the same language?

Is there any possibility you could elucidate at greater length?
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 27, 2015, 05:18:45 AM
Jim,

I grew up in a maritime community. I learned words regarding the sea before I can remember. But "wave" and "swell" were two distinct and different terms. I lived on Virginia beach and as a four year old played in the eye of hurricane Hazel. But, yesterday, my sister came back from sailing on the Santa Monica bay and remarked about the "swells" that were coming in. I realized that she shared my linguistics.

On the sea, there are very specific terms to describe the situation. "Aft" "Forward", "Port", "Starboard", these are not colloquialisms, these are terms that save the ship in distress. "Swell" and "Wave" are in the same category. They are not the same thing at all.

Verg
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 27, 2015, 05:28:46 AM
Jim,

As a surfer, I thought you knew the distinction. That is why I thought you were "playing the troll". I have been hesitant to apologize because, well, the foundations of linguistics are in early childhood. No-one is guilty of that. We use words differently. We have to live with that. But on the bridge of an ocean going ship,....you better know the difference between a swell and a wave.

Verg
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 27, 2015, 11:59:46 AM
Verg,

I am well aware of the difference between a wave and a swell, even though some authors of papers in scientific journals seem not to be. That's one reason why many moons ago (http://forum.arctic-sea-ice.net/index.php/topic,1149.msg54491) I posted webcam pictures of some "waves" in the Arctic Basin:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fgreatwhitecon.info%2Fwp-content%2Fuploads%2F2015%2F03%2FBarrowCam_20140904_0834-1024x768.jpg&hash=68209611ce908ac19aecdb3254fd5ddf)

and "a modest swell" in the Arctic Basin:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Ficefloe.net%2FAloftcon_Photos%2Falbums%2F2014%2F20140823-2001.jpeg&hash=32befff8549dbd1684f819f60fe4e7eb)

Do those images conform to your own "linguistics"?
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 28, 2015, 04:16:58 AM
Jim,

Quote
even though some authors of papers in scientific journals seem not to be.

We have another point of agreement.

Verg
Title: Re: Importance of waves in the Arctic
Post by: Michael Hauber on June 28, 2015, 08:53:57 AM
Science has a specific definition for wave, which goes beyond just ocean waves to cover an extremely wide range of physical phenomena.    This definition can apply to surf, sound, light, gravity, traffic jams and plenty more.  According to this definition all swells are a wave.  After all we refer to the 'wavelength' of a swell, and not the 'swelllength'.
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 28, 2015, 10:12:24 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FbF7Wz9F.png&hash=8ee2de4327a97fcc4ab785c698ea8ef0)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FWTuZaoK.png&hash=75f13dd0ceb6c7a589e5c21ee4bbe1fa)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F6RowKvo.png&hash=07ba84124713c7430015d60cb58880de)

Actually, some scientists refer to the "period of total swell".

Verg
Title: Re: Importance of waves in the Arctic
Post by: Andreas T on June 28, 2015, 11:00:43 AM
This whole discussion is rather odd and puzzling to me. From the basic physics (and the quotes from observations above) it looks obvious to me what the issues are.
Short waves are dissipated quickly in sea ice where it breaks up floes and crushes them against each other. This of course is an energy input as well as increasing surface area of the ice and increasing mixing around them.
Every blog from an icebreaker I have read includes the observation that the ship is a lot calmer once it is among ice floes, the sea surface is moving about less (to avoid using a wrong word)
Swells of long wavelength are dissipated less but that also means they have less energy input, if they had they would become weaker as their energy is dissipated. They can on the other hand break larger floes further from the edge. The larger floe will experience large forces from change in surface height over a long distance (wavelength) which a smaller floe doesn't even notice.
Thus long swells reach further into the pack, have a selective impact on large floes but less impact on the smaller floes.
Could this be something everybody agrees on?
Title: Re: Importance of waves in the Arctic
Post by: Vergent on June 28, 2015, 04:28:41 PM
This whole discussion is rather odd and puzzling to me. From the basic physics (and the quotes from observations above) it looks obvious to me what the issues are.
Short waves are dissipated quickly in sea ice where it breaks up floes and crushes them against each other. This of course is an energy input as well as increasing surface area of the ice and increasing mixing around them.
Every blog from an icebreaker I have read includes the observation that the ship is a lot calmer once it is among ice floes, the sea surface is moving about less (to avoid using a wrong word)
Swells of long wavelength are dissipated less but that also means they have less energy input, if they had they would become weaker as their energy is dissipated. They can on the other hand break larger floes further from the edge. The larger floe will experience large forces from change in surface height over a long distance (wavelength) which a smaller floe doesn't even notice.
Thus long swells reach further into the pack, have a selective impact on large floes but less impact on the smaller floes.
Could this be something everybody agrees on?

Yes.

Verg
Title: Re: Importance of waves in the Arctic
Post by: Michael Hauber on June 28, 2015, 09:23:01 PM
This whole discussion is rather odd and puzzling to me. From the basic physics (and the quotes from observations above) it looks obvious to me what the issues are.
Short waves are dissipated quickly in sea ice where it breaks up floes and crushes them against each other. This of course is an energy input as well as increasing surface area of the ice and increasing mixing around them.
Every blog from an icebreaker I have read includes the observation that the ship is a lot calmer once it is among ice floes, the sea surface is moving about less (to avoid using a wrong word)
Swells of long wavelength are dissipated less but that also means they have less energy input, if they had they would become weaker as their energy is dissipated. They can on the other hand break larger floes further from the edge. The larger floe will experience large forces from change in surface height over a long distance (wavelength) which a smaller floe doesn't even notice.
Thus long swells reach further into the pack, have a selective impact on large floes but less impact on the smaller floes.
Could this be something everybody agrees on?

Yes, but one more important fact is that waves with a longer period have more energy in total.  The circulation reaches deeper into the ocean and moves more water below the surface. 
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on June 30, 2015, 06:50:29 PM
One more important fact is that waves with a longer period have more energy in total.

It's the hottest day of the year here. I don't know about you guys, but I'm off to the beach. 3 feet at 9 secs plus a newly arrived 1 foot at 17 secs. And an offshore breeze to boot  :)
Title: Re: Importance of waves in the Arctic
Post by: Vergent on July 01, 2015, 01:23:01 AM
Good surfing Jim.

I stumbled on this, while searching for Canadian ice charts.:

A Review of Extreme Wave Conditions in the Beaufort Sea

http://www.dfo-mpo.gc.ca/Library/90666.pdf (http://www.dfo-mpo.gc.ca/Library/90666.pdf)

I suggest you read section 3 & 4 first, some of the previous studies they describe are found to be flawed.

Verg



Title: Re: Importance of waves in the Arctic
Post by: A-Team on July 01, 2015, 04:13:10 AM
Verg, that pdf is dated 1985, thirty years ago. What possible relevance could that have to modern reports, cited above, of swells interacting with pack ice that no one on this forum troubles themselves to read?

The two recent studies on the Beaufort event describe an event observed before, during, and after with a very heavily instrumented ship -- this is completely unprecedented. Maybe start with reading those. Full text.

I'm thinking we should delete this entire forum and start over with an active moderator. The open water reach has become much longer in August and September in the Arctic Ocean these days and the opportunities for breaking up pack ice much greater. This is an important new negative feedback on Arctic Ocean ice and one that deserves better.

Commentary on sea wave and swell so far has been not been at the level of the respective wikipedia articles. We are aiming a bit higher than that on these forums. At a bare minimum, people need to learn how to do Google Scholar searches to locate and read full text scientific articles on this topic from the last 2-3 years -- these will better explain current thinking and review all earlier work.

The great thing about this topic is Arctic open reach is so new that a half dozen papers about covers it. So folks, ok to ask questions but not ok to post personal musings until AFTER you have READ these few. (I'm getting about as exasperated as AbruptSLR on the methane forum!)
 
To learn what a swell really means in terms of a 3000 m moored buoy with upward looking sonar observing waves 50 m above in the Beaufort, here is a reader-friendly one -- and it's only FOUR PAGES (sampler below). 

There you can learn how scientists unwrap actual waves into their wave energy spectra by fourier transform and determine 'significant wave height' as 4 * square root in sea surface elevation variance at moderate frequency, etc. etc. etc.

Wave theory gets real complicated in a hurry. Spare me your thoughts on that, years ago I was teaching nonlinear dispersive partial differential equations -- cnoidal waves, solitons, KdV and all that, not in some 1834 English canal but rather non-abelian Yang-Mills vacua. Here we just want to touch on the most basic basics of wind waves in deep water.

Once a wave train hits an ice pack heterogenous in so many ways, forget it -- theory is worthless (for lack of specifiable boundary conditions). Fortunately we have a few outstanding observations of what actually happens next.

But best of all, thanks to Asplin 2014, we don't actually need a ship out there anymore because we know when and where major wind events are happening so with Radarsat/Sentinel we can maybe monitor the aftermath directly on floe size and predict enhanced lateral melt.

1. http://www7320.nrlssc.navy.mil/pubs/2014/rogers2-2014.pdf (http://www7320.nrlssc.navy.mil/pubs/2014/rogers2-2014.pdf)

2. 10.1002/2013JC009557 Implications of fractured Arctic perennial ice cover on thermodynamic and dynamic sea ice processes. MG Asplin et al

 
Title: Re: Importance of waves in the Arctic
Post by: Vergent on July 01, 2015, 11:36:08 AM
A-Team,

What??? I shared a link. I made no conclusion about it. It was just a source of information, relevant to this thread. It documented several storms, and showed the expected frequency of them in the past. So, why the hostility?  "we should delete this entire forum" Why? Because I shared a link to a scientific paper?

Verg
Title: Re: Importance of waves in the Arctic
Post by: Vergent on July 01, 2015, 11:43:02 AM
Good surfing Jim.

I stumbled on this, while searching for Canadian ice charts.:

A Review of Extreme Wave Conditions in the Beaufort Sea

http://www.dfo-mpo.gc.ca/Library/90666.pdf (http://www.dfo-mpo.gc.ca/Library/90666.pdf)

I suggest you read section 3 & 4 first, some of the previous studies they describe are found to be flawed.

Verg

A-Team

Please Quote and highlight what you find so offensive.

Verg
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 01, 2015, 12:05:17 PM
Good surfing Jim.

Thanks Verg.

It was a perfect evening, apart from the angle of the swell. I even got to illustrate a "clean up set" from the inside, a topic I discussed with a climate modeller from the Hadley Centre only recently. You will note that I was further out than the rest of the lineup, but unfortunately nowhere near far enough!

If you all promise not to laugh I can provide a video recording of the longest "hold down" of my career since I tried to take on triple overhead Soup Bowl and lost.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 01, 2015, 12:17:43 PM
Please Quote and highlight what you find so offensive.

Verg,

Your overly concise "linguistics" are all too easily misunderstood, as are mine occasionally!
Title: Re: Importance of waves in the Arctic
Post by: Vergent on July 01, 2015, 12:35:12 PM
Thanks Jim, for the surf report.

Verg

Edit: BTW, here is the "surf report" for the north pole;

Quote
The broadband signals are mostly dominated by the ice
swell, which has a peak period ranging from 20 to 30 s.
The ice swell manifests itself with equal amplitude on the
vertical and horizontal channels. Figure 2a shows 1 hour of
recording that only contains the ice-swell signal, which at
this time has a peak period of 27 s. Peak-to-peak amplitude
is ∼0.1 mm s−1, which corresponds to ∼0.5 mm of peak to-peak
vertical and horizontal displacement, as is typically
observed (e.g. Hunkins, 1962; LeSchack and Haubrich,
1964; Dugan and others, 1992).

http://oceans.taraexpeditions.org/wp-content/uploads/2015/01/Marsan_JG2011.pdf (http://oceans.taraexpeditions.org/wp-content/uploads/2015/01/Marsan_JG2011.pdf)

http://onlinelibrary.wiley.com/doi/10.1029/JZ067i006p02477/full (http://onlinelibrary.wiley.com/doi/10.1029/JZ067i006p02477/full)

Title: Re: Importance of waves in the Arctic
Post by: Michael Hauber on July 02, 2015, 12:59:05 AM
Verg, that pdf is dated 1985, thirty years ago. What possible relevance could that have to modern reports, cited above, of swells interacting with pack ice that no one on this forum troubles themselves to read?


