The Nares Strait thread

[blumenkraft]

Coldest New Years Eve Cold Temperature North Pole in Meteorological history, since 1948

December 31 2019,  with Polar Vortex off center weighted temperature measuring -48 C CTNP over Ellesmere Island, the coldest such air ever measured for this date,  surpassing all others by 4 degrees C (1948-2018).

Link >> https://eh2r.blogspot.com/2020/01/coldest-new-years-eve-cold-temperature.html

[blumenkraft]

Looks like the lower part of the Kennedy channel just became static as well.

There is still tidal movement around the arch in Lincoln and northern Kennedy.

[blumenkraft]

Confirmed!

Today's DMI shots haven't arrived yet, so include them next Sunday.

Here are last weeks Lincoln, Kennedy, and Kane DMI crops via SAR. Click to play.

[blumenkraft]

It's now frozen up also in the upper Kennedy including the northern arch. Complete standstill!

[blumenkraft]

The 7-day hindsight mean temps (anomalies) might explain the complete freeze.

[blumenkraft]

I'm a little concerned now if ITP116 might overshoot and end up in Alaska someday... 

[uniquorn]

arch looking solid today.  https://go.nasa.gov/2QYWQx9  jan5-9

[uniquorn]

just a flesh wound

[blumenkraft]

Was very windy yesterday.

15° @ 15 m/s

[uniquorn]

Small movement in the Lincoln Sea.

[blumenkraft]

I never posted the DMI Sunday movies, since i thought nothing happened. But Uniquorn made me do at least Lincoln. Still kinda interesting.

Click to play.

[uniquorn]

Full moon march 9th. A tiny chip off the west side
https://col.st/uJMHJ  mar9-10

[blumenkraft]

First Sentinel 2 pictures are coming in and they already deliver a surprise.

There is a polynya in the northern Kane Basin.

[Niall Dollard]

It is about 3 or 4 km² in size. So quite small.

[Niall Dollard]

A "greenstick" fracture on the western side on 23rd March.

[uniquorn]

Looking back, a few small sections of younger ice have broken off since the 16th.
https://go.nasa.gov/2JhllSO

[blumenkraft]

That's the wrong way, buddy! We like you anyway, ITP116.

[tybeedave]

blumenkraft, uniquorn, and Niall,

Does it appear to you, as it does to me, that the bridge seems to be breaking up?

td

[Niall Dollard]

I dont think so td.

This would be about 3 months too early.

Just below the main arch, new ice can form over the open sea from time to time dependent on wind, tides and current. But usually this new ice does not last for long and breaks away southward.

Sometimes too the new ice, where it is adhered to the older ice, can bring away small pieces of the older original ice arch with it.

But typically most of the arch remains until early summer.

Having said all this, we do have to remember that old rules increasingly may no longer apply, which makes the Nares a fascinating area to watch. 

[blumenkraft]

blumenkraft, uniquorn, and Niall,

Does it appear to you, as it does to me, that the bridge seems to be breaking up?

td

I would say it's rather unlikely at this point. The region was colder than average throughout winter. I suspect the arch and the ice behind it to be rather thick.

That said, the current coming down from the Lincoln Sea seems strong. There could be warm Atlantic water involved thinning the ice from below. But those are unknowns. We don't have data on these variables.

I'm with Niall on this, just watch and enjoy.

[tybeedave]

aye aye mates, I tend to take liberal stances, the advice to wait and enjoy seems the most prudent.  But I will offer my reasoning.  !st, it looks to me like leads are developing almost along the whole length.  Maybe I'm only seeing what I want to see, so that observation is on shaky ground, however,
Pulses of warm water have entered the Arctic from the Atlantic and especially through the Bering st from the Pacific. The pulsating turbulence caused by a melt as is evident by the polynyas in the Chuchi Sea, I documented this with an image in one of my 1st posts on the Melt thread. They and most other polynyas are formed by turbulence.  water at -1.8C will melt ice if there is enough energy in the chaotic movements at the surface.  It is true that the air was cold, but doesn't ice have an insolating effect on its own further growth?   Even now, with a still intact bridge, there is a strong current under the bridge with its attendant turbulence and  winter-long melt from underneath.  the pulse thru the Bering pushed much more water into the CAB than normal and its exit was somewhat blocked by the near jam of ice in the Fram.  The result was a higher than normal tide at Nares running at higher than normal speed a few days after this pulse.  and the entire pack could have been lifted and cracked by the wave from the Pacific.
just my thoughts
I cite nothing but the images I have seen recently in Worldview and here and a bit about fluid dynamics and heat exchange that I learned thru my experience on the ocean

so, i watch and will be amazed, whether my guesses are right or wrong.

