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Author Topic: The Nares Strait thread  (Read 980619 times)

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1400 on: February 04, 2019, 10:09:10 AM »
"Big chunk" bounced back again today while ice in Hall Basin keeps flowing.

I have the impression it's bouncing against the rock there - for the second time now.

uniquorn

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Re: The Nares Strait thread
« Reply #1401 on: February 04, 2019, 02:32:38 PM »
Probably not bouncing as all the 'loose' ice in the Lincoln sea moves north from feb3 to feb4.
Interesting that the fast ice in the strait is disturbed in two places near to large slow moving floes.

edit: Perhaps being affected by weather further north (second image) and west, though it is too cloudy to see much.

added ascat, jan14-feb3.
« Last Edit: February 04, 2019, 10:03:34 PM by uniquorn »

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1402 on: February 06, 2019, 05:37:39 AM »
Big chunk stuck! No movement since yesterday.

Data: Brightness Temperature (Band 31-Night) Terra / MODIS
Left hand: 06.02. right hand: 05.02

Niall Dollard

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Re: The Nares Strait thread
« Reply #1403 on: February 06, 2019, 10:32:49 AM »
And motion downstream in the Kane Basin was very slow yesterday. We may not be far now from full blockage.

uniquorn

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Re: The Nares Strait thread
« Reply #1404 on: February 06, 2019, 01:56:46 PM »
A second opinion from worldview,viirs,bt15,night, feb5-6. Probably some serious grinding. Are there any sound recordings from the Nares Strait?
Close up courtesy of polarview, feb5

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1405 on: February 06, 2019, 02:07:51 PM »
Haha, sound recordings!  ;D

I would love to see that in real...

Though one standing on the cliff looking down the strait there wouldn't necessarily see the fractures the satellites are able to see i guess.

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1406 on: February 06, 2019, 02:14:52 PM »
Could be Terra / MODIS flew over the place late 05.02 and early 06.02. so that both shots are close together whereas the shots of the other satellites have a longer time span between two shots. A bummer the shots are not timestamped.

gerontocrat

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Re: The Nares Strait thread
« Reply #1407 on: February 06, 2019, 03:46:56 PM »
A second opinion from worldview,viirs,bt15,night, feb5-6. Probably some serious grinding. Are there any sound recordings from the Nares Strait?
Close up courtesy of polarview, feb5
On the one hand the perfect shape from image 1 to get stuck as the strait narrows,
and on the other hand from image 2- close up looks like it will fall apart when it does get squashed in the narrows.

So I am going for disintegration by the weekend.
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1408 on: February 06, 2019, 04:53:22 PM »
I second that opinion, gerontocrat.  My observation, over several years, is that arches form because south winds stop the flow of ice, not because large floes get stuck.  With generally thinner floes today than in previous decades, I suspect this to be more true today than yesteryear.
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Niall Dollard

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Re: The Nares Strait thread
« Reply #1409 on: February 06, 2019, 09:02:07 PM »
Here we go Tor.

By next Saturday most models are forecasting southerlies in the Nares.

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1410 on: February 07, 2019, 04:22:47 PM »
Big Chunk broke in two pieces and is now in hight of Petermann.

Goodbye Big Chunk. Was a hell of a ride with you.  ;D

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Re: The Nares Strait thread
« Reply #1411 on: February 08, 2019, 09:24:00 PM »
It's 4 years today since I wrote that this was quietly becoming one of the most interesting threads on the planet. It wasn't long before I saw Neven using the same words in his blog . This year is interesting again .. the cold is not stopping things in Nares .. the last 2 days suggest it will be hard to do so .. of course .. having said this , it could well freeze over tomorrow :) .. b.c.
Conflict is the root of all evil , for being blind it does not see whom it attacks . Yet it always attacks the Son Of God , and the Son of God is you .

uniquorn

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Re: The Nares Strait thread
« Reply #1412 on: February 09, 2019, 09:11:38 PM »
2chunks are up for the ride, everyone else hesitating at the entrance.
worldview feb8-9

uniquorn

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Re: The Nares Strait thread
« Reply #1413 on: February 13, 2019, 07:35:12 PM »
Looking back using uni-bremen smos to see how it showed the flow from Nares into Baffin, may2010-feb2019