I read some of the stuff you posted, and agree with you that waves are a significant issue within the Arctic and reach deep within the pack.  I see Jim Hunt also responded to your previous post:

Quote
Thanks for the ResearchGate tip A-Team. Whilst there I noticed that one of LRC's original ("behind paywall") articles is available:

I do see that one member of this forum follows up your post full of useful scientific information with a post suggesting that everyone reads a basic introductory primer on wave/swell issues and then a link to what wave conditions were in the Arctic 30 years ago.  But that is just one person, and doesn't mean that no one is reading or understanding what you have said, or that the forum is a waste of time and should be deleted.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 02, 2015, 07:50:03 AM
I'm thinking we should delete this entire forum and start over with an active moderator.

I disagree. I've been studying this stuff since long before Asplin et al. published anything. I hope you'll forgive me when I point out that I'm currently in the midst of a robust online "debate" with the likes of David Rose, Judy Curry and Michael Shellenberger?

Have you bothered to click any of my links, and if so did you comprehend the content? My own introduction to the subject, linked to above, was written for the benefit of the global surfing community in general and the long serving Great White Con Arctic Basin Big Wave Surfing (http://greatwhitecon.info/tag/gwcabbwfsc/) team leader in particular:

https://twitter.com/andrew_cotton/status/616390191390003201 (https://twitter.com/andrew_cotton/status/616390191390003201)

Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 04, 2015, 08:47:09 PM
I recommend watching both videos in my latest Arctic article from cover to cover:

Is Time Running Out for Arctic Sea Ice? (http://greatwhitecon.info/2015/07/is-time-running-out-for-arctic-sea-ice/)

However if you're in a rush skip to 28:30 minutes into the second one, where Prof. Peter Wadhams points out that on his cruise around the Arctic this coming September:

Quote
We're looking at one particular thing, which may not be the most important thing, but the retreat of the sea ice in summer is going much faster than computer models predict, and we think that one factor there is the fact that as the sea ice retreats it opens up this huge area of open water in the Arctic Ocean which then becomes like an ocean with lots of waves and storms and swell, and the waves themselves break the remaining ice up and cause it to retreat faster so that there's a kind of collaborative effect there that the remaining ice is vanishing faster because of so much open water producing wave action.



Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 05, 2015, 02:01:50 AM
Some additional sources of numerous "waves-in-ice" papers:

The NERSC WIFAR project: http://msc.nersc.no/?q=node/69 (http://msc.nersc.no/?q=node/69)

P.Wadhams@ResearchGate: https://www.researchgate.net/profile/P_Wadhams (https://www.researchgate.net/profile/P_Wadhams)
Title: Re: Importance of waves in the Arctic
Post by: Seumas on July 05, 2015, 11:00:22 AM
Not exactly contemporary science, but it sprang to my mind on reading this thread. Back in the 18th century, they didn't know about the North polar ice cap.

In James Boswell's "THE JOURNAL OF A TOUR TO THE HEBRIDES WITH SAMUEL JOHNSON", which occurred in 1773, he writes:

"Talking of Phipps's voyage to the North Pole, Dr Johnson observed, that it 'was conjectured that our former navigators have kept too near land, and so have found the sea frozen far north, because the land hinders the free motion of the tide; but, in the wide ocean, where the waves tumble at their full convenience, it is imagined that the frost does not take effect'."

So you're in good company supposing that waves might have an effect!
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 06, 2015, 05:59:11 PM
An extract from a personal communication from Peter Wadhams:

Quote
I'm going out in September in the "Sikuliaq (https://en.wikipedia.org/wiki/RV_Sikuliaq)" (University of Alaska) to do some more specific wave-ice interaction experiments, assuming there is any ice to experiment on.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 07, 2015, 04:14:49 PM
If you all promise not to laugh.....

I went to the beach this time last week to cool off a bit. This is what happened next:

http://youtu.be/ZYo9q_RRKTE (http://youtu.be/ZYo9q_RRKTE)
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on July 08, 2015, 08:50:14 PM
This is a paper on internal waves in the arctic http://psc.apl.washington.edu/northpole/Mixing.html (http://psc.apl.washington.edu/northpole/Mixing.html)
 to get some idea of the possible scale of these
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.livescience.com%2Fimages%2Fi%2F000%2F061%2F114%2Foriginal%2Finternal-waves.jpg%3F1389299751&hash=a7285fcc88ffb5738b7b7ff86153729d)
This shows that atoll https://en.wikipedia.org/wiki/Pratas_Islands (https://en.wikipedia.org/wiki/Pratas_Islands) in context, the image is from http://www.livescience.com/42459-huge-ocean-internal-waves-explained.html?li_source=pm&li_medium=most-popular&li_campaign=related_test (http://www.livescience.com/42459-huge-ocean-internal-waves-explained.html?li_source=pm&li_medium=most-popular&li_campaign=related_test) " In the tank, the internal waves formed when tidal currents pushed cold, heavy bottom water over two seafloor ridges, setting up a disturbance called a standing wave" and there's a short vid.
More from the Andaman sea
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.livescience.com%2Fimages%2Fi%2F000%2F041%2F787%2Foriginal%2Findian-ocean-internal-waves-110207-02.jpg%3F1320191661&hash=49dab822938bd799a59a49a49e38721c)
from http://www.livescience.com/30098-indian-ocean-internal-waves.html (http://www.livescience.com/30098-indian-ocean-internal-waves.html) which is fairly short.
Where might these be generated in the arctic? well, just guessing, but likely where tidal forces race adjacent to steep shelves or ridges.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.esr.org%2FAOTIM%2Ffig3_full.png&hash=3dccdfc892d45bc8c2840eca7bf69acd)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FiRGwJ%2F431f9fba55.jpg&hash=55275545a6ada93a02911cf6bfe938c9)
worth looking how these match up, images from here http://www.esr.org/arctic_tides_index.html (http://www.esr.org/arctic_tides_index.html) and here http://geology.com/world/arctic-ocean-bathymetry-map.shtml (http://geology.com/world/arctic-ocean-bathymetry-map.shtml)
Not that tides themselves are really sufficient but if you've got a significant fraction of 15,000 cubic kilometers on the move, or a high/ low pressure system moving, across those areas then I suspect that would do it.
There's a brief explanation of atmospheric effects on sea height here http://weather.mailasail.com/Franks-Weather/Pressure-And-Tides (http://weather.mailasail.com/Franks-Weather/Pressure-And-Tides)
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on July 09, 2015, 11:26:14 AM
Perhaps it's wishful thinking on my part but some of these leads show signs of being caused by internal wave action. Where the deeper dense layers are sloughing around in the Canadian Basin getting within a few meters of the surface and the surface waters moving independently pass over the crests picking up heat and inherent turbulence as they calm the storm beneath them.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortopening_nowcast_anim30d.gif&hash=57199a0319c4f3e34315746f1aa9d92f)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 09, 2015, 05:31:02 PM
This is a paper on internal waves in the Arctic.

Thanks for the heads up John. I've not read that before. My focus up to now has been on surface gravity waves (http://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-802-wave-motion-in-the-ocean-and-the-atmosphere-spring-2008/lecture-notes/MIT12_802S08_lec03.pdf), which at long periods can happily do quite a bit of vertical mixing. See my video for an anecdotal example!

Some more reading to be added to my ever growing to do list!
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 18, 2015, 11:27:08 PM
Harvey Goodwin works off the RV Lance, and reports via Twitter that:

Quote
When a light swell comes in the 5km sea ice floe we'd been working on broke into pieces not more than 30m in an hour!. Equipment rescue after sea ice breakup. Some cables cut but no equipment lost!

https://twitter.com/Harvey_Goodwin/status/622413054618279936 (https://twitter.com/Harvey_Goodwin/status/622413054618279936)

(https://pbs.twimg.com/media/CKNBXg3WEAAKw8A.jpg)

A bit of digging suggests the picture was taken on June 22nd or thereabouts.

https://twitter.com/OceanSeaIceNPI/status/612971542385946624 (https://twitter.com/OceanSeaIceNPI/status/612971542385946624)

(https://pbs.twimg.com/media/CIG2Xr1WIAAenY7.jpg)

Now more fully documented at:

"R/V Lance Encounters Another Energetic Wave Event in the Arctic (http://greatwhitecon.info/2015/07/rv-lance-encounters-another-energetic-wave-event-in-the-arctic/)"

Title: Re: Importance of waves in the Arctic
Post by: Andreas T on July 21, 2015, 11:09:03 AM
Obuoy9 which is now near the Greenland coast in the north east water polynya at about 81N 11.5W showed this image today. Does that show a swell Jim? Swells which are not attenuated by ice could reach that position from the atlantic, I guess.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 21, 2015, 04:45:53 PM
Does that show a swell Jim? Swells which are not attenuated by ice could reach that position from the atlantic, I guess.

It's a bit too fuzzy to be sure Andreas! When I have a spare second I'll check the WW3 forecast. It certainly looks as though some local wind is chopping up the surface a bit.
Title: Re: Importance of waves in the Arctic
Post by: Andreas T on July 21, 2015, 05:38:54 PM
I am thinking of the darker shades in the sea surface which seem to form lines at about 120 deg to the floe edge. This could be caused by different angle toward the sky i.e. a long swell from southeast (camera is looking south in this image) or it could be just gusts of wind rippling the surface in different ways. It was visible in several images around that time in different place but similar direction I thought.
Can't see anything now in the 15:00 image so probably nothing. camera looking further towards west. Azimuth at 110 corresponds to 200deg from north by my observations of sun position.
Title: Re: Importance of waves in the Arctic
Post by: Neven on July 27, 2015, 01:15:40 PM
This (https://www.adn.com/article/20150726/study-beaufort-chukchi-and-bering-waves-are-getting-bigger) popped up in my mail box today via Google Alerts, from Alaska Dispatch News:

Quote
Study: Beaufort, Chukchi and Bering waves are getting bigger

Waves grew bigger and spaced farther apart as ice cover diminished in the Arctic and sub-Arctic waters off Alaska and western Canada, new research shows.

Since the 1970s, the biggest waves in the Beaufort, Chukchi and Bering Seas have grown at a rate of 0.3 to 0.8 percent per year, according to a comprehensive study led by Environment Canada. The time it takes waves to cycle, a measurement known as period, has grown even more, by 3 to 4 percent per year, more than tripling since 1970, according to the study, published by the American Meteorological Society’s Journal of Climate.

The study tracks significant wave height, which is the height of the biggest third of the waves, and mean wave period, which is the average of time for wave crests and troughs to complete their cycles.

It uses a wide variety of weather and climate observations collected over the years, including recorded sea-surface temperatures, atmospheric conditions, wind speeds and other parameters, to calculate the wave patterns going back over the past decades.

While wind patterns have changed over the period of time covered in the study, wind changes are not responsible for most of the increase in wave action, the study found. Instead, swells -- the rolling mechanical waves that travel long distances over the ocean --  account for most of the wave changes researchers measured, said lead author Xiaolan Wang, a research scientist with Environment Canada.

The study does not conclude that the expanding open water caused the bigger waves. “It’s not my area of research,” Wang said.

Still, it points out the correlation, and includes maps showing the expansion of open-water area in the three seas over the decades.

“Waves cannot be generated in ice-covered conditions,” she said.

Read the rest here (https://www.adn.com/article/20150726/study-beaufort-chukchi-and-bering-waves-are-getting-bigger).

PS I'm moving this thread to the more appropriate Arctic Background category.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 27, 2015, 03:24:36 PM
PS I'm moving this thread to the more appropriate Arctic Background category.

But I just had a long chat this morning with a certain Cambridge Professor about the recent work of Walter Munk with a bunch of Californian surfers  :o
Title: Re: Importance of waves in the Arctic
Post by: Neven on July 27, 2015, 06:27:21 PM
Sorry, Jim, hadn't noticed this has more to do with the Arctic than AGW in general.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 27, 2015, 08:12:41 PM
Hadn't noticed this has more to do with the Arctic than AGW in general.

