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Author Topic: The Nares Strait thread  (Read 580820 times)

JayW

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Re: The Nares Strait thread
« Reply #1750 on: May 30, 2019, 09:11:33 AM »
"To defy the laws of tradition, is a crusade only of the brave" - Les Claypool

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1751 on: May 30, 2019, 09:28:26 AM »
Woah, you and your eagle eyes, Jay!  :D

This GIF shows yesterdays last frame (20:42h UTC) vs. latest frame (04:18h UTC, M10).

I think Second is directly below this hole in the clouds which would mean it moved a lot since it came loose.

oren

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Re: The Nares Strait thread
« Reply #1752 on: May 30, 2019, 09:49:57 AM »
Someone should put a webcam on the north corner of Hans Island. Would make for some spectacular imagery.

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1753 on: May 30, 2019, 09:58:50 AM »
That would be awesome! I'm all for it.

Stephan

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Re: The Nares Strait thread
« Reply #1754 on: May 30, 2019, 11:02:38 AM »
So who of us is going to fix it there? Maybe next week or so?  ;)
It is too late just to be concerned about Climate Change

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1755 on: May 30, 2019, 11:17:24 AM »
Only one member nearby... ;)

Espen

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Re: The Nares Strait thread
« Reply #1756 on: May 30, 2019, 12:19:34 PM »
Hans Ø:
Have a ice day!

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1757 on: May 30, 2019, 12:29:29 PM »
Such a brave little rock. <3

Sailaway

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Re: The Nares Strait thread
« Reply #1758 on: May 30, 2019, 03:54:57 PM »
Woah, you and your eagle eyes, Jay!  :D

This GIF shows yesterdays last frame (20:42h UTC) vs. latest frame (04:18h UTC, M10).

I think Second is directly below this hole in the clouds which would mean it moved a lot since it came loose.

Any correlation with tides?

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1759 on: May 30, 2019, 04:10:22 PM »
Sorry Sailaway, i can't say that for sure.

Yesterday's 20:42h UTC shot was the last one you could see something but this one showed no backwards movement so my educated guess is no.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1760 on: May 30, 2019, 04:45:20 PM »
First (the floe currently stuck on Hans Island) appears to have moved a smidgeon (on Canadian side) or a lille beløb (on the Greenland side) between the May 28 and May 29 DMI Sentinel images

For starters, there is surface flow on both sides of First:  in the GIF, the yellow circle follows a distorting 'coloration'.  Therefore I do not expect First to stay where it is for long.

The two rectangles are unmoving in relation to Hans Island mask; on the 28th no part of First is to the left of the larger box while on the 29th, a set of pixels shows just outside it [yes, I was looking at enlargements of the two frames before creating the GIF]; also a 'coloration' just inside the larger box on the right moves a pixel to the left.  The smaller box shows the bottom edge of First not moving down at all.  I'm not, however, going to declare one pixel of lateral movement to be proof of anything - Edit: I note the Greenland coast changes in relation to the mask as well.

« Last Edit: May 30, 2019, 04:52:06 PM by Tor Bejnar »
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b_lumenkraft

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Re: The Nares Strait thread
« Reply #1761 on: May 30, 2019, 05:24:19 PM »
What's a pixel in meter, Tor? ;)

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1762 on: May 30, 2019, 06:29:45 PM »
Petermann Fjord is "15" km wide and 73 pixels, so 15,000/73 = 200 m/pixel (to 1.9 significant digits)
So 1 pixel represents between 150 and 250 meters of movement IF the two images were properly oriented in the first place.  (As I suggested, I think the two images were not exactly aligned.)  [but it is nice to know the pixel size of DMI images!]
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b_lumenkraft

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Re: The Nares Strait thread
« Reply #1763 on: May 30, 2019, 06:33:35 PM »
Hah! That's cool Tor. Very good to know. Thanks a lot. :)

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1764 on: May 31, 2019, 02:43:34 AM »
DMI doesn't have a good Sentinel image from today, but PolarView has one dated today @ 10 pm Zulu.  Franklin Is. is at the lower left corner; Hans Is. is center top and "First" is still stuck on Hans. (only partly included in the image).  A piece of Greenland is on the lower right corner.  First is darker than the open water south of it.

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be cause

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Re: The Nares Strait thread
« Reply #1765 on: May 31, 2019, 03:27:56 AM »
Thanks Tor , for the image of the day !

                                .. ' All Hans on deck ! '

 Could the last of the 'old ice' help save the day ? b.c. :)
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1766 on: May 31, 2019, 09:05:37 AM »
Still cloudy...   :(

This GIF showing last clear pic vs. last pic.

Something is moving, that's all i can say for sure.

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1767 on: May 31, 2019, 10:49:41 AM »
Here we go.

A closeup in ping-pong mode showing Second on the move and cracked.

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1768 on: May 31, 2019, 11:11:40 AM »
This GIF is showing First (iconic, colorized).