Niall Dollard

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Re: The Nares Strait thread
« Reply #1414 on: February 14, 2019, 10:48:31 PM »
Very little movement in past 24 hours in the Kennedy Channel.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1415 on: February 15, 2019, 04:11:30 AM »
It is interesting to me to see the narrow stream on the west side of the Kennedy Channel moving right along.  I don't recall seeing anything like this in past years.  Will it get blocked or slow to a halt or reinvigorate the whole channel?  We will probably know in a few days, as on Sunday [and again in a week](per Windy.com), the winds that are currently out of the north will become confused or out of the south.
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1416 on: February 15, 2019, 07:40:33 PM »
Well, the gods choose reinvigorated movement: DMI Satellite Images yesterday and today.
I've marked three floes and added a couple of lat-longs to help with location.  (Yes, the left image is wider; the right image shows the current satellite pass with 'no data' being black.)  What was above 82ºN is now below 82ºN; what was above 81.5ºN is now at 81.5ºN; etc.
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1417 on: February 18, 2019, 04:59:58 PM »
Uniquorn has a movie in "The 2018/2019 freezing season" thread showing the short-lived stall of "Big Chunk Block" in Kennedy Channel

[Edit: chunk, block: gotta get those terms right, now.  Note that B.C. is hitting Hans Island and will be further broken the next time we see it.  I recall now: that "Big Block" was in the Beaufort, a very resilient piece of ice, until it melted.]
« Last Edit: February 18, 2019, 05:59:03 PM by Tor Bejnar »
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1418 on: February 18, 2019, 05:06:38 PM »
Chunk, Tor,

big chunk! ;)

Thank you for making the link here. And thanks, Uniquorn for the blockbuster.

uniquorn

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Re: The Nares Strait thread
« Reply #1419 on: February 18, 2019, 11:03:20 PM »
I'm not sure we'll see the like of Big Block again. Rumour has it there's a breakaway called 2Chunks.

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Re: The Nares Strait thread
« Reply #1420 on: February 22, 2019, 12:08:35 PM »
Kane Basin on the move. https://go.nasa.gov/2Ir5yD1
I wonder if pressure builds up behind large floes then destabilises land fast ice as it releases.

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Re: The Nares Strait thread
« Reply #1421 on: February 22, 2019, 04:16:19 PM »
I was having a look at Sentinel earlier .. plenty of movement everywhere but no new ice has joined the queue .. has a northern arch formed .. or will demand be met by new suppy ?
b.c.
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b_lumenkraft

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Re: The Nares Strait thread
« Reply #1422 on: February 22, 2019, 05:03:13 PM »
Yeah, there are fewer cracks in the north than in the last weeks/months.

Still, i guess it will crack soon. You can see in the NASA data that the ice is inhomogeneous, not very solid up there and the current is still flowing.

uniquorn

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Re: The Nares Strait thread
« Reply #1423 on: February 25, 2019, 12:47:31 AM »
It is interesting to me to see the narrow stream on the west side of the Kennedy Channel moving right along.  I don't recall seeing anything like this in past years. <>
Perhaps I can entice you to expand further on this... Mercator model shows higher salinity at 0m (from depth?) on the eastern side which you imply may be expected. Arch may be forming but current continues to snip off thinner chunklets.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1424 on: February 25, 2019, 05:21:08 AM »
The Lincoln Sea Polynya has been remarkably stable for a week or more, as "be cause" noted.  Viewing the DMI composite Sentinel images may be a bit overstating the stability, however.  From the DMI-Lincoln webpage, if you select "Sentinel" from the 'Select satellite or instrument' section, you'll see how fragmented the Sentinel originals actually are.
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Niall Dollard

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Re: The Nares Strait thread
« Reply #1425 on: February 25, 2019, 11:07:46 PM »
Tor, those are all Sentinel 1A images. What about Sentinel 1B ?