But surely it should really be in the Arctic foreground, or even in "Science"?  ;)
Title: Re: Importance of waves in the Arctic
Post by: TerryM on August 06, 2015, 04:05:59 AM
The long fetch that's opened in the ESS is troubling.
Isn't this what Shakhova warned about WRT the possibility of vast methane deposits being released as wave action warms the frozen sea floor?
Terry
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on August 28, 2015, 02:06:23 PM
The long fetch that's opened in the ESS is troubling.

There's a fair fetch in the Chukchi/Beaufort Seas at the moment also:

Barrow Battered By Big Waves (http://greatwhitecon.info/2015/08/barrow-battered-by-big-waves/)

Flooding at Barrow, whilst water temperatures reported by IMB buoy 2014G north of the Chukchi Sea were at around -0.7 °C before the current cyclone arrived.

Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on September 07, 2015, 02:48:17 AM
Walter Munk is still hard at work at the age of 97

http://www.nytimes.com/2015/08/25/science/walter-munk-einstein-of-the-oceans-at-97.html (http://www.nytimes.com/2015/08/25/science/walter-munk-einstein-of-the-oceans-at-97.html)

Quote
Nowadays, as he forges ahead on wind, waves and other projects, he occasionally forgets the times of meetings and gets around with a walker. But he remains a frequent presence in Scripps, walking the halls of a building that now bears his name. The secret to his longevity?

“I like my work and I like my life, and I enjoy doing it,” he said.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on September 15, 2015, 07:13:21 PM
A video showing "ice waves" in the Bering Strait during the final trials of the University of Alaska's R/V Sikuliaq (http://forum.arctic-sea-ice.net/index.php/topic,1385.0.html):

http://youtu.be/yaWBW7Oywc8 (http://youtu.be/yaWBW7Oywc8)
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on September 17, 2015, 01:40:10 PM
Jim H. posted this elsewhere I'm just putting the link in this thread too for future reference.
https://scripps.ucsd.edu/news/oceanographers-find-clues-behind-arctics-fourth-lowest-sea-ice-minimum
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on September 23, 2015, 04:05:14 PM
Linked by A-Team in the Sikuliaq thread this is a paper on the internal waves so of interest to anyone following this thread too. http://www-pord.ucsd.edu/~jen/research.html (http://www-pord.ucsd.edu/~jen/research.html)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on September 27, 2015, 12:55:23 PM
There's plenty of potential overlap with the R/V Sikuliaq (http://) thread for the next couple of months, but here's the plan for the US Office of Naval Research's "Sea State and Boundary Layer Physics of the Emerging Arctic Ocean" research cruise which starts from Nome, Alaska on October 1st:

ONR Sea State DRI Cruise Plan R/V Sikuliaq, Fall 2015 (http://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1385.0;attach=21378)

The associated web site can be viewed at:

http://www.apl.uw.edu/project/project.php?id=arctic_sea_state (http://www.apl.uw.edu/project/project.php?id=arctic_sea_state)

Quote
The cruise will be organized into modules, each targeting specific processes and
conditions from the science objectives and each emphasizing a subset of observational
assets. Complimenting the modules will be event (storm) based sequences: transect
before, buoys during, transect after. Both shipboard (e.g., cameras, wave radars, CTD)
and autonomous measurements (e.g., AUVs, wave buoys) will be employed during the
cruise, often simultaneously.



Title: Re: Importance of waves in the Arctic
Post by: johnm33 on September 29, 2015, 12:35:58 PM
Linked to by Jim Hunt on the Sikuliaq thread, preliminary results from their deep sea mooring. https://scripps.ucsd.edu/projects/arcticmix/bringing-it-all-home/ Internal waves and mixing.
Curiously the first reports [BBC radio4] about shell pulling out of the arctic mentioned 'arctic mix' findings of extreme turbulence as the prime reason for pulling out, but by the third repeat the narrative had shifted to poor reserves.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on November 17, 2015, 10:19:37 AM
Here's the plan for the US Office of Naval Research's "Sea State and Boundary Layer Physics of the Emerging Arctic Ocean" research cruise which starts from Nome, Alaska on October 1st

Here's Jim Thomson's final report on the Sikuliaq's recent "Sea state cruise":

http://www.apl.uw.edu/project/projects/arctic_sea_state/pdfs/cruise_report.pdf (http://www.apl.uw.edu/project/projects/arctic_sea_state/pdfs/cruise_report.pdf)

Quote
Our measurements suggest that waves play an important role in the fall freeze-up of the Beaufort
and Chukchi Seas, especially near the ice edge facing the prevailing easterly winds. Pancake ice
formation was common, and, in one particular event, extended for almost 100 nm. Our
measurements suggest that ocean heat also is important, and that mixing can delay or temporarily
reverse the formation of first-year ice. Eventually, strong heat loss to the atmosphere becomes
the dominant process, especially during off-ice wind events, and large expanses of the ocean
freeze rapidly. As intended, we observed a significant advance in ice cover, and we sampled
several wave/wind events.

According to the associated section (http://www.apl.uw.edu/project/project.php?id=arctic_sea_state) of the Office of Naval Research web site:

By the numbers, we have collected:


Note also that:

Quote
The Sea State DRI team is funded by the Office of Naval Research for two more years to analyze
and synthesize the data collected during this effort. Results will be presented in a special issue of
an academic journal and at academic conferences. A preliminary list of paper topics was drafted
by the team onboard the ship. Results will be used to improve forecasts of ice and waves in the
Arctic region.

In a report from October 12th on the web site:

Quote
The storm we have been measuring has just peaked at 5-m waves and 35-kt winds. We deployed a total of 14 buoys spanning almost 200 km. As the storm built, the whole region was covered in pancake ice — an ice formation pattern that is common when waves are present. As we re-surveyed the line this morning, the pancakes are gone. Much of the region is open water now, suggesting that the wave energy exceeded a threshold for pancake ice and mixed the newly forming ice away instead. Even early in the storm, we can see this process in this short video clip:

http://youtu.be/WuV36b2Yzo0 (http://youtu.be/WuV36b2Yzo0)

Here's how the cruise panned out in practice:



Title: Re: Importance of waves in the Arctic
Post by: Neven on February 25, 2016, 10:23:59 AM
A new paper was posted in The Cryosphere (http://www.the-cryosphere-discuss.net/tc-2016-37/):

Quote
Wave climate in the Arctic 1992–2014: seasonality and trends

Justin E. Stopa, Fabrice Ardhuin, and Fanny Girard-Ardhuin Univ. Brest, CNRS, IRD, Ifremer, Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, 29280, Brest, France

Abstract. Over the past decade, the diminishing Arctic sea ice has impacted the wave field which is principally dependent on the ice-free area and wind. This study characterizes the wave climate in the Arctic using detailed sea state information from a wave hindcast and merged altimeter dataset spanning 1992–2014. The wave model uses winds from the Climate Forecast System Reanalysis and ice concentrations derived from satellites as input. The ice concentrations have a grid spacing of 12.5 km, which is sufficiently able to resolve important features in the marginal ice zone. The model performs well, verified by the altimeters and is relatively consistent for climate studies. The wave seasonality and extremes are linked to the ice coverage, wind strength, and wind direction. This creates distinct features in the wind-seas and swells. The increase in wave heights is caused by the loss of sea ice and not the wind verified by the altimeters and model. However, trends are convoluted by inter-annual climate oscillations like the North Atlantic Oscillation (NAO) and Pacific Decadal Oscillation. The Nordic-Greenland Sea is the only region with negative trends in wind speed and wave height and is related to the NAO. Swells are becoming more prevalent and wind-sea steepness is declining which make the impact on sea ice uncertain. It is inconclusive how important wave-ice processes are within the climate system, but selected events suggest the importance of waves within the marginal ice zone.

Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on February 25, 2016, 12:20:44 PM
I've been too busy winding up the denizens over at Judy Curry's (http://neven1.typepad.com/blog/2016/02/global-sea-ice-extent-minimum-record.html?cid=6a0133f03a1e37970b01bb08bee47a970d#comment-6a0133f03a1e37970b01bb08bee47a970d) with waves, and you beat me to it  :(

For more from Ardhuin, Wadhams et al. see also:

"Ocean waves across the Arctic: attenuation due to dissipation dominates over scattering for periods longer than 19 s (https://www.researchgate.net/publication/294799613_Ocean_waves_across_the_Arctic_attenuation_due_to_dissipation_dominates_over_scattering_for_periods_longer_than_19_s)"

Quote
The attenuation of surface waves in sea ice is poorly understood but has been attributed to the combination of scattering and dissipation.  Scattering and dissipation have very different  effects  on  the  directional  and  temporal  distribution  of  wave  energy,  making  it  possible  to  better  understand their relative importance by analysis of swell spectral spreading  and  arrival  times.   Here  we  compare  wave  measurements from far inside the ice pack with a spectral wave model that has adjustable scattering and dissipation attenuation  formulations.   It  was  found  that  scattering  plays  a negligible role in the attenuation of long swells.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on March 11, 2016, 01:43:27 PM
Intriguingly Sentinel 3A (http://www.esa.int/spaceinimages/Missions/Sentinel-3)'s synthetic aperture radar appears to already be measuring "significant wave height" in the Central Arctic Basin!

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.esa.int%2Fvar%2Fesa%2Fstorage%2Fimages%2Fesa_multimedia%2Fimages%2F2016%2F03%2Fwave_height%2F15848237-1-eng-GB%2FWave_height_node_full_image_2.jpg&hash=f9c8b35f03a2987f37835ccd3a3c45ae)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on April 30, 2016, 07:54:50 PM
Somewhat earlier than originally anticipated this year, my first look at waves in the Beaufort Sea of 2016:

Wind Waves in the Beaufort Sea in April 2016 (http://greatwhitecon.info/2016/04/wind-waves-in-the-beaufort-sea-in-april-2016/)

Sentinel 3A data isn't flowing freely yet, so I ponder using CryoSat-2 to measure Beaufort Sea wave height. The data may well be out there, but not in a form that I can readily decode.
Title: Re: Importance of waves in the Arctic
Post by: A-Team on May 01, 2016, 05:02:34 AM
Looks very similar to what Navy Hycom was showing the other day ... apparently from WaveWatch III. Needs a 90º rotation but seems to be the very same area. Waves will prove a huge issue as the Arctic Ocean has more blue water, longer fetches, longer in the season.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fforum.arctic-sea-ice.net%2Findex.php%3Faction%3Ddlattach%3Btopic%3D1493.0%3Battach%3D28704%3Bimage&hash=479cf86e05df17eee54abe6f408c591c)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on May 01, 2016, 12:39:59 PM
Waves will prove a huge issue as the Arctic Ocean has more blue water, longer fetches, longer in the season.

Quite so!

I don't suppose you know how to persuade PanoplyJ to display 1D lat/long/wave height in a georeferenced human readable format do you?
Title: Re: Importance of waves in the Arctic
Post by: A-Team on May 01, 2016, 04:24:27 PM
Quote
how to persuade PanoplyJ to display 1D lat/long/wave height readably

Do you have the link to the netCDF handy? (Not that I have time today but sidd or wipneus might.) Normally it will display the numeric array. Panoply is a glass half full, the monkey at the keyboard approach will occasionally get something ok to display.

http://www.giss.nasa.gov/tools/panoply/ (http://www.giss.nasa.gov/tools/panoply/)
Title: Re: Importance of waves in the Arctic
Post by: Shared Humanity on May 01, 2016, 04:25:43 PM
Jim,

I want to thank you for creating this thread some time ago. I have always been fascinated by the mechanical forces at work on the Arctic Ocean as the ice weakens. Certainly waves, as you argued a couple years ago are one of the largest. When ice starts moving around rapidly it has an amazing ability to alter the properties of the ice around it. This is true for existing ice and ice that is forming.

As mentioned elsewhere on this blog, ice tends to form more rapidly in areas adjacent to the shores or existing ice. I am not sure if this is due to the calming effect that this ice has on the sea around it but this seems plausible. Where ice forms on open water that are buffeted with waves, ice can behave oddly indeed. I am wondering if newly formed ice might look like this in the open Arctic Ocean. Might it act similarly to seeding clouds, providing a surface for new ice to form. What would the mechanical strength of flows look like when they form like this. I would imagine it is far different than the leads that freeze in newly formed cracks in the ice.

https://www.youtube.com/results?search_query=video+of+ice+balls+on+lake+michigan (https://www.youtube.com/results?search_query=video+of+ice+balls+on+lake+michigan)

Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on May 01, 2016, 04:39:41 PM
Do you have the link to the netCDF handy?