thanks for the replies, this thread is what originally hooked me on ASIf.  I reserve the right to change my mind about the bridge as new data becomes available

td

[blumenkraft]

Be sure to also check out Sentinel 2, Dave.

https://apps.sentinel-hub.com/sentinel-playground/?source=S2&lat=78.99959151488052&lng=-72.76313781738281&zoom=10&preset=CUSTOM&layers=B01,B02,B03&maxcc=100&gain=0.1&gamma=6.3&time=2019-09-01%7C2020-03-27&atmFilter=&showDates=true&evalscript=cmV0dXJuIFtCOEEqMSxCMDMqMSxCMDIqMV0%3D

[oren]

On Sentinel 2 (thanks BL) the bridge looks quite intact and strong, except for that recently lost piece of on the left bottom side, which could cause some trouble later down the road. It broke cleanly but its absence makes the structure less ideal for resistance to pressure.

[tybeedave]

bk and oren,

I sit corrected. What I saw musta been clouds, as I said, it was shaky, but I stand by my statement as to turbulence and melt from underneath creating an environment for it just washing away by April 30th. The rise in water level in Nares due to the pulse from the Pacific around Mar 24th was of course, just an opinion based on my common-sense assumption that when water levels rise, it seeks outlet via any means possible.  So, i see the entire bridge having been raised and lowered a few feet causing the ice to crack.  Using the term 'leads' was wrong, i was thinking cracks.

 Though it is holding firm currently, I hope that the CAA isn't the arctic's version of Custer's Last Stand.

td

[blumenkraft]

Dave, ice is unbelievably flexible. It may rise and move back without cracking depending on thickness. If it's thin, it would crack very easily, but here we might have multiple meters of thickness where it's landfast.

You are right about warm water influx (how else would there be a polynya in the northern Kane Basin, right?). We just can't say where the heat is coming from and where it's going. You can see a sink where the arch is at the moment. I think this goes along with turbulences.



BTW, here is a site showing the tides.

This is for the northern Nares >> https://www.tide-forecast.com/locations/Alert-Nunavut/tides/latest

And here for the south >>https://www.tide-forecast.com/locations/Payer-Harbour-Cape-Sabine-Ellesmere-Island-Nunavut/tides/latest

[tybeedave]

ty for the links blumenkraft, they are bookmarked

I have wondered what kind of tides occur in the Nares.  I thought the height would be higher in the north.  In the south, the range is just a bit less than the ave 6 ft range we experience here in coastal Ga. and is more in line with my expectations.

I know that ice can bend without cracking.  I hope it knows how to be flexible in the coming weeks.

td

[Andreas Muenchow]

The 2019 peer-reviewed publication entitled "Propagation and Vertical Structure of the Tidal Flow in Nares Strait" is open-access at

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JC014122

while non-peer reviewed data (1881 through 2012) and my interpretation of them can be accessed at

https://icyseas.org/tag/tides/

Enjoy and stay healthy ;-)

[Tor Bejnar]

In 1887 a computers was a man hired to crunch numbers with pen and paper.

Ghosts of Discovery Harbor: Digging for Data
Posted on February 11, 2016 by Andreas Muenchow | 3 comments

For a 'more recent' (1920's) description of a computer, read about Nevil Shute's Slide Rule: Autobiography of an Engineer or read the book (in PDF form).

[blumenkraft]

Enjoy and stay healthy ;-)

Thank you, Andreas. You stay healthy too, please. I want to read some more of your great work.

While you are here, let me ask you something. From observation, i've found that ice floes moving south in NS are bound to Ellesmere island. When the current is northwards, the floes are bound to the Greenland side. Can you comment on that? Are you aware of any research done on this topic?

[Andreas Muenchow]

From observation, i've found that ice floes moving south in NS are bound to Ellesmere island. When the current is northwards, the floes are bound to the Greenland side. Can you comment on that?

Excellent observation and the answer goes back to a Norwegian oceanographer Ekman:

In 1905 or so he computed that in the ocean a balance of forces between friction (imposed by the winds) and the Coriolis force results in a flow at the surface (where it moves ice) that is 45 degrees to the right of the wind. As one goes down into the water column, the currents become weaker and change their direction in a clockwise sense. Adding up all these different currents over the top 10-30 meters or so, Ekman (1905) found that the vertically averaged flow is to the right of the wind. In Nares Strait this means that winds from the south move the ice to the east and pile it up off Greenland. The winds (and currents) are mostly from the north in Nares Strait, so this would pile up ice off Ellesmere Island.

