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Author Topic: The Nares Strait thread  (Read 310872 times)

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1000 on: April 16, 2017, 10:36:08 PM »
I think that's out of the new ice in the "polynya" which is breaking up. If you look carefully you can see the outline of the original boot arch which is bigger.


Agreed. ...

Here are the DMI Sentinel images of April 6 & 12 showing this.
« Last Edit: April 16, 2017, 10:49:02 PM by Tor Bejnar »
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1001 on: April 16, 2017, 10:42:29 PM »
The 'last Arctic Ocean ice' to break off the Lincoln Sea bridge (that broke off about March 5) was in Kane Basin on April 14.

Very nearly all the ice around it, all the way upstream to the Lincoln Sea bridge, is ice that froze in Nares Strait (or the little piece of Lincoln Sea below the bridge) since early February (when 1- the bridge formed and 2- virtually all the non-fast ice in the Strait flushed out within 10 days).
« Last Edit: April 16, 2017, 10:54:23 PM by Tor Bejnar »
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gerontocrat

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Re: The Nares Strait thread
« Reply #1002 on: April 18, 2017, 07:07:39 PM »
According to Jaxa, what a lot of sea ice drift in Baffin bay and Davis Strait + very thin low concentration ice in the Nares Strait

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1003 on: April 18, 2017, 08:59:31 PM »
The 'last Arctic Ocean ice' to break off the Lincoln Sea bridge (that broke off about March 5) was in Kane Basin on April 14.
...

Exit, stage left.  The March 5 floe has now all-but-exited Nares Strait, depending on where you draw the line between Smith Sound and Baffin Bay. March 5 to April 18 = 44 days.  Curious that the previous identifiable floe we watched took 10 days in early February. (Screen shot from PolarView.)
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1004 on: April 19, 2017, 07:31:28 PM »
The Lincoln Sea ("foot") bridge lost some of it's edge (or "cleaned up its act" or "got more space for the toes") sometime between 6 pm yesterday and noon today (probably GMT).  Along with some of the fast ice that grew on the bridge, some slivers (smaller than the March 5 floe) peeled off the bridge near the Ellesmere side.  You can contrast the edge with the image posted on April 16. (image from Polar View)
« Last Edit: April 19, 2017, 07:48:57 PM by Tor Bejnar »
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1005 on: April 19, 2017, 07:54:58 PM »
The March 5 floe is definitely in Baffin Bay now, broken hearted, well, at least broken.  It was fun while it lasted.  I'm curious why it broke now. [my post #1111 - a duplicative milestone]
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mati

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Re: The Nares Strait thread
« Reply #1006 on: April 19, 2017, 10:56:08 PM »
lovin' the boot
lol can't belive the moniker stuck, but i'm happy :O
having a bunion, i hope the boot does not fall to one
and so it goes

oren

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Re: The Nares Strait thread
« Reply #1007 on: April 19, 2017, 11:30:57 PM »
Here's a quick animation of Apr 18 and 19. The ice is more broken, the cracks are getting closer to the "arch" while the newer ice inside the arch falls away.
I would not be surprised to see the arch crumbling within a few days under the stresses.  It's not a given but quite possible. And if it does go, I don't expect a new arch to form and stabilize as temps are going up already and the strait itself has been flushed away.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1008 on: April 24, 2017, 05:46:56 AM »
The pieces of "foot" bridge ice that broke off the "toe section" on April 19 are past or opposite Petermann Fjord (as of yesterday's DMI Sentinel image):
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1009 on: April 25, 2017, 05:57:36 PM »
The April 19 "toes" floes were at or just past Hans Island yesterday, per PolarView (image below).
They are certainly not taking a leisurely trip through Nares Strait as the March 5 floes did!