My first thought was to try and make some sense out of this lot:

ftp://ftp.star.nesdis.noaa.gov/pub/sod/lsa/cs2igdr/c079/
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on May 01, 2016, 06:04:10 PM
I was looking at 73/4 above and wondering if the waves here starting at 71deg/135deg and moving north and west are the same phenomenon.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortopening_nowcast_anim30d.gif&hash=57199a0319c4f3e34315746f1aa9d92f)
Title: Re: Importance of waves in the Arctic
Post by: A-Team on May 01, 2016, 09:08:06 PM
Quote
wondering if the waves here starting at 71deg/135deg and moving north and west are the same phenomenon.

jnm, i wondered about that lead area animation too. It seems to visually mix opening fractures with established fetches along the coast that are different from ice fractures.

Jim, I am wondering what it takes for waves to wash over floes (which would soon be the end of them). It seems for ice 1m thick, the freeboard is only the height of a cigarette; meanwhile we are seeing waves 1-2m along the coast, fairly high winds and presumably chop. C

an a really massive floe like Big Block just bob up and down like a cork with the top staying dry? They seem more like heavily loaded barges than corks. And if Beaufort floes are lifted up by passing waves, why aren't they broken into smaller pieces (as reported elsewhere)?

Quote
make some sense out of this ftp://ftp.star.nesdis.noaa.gov/pub/sod/lsa/cs2igdr/c079/ (http://ftp://ftp.star.nesdis.noaa.gov/pub/sod/lsa/cs2igdr/c079/)

So far I've learned that my Panoply 4.05 is 14 versions back from the current release. This is really an admirable software effort but I haven't put enough effort in at my end. As with SNAP Toolbox, gdal and imagemagick.

http://www.giss.nasa.gov/tools/panoply/versions.html (http://www.giss.nasa.gov/tools/panoply/versions.html)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on May 02, 2016, 10:16:33 AM
Jim,

I want to thank you for creating this thread some time ago.

You're very kind, but actually LRC created this thread. I had been banging on about the effect of waves on sea ice for quite some time before that though! For an insight into how sea ice forms in open ocean I suggest taking a look at this video instead, starting at around 3 minutes 25 seconds:

http://youtu.be/mxWIiX-jEQo?t=3m25s (http://youtu.be/mxWIiX-jEQo?t=3m25s)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on May 02, 2016, 10:30:12 AM
Quote
wondering if the waves here starting at 71deg/135deg and moving north and west are the same phenomenon.

jnm, i wondered about that lead area animation too. It seems to visually mix opening fractures with established fetches along the coast that are different from ice fractures.

Using surfing terminology the winds have been "cross shore" for much of April, but are turning "offshore" at the start of May. Wouldn't that explain the change in direction of the forecast fractures?

Quote
Jim, I am wondering what it takes for waves to wash over floes (which would soon be the end of them). It seems for ice 1m thick, the freeboard is only the height of a cigarette; meanwhile we are seeing waves 1-2m along the coast, fairly high winds and presumably chop. Can a really massive floe like Big Block just bob up and down like a cork with the top staying dry? They seem more like heavily loaded barges than corks. And if Beaufort floes are lifted up by passing waves, why aren't they broken into smaller pieces (as reported elsewhere)?

As per above, the "chop" has been travelling parallel to the ice edge up to now. That is changing, but the "fetch" will be reduced as a consequence.

I fancy I can see wave washed ice in some of the recent images, but I could easily be imagining it!

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fforum.arctic-sea-ice.net%2Findex.php%3Faction%3Ddlattach%3Btopic%3D1493.0%3Battach%3D28662%3Bimage&hash=584c83a41c622303b83345a3cd8d7593)

Quote
So far I've learned that my Panoply 4.05 is 14 versions back from the current release. This is really an admirable software effort but I haven't put enough effort in at my end. As with SNAP Toolbox, gdal and imagemagick.

I've upgraded to Panoply 4.5, and read what I can find of TFM, but no joy so far :(
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on May 09, 2016, 11:00:07 AM
It's just speculation but I wonder if the breaks stretching from NE-SW are the result of internal waves, caused by water rushing towards Banks Is./ Canadian shores and forming an interference pattern of broad waves over which the ice breaks.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortictn_nowcast_anim30d.gif&hash=a545ff636fc54ca2011c39d16a46223a) 
even more pronounced on compressive strength.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortstrength_nowcast_anim30d.gif&hash=36aafa72fbac7b0e7f3d05e4925b588f)
Title: Re: Importance of waves in the Arctic
Post by: plinius on May 09, 2016, 07:29:02 PM
It's just speculation but I wonder if the breaks stretching from NE-SW are the result of internal waves, caused by water rushing towards Banks Is./ Canadian shores and forming an interference pattern of broad waves over which the ice breaks.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortictn_nowcast_anim30d.gif&hash=a545ff636fc54ca2011c39d16a46223a) 
even more pronounced on compressive strength.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortstrength_nowcast_anim30d.gif&hash=36aafa72fbac7b0e7f3d05e4925b588f)

The interference pattern isn't waves, but a reaction of the ice to a distortion - any fault line propagates very fast (same physics as in seismic activity) and stretches through the pack until there is no more windstress/distortion acting along the fault line. Next to a fault line, you cannot have another fault line, because all the distortion/stress has been accounted for by the existing fault line. So you go into a pseudo-equal spacing of parallel faults. Different systems of fault lines can overlap, but the have to be at a significant angle to each other, and they only run through as long as there are no significant leads in between the ice-pack (otherwise a fault line ends at the lead). Similar issue by the way with the frequent glacier terminus having near-rectangular blocks.
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on May 20, 2016, 11:36:01 AM
" The interference pattern isn't waves," Can we agree to disagree? I've reassessed my take on the prescence of internal waves and perhaps I'm just seeing what I want to see but I've grown more convinced and think they are manifest in all the basins, though I'll leave it to a proffessional to call it. They appear when the ice has built up a head of steam and are then accelerated by more powerful winds, or when powerful winds apply the brakes to an area already moving in concert. The most unambiguous signal of movement in the basins is in Beaufort where there's the most movement of ice. Looking at the central feature
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortopening%2Fnowcast%2Fopening2016050718_2016050800_042_beaufortopening.001.gif&hash=87996bc6e285daf30534c43206c2db9f)
and the underlying bathymetry
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FoYwsy%2F5cc8f60867.jpg&hash=6c35b55d4ad6aa6306ee5784154faced)
again 76/155 why the drop in salinity if it's not warm basal water melting the ice?
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortsss_nowcast_anim30d.gif&hash=79e271d376e7566dee3b5883a755e7a6)
I also did another google seach for internal waves, images this link has an interesting interactive http://www.whoi.edu/oceanus/feature/the-waves-within-the-waves (http://www.whoi.edu/oceanus/feature/the-waves-within-the-waves)
This ones more technical http://psc.apl.washington.edu/northpole/Mixing.html (http://psc.apl.washington.edu/northpole/Mixing.html)  abstract
    "Recent findings demonstrate the sensitivity of Arctic Ocean circulation to background, deep-ocean mixing. Results with a large-scale coupled ice-ocean model [Zhang and Steele, 2007] suggest the appropriate model background mixing for the Arctic Ocean is an order of magnitude lower than for ice-free oceans. Background mixing in the deep ocean is related to internal wave energy, which in ice-covered seas has been observed to be lower than in ice-free oceans, and to change with time and bathymetric conditions [Levine et al., 1985 and 1987; Halle and Pinkel, 2003; Pinkel, 2005]. Present thinking is that internal wave energies and background mixing are reduced in ice-covered seas by, among other things, dissipation of internal wave energy in the surface boundary layer immediately below the ice. Consequently, if the ice cover is reduced due to global warming, we may see a climate feedback that has not been considered before. If the ice cover is reduced, we may see increased internal wave energy, mixing, and heat flux in the deep ocean because less internal wave energy would be lost in the under-ice boundary layer. This would tend to result in increased heat flux to the ice, a positive climate feedback that would melt more ice. The effect could arguably be greatest near the continental slopes and submarine ridges, which are the likely areas of greatest internal wave increase and the paths of warm Atlantic water through the Arctic Basin."
  As is this http://folk.uib.no/ngfif/Reprints/Guthrie_etal_JGR13.pdf (http://folk.uib.no/ngfif/Reprints/Guthrie_etal_JGR13.pdf)
abstract "To determine whether deep background mixing has increased with the diminishment of
the Arctic sea ice, we compare recent internal wave energy and mixing observations with
historical measurements. Since 2007, the North Pole Environmental Observatory has
launched expendable current probes (XCPs) as a part of annual airborne hydrographic
surveys in the central Arctic Ocean. Mixing in the upper 500 m is estimated from XCP
shear variance and Conductivity-Temperature-Depth (CTD) derived Brunt-V

ais

al

a
frequency. Internal wave energy levels vary by an order of magnitude between surveys,
although all surveys are less energetic and show more vertical modes than typical
midlatitude Garrett-Munk (GM) model spectra. Survey-averaged mixing estimates also vary
by an order of magnitude among recent surveys. Comparisons between modern and
historical data, reanalyzed in identical fashion, reveal no trend evident over the 30 year
period in spite of drastic diminution of the sea ice. Turbulent heat fluxes are consistent with
recent double-diffusive estimates. Both mixing and internal wave energy in the Beaufort
Sea are lower when compared to both the central and eastern Arctic Ocean, and expanding
the analysis to mooring data from the Beaufort Sea reveals little change in that area
compared to historical results from Arctic Internal Wave Experiment. We hypothesize that
internal wave energy remains lowest in the Beaufort Sea in spite of dramatic declines in sea
ice there, because increased stratification amplifies the negative effect of boundary layer
dissipation on internal wave energy."
It's worth taking a look at http://www7320.nrlssc.navy.mil/hycomARC/navo/arc_list_beaufortopening.html (http://www7320.nrlssc.navy.mil/hycomARC/navo/arc_list_beaufortopening.html) from the 3rd and following the evolution of the movement on a frame by frame, unless your computer literate and can slow the animation down.

Title: Re: Importance of waves in the Arctic
Post by: plinius on May 20, 2016, 04:19:49 PM
It seems to me that the waves they are talking about are not equal to the waves you are hypothesizing about.  Just figure what your "wavelengths" are (it is actually a pseudowavelength for the lead opening) and why they get shorter the weaker the ice becomes. Or do you think that the deep ocean is suddenly producing short-wave tsunamis because the ice-cover gets weaker?
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on May 20, 2016, 08:22:18 PM
"It seems to me" No I'm definitely talking about internal waves, though I can't say the evidence for any particular lead being formed by them is unambiguous. But if you have say a 2k wavelength wave raising the ice surface slowly by 2-3m first theres the tendency of the ice to flow to the trough then with an opening the wind gains purchase, how do you call that? Sensors in the ocean has to be the answer.
2K wavelength
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fnews.mit.edu%2Fsites%2Fmit.edu.newsoffice%2Ffiles%2Fstyles%2Fnews_article_image_top_slideshow%2Fpublic%2Fimages%2F2009%2F20090917115859-1_0.jpg%3Fitok%3DU51WbClp&hash=73fa46d4174926c86e198157234dc690)
9 mile wavelength [byeyeball]
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic.ddmcdn.com%2Fgif%2Fblogs%2Fdnews-files-2015-07-internal-waves-sulu-sea-20150727-jpg.jpg&hash=00f6af457ac72183480cb410f0b1e533)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FoZKb2%2F4dec7efa83.jpg&hash=a5a46a736924f2b1ade2102b0e596d51)
from http://maps.ngdc.noaa.gov/viewers/bathymetry/ (http://maps.ngdc.noaa.gov/viewers/bathymetry/)
http://go.nasa.gov/1TtB8w6 (http://go.nasa.gov/1TtB8w6) [EOSDIS]
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on May 26, 2016, 12:14:36 PM
Thanks to timallard for bringing to my attention (http://forum.arctic-sea-ice.net/index.php/topic,1561.msg78043.html#msg78043) this longer video about the October 12th 2015 storm in the Beaufort Sea:

http://youtu.be/tDmM5zsxd4E (http://youtu.be/tDmM5zsxd4E)

A transcript is available on the APL web site:

http://www.apl.washington.edu/project/project.php?id=arctic_sea_state (http://www.apl.washington.edu/project/project.php?id=arctic_sea_state)

Quote
The main portion of the Beaufort was still open water at that point. And a strong easterly wind event came through that built large waves — waves that got to almost five meters in height. And the winds were something like up to thirty knots. And these waves were coming into the newly forming ice and making pancake ice.