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1769 on: May 31, 2019, 01:28:00 PM »
Sentinel gives a glimpse and shows Second cracking.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1770 on: May 31, 2019, 04:11:00 PM »
State of affairs as of May 30 at 8:50 pm GMTPolarView image with First on Hans and Second on Joe. [Note: DMI now has a May 30 image using this PolarView image.]  I believe Second has cracked (per B_'s GIF - do you know at what time on "30.05." - 30th of May - the image is from?), but PolarView gives pretty clear evidence of what 'was'.  (Yes, First and Second have hand-drawn yellow in-sets ["outlines" drawn inside the actual edge] to help those new to looking at radar images of ice floes.)
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b_lumenkraft

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Re: The Nares Strait thread
« Reply #1771 on: May 31, 2019, 04:22:57 PM »
Sorry Tor, so far i can't make sense of the Sentinel2 acquisition plans.

Would be cool if someone could give a hint on how to read this doc:

https://sentinel.esa.int/documents/247904/3690953/Sentinel-2A_MP_ACQ_KML_20190521T120000_20190610T150000.kml

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1772 on: May 31, 2019, 04:36:53 PM »
As of 10:45 UTC you can see large floes floating downstream behind Hans.

This means First must have gone bust.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1773 on: May 31, 2019, 04:37:16 PM »
The "20190521T120000" part of it means 2019 May 21 Time 1200 [exactly noon-24 hr clock]  '00' seconds

[Isn't "green glow" - the "G" in the menu with green highlighting - "red" can be changed to other rainbow colors - fun?]
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Tor Bejnar

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Re: The Nares Strait thread
« Reply #1774 on: May 31, 2019, 04:40:55 PM »
Here, for history's sake (B_ is faster than a speeding bullet), is an animated enlargement of First being stuck on Hans Island, 'enlarged' to 61% of full resolution.
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oren

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Re: The Nares Strait thread
« Reply #1775 on: May 31, 2019, 04:49:13 PM »
I must say First is showing (has shown?) outstanding resilience, surviving the head-on collision with Hans Island and then resisting the stuff knocking behind it.

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1776 on: May 31, 2019, 05:35:15 PM »
Not so sure about that being fast ice there Tor.

Note how this area is almost cleaned out on 24th.

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1777 on: May 31, 2019, 05:58:22 PM »
B_,
Re "fast ice".  Fair enough.  Much of the fast ice broke loose (above Franklin Island) a few days before First showed up (supported by your GIF), and some of it appeared to me to get stuck again nearly where it had spent the winter.  Once First showed up, it is apparent to me that some ice wasn't moving southward and was part of what kept First from moving southward.  But I accept that ice flows that get stuck for a few days shouldn't be called fast ice.  Boy am I lucky to have written "probably"!  8) ::) :P
« Last Edit: May 31, 2019, 07:37:12 PM by Tor Bejnar »
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b_lumenkraft

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Re: The Nares Strait thread
« Reply #1778 on: May 31, 2019, 06:14:46 PM »
Hehehe. subjunctive always saves ass! :D

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1779 on: May 31, 2019, 06:55:35 PM »

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1780 on: May 31, 2019, 07:42:04 PM »
And "Second" is in the image as well, bulleting down the fast lane.  I don't think it can squeeze past Hans Island intact …  more drama to come!
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b_lumenkraft

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Re: The Nares Strait thread
« Reply #1781 on: May 31, 2019, 07:45:42 PM »
Agreed Tor, moah drama ahead!

It's either someone sets up a poll thread 'Will Second go bust or stuck?' or i'll spam this thread. As you guys wish. ;)

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1782 on: May 31, 2019, 08:14:56 PM »
Just came across this article in the floods thread.

Some more about the US floodings, and still more rain to come. https://watchers.news/2019/05/31/levees-breaching-along-the-mississippi-and-arkansas-rivers-us/

And there is this Tweet showing a water breach. And look what the water is doing. It's developing an arch!

Is this a variable we need to consider in the context of the northern arch or is this not applicable?

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1783 on: May 31, 2019, 08:26:52 PM »
And since we are at it with the stupid question, can anyone (looking at Tor) explain to me why the floes from Lincoln are brightish and the fast ice, fast ice floes here in Kane basin are darkish in the Sentinel-1 SAR imagery?

oren

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Re: The Nares Strait thread
« Reply #1784 on: May 31, 2019, 08:54:04 PM »
And since we are at it with the stupid question, can anyone (looking at Tor) explain to me why the floes from Lincoln are brightish and the fast ice, fast ice floes here in Kane basin are darkish in the Sentinel-1 SAR imagery?
I'd say the floes down from Lincoln are old ice with a rough surface, while the fast ice in Kane basin is first year ice that is flat and smooth and never got a chance to compress or deform thanks to its static and protected position. Just a guess though...