You can see the fast ice held by Franklin Island in this screen print.  (Some of it was from the Arctic Ocean - it solidified before the early February cleansing of all the ice in the open parts of Nares Strait. [Of course, while all the ice was getting flushed, new ice was forming 'upstream' within the Strait & Lincoln Sea.])  More recent fast ice is held in place by Hans Island, the Franklin fast ice, and Greenland.
« Last Edit: April 25, 2017, 06:10:55 PM by Tor Bejnar »
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1010 on: April 27, 2017, 02:47:55 AM »
The April 19 "toes" floes are in the central part of Kane Basin, as of mid-day today, per PolarView.  The biggest floe (that I'm watching) may make it to Baffin Bay in under 10 days. (Images: larger scale 'closeup' first, smaller scale screen shot for better orientation second [shows the top of Kane Basin])
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Re: The Nares Strait thread
« Reply #1011 on: April 27, 2017, 01:03:05 PM »
Tor, thank you for posting these images with your commentary. I want to learn more about what I am looking at here, and find your posts instructive and helpful.

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Re: The Nares Strait thread
« Reply #1012 on: April 27, 2017, 01:24:37 PM »
Jaxa sea ice drift graph shows strong to very strong drift down Baffin Bay and Davis Strait. Yet cci-reanalyzer says very little wind. So strong southerly currents?

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Re: The Nares Strait thread
« Reply #1014 on: April 28, 2017, 12:21:04 AM »
Zoom in and look at LIncoln it seems a collapse may be imminent. https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticictn_nowcast_anim30d.gif

mati

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Re: The Nares Strait thread
« Reply #1015 on: April 28, 2017, 04:45:06 AM »
toes are showing :)
and so it goes

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Re: The Nares Strait thread
« Reply #1016 on: April 28, 2017, 12:32:49 PM »
Indeed, here seen by the Sentinel 1 radar.

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Re: The Nares Strait thread
« Reply #1017 on: April 28, 2017, 02:42:23 PM »
That animation shows open water still freezing.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1018 on: April 28, 2017, 07:17:16 PM »
The April 19 big "toe" floe is in southernmost Kane Basin (almost in Smith Sound) as of mid-day today (screen shot from PolarView), so it won't beat the 10 day pace the early February floe had. (Will it tie?)  Now that this floe is nearing the Nares exit, I'll get to watch the April 27 "toe".
« Last Edit: April 28, 2017, 07:22:47 PM by Tor Bejnar »
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1019 on: April 30, 2017, 10:28:52 PM »
The April 19 "toe" floe was in Smith Sound yesterday (frist screen print from DMI-Kane-Sentinel is dated April 29), so probably 11 days to transit the length of Nares Strait. Edit: the 3rd image below, from PolarView, shows this floe in Baffin Bay on the 30th, so, yes: 11 days.

Meanwhile, the April 27 "toe" floe is half way to Petermann Fjord. (second screen print - DMI-Kennedy-Sentinel is dated April 30)

[For those who wonder why I'm calling these "toe" floes, the Lincoln Sea ice bridge (or arch) left the shape of a foot (therefore a "foot bridge") or boot, with the ankle being the Kennedy Channel (northern part of Nares Strait).  When these floes broke off of the ice bridge, they came from the area where toes would be if it had been a real foot or boot, therefore "toes".  That these two floes are elongated just adds to the illusion. (That their length came from the width of the boot's toe section could be cause to call them each a set of "toes", but the anthropomorphizing can go too far, even for me).]
« Last Edit: April 30, 2017, 10:35:16 PM by Tor Bejnar »
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bairgon

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Re: The Nares Strait thread
« Reply #1020 on: May 03, 2017, 09:32:03 PM »
I've been watching this ice separating in the Kane basin recently. For the latest picture see https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2017-05-03&z=3&v=-749189.3189376687,-1208306.8597371846,-257669.3189376687,-956146.8597371846&ab=on&as=2017-04-18&ae=2017-05-03&av=2&al=true

I think it's about 30km by 80km, which is 2400 km^2. Rather a lot really!

Winds are forecast to be from the southwest so it may travel up the strait a bit before being flushed out.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1021 on: May 04, 2017, 09:28:33 PM »
The April 27 "toe" floe flew past Hans and Franklin Islands yesterday and is probably in Kane Basin today.  It might, however, get "stuck" in Kane Basin for a while.  Screen shot with a red dot on the floe is from yesterdays DMI-Sentinel.

Separately, I'm intrigued by the large section of fast ice in the southwestern part of Kane Basin that broke free so early in the year. (Thanks, bairgon!)  Windytv shows confused winds until Sunday.
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1022 on: May 05, 2017, 02:54:06 PM »
The April 27 "toe" floe flew past Hans and Franklin Islands yesterday and is probably in Kane Basin today.  ...