We saw this happening so we quickly made a plan. And we put out this long array of buoys. We put out a total of 16 different types of wave measurement buoys.

So what we thought we were going to do was put these buoys out and they would measure the waves for awhile until the ice slowly started to mature enough so that it damped the waves. And the pancakes would start to lock  together and then the waves wouldn’t be able to penetrate further into the ice pack and that would be the end of the event. But that’s not what happened. What happened is the ice went away. Almost all the ice melted - really unexpected by everyone on board the ship.

There was a very warm layer of water 20 meters down beneath the surface. And these waves coming in were  enough to drive additional mixing and bring that warm water up from the subsurface and that warm water melted the ice and changed that balance happening at the surface.
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on May 28, 2016, 04:14:27 PM
I've convinced myself that a body of Pacific water is about to slam into Banks Is/Amundsen Gulf area from the direction of NSI, so we should see a positive anomoly show up on Nullschool, some evaporation and if it's as warm as I'm guessing then perhaps enough to create it's own weather locally. It'll then bounce back and should smash up and melt the nearest ice, after that it's up to the wind but an interesting week ahead.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortopening%2Fnowcast%2Fopening2016052618_2016060100_042_beaufortopening.001.gif&hash=7a601bef8840acf2b078e37b9491f141)
anim. http://www7320.nrlssc.navy.mil/hycomARC/navo/beaufortopening_nowcast_anim30d.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/beaufortopening_nowcast_anim30d.gif)
from http://www7320.nrlssc.navy.mil/hycomARC/beaufort.html (http://www7320.nrlssc.navy.mil/hycomARC/beaufort.html)
Title: Re: Importance of waves in the Arctic
Post by: LRC1962 on June 03, 2016, 12:11:51 AM
"It seems to me" No I'm definitely talking about internal waves, though I can't say the evidence for any particular lead being formed by them is unambiguous. But if you have say a 2k wavelength wave raising the ice surface slowly by 2-3m first theres the tendency of the ice to flow to the trough then with an opening the wind gains purchase, how do you call that? Sensors in the ocean has to be the answer.
https://www.insidescience.org/content/undersea-waves-may-melt-arctic-ice/3976 (https://www.insidescience.org/content/undersea-waves-may-melt-arctic-ice/3976) May help with the needed physicsof internal waves.
Title: Re: Importance of waves in the Arctic
Post by: LRC1962 on June 03, 2016, 12:24:39 AM
@JimH: for the crazies of the world

https://vimeo.com/166930720
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on July 10, 2016, 10:35:42 PM
I've stated above that I think the type of cracks on this [random] image, here stretching from north of bering towards the archipelago are signals of internal waves. Due no doubt to winds shifting the ice around, so how to distinquish between the simple effects of wind and the signs of internal waves? The best candidates, for internal waves are those which have low numbers of more or less parallel cracks, especially when they are followed by orthogonal cracks in fairly short order. You get very few of these appearing when the ice reaches the coastlines and becomes locked. What I think I'm observing now is a reduction due to the fragmentation  of the ice, such that no coherent crack exists for long enough to get picked up by the satelite. That doesn't mean they're not happening, but they're getting lost in the general wind driven movement, and the likely smaller surface waves.
(https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2016050918_2016051000_042_arcticictn.001.gif)
if you want to expand the image http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2016050918_2016051000_042_arcticictn.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2016050918_2016051000_042_arcticictn.001.gif)
[edit updated links]
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on July 23, 2016, 11:07:45 PM
I've been looking at this, http://marine.copernicus.eu/web/69-interactive-catalogue.php (http://marine.copernicus.eu/web/69-interactive-catalogue.php) since Jim Hunt recently linked to it elsewhere. I found this interesting
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FqbYkN%2F111fa6f2ee.jpg&hash=7096e9c023765bb7cdcb55d8adbfc329)
it shows [imo] the waves and subsequent break-up of the ice this season quite well. Open the link, it's the first product, basket, view, +below the hand gives you arctic option, i like the pallette i've chosen but there's a selection,  bottom left is the animation icon, i run it from 06:01 at 2fps.
Not waves but this one gives some sense of the oceans daily movements.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FqbY7D%2F86e3bf0089.jpg&hash=04b1cd2ab87f99811ffa332a0859355e)
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on August 04, 2016, 10:45:33 AM
Adding to 92 above, I've seen no signs of internal waves since the 16th july
(https://www7320.nrlssc.navy.mil/hycomARC/navo/beauforticen/nowcast/icen2016071518_2016071600_042_beauforticen.001.gif)
The ice is now so smashed that the winds and surface gravity waves move the ice around disguising any signs of them. The other side of this coin is that now the ice is at the mercy of gravity waves, the peices will smash into each other dousing themselves in brine and breaking apart. Nullschool is showing powerful winds blowing into the Arctic from SE of NSI poleward. My opinion is that the ice here is largely lightweight layer cake and could disappear at a shocking rate. We'll see in the next few days.
https://earth.nullschool.net/#current/wind/surface/level/orthographic=-0.48,86.69,811/loc=155.151,79.500 Unfortunately waves north of about 77N are not being looked for.
https://earth.nullschool.net/#current/ocean/primary/waves/overlay=sea_surface_temp_anomaly/orthographic=-0.48,86.69,811/loc=155.151,79.500
Title: Re: Importance of waves in the Arctic
Post by: Tor Bejnar on August 19, 2016, 09:16:44 PM
I expect we are going to learn something of the importance of waves in the Arctic as soon as the current series of regenerating high-Arctic lows passes into history.  The Windyty (https://www.windyty.com/?waves,2016-08-23-18,79.742,-44.121,3) wind forecast for next Tuesday suggests 3 meter seas fairly close to the ice. (Yes, I know 4 days out is 'just guessing'.)
Title: Re: Importance of waves in the Arctic
Post by: Tor Bejnar on August 24, 2016, 02:43:35 AM
So, how are the winds, now that Tuesday is here?  4m waves near the ice!
Image from today (https://www.windyty.com/?waves,90.000,-43.295,3).
2nd image is a forecasts for Saturday (https://www.windyty.com/?waves,2016-08-27-18,90.000,-43.295,3) (I know: 4 days is an eternity for arctic weather forecasting).
Title: Re: Importance of waves in the Arctic
Post by: ghoti on August 24, 2016, 03:16:52 AM
I haven't been able to find any near real time data from CCGS Louis St Laurent or IB Oden. They are in the thick of it and wave height info would be amazing to have.

Anyone know if there is a source that I just haven't found yet?
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on September 08, 2016, 06:55:46 PM
Courtesy bftv, for future reference
http://nsidc.org/arcticseaicenews/2016/09/arctic-sea-ice-nears-its-minimum-extent-for-the-year/ (http://nsidc.org/arcticseaicenews/2016/09/arctic-sea-ice-nears-its-minimum-extent-for-the-year/)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on October 02, 2016, 10:46:33 AM
A new paper from Jim Thomson et al.

"Emerging trends in the sea state of the Beaufort and Chukchi seas (http://www.sciencedirect.com/science/article/pii/S1463500316300622)"

Quote
The autumn storms that regularly occur in the Beaufort and Chukchi Seas are elevating the sea state now, and will continue so into the future, simply because it is increasingly likely that the storms will occur over larger open water areas that persist longer into autumn. It is yet to be determined if the higher sea states will in turn feed back to the large-scale evolution of the sea ice. The increasing sea state may affect not only the ice cover development, but also wave forcing in the coastal zone. Either way, the increasing sea states may alter air-sea fluxes and associated ecosystem processes. It is possible that the increasing sea state may play an important role in modulating the presumed changes in air-sea fluxes and upper ocean properties that are occurring, and in turn may modulate the response of sea ice to climate change. Finally, higher sea states are of operational importance to mariners and seabed drilling operators in the region, for whom higher sea states can increase the likelihood of dangerous icing conditions on ships and structures.

not to mention:

Quote
The process of wind-wave generation in partial ice cover is likely far more complex than present models suggest and is in acute need of improved understanding.
Title: Re: Importance of waves in the Arctic
Post by: Tigertown 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
Title: Re: Importance of waves in the Arctic
Post by: johnm33 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 (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
(https://www7320.nrlssc.navy.mil/hycomARC/navo/beaufortstrength/nowcast/strength2016100918_2016101000_046_beaufortstrength.001.gif)
changed the animated gif for a date relevent snapshot
Title: Re: Importance of waves in the Arctic
Post by: johnm33 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.
(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticicespddrf/nowcast/icespddrf2016102612_2016102700_927_arcticicespddrf.001.gif)
Will the ice arriving at the NSI persit or is enough heat being transported there by atlantic waters to melt it?
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on November 07, 2016, 01:14:18 AM
Completely different wind patterns.
(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticicespddrfnowcast.gif)
Good news is the ice seems to be thickening suppressing the waves except at the periphery
(https://www7320.nrlssc.navy.mil/hycomARC/navo/beaufortstrength/nowcast/strength2016110318_2016110400_046_beaufortstrength.001.gif)
Already lots of Atlantic waters pouring in by Laptev where the ice still looks vulnerable
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fcmems-view.cls.fr%2F%2FViewService%2Fscreenshots%2FcreateScreenshot%3Fdataset%3Dhttp%253A%252F%252Fnrtcmems.mercator-ocean.fr%252Fthredds%252Fwms%252Fglobal-analysis-forecast-phy-001-024%26amp%3BnumColorBands%3D20%26amp%3BlogScale%3Dfalse%26amp%3Bbbox%3D-1832324.21875%252C40429.6875%252C4988964.84375%252C5001367.1875%26amp%3Babovemaxcolor%3D0x000000%26amp%3Bbelowmincolor%3D0x000000%26amp%3Bnodatacolor%3Dnull%26amp%3Blayer%3Duo%26amp%3Btime%3D2016-11-06T12%25253A00%25253A00.000Z%26amp%3Belevation%3D-0.49402499198913574%26amp%3Bpalette%3Drainbow%26amp%3Bstyle%3Dboxfill%26amp%3BscaleRange%3D-0.5383465%252C0.7904294%26amp%3BdisplayScaleRange%3D-0.5383465%252C0.7904294%26amp%3Bopacity%3D1%26amp%3Bbbox%3D-1832324.21875%252C40429.6875%252C4988964.84375%252C5001367.1875%26amp%3BlayerTitle%3Deastward_sea_water_velocity%252Cdaily%2Bmean%2Bfields%2Bfrom%2BGlobal%2BOcean%2BPhysics%2BAnalysis%2Band%2BForecast%2Bupdated%2BDaily%26amp%3Bcrs%3DEPSG%253A32661%26amp%3BmapHeight%3D800%26amp%3BmapWidth%3D1024%26amp%3Bstyle%3Dboxfill%26amp%3BzUnits%3Dm%26amp%3Bunits%3Dm%2Bs-1%26amp%3BbaseUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BbaseLayers%3Dcls%253Anoaa_blue_marble_north_pole%26amp%3BoverlayUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BoverlayLayers%3Dcls%253Anoaa_blue_marble_north_pole_no_ocean&hash=051cf6e72b6003ab6eb46e0603a02350)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fcmems-view.cls.fr%2F%2FViewService%2Fscreenshots%2FcreateScreenshot%3Fdataset%3Dhttp%253A%252F%252Fnrtcmems.mercator-ocean.fr%252Fthredds%252Fwms%252Fglobal-analysis-forecast-phy-001-024%26amp%3BnumColorBands%3D20%26amp%3BlogScale%3Dfalse%26amp%3Bbbox%3D-1410644.53125%252C-480468.75%252C5410644.53125%252C4480468.75%26amp%3Babovemaxcolor%3D0x000000%26amp%3Bbelowmincolor%3D0x000000%26amp%3Bnodatacolor%3Dnull%26amp%3Blayer%3Dsithick%26amp%3Btime%3D2016-11-06T12%25253A00%25253A00.000Z%26amp%3Bpalette%3Drainbow%26amp%3Bstyle%3Dboxfill%26amp%3BscaleRange%3D0%252C4.5762506%26amp%3BdisplayScaleRange%3D0%252C4.5762506%26amp%3Bopacity%3D1%26amp%3Bbbox%3D-1410644.53125%252C-480468.75%252C5410644.53125%252C4480468.75%26amp%3BlayerTitle%3Dsea_ice_thickness%252Cdaily%2Bmean%2Bfields%2Bfrom%2BGlobal%2BOcean%2BPhysics%2BAnalysis%2Band%2BForecast%2Bupdated%2BDaily%26amp%3Bcrs%3DEPSG%253A32661%26amp%3BmapHeight%3D800%26amp%3BmapWidth%3D1024%26amp%3Bstyle%3Dboxfill%26amp%3BzUnits%3Dnull%26amp%3Bunits%3Dm%26amp%3BbaseUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BbaseLayers%3Dcls%253Anoaa_blue_marble_north_pole%26amp%3BoverlayUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BoverlayLayers%3Dcls%253Anoaa_blue_marble_north_pole_no_ocean&hash=7bccd8217f9a07e775d11f3dbff5c539)
So if this http://cci-reanalyzer.org/DailySummary/#T2 (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
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2Fs8VJD%2F185eadaeb7.jpg&hash=ab7f01c36e158df95e8926959bfa565c)
Maybe that's already happening
(https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticsssnowcast.gif)
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.
Title: Re: Importance of waves in the Arctic
Post by: johnm33 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 (https://www.youtube.com/watch?v=tDmM5zsxd4E)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on November 21, 2016, 12:05:38 PM
timallard posted this over at Area and Extent