All physics is fun and the above argument also explains the fog in San Francisco or, as Mark Twain is said to once said, "The coldest winter I ever spent was a summer in San Francisco." Winds from the South North along the California coastline move surface waters offshore. This surface water is replaced along the coast by much colder waters below the surface. This "upwelling" also is the reason for the great fishing industries that these physics supported - think Cannery Row by Steinbeck.

EDIT: Confused South and North off California, silly me.

[blumenkraft]

OMG, so i'm not crazy! 

Thank you so much for your answer, Andreas! I was thinking it has to do with Coriolis force. It's great to have that confirmation.

Also, great Mark Twain trivia.

[uniquorn]

kane basin arch, mar19-apr6   https://go.nasa.gov/3dUa8FP

[tybeedave]

ty uniquorn for another cool movie,

One thing that I see is very cold air from the north constantly creating new ice which constantly gets swept away by upwelling warm turbulence in the Kane Basin.   I still feel there is a high probability that the bridge will disintegrate by month's end, but what do i know?

td

[oren]

td, bear in mind the process you describe is not unique to this year. This is the mechanism that keeps the North Water Polynya from freezing over. And while the race to guess the Nares breakup is always on early, and no one can know the outcome with certainty, statistics say that a stable southern arch that's been there all winter will strongly resist breakup before June.

From Wikipedia:

The North Water Polynya (Saqvaaq) is closely connected to Lancaster Sound and Baffin Bay by a powerful system of ocean currents that directly affect the region's climate and biology. In a sense the NOW polynya is a result of the merging of three smaller polynya's Smith Sound, Lady Ann Strait, and Lancaster Sound. The West Greenland Current follows that country's coastline and moves warm and salty Atlantic water north, reaching all the way to the North Water Polynya. An upwelling of warmer water in this polynya helps keep it partially ice-free throughout the year, even when the ocean directly north and south is frozen. Another arm of the West Greenland Current reaches into Lancaster Sound, delivering Atlantic waters into the Arctic Ocean and contributing to that area's rich ecology.

[Niall Dollard]

Thanks Oren.

And sometimes too a second arch can form across the polynya, like in spring 2018.

Although time is against that happening this year. But you never know.

Attached image from 20 April 2018, shows 1st and 2nd arch below it.

[blumenkraft]

... a second arch can form ...

[uniquorn]

https://go.nasa.gov/2xdL7oD  kane basin arch, apr7 and 12.
The piece by piece erosion slowly approaching the weaker spot to the north west

[blumenkraft]

Day&Night band NASA Worldview movie.

21.03. to 20.04.

[uniquorn]

Some discussion about 'greying' on the melting thread.
https://go.nasa.gov/3eTnW3C, heavy contrast
ImageJ, contrast minimum115, clahe 127,256,3.1

[blumenkraft]

Re: Greying

Kane Basin on the left, Humbold Glacier upper right.

[uniquorn]

https://go.nasa.gov/2Su36hU  may1 or 2, 2000-2020

[bluice]

Windy predicts 20-30 kt winds blowing south west along the basin until Friday noonish.

[blumenkraft]

Something-something melt in Kane basin.

I don't know how to interpret this exactly.

It might be its surface melt due to sunlight, temperatures are below freezing still (-10 ˚C on 14th).

Or it's that the warm water from below has an effect.

Or both.

[gerontocrat]

http://ocean.dmi.dk/arctic/image_container.php

Kane 15th May - a nice clear image

[blumenkraft]

There is another polynya in the northern Kane Basin (bottom right) around some grounded icebergs. Here the water is quite shallow.

Fist signs of melting here on 10.04.

[blumenkraft]

And another one, north of the big one. This one started developing at 02.05.

[uniquorn]

I missed this little break off on may15

[blumenkraft]

Just an iceberg in the Kane basin calving.

I found it to be cute, that's all.

[paolo]

But this is interesting:
the small iceberg, which broke off, turned over, the height being greater than the width, and gave a blow to the big one, which retreated...

EDIT: It's a textbook case, here there were no other actors to interfere, he did it on his own.

[uniquorn]

Ice thinning over a potential small polynya close to land west of the arch.
On May22 2016 a similar polynya didn't affect the arch until June6 2016. This year the arch is much closer.