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Author Topic: Petermann Gletscher / Petermann Fjord / North West Greenland  (Read 129836 times)

Hunter

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #450 on: April 14, 2017, 05:55:09 PM »
Might have a pic for you later on, flew over Petermann about 2 hours ago.
« Last Edit: April 14, 2017, 10:23:18 PM by Hunter »

Hunter

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #451 on: April 14, 2017, 09:51:06 PM »
Credit NASA

Hunter

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #452 on: April 14, 2017, 09:53:13 PM »
Credit NASA

preliminary data plot not for scientific use.

Last pic is the Kee Bird as it sits today.
https://en.wikipedia.org/wiki/Kee_Bird

Tealight

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #453 on: April 14, 2017, 10:13:45 PM »
Scientists just found a strange and worrying crack in one of Greenland’s biggest glaciers https://www.washingtonpost.com/news/energy-environment/wp/2017/04/14/scientists-just-found-a-strange-and-worrying-crack-in-one-of-greenlands-biggest-glaciers

This crack was already known in December last year. I posted an image of it in Reply #438 on: December 01, 2016, 09:39:09 PM »
S1B_20161201_Petermann.jpg (1840.12 kB, 2260x1624 - viewed 79 times.)

oren

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #454 on: April 14, 2017, 10:59:53 PM »
Hunter, thanks for the amazing images.

Neven

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #455 on: April 14, 2017, 11:10:48 PM »
This crack was already known in December last year. I posted an image of it in Reply #438 on: December 01, 2016, 09:39:09 PM »
S1B_20161201_Petermann.jpg (1840.12 kB, 2260x1624 - viewed 79 times.)

I remember that, and I believe Andreas Muenchow has also mentioned it, if memory serves me well.

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Cate

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #456 on: April 15, 2017, 12:23:07 AM »
Hunter, thanks for the amazing photos and the link re the Kee Bird---very informative. :)

Adam Ash

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #457 on: April 15, 2017, 05:52:51 AM »
'A sensor in 3,000-foot-deep waters had found that in the warm, salty Atlantic layer, temperatures were even warmer than just a year earlier, in 2015. Those waters are likely flowing toward Petermann glacier’s grounding line and helping to melt the shelf from below.'

http://www.washingtonpost.com/sf/business/2016/12/30/with-enough-evidence-even-skepticism-will-thaw/?utm_term=.62144c2fdb37

Great views of the Petermann and Jakobshavn canyons in the video on this page too
The canyon feeding Petermann gives a direct connect to all of inland Greenland.  Huge, and its already melting into a groove...
https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4097
Video at:  'The Earth layer alone with transparency at gamma 1.0.'

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Xela

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #459 on: April 17, 2017, 12:08:27 PM »
This crack was already known in December last year. I posted an image of it in Reply #438 on: December 01, 2016, 09:39:09 PM »
S1B_20161201_Petermann.jpg (1840.12 kB, 2260x1624 - viewed 79 times.)

I remember that, and I believe Andreas Muenchow has also mentioned it, if memory serves me well.
According to Andreas Muenchow https://twitter.com/AndreasMuenchow/status/852491527796523008 and Stef Lhermitte https://twitter.com/StefLhermitte/status/852873863427969024 it seems like it's a new crack.

More here: https://twitter.com/Petermann_Ice
« Last Edit: April 17, 2017, 12:18:48 PM by Xela »

Cate

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« Last Edit: April 26, 2017, 05:14:35 PM by Cate »

Tor Bejnar

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #461 on: April 30, 2017, 06:32:20 AM »
I've been thinking about that new crevasse (rift, crack) that appears to 'start' at the longitudinal trough (river bed, "feature") that runs down the middle of Petermann Glacier. (screen shot from the 2nd link above) 
... Brunt points out that the rift currently appears to end at a feature running down the center of the glacier. “That’s pretty typical,