See also http://forum.arctic-sea-ice.net/index.php/topic,1385.msg63897.html#msg63897 (http://forum.arctic-sea-ice.net/index.php/topic,1385.msg63897.html#msg63897) et seq.
Title: neXtWIM: Waves in a next-generation sea ice model
Post by: Jim Hunt 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 (https://www.nersc.no/project/nextwim):

Quote
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.
Title: Re: Importance of waves in the Arctic
Post by: johnm33 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 (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/ (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.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fcmems-view.cls.fr%2F%2FViewService%2Fscreenshots%2FcreateScreenshot%3Fdataset%3Dhttp%253A%252F%252Fnrtcmems.mercator-ocean.fr%252Fthredds%252Fwms%252Fglobal-analysis-forecast-phy-001-024%26amp%3BnumColorBands%3D20%26amp%3BlogScale%3Dfalse%26amp%3Bbbox%3D-1410644.53125%252C-480468.75%252C5410644.53125%252C4480468.75%26amp%3Babovemaxcolor%3D0x000000%26amp%3Bbelowmincolor%3D0x000000%26amp%3Bnodatacolor%3Dnull%26amp%3Blayer%3Dsiconc%26amp%3Btime%3D2016-11-26T12%25253A00%25253A00.000Z%26amp%3Bpalette%3Drainbow%26amp%3Bstyle%3Dboxfill%26amp%3BscaleRange%3D0%252C1.0000916%26amp%3BdisplayScaleRange%3D0%252C1.0000916%26amp%3Bopacity%3D1%26amp%3Bbbox%3D-1410644.53125%252C-480468.75%252C5410644.53125%252C4480468.75%26amp%3BlayerTitle%3Dsea_ice_area_fraction%252Cdaily%2Bmean%2Bfields%2Bfrom%2BGlobal%2BOcean%2BPhysics%2BAnalysis%2Band%2BForecast%2Bupdated%2BDaily%26amp%3Bcrs%3DEPSG%253A32661%26amp%3BmapHeight%3D800%26amp%3BmapWidth%3D1024%26amp%3Bstyle%3Dboxfill%26amp%3BzUnits%3Dnull%26amp%3Bunits%3D1%26amp%3BbaseUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BbaseLayers%3Dcls%253Anoaa_blue_marble_north_pole%26amp%3BoverlayUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BoverlayLayers%3Dcls%253Anoaa_blue_marble_north_pole_no_ocean&hash=6cc3001968712cc08cae6a50e91ded07)
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 (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)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on December 12, 2016, 01:49:57 PM
A special edition of the intriguingly titled open-access journal "Elementa (https://home.elementascience.org/about/about-us/): Science of the Anthropocene ":

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

Articles include:

Quote
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:

Quote
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.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on December 14, 2016, 03:28:27 PM
With a hat tip to DavidR:

http://youtu.be/qBjEwK3oJ_M (http://youtu.be/qBjEwK3oJ_M)

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

Quote
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/ (http://magicseaweed.com/news/massive-atlantic-wave-doesnt-set-record/9799/)
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on December 16, 2016, 12:53:34 AM
During the Fall 2016 AGU conference (http://greatwhitecon.info/2016/12/arctic-sea-ice-news-from-agu/#NICE2015) 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 (http://GreatWhiteCon.info/2015/07/rv-lance-encounters-another-energetic-wave-event-in-the-arctic/#comment-216687)
Title: Re: Importance of waves in the Arctic
Post by: johnm33 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
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FsRqd2%2F42379921ce.png&hash=55d889461f00beac3b27c23192c17eae)
from here http://marine.copernicus.eu/services-portfolio/access-to-products/ (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.
Title: Re: Importance of waves in the Arctic
Post by: Tor Bejnar on January 12, 2017, 02:40:27 PM
I came across this abstract:  Wind waves in arctic seas (http://elib.dlr.de/101342/) by Gemmrich, Johannes und Rogers, Erick und Thomson, Jim und Lehner, Susanne und Pleskachevsky, Andrey (2015)
Quote
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!
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on January 24, 2017, 04:25:32 PM
With a hat tip to Cate (http://forum.arctic-sea-ice.net/index.php/topic,1611.msg100347.html#msg100347), more from Thomson et al. on the Autumn 2015 voyage of R/V Sikuliaq (http://forum.arctic-sea-ice.net/index.php/topic,1385.0.html):

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

Quote
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.
Title: Re: Importance of waves in the Arctic
Post by: Cate on January 25, 2017, 12:14:49 AM
Jim, thank you for putting me in the right place. :D
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on March 26, 2017, 10:12:22 AM
A couple of papers from Pierre Rampal et al.:

neXtSIM: a new Lagrangian sea ice model (http://www.the-cryosphere.net/10/1055/2016/tc-10-1055-2016.pdf)

and currently under discussion:

Wave-ice interactions in the neXtSIM sea-ice model (http://www.the-cryosphere-discuss.net/tc-2017-24/)

Quote
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.
Title: Re: Importance of waves in the Arctic
Post by: DrTskoul on March 26, 2017, 12:49:39 PM
A couple of papers from Pierre Rampal et al.:

neXtSIM: a new Lagrangian sea ice model (http://www.the-cryosphere.net/10/1055/2016/tc-10-1055-2016.pdf)

and currently under discussion:

Wave-ice interactions in the neXtSIM sea-ice model (http://www.the-cryosphere-discuss.net/tc-2017-24/)

Quote
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.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on April 29, 2017, 12:29:03 AM
Possibly paywalled, but according to The Economist (http://www.economist.com/news/science-and-technology/21720608-russian-researchers-investigate-new-ways-make-waves-quickest-way-break):

Quote
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.

Title: Re: Importance of waves in the Arctic
Post by: gerontocrat on April 29, 2017, 11:04:05 AM
Possibly paywalled, but according to The Economist (http://www.economist.com/news/science-and-technology/21720608-russian-researchers-investigate-new-ways-make-waves-quickest-way-break):

Quote
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 !
Title: Re: Importance of waves in the Arctic
Post by: Shared Humanity on April 29, 2017, 06:24:07 PM
Possibly paywalled, but according to The Economist (http://www.economist.com/news/science-and-technology/21720608-russian-researchers-investigate-new-ways-make-waves-quickest-way-break):

Quote
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!
Title: Re: Importance of waves in the Arctic
Post by: Shared Humanity 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.
Title: Re: Importance of waves in the Arctic
Post by: johnm33 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
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fforum.arctic-sea-ice.net%2Findex.php%3Faction%3Ddlattach%3Btopic%3D1834.0%3Battach%3D45404&hash=77b5ab4aef1bf66fa366bf930969214e)
So I took a look at beaufort https://www7320.nrlssc.navy.mil/hycomARC/beaufort.html (https://www7320.nrlssc.navy.mil/hycomARC/beaufort.html)
(https://www7320.nrlssc.navy.mil/hycomARC/navo/beauforticen_nowcast_anim30d.gif)
* 85.3694_-149.4939_to_81.4305_-127.7995__16May2017.jpg
To me it looks like huge disturbances taking place at depth.
Title: Re: Importance of waves in the Arctic
Post by: johnm33 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
Title: Re: Importance of waves in the Arctic
Post by: Tor Bejnar on January 12, 2018, 01:58:04 PM
cross post:
More recent gfs runs don't have ptype mixing to rain as deep over the Arctic as subgeometer's attachment above. However, this cyclone looks like it's still going to be very deep and cause extreme issues for Fram ice due to wave action:
(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=2141.0;attach=95621;image)
Title: Re: Importance of waves in the Arctic
Post by: Neven on February 26, 2018, 08:18:49 PM
The Cryosphere (https://www.the-cryosphere.net/12/685/2018/):

Quote
Floe-size distributions in laboratory ice broken by waves

Received: 29 Aug 2017 – Discussion started: 11 Oct 2017
Revised: 10 Jan 2018 – Accepted: 26 Jan 2018 – Published: 26 Feb 2018

Abstract. This paper presents the analysis of floe-size distribution (FSD) data obtained in laboratory experiments of ice breaking by waves. The experiments, performed at the Large Ice Model Basin (LIMB) of the Hamburg Ship Model Basin (Hamburgische Schiffbau-Versuchsanstalt, HSVA), consisted of a number of tests in which an initially continuous, uniform ice sheet was broken by regular waves with prescribed characteristics. The floes' characteristics (surface area; minor and major axis, and orientation of equivalent ellipse) were obtained from digital images of the ice sheets after five tests. The analysis shows that although the floe sizes cover a wide range of values (up to 5 orders of magnitude in the case of floe surface area), their probability density functions (PDFs) do not have heavy tails, but exhibit a clear cut-off at large floe sizes. Moreover, the PDFs have a maximum that can be attributed to wave-induced flexural strain, producing preferred floe sizes. It is demonstrated that the observed FSD data can be described by theoretical PDFs expressed as a weighted sum of two components, a tapered power law and a Gaussian, reflecting multiple fracture mechanisms contributing to the FSD as it evolves in time. The results are discussed in the context of theoretical and numerical research on fragmentation of sea ice and other brittle materials.
Title: Re: Importance of waves in the Arctic
Post by: solartim27 on March 09, 2018, 06:57:41 PM
Pretty cool video of people rushing off the ice as waves come in to shore
https://boingboing.net/2018/03/09/wave-under-frozen-sea-breaks-u.html
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on July 01, 2018, 10:52:08 PM
(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=2278.0;attach=103758)
 animation courtesy of Aluminium, I've been looking at where the ice breaks, more or less where the shelf drops into the basin. To start with i was convinced that waves coming up from the atlantic, or from the south through barents were responsible, and their lack of penetration was due to them dropping off into the deep. I now wonder if long fetches over thin ice set up waves across the basins and when these reach the shelf they break up and cause the turbulence on the shelf. That would better explain the protection FJL seems to provide.
This (https://www.youtube.com/watch?v=zXZZJbGteWE) is an animation of an internal wave breaking against a shelf. This type of movement, less exagerated, may also be initiated whenever a particularly high or low mslp passes over the shelf or the lomonosov ridge. 
This (https://www.youtube.com/watch?v=U2lq8TpLqR4) is an animation of an internal wave breaking over a seamount, or ridge, and is a possible explanation for the break in the ice on the NSI side of the pole in the above animation.
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on July 04, 2018, 11:39:05 AM
(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=143.0;attach=103952)
Hyperion made this gif for stupid questions here it's to illustrate my point above. This (https://earth.nullschool.net/#2018/06/08/0000Z/wind/surface/level/overlay=mean_sea_level_pressure/orthographic=-149.97,87.17,512/loc=-158.551,76.380) is a link to nullschool june8, there's a huge low over Barents barely crossing Lomonosov, check the pressure over Beaufort/Barents then click through the days to see the low move over to Beaufort. The low represents a dome of water that doesn't move as fast as the low but approaches 40cm. difference in sea level. OK it has to be a fraction of that over the area of the low but 5cm? depth of an area the size of Greenland is a non trivial amount of water to shift over the ridge.
Title: Re: Importance of waves in the Arctic
Post by: Tor Bejnar on July 26, 2018, 09:29:14 PM
cross post from "Stupid Questions"
Seemed like it belongs here...
Hi JamesW, these questions are above my pay grade and perhaps should have been posted in the smart questions thread had such existed... but I just want to say welcome. The first post is always the hardest.