Well, it got to the edge of Kane Basin, anyway.  Screen shot (red dot added) from Polar View dated 2017-05-04 at 8:50 PM
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Cate

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Re: The Nares Strait thread
« Reply #1023 on: May 05, 2017, 03:47:18 PM »
Tor, great chronology of the "toe floe"--thanks.

That big ship-shaped piece on the Greenland side of Kane Basin has floated her substantial stern well out into the road today.

:)

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Re: The Nares Strait thread
« Reply #1024 on: May 05, 2017, 09:35:52 PM »
Tor"I'm intrigued" My guess high pressure+low tides

DavidR

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Re: The Nares Strait thread
« Reply #1025 on: May 06, 2017, 12:51:33 AM »
I've been watching this ice separating in the Kane basin recently.
I think it's about 30km by 80km, which is 2400 km^2. Rather a lot really!

Winds are forecast to be from the southwest so it may travel up the strait a bit before being flushed out.

This seems large enough to block the channel if it moves down in the right way.  So while its possible it could flush out or break up, there is also a chance it could form the basis of a late arch blocking the channel.  Having come from a shelf it  could be more solid than the ice that  is forming in the channel and flowing  down.

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Re: The Nares Strait thread
« Reply #1026 on: May 08, 2017, 01:27:16 PM »
I was just looking at Worldview and I see huge cracks getting 'near' the arch from Beaufort Sea - it just flew by the Queen Elizatbeth Islands and a new one forming above Ellesmere...
Just in 3 days from almost nothing visible to a I think 5 km wide crack

And also a lot of cracks forming above greenland getting nearer to the arch.

Just as if the nares strait arch will be the last man standing

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1027 on: May 08, 2017, 06:52:42 PM »
The April 27 "toe" floe past through Smith Sound yesterday - 10 days to go the distance (just like the early February floe). (image from DMI)  So much for (much of) a slowdown in Kane Basin!
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1028 on: May 08, 2017, 07:39:24 PM »
I was just looking at Worldview and I see huge cracks getting 'near' the arch from Beaufort Sea - it just flew by the Queen Elizatbeth Islands and a new one forming above Ellesmere...
Just in 3 days from almost nothing visible to a I think 5 km wide crack

And also a lot of cracks forming above greenland getting nearer to the arch.

Just as if the nares strait arch will be the last man standing
Windytv forecast shows winds out of the south for the Lincoln Sea on Wednesday.  It is still early in the season, but with other ice shifting (and cracks forming), maybe this will break the Nares Strait "foot" bridge.
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Wipneus

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Re: The Nares Strait thread
« Reply #1029 on: May 09, 2017, 07:39:07 PM »
The floe in the Kane Basin breaks away.

Click for the animation.


oren

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Re: The Nares Strait thread
« Reply #1031 on: May 09, 2017, 11:33:07 PM »
Nice catch. At zoom-out they are invisible.
Definitely can't be good for the arch.
Edit: two tiny pieces already broke off the heel.
« Last Edit: May 10, 2017, 12:03:38 AM by oren »

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Re: The Nares Strait thread
« Reply #1032 on: May 10, 2017, 01:36:27 AM »
This is likely the end of the 2017 Nares Strait arch. Cracks propogated all the way down to the arch and a large floe from atop the arch was released. Another crack may be continuous all the way to Ellesmere Island, but the resolution of Terra Worldview is too poor to tell. There is a third less well-defined crack that definitely extends over to Ellesmere Island from the top of the arch.

I would not be surprised if large quantities of MYI started flowing down through the Nares Strait soon, although I also would not be surprised if it somehow held together as these arches definitely manage to take a beating before collapsing in the summer.

GIF-making over this region as the next week comes in will be instructive.

mati

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Re: The Nares Strait thread
« Reply #1033 on: May 10, 2017, 01:51:02 AM »
the toe has hangnails :O
and so it goes

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1034 on: May 10, 2017, 05:04:14 AM »
windytv "current" forecast winds aren't helping the bridge/arch any!
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Re: The Nares Strait thread
« Reply #1035 on: May 10, 2017, 10:51:34 AM »
Cracks coming across from Fram too

from https://go.nasa.gov/2pv9yE8

romett1

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Re: The Nares Strait thread
« Reply #1036 on: May 10, 2017, 01:46:32 PM »
Some rapid changes overnight. Seems like the first block is now trying to enter the Nares Strait. Bit cloudy on May 10.