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1785 on: May 31, 2019, 08:55:45 PM »
Makes sense to me. Thanks, Oren. :)

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1786 on: May 31, 2019, 09:26:01 PM »
Oren's understanding matches mine.  I wonder if some of the (Sentinel radar) 'black' markings on floes are frozen melt ponds. 

No comment on the 'arch' associated with breached levees, other than they don't hold any ice back.   ;D
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Re: The Nares Strait thread
« Reply #1787 on: June 01, 2019, 01:50:54 AM »
Animation from DMI's Sentinel-1 ASAR Lincoln Sea images. May 23-31
Images from http://ocean.dmi.dk/arctic/lincoln.uk.php

The May 30 image was not very good, so I skipped it.
I scaled it down to 70% this time and it looks like some detail was lost. It still looks okay in full screen mode, but the loss of detail is visible now.

ArcticMelt2

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Re: The Nares Strait thread
« Reply #1788 on: June 01, 2019, 02:02:56 AM »
It is a pity that both the ice floes from the oldest ice have collapsed. And I was already beginning to hope that they could delay the process of destroying the oldest ice for several weeks (in fact, they lasted a couple of days).

By the way, the third big ice floe, which has not yet entered the strait, also recently cracked in half.

ArcticMelt2

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Re: The Nares Strait thread
« Reply #1789 on: June 01, 2019, 02:16:59 AM »
Maybe people should build a dam in the strait to slow down the process of losing the oldest ice?

ArcticMelt2

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Re: The Nares Strait thread
« Reply #1790 on: June 01, 2019, 02:36:56 AM »
By the way, I looked at the archived images for today's date. Exports of ice through the strait went only in 2017, 2010 and 2007.

2019 is one of the four worst years in the 21st century.

b_lumenkraft

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Re: The Nares Strait thread
« Reply #1791 on: June 01, 2019, 06:38:01 AM »
Oren's understanding matches mine.  I wonder if some of the (Sentinel radar) 'black' markings on floes are frozen melt ponds. 

No comment on the 'arch' associated with breached levees, other than they don't hold any ice back.   ;D

Thanks, Tor. i had this idea of melt ponds being black too. Good, you confirmed it. :)

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Re: The Nares Strait thread
« Reply #1792 on: June 01, 2019, 08:40:00 AM »
Kane was basically floefree yesterday due to the attempt of First and Second to block Hall.

Alphabet Hotel

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Re: The Nares Strait thread
« Reply #1793 on: June 02, 2019, 03:40:27 AM »
Animation from DMI's Sentinel-1 ASAR Lincoln Sea images. May 24-Jun 01
Images from http://ocean.dmi.dk/arctic/lincoln.uk.php

I'm having problems with Firefox sometimes showing the last frame for only an instant before going back to the first when looping, so I duplicated the final frame. (I like to watch it loop in full screen mode.) I made it just a little bit larger too.

The Greenland coast looks like it's getting scraped clean. And it's flowing in from the other side too.


oren

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Re: The Nares Strait thread
« Reply #1794 on: June 02, 2019, 08:11:13 AM »
Thanks for these animations AH.
It seems flow direction has been more from the Greenland direction recently, while normally it's more from the north. This is bad for the traditionally thick ice founs just north of Greenland, but maybe good for reducing overall export of thick old ice from the pack, as it keeps a good part away from the direction of the Fram.

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Re: The Nares Strait thread
« Reply #1795 on: June 02, 2019, 09:38:26 AM »
A chunk of Peterman fast ice broke up.

01.06. 05:25 to 18:54.

Note how much ice is floating by in these few hours...

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1796 on: June 02, 2019, 03:11:14 PM »
I think there is a going out of business sale at PolarDisplay*.

_____
* - not to be confused with any internet-listed enterprise.
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b_lumenkraft

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Re: The Nares Strait thread
« Reply #1797 on: June 02, 2019, 06:42:16 PM »
This rather big floe that just entered the Nares Strait has melt ponds.

(GIF requires a click to play)

Alphabet Hotel

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Re: The Nares Strait thread
« Reply #1798 on: June 03, 2019, 12:45:59 AM »
Animation from DMI's Sentinel-1 ASAR Lincoln Sea images. May 25-Jun 02
Images from http://ocean.dmi.dk/arctic/lincoln.uk.php

Tor Bejnar

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Re: The Nares Strait thread
« Reply #1799 on: June 03, 2019, 03:11:55 AM »
Down in the Kennedy Channel, Second 'disappeared' at Hans Island.  Was it clear enough when its tried to slide by the mid-channel island (but was too big to do so) to get hourly images? The Sentinel images went from 'approaching' to 'nothing to see'  (keep on moving folks, nothing to see, next ...). I was so looking forward to Second playing bumper cars with First.  Except for the couple of days of First practicing the balancing act with Hans, and Second taking a break in Hall Basin (while making a pass at Joe [Island]), another disappointment. 
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