Thanks Oren for your reply. I have found this study on wave ice action concluded July 2016 by the American Meteorological Society (AMS) which is mainly studying wind/wave effects on ice August/September when the arctic has more open seas. Basically positive wind wave ice feedback action has not yet been quantified as yet fully it appears, although it is stated it should be so models in the future are portrayed more accurately. So renders my question a little in to the unknown, although this paper if anyone has a spare half an hour does give quite a bit of insight in to what is happening in the arctic regards climate change and its effects in the arctic on wave/wind ice action feedbacks changes during August/September....i.e. decadal averages increases/decreases in wave heights etc. which is helpful when looking at certain seas and why they are possibly changing faster than others during the melt season. Among all the other feedbacks changes etc etc...

For example 'The maximum positive trends of wave height (0.3–0.4 m decade−1) appeared in the Laptev Sea, followed by trends of ~0.3 m decade−1 north of the Alaskan coast. It also has tonnes of side data if anyone wants to delve deeper in to specific areas of the report as highlighted within it.

It has some very interesting points showing that wind/wave mechanical strain is enough to break iceshields of between 0.5 - 0.6m and then to propagate the ice quickly for melt. This would help realise ice thickness as it breaks up quickly would generally be less than 0.6m. So some simple and good information to gain among the more sophisticated areas of the report.

I hope this detail enlightens peoples knowledge a little to help understand more of how the chaotic system is altering.

I also thought this would be helpful as we are about to enter August where this report is relevant.

https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-16-0219.1


Title: Re: Importance of waves in the Arctic
Post by: johnm33 on August 24, 2018, 03:15:45 PM
I think it was looking at an early season animation of Beaufort that suddenly gave me the impression of the Amundsen gulf acting like a bellows. Possibly the driving force behind the gyre? Looking at the most recent ice concentration (https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/beauforticen_nowcast_anim30d.gif) from hycom there's a pulse that reaches north just west of 130lat that breaks up a large flow then peters out west of Prince Patrick Is. . Much more interesting is the lead opening (https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/beaufortopening_nowcast_anim30d.gif) gif where there are clear giant swells/internal waves radiating away from Amundsen like ripples in a pond.
This animation (https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=2278.0;attach=107065) of uniquorns shows the bellows effect is not just a surface phenomenon.
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on August 24, 2018, 03:21:26 PM
Any ideas at to what may have caused this?
(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/beaufortopening/nowcast/opening2018072512_2018072600_930_beaufortopening.001.gif)
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on September 01, 2018, 11:52:47 AM
So i saw an arc in the last frame of slow wing' animation, this shows it too.
(https://www.polarview.aq/images/27_AMSR2/latestN/arctico.gif)
It's harder to miss than see, but low left. It's point of origin seems to be shown here, just west of 150ww/78n, an upwelling, caused by earlier wave action, with already developed concentric rings/openings moving away among the chaos.
(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/beaufortopening/nowcast/opening2018082812_2018082900_930_beaufortopening.001.gif)
Looks like it's going to persist
(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/beaufortopening/nowcast/opening2018083012_2018090400_930_beaufortopening.001.gif)
I'm guessing that the waves generated here will sort the ice by size, pushing lighter fractions south in windrows between swells to melt, within the pack we have to wait and see just how deep the stirring goes.
Title: Re: Importance of waves in the Arctic
Post by: Phil. on September 01, 2018, 03:46:36 PM

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/beaufortopening/nowcast/opening2018082812_2018082900_930_beaufortopening.001.gif)
Looks like it's going to persist
(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/beaufortopening/nowcast/opening2018083012_2018090400_930_beaufortopening.001.gif)
I'm guessing that the waves generated here will sort the ice by size, pushing lighter fractions south in windrows between swells to melt, within the pack we have to wait and see just how deep the stirring goes.
[/quote]

The figures you've added don't show for me, perhaps site doesn't like gif?
Title: Re: Importance of waves in the Arctic
Post by: johnm33 on September 01, 2018, 04:48:05 PM
Phil, the images are from here https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/beaufort.html
  ice opening 29th and 4th
Title: Re: Importance of waves in the Arctic
Post by: Sleepy on November 19, 2018, 08:36:44 AM
A new satellite wave product from the Sentinel 1-A and 1-B Synthetic Aperture Radar (SAR) instrument. This product is part of a long series of wave products that began with April 2017 with wave product based on wave models, and was followed by a wave product based on Sentinel-3 satellite altimetry in July 2017.

http://marine.copernicus.eu/services-portfolio/access-to-products/?option=com_csw&view=details&product_id=WAVE_GLO_WAV_L3_SPC_NRT_OBSERVATIONS_014_002 (http://marine.copernicus.eu/services-portfolio/access-to-products/?option=com_csw&view=details&product_id=WAVE_GLO_WAV_L3_SPC_NRT_OBSERVATIONS_014_002)

https://youtu.be/po7TDTmaQMA

Title: Re: Importance of waves in the Arctic
Post by: Glenn_Tamblyn on July 01, 2019, 07:56:06 AM
Rich

I don't know if you are familiar with Stokes Drift. This is essentially about how much water is moved horizontally by waves. A wave at the ocean surface is a vertical disturbance that then moves horizontally through the water rather than a disturbance that moves water horizontally. This article at Wikipedia has a discussion on it including this animation that is worth looking at.

https://en.wikipedia.org/wiki/Stokes_drift (https://en.wikipedia.org/wiki/Stokes_drift)

(https://upload.wikimedia.org/wikipedia/commons/4/4a/Deep_water_wave.gif)

The upshot is that the speed of the wave doesn't match the speed with which water is transported in the direction of the wave. So can waves propagate significant distances and reach and go under the ice. Yes. But it doesn't follow that warm water from a distance away will reach that far just as quickly.

So any waves would me a mechanical action on the ice based on the temperature/salinity of the local water. Any impact from the arrival of warmer water driven by this wave action will be a long way behind that.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 01, 2019, 09:38:37 AM
Rich

Compare and contrast past and present views from the Utqiaġvik "surf cam":

http://GreatWhiteCon.info/2015/08/barrow-battered-by-big-waves/

Sea ice in the Chukchi Sea (or what's left of it) is damaged by significant swells in the Chukchi Sea, not by huge swells in the North Pacific.
Title: Re: Importance of waves in the Arctic
Post by: Rich on July 01, 2019, 09:44:58 AM
Rich

I don't know if you are familiar with Stokes Drift. This is essentially about how much water is moved horizontally by waves. A wave at the ocean surface is a vertical disturbance that then moves horizontally through the water rather than a disturbance that moves water horizontally. This article at Wikipedia has a discussion on it including this animation that is worth looking at.

https://en.wikipedia.org/wiki/Stokes_drift (https://en.wikipedia.org/wiki/Stokes_drift)

(https://upload.wikimedia.org/wikipedia/commons/4/4a/Deep_water_wave.gif)

The upshot is that the speed of the wave doesn't match the speed with which water is transported in the direction of the wave. So can waves propagate significant distances and reach and go under the ice. Yes. But it doesn't follow that warm water from a distance away will reach that far just as quickly.

So any waves would me a mechanical action on the ice based on the temperature/salinity of the local water. Any impact from the arrival of warmer water driven by this wave action will be a long way behind that.

I believe I comprehend what what you are saying and it would make a lot of sense if the water currently at the ice front was cold while the water coming in through the Strait was warm.

But that's not the case.

The water is already warm at the ice front in the Chuchki. To the extent that a wave of warm water is propelling itself through the Strait, it pushing a different body of equally warm water at the other end.

The other, and completely different argument is the property of the wave. I'll save that for now.
Title: Re: Importance of waves in the Arctic
Post by: Rich on July 01, 2019, 09:55:57 AM
Rich

Compare and contrast past and present views from the Utqiaġvik "surf cam":

http://GreatWhiteCon.info/2015/08/barrow-battered-by-big-waves/

Sea ice in the Chukchi Sea (or what's left of it) is damaged by significant swells in the Chukchi Sea, not by huge swells in the North Pacific.

Hi Jim,

With all due respect, what's happening in Utqiagvik at the moment isn't a barometer for what's going on where the action is at in the Chuchki.

Once entering the Arctic, any incoming water is subjected to 15 knot winds pushing from the Beaufort toward the ESS. The action is at the ocean / ice interface in the Chuchki and unfortunately we don't have a webcam there.

I'm not so stupid as to think N. Pacific swells are impacting Arctic ice LOL.

We've got 1.3m swells reported thus far at the ice front in the Chuchki.

It's a nice view from that webcam you're showing... but how is it relevant?
Title: Re: Importance of waves in the Arctic
Post by: Glenn_Tamblyn on July 01, 2019, 10:15:11 AM
Rich

My point would be that warm water and waves certainly could have a significant impact at the ice edge in the Chukchi - warm waves splashing over or breaking it up. But propagation of this effect further into the ice pack will be limited by the speed of bulk movement of the water. Waves could break the pack up for many more kms in from the edge, but the water under that ice will not yet be warm, so the impact will be more limited until water temperature can increase due to slower bulk transport.

A perhaps significant effect that waves might propagate under the pack might be the break up of the halocline. The circular vertical movement waves produce might mix the fresher water directly under the ice with saltier water from below. Just increasing the salinity of the water in direct contact with the ice, lowering the freezing point, would have the same impact as a temperature increase of a degree or two.
Title: Re: Importance of waves in the Arctic
Post by: Neven on July 01, 2019, 11:24:19 AM
Post by Rich in the wrong thread:


Those winds/swells are weak suace.  We have seen wind fetches 2000 miles+ long with 25-45 KT winds 500 miles wide slam into the ice for days coming through the North Atlantic.

We have seen this actually set up with a near straight path from the Norwegian Seas to Svalbard come for a couple days in a row with swells 2-3X the height of those you are talking about.


Just out of curiosity Friv. In the historical examples you are citing, what was the temperature of the water?

I confess here that my case is resting on extremely shaky grounds, but I'm not letting my client get convicted so long as I can preserve a thread of reasonable doubt.

At this point, I'm left with the theory that the warm fresh water adjacent to the Chuchki ice front will not sink to the extent that it is able to make it beyond the ice barrier / wall in front of it. This would IMO be the least dense water around.

I'm certainly not claiming that this is the most substantial wind driven water movement in Arctic history.

One way to learn is through the process of elimination. I've floated up a straw man and everyone has stepped up to volunteer to knock it down.

The last leg my straw man has to stand on is that it is differentiated from the previous events you are describing because the water being forced into the gaps on the other side of the ice wall wouldn't sink. It could just fill in the gaps above the existing water line.

If you kill my argument I still win by learning.
Title: Re: Importance of waves in the Arctic
Post by: KiwiGriff on July 01, 2019, 11:37:48 AM
Quote
A perhaps significant effect that waves might propagate under the pack might be the break up of the halocline. The circular vertical movement waves produce might mix the fresher water directly under the ice with saltier water from below. Just increasing the salinity of the water in direct contact with the ice, lowering the freezing point, would have the same impact as a temperature increase of a degree or two.
I had the same thought.
What is the temperature and salinity profile of the ocean under the ice?
I would guess that the surface would be both less salty and cooler than the deeper ocean water below at this time of the year.
A swell could result in significant mixing of the surface layer with the deeper water .
 