For Lincoln area, there are regular Sentinel 1B images 24th/23rd/22nd Feb etc.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1426 on: February 25, 2019, 11:31:12 PM »
I have no idea.  (You clearly know more than me.)  Other 'current' data can be found on Polar View.  Below is a part of the latest available (February 23) image.  (The entrance to Nares Strait would be about the bottom center of the black part of the image.  NW Greenland is on the lower right left of the image.)
« Last Edit: February 26, 2019, 04:32:58 AM by Tor Bejnar »
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Niall Dollard

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Re: The Nares Strait thread
« Reply #1427 on: February 26, 2019, 12:31:19 AM »
I have no idea.  (You clearly know more than me.) 

No I never noticed this before either, until you mentioned it.  :)

When you select the Sentinel radio button on the bottom right of the webpage, it only selects the images from the older Sentinel 1A satellite and doesn't pull down the Sentinel 1B images.

For some ice areas (Kane) there are still quite frequent 1A images but for areas further north Lincoln and Morris Jessup it seems the sentinel 1A only passes quite rarely. We need the 1B satellite to get coverage for these areas.

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Re: The Nares Strait thread
« Reply #1428 on: February 26, 2019, 01:20:21 AM »
I notice the dmi page for Satellite images no longer specifies and seperates Sentinel 1A and 1B .. now a daily Sentinel 1 image is provided and is complete or nearly so every day .. like worldview they show that there has been no change to the N. arch since the 15th although several fragments of recently frozen ice have moved in the last few days .
 b.c.
Conflict is the root of all evil , for being blind it does not see whom it attacks . Yet it always attacks the Son Of God , and the Son of God is you .

Niall Dollard

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Re: The Nares Strait thread
« Reply #1429 on: February 26, 2019, 01:56:56 AM »
I notice the dmi page for Satellite images no longer specifies and seperates Sentinel 1A and 1B ..

When you click on each image, you will see whether the image is from 1A or 1B detailed to the RHS of each image. 

I agree that it's only in the most southwestern part of the Lincoln Sea that there is any movement of ice. In this open area, new ice is continuing to form and then be pulled down into the Nares Strait, but there aren't many thick floes left to come down, if the ice sheet in the main part of the Lincoln Sea holds firm.

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Re: The Nares Strait thread
« Reply #1430 on: February 26, 2019, 02:43:39 AM »
It does seem stuck in place at last, since Feb 16th (looking at WorldView). The shape is quite smooth so it has a chance of holding for the rest of the winter and spring, though it's still not guaranteed.

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1431 on: February 26, 2019, 11:38:06 AM »
For the records, a GIF.

Nares Strait, Date Range:21.01. to 24.02. 2019
« Last Edit: February 26, 2019, 11:52:02 AM by b_lumenkraft »

uniquorn

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Re: The Nares Strait thread
« Reply #1432 on: February 26, 2019, 12:18:54 PM »
But why the larger encatchment area? Stronger current? higher tide? Thinner ice? Full moon? SSW mslp? Warmer water from depth?
It was a very cold winter in the Lincoln Sea.

uniquorn

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Re: The Nares Strait thread
« Reply #1433 on: February 26, 2019, 08:06:19 PM »
Not expecting an answer  ;)
Tor may be right. New fracture today.  https://go.nasa.gov/2GLZ5RC

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Re: The Nares Strait thread
« Reply #1434 on: February 26, 2019, 08:34:53 PM »
That thicker ice is moving pretty darn quick into the Nares.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1435 on: February 26, 2019, 09:06:56 PM »
I recall watching floes go from top to bottom in about a week.  (In 2016 I declared it never takes less than a week.  This old thread references some published 'facts' about floe speed.)

I do find it interesting to think that there could be nearly no 'old ice' travelling through the Strait after the current batch reaches Smith Sound (then Baffin Bay)(for a while).  All the new mobile ice in Lincoln Sea (except for the just-mobilized ice at the 'north' end of the polynya) is thin '1-2-week-old' ice.  Will (if it comes to pass) no real floes flowing make it easier for an ice bridge to form?  (nothing to torpedo a nascent bridge)  Or will an open Strait make an ice bridge impossible? (nothing with any strength)
« Last Edit: February 26, 2019, 09:22:23 PM by Tor Bejnar »
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oren