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Re: The Nares Strait thread
« Reply #1037 on: May 10, 2017, 03:25:45 PM »
That crack that is running along the coast of Greenland is evidence of the ice directly north of Nares sheering away from the coastal ice. Would not be at all surprised if this ice floe is the first of many to peel off and head south through the strait.




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Re: The Nares Strait thread
« Reply #1041 on: May 11, 2017, 12:10:54 AM »
Amazing how it all went in one blow. I did expect it to break a few weeks ago when the cracks first showed up in the area, but when the initial danger passed I was hoping the arch could survive.
Considering the Lincoln Sea is one of the last resorts of thick old static MYI, this is another piece of bad news for the melting season. There is no arch in Kane Basin and the strait has already been flushed recently, so resistance to southbound export will be minimal besides the normal "traffic jams". Extent might not suffer in the beginning, should even go up in the vicinity, but volume-wise and fast forwarding to the next few months, it's one more nail in the coffin.

be cause

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Re: The Nares Strait thread
« Reply #1042 on: May 11, 2017, 02:14:03 AM »
we could be chatting about that snap for a while . the last thing the Arctic needed was an outlet for more of the thicker ice . What happened suggests that being in the coldest safest place for several months has done nothing to give our best ice any staying power .. bc

  p.s. .. i suppose we could say this foot now has a fallen arch .. boom boom :)
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Re: The Nares Strait thread
« Reply #1043 on: May 11, 2017, 10:53:17 AM »
The big berg in the south is not moving very much, considering the tides, if it stays put Kane may fill with the sea ice from Lincoln.

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Re: The Nares Strait thread
« Reply #1044 on: May 11, 2017, 03:06:38 PM »
The latest break to the Nares boot may release some thicker multi year ice that is more resistant to  break up and thus more likely to jam up as it  flows through the strait.  Seems to  be the only  way  an arch  could form in Kane basin now.

The next  week  or two will be interesting to  see whether it all just  flows through.

Winds in Nares are turning southwest  from tomorrow so the ice should resume flowing steadily down the strait for several days.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1045 on: May 11, 2017, 04:10:15 PM »
DMI Sentinel before (May 8 ) and after (May 10) images show the 'left' 2/3rds of Lincoln Sea ice rotating counterclockwise and the 'right' 1/3rd (but including the 'heel' and 'foot' part of the boot, but not the tip of the 'toes' [yet]) sliding very slightly (except for areas closest to the 'boot') SW-ward (straight for Nares Strait).  Most of the ice from the 'toe' section that broke off is young fast ice.

Temporarily, the boot's arch looks better than ever!  Seeing is deceiving!
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1046 on: May 11, 2017, 06:11:30 PM »
I wonder how quickly the large floe in Kane Basin (that recently was fast ice in Kane Basin, most of which had been in place since early December 2016) will pass through Smith Sound.  I doubt it will go through mostly intact, but we'll see.  The current 'forecast', according to windytv has fairly calm winds, but north winds are forecast (see image below) to help move the floe southward by tomorrow. (1st image below is from WorldView.)

I'll hazard a guess the tail end of the floe will pass into Baffin Bay on Tuesday, May 16.

By the way, folks who post long links should link a word or phrase instead of the long ling.  To do so,
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« Last Edit: May 12, 2017, 02:59:29 AM by Tor Bejnar »
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romett1

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Re: The Nares Strait thread
« Reply #1047 on: May 11, 2017, 08:33:55 PM »
Nares Strait May 9 - May 11, Worldview.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1048 on: May 11, 2017, 09:32:10 PM »
I don't often look at NOAA imagery on the DMI site, but here is today's Lincoln Sea.  Looks like  a shoe now (no longer a boot). (Is this where we remind each other "Don't eat yellow snow"?)
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Re: The Nares Strait thread
« Reply #1049 on: May 11, 2017, 09:47:22 PM »
Tor thanks for the URL help (and the great info you always post here...)