Title: Re: Importance of waves in the Arctic
Post by: oren on July 01, 2019, 12:13:35 PM
At this point, I'm left with the theory that the warm fresh water adjacent to the Chuchki ice front will not sink to the extent that it is able to make it beyond the ice barrier / wall in front of it. This would IMO be the least dense water around.
...
The last leg my straw man has to stand on is that it is differentiated from the previous events you are describing because the water being forced into the gaps on the other side of the ice wall wouldn't sink. It could just fill in the gaps above the existing water line.
There is no ice barrier or ice wall in the Chukchi. The ice is mobile and free to move away with the current and the wind, and the water cannot be forced onto it (unless it is splashed from tall waves onto the very edge of a floe). Only when the ice is piled up against the coast or a large island will you get a sort of "ice barrier", and even then it will be ice deforming and piling on ice, not water piling on ice.
I repeat, Miami intuition does not transfer well to the Arctic.
Title: Re: Importance of waves in the Arctic
Post by: Neven on July 01, 2019, 01:53:22 PM
Post by friv in the wrong thread:

I totally agree with you Sterks on the effect of warm water, though i still don't fully understand how it has such a striking effect in august but is lacking now when it has most insolation and already high temps against fragmented places like beaufort.

The ice is a lot thicker right now. 


Quote
I think there’s being massive transport of warm water but underneath of the ice.


That's not happening we have Obuoys, itps, whatever else they call them prove otherwise.

We have an extensive data record with hundreds of buoys, maybe thousands going back decades showing this is not the case.


As you know anywhere there is decently concentrated sea ice thee is a fresh water cold layer on average 40-60 meters thick.

Our bouts and moorings show there is no warm current or nearby warm ssts that ever penetrate this.

We have data from buoys that were near the ice edge in 30-50 percent concentration ice and the cold fresh water layer was never disrupted by nearby near surface. 


The main warm intrusion in 98-99% of cases was from solar insolation. 

One solar insolation start accumulating in that cold freshwater layer it will penetrate pretty deep into it sometimes touching any possible want layer below especially in the Bufort area where there is a Pacific warm layer below.

However that pacific warm layer isnt coming from near the ice.

just water probably dives down underneath the cold fresh water during the fall or winter through the Bering strait.


And I guess the nation roughly 1% of the time that warm water penetrates the cold freshwater layer at the surface it's from ekman pumping. 

When's disrupting the cold freshwater layer I'm guessing through some sort of overturning or torque mechanism.

In fact this process can happen pretty much anytime of the year but it usually happens in August or September.


Another potential way warm water underneath the cold freshwater layer to mix with it could happen if wind or strong enough and can dig deep enough into the upper ocean water layers that water is pushed in a certain way against another parallel or perpendicular current black causes mixing and the water to rise to the surface.

I have attached some images the first Bouy was deployed in 2006 over the north central Beaufort.

it's basically barely moved from the fall of 2006 until mid-summer 2007 when it started to take the drive towards the fram.

but what's remarkable is when it was in the Beaufort and the far Western cab. 

you can see there is a very warm water layer not far below the surface really directly below the fresh cold water pool near the surface.

And we can also see that the warm water layer had essentially no interaction with the surface.

even when the surface started to accumulate a massive amount of heat.

It still didn't push really any mixing with that warm layer.

And as you can see once the melt season ended.  All of that heat from the summer quickly vanished.

I attached another example of this that took place from fall 2007 though 2008.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 01, 2019, 02:04:57 PM
Hi Jim,

With all due respect, what's happening in Utqiagvik at the moment isn't a barometer for what's going on where the action is at in the Chuchki.

Hi Rich,

With all due respect, with his permission I'll quote Neven in another place (https://forum.arctic-sea-ice.net/index.php/topic,2591.msg209712.html#msg209712):

Quote
Announce the prediction, preferably with graphs/maps/other images, and then wait how it plays out, post animations or whatever to show how the surge affected the ice, beyond what would normally be expected.

I'm currently on the train to London without easy access to Worldview/Sentinel Playground etc.

I'll leave all that to you shall I?
Title: Re: Importance of waves in the Arctic
Post by: Rich on July 01, 2019, 02:32:57 PM
Hi Jim,

With all due respect, what's happening in Utqiagvik at the moment isn't a barometer for what's going on where the action is at in the Chuchki.

Hi Rich,

With all due respect, with his permission I'll quote Neven in another place (https://forum.arctic-sea-ice.net/index.php/topic,2591.msg209712.html#msg209712):

Quote
Announce the prediction, preferably with graphs/maps/other images, and then wait how it plays out, post animations or whatever to show how the surge affected the ice, beyond what would normally be expected.

I'm currently on the train to London without easy access to Worldview/Sentinel Playground etc.

I'll leave all that to you shall I?

With all due respect Jim, I can't begin to understand what you are trying to say with this post.

Title: Re: Importance of waves in the Arctic
Post by: be cause on July 01, 2019, 02:49:28 PM
^^ .. sounds like do your homework .. and report back .. :) b.c.
Title: Re: Importance of waves in the Arctic
Post by: Sterks on July 01, 2019, 02:58:20 PM
Post by friv in the wrong thread:

I totally agree with you Sterks on the effect of warm water, though i still don't fully understand how it has such a striking effect in august but is lacking now when it has most insolation and already high temps against fragmented places like beaufort.

The ice is a lot thicker right now. 


Quote
I think there’s being massive transport of warm water but underneath of the ice.


That's not happening we have Obuoys, itps, whatever else they call them prove otherwise.

We have an extensive data record with hundreds of buoys, maybe thousands going back decades showing this is not the case.


As you know anywhere there is decently concentrated sea ice thee is a fresh water cold layer on average 40-60 meters thick.

Our bouts and moorings show there is no warm current or nearby warm ssts that ever penetrate this.

We have data from buoys that were near the ice edge in 30-50 percent concentration ice and the cold fresh water layer was never disrupted by nearby near surface. 


The main warm intrusion in 98-99% of cases was from solar insolation. 

One solar insolation start accumulating in that cold freshwater layer it will penetrate pretty deep into it sometimes touching any possible want layer below especially in the Bufort area where there is a Pacific warm layer below.

However that pacific warm layer isnt coming from near the ice.

just water probably dives down underneath the cold fresh water during the fall or winter through the Bering strait.


And I guess the nation roughly 1% of the time that warm water penetrates the cold freshwater layer at the surface it's from ekman pumping. 

When's disrupting the cold freshwater layer I'm guessing through some sort of overturning or torque mechanism.

In fact this process can happen pretty much anytime of the year but it usually happens in August or September.


Another potential way warm water underneath the cold freshwater layer to mix with it could happen if wind or strong enough and can dig deep enough into the upper ocean water layers that water is pushed in a certain way against another parallel or perpendicular current black causes mixing and the water to rise to the surface.

I have attached some images the first Bouy was deployed in 2006 over the north central Beaufort.

it's basically barely moved from the fall of 2006 until mid-summer 2007 when it started to take the drive towards the fram.

but what's remarkable is when it was in the Beaufort and the far Western cab. 

you can see there is a very warm water layer not far below the surface really directly below the fresh cold water pool near the surface.

And we can also see that the warm water layer had essentially no interaction with the surface.

even when the surface started to accumulate a massive amount of heat.

It still didn't push really any mixing with that warm layer.

And as you can see once the melt season ended.  All of that heat from the summer quickly vanished.

I attached another example of this that took place from fall 2007 though 2008.
Wow thanks Neven for not keeping my post which was in the middle and to which Friv was responding, shows quite delicate use of the scissors from your side. Hey safety first, don’t cut yourself.

<edit Neven: Yes, sorry I had to make you the sacrificial lamb, and even more sorry that it didn't work.
edit: Mr. Sterk: Sure I understand, it's no big deal, apologies for being an ass about it>

I think Friv is right. I was thinking more of an abundance of warm water reaching the edge and mixing to some extent with colder water (we have seen those swirling structures for years in Chukchi ice edge). Then this can get underneath the very edge or the swirling floes. But yeah what happens with the bulk of the Bering inflow is not a simplistic creeping right under the ice.
Title: Re: Importance of waves in the Arctic
Post by: Rich on July 01, 2019, 03:11:18 PM
^^ .. sounds like do your homework .. and report back .. :) b.c.

Would you like to suggest the Google search terms for my homework project?

I will be mightily surprised if anyone has tackled this question with enough specificity to yield the correct answer.

As Neven directed, I took the question out of the melting season thread. At this point, you're just stalking me. You"re not adding any value to the discussion. If you don't like it...ignore it.
Title: Re: Importance of waves in the Arctic
Post by: Jim Hunt on July 01, 2019, 03:27:37 PM
Hi Rich,

My train has been invaded by hordes of Glasto goers!

How about "waves in ice" and/or "Arctic storm surge"?
Title: Re: Importance of waves in the Arctic
Post by: Rich on July 01, 2019, 03:38:05 PM
Hi Rich,

My train has been invaded by hordes of Glasto goers!

How about "waves in ice" and/or "Arctic storm surge"?

My question is very specific Jim.

If the fresh warm water sitting at the edge of the Chuchki ocean ice interface is pushed further east in any meaningful volume, will the incoming water be dense enough to force water underneath the ice that's currently floating in the ice pack??

There's no realistic expectations that I'm going to find the answer to that specific question via a Google search.
Title: Re: Importance of waves in the Arctic
Post by: Sterks on July 01, 2019, 04:10:12 PM
Hi Rich,

My train has been invaded by hordes of Glasto goers!

How about "waves in ice" and/or "Arctic storm surge"?

My question is very specific Jim.

If the fresh warm water sitting at the edge of the Chuchki ocean ice interface is pushed further east in any meaningful volume, will the incoming water be dense enough to force water underneath the ice that's currently floating in the ice pack??

There's no realistic expectations that I'm going to find the answer to that specific question via a Google search.
I think there is some mixing between the incoming Bering water and the ice edge water, and ice melt is accelerated around the pathways coming from Bering, you can see these fingers forming right now, and I have seen them every year. Ice stays for longer on top of the shoals (elevations of the shelf bathymetry) because currents are forced to surround these shoals by Coriolis.

So it is clear a pulse of Pacific water affects directly the water under the ice edge as long as the ice edge lies over the shelf (low depth)
Once we reach the shelf break and depths go from 50 m to ~ thousands of meters, the Chukchi currents are free to sink and there is less interaction with the ice edge.
That’s how I see it.
But this has nothing with waves, by the way, it is Bering inflow-ice edge interaction.
Title: Re: Importance of waves in the Arctic
Post by: Neven on July 01, 2019, 04:28:54 PM
My question is very specific Jim.

If the fresh warm water sitting at the edge of the Chuchki ocean ice interface is pushed further east in any meaningful volume, will the incoming water be dense enough to force water underneath the ice that's currently floating in the ice pack??

There's no realistic expectations that I'm going to find the answer to that specific question via a Google search.

How about you wait and see what happens, and if you see evidence for whatever it is you think will happen, you post it here? That is what Jim and I are alluding to. It would make this exercise a whole lot less useless for everyone involved.
Title: Re: Importance of waves in the Arctic
Post by: FishOutofWater on July 03, 2019, 03:43:08 PM
Rich, you can see Mercator's animations of the warming waters on the Alaskan side of the Arctic. There is nothing to see this time of year below 30m on these animations relevant to Bering Pacific water inflow.

The Coriolis effect directs Pacific water into the Alaska coastal current which wraps around point Barrow. Eddies, subsea topography and islands cause some mixing of waters.

http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20190501/20190702/1/1

http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20190501/20190702/1/2

http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20190501/20190702/2/1

http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20190501/20190702/2/2
Title: Re: Importance of waves in the Arctic
Post by: Bruce Steele on July 03, 2019, 08:14:31 PM
Fish, I don't understand what you mean" nothing to see below 30 meters."  Mercator does show warm water with increased salinity moving north through the Berring Strait around either side of the Hanna Shoals and up to the edge of the basin where it sinks and disappears from the 30 meter contour.  The Mercator model isn't showing the same temperature increase that the ITP 110 buoy is showing with surface temps at 6 meters between -.6 and -.8 .  The ITP 110 also showed some heat increases in the Pacific warm water layer. 
 I have to believe the bouy data over the model runs but maybe I am missing something ?