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Re: The Nares Strait thread
« Reply #1436 on: February 26, 2019, 09:56:30 PM »
I'd venture to guess that once a northern arch is formed and the strait is cleared, it is much more difficult for a southern arch to form as well.

uniquorn

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Re: The Nares Strait thread
« Reply #1437 on: February 26, 2019, 10:33:42 PM »
Probably, though I think that fracture will provide a few more chunks. Any one still betting?  :)

Niall Dollard

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Re: The Nares Strait thread
« Reply #1438 on: February 27, 2019, 01:07:47 AM »
Null school is showing a light southerly through much of the strait for much of Wednesday before turning back to northerly through the Kane Basin for Thursday. The next 24 hours will tell a lot.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1439 on: February 27, 2019, 01:17:23 AM »
Thanks for looking (and reporting), Niall!
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uniquorn

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Re: The Nares Strait thread
« Reply #1440 on: February 27, 2019, 11:56:53 AM »
That fracture has closed. Yes, perhaps it will heal with light winds.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1441 on: March 01, 2019, 03:03:52 PM »
That fracture has remained closed.  "Physician, heal thyself."
PolarView from yesterday and the 26th (with dots showing crack)
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1442 on: March 05, 2019, 03:26:10 PM »
By the way, there is a poll on "Old ice moving through Nares Strait" that closes in an hour or so.  Some images and discussion of the Lincoln Sea Polynya and Nares Strait are included in that thread.
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Re: The Nares Strait thread
« Reply #1443 on: March 18, 2019, 12:59:47 PM »
Seemed like a good day to go historical. Here is worldview Terra/Modis, least cloudy days between mar16-20, 2000-2019.

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1444 on: March 18, 2019, 01:23:40 PM »
Thanks so much for this, Uniquorn! Very useful comparison.

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Re: The Nares Strait thread
« Reply #1445 on: March 18, 2019, 05:42:37 PM »
By the way, there is a poll on "Old ice moving through Nares Strait" that closes in an hour or so.  Some images and discussion of the Lincoln Sea Polynya and Nares Strait are included in that thread.

I kind of wish that thread had not been created as it caused this thread to go silent.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1446 on: March 18, 2019, 08:34:41 PM »
That distraction may well end tomorrow.

The quickest part of the last 'old' ice to leave Lincoln Sea after the Lincoln Polynya arch became quite stable in mid-February took 3 weeks to go the length of Nares Strait.  Some of that ice got stuck in fast ice in Kane Basin.  As no 'thick' ice has entered Nares Strait for 3 weeks, the active channel through the Strait has (virtually?) no 'thick' ice in it above Smith Sound.  How thick can that ice be, having grown for up to 6 weeks?  (I remember a formula somewhere on these ASIF threads …)

[Edit: DMI posted a second Sentinel Kane Basin image dated March 18 which shows that Slowpoke and the Matched Pair are moving again, so again there is a little 'thick' ice above Smith Sound moving southwards within the 'active channel'.]
« Last Edit: March 19, 2019, 03:55:41 PM by Tor Bejnar »
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Re: The Nares Strait thread
« Reply #1447 on: March 18, 2019, 11:29:48 PM »
So the Nares is mostly flushed of old ice.
I enjoyed Tor's poll. It encouraged me to actually read the scientific papers on the Nares that he and others suggested and it made me look (eventually) at terramodis brightness temp back to 2000. Useful for longer time comparisons despite the lower resolution than suomi/npp. https://go.nasa.gov/2Jn5YuX
If it showed one thing it was that Nares watchers are reluctant to vote.  ;)
My vote was incorrect and the arch has held for longer than 'soon' now.

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Re: The Nares Strait thread
« Reply #1448 on: March 19, 2019, 07:14:06 AM »
That said, today we see further minor breakups from the arch.


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Re: The Nares Strait thread
« Reply #1449 on: March 19, 2019, 10:38:47 AM »
That said, today we see further minor breakups from the arch.
It is possible that the new breakups are made of ice that was created after the initial arch froze in place. To verify this a comparison is needed between the arch shape on Feb 16th and its shape now, or even best an animation of the shape every few days since then til now, if anyone is up to the task.
I think this ice can even seem like relatively old ice, after it grew for a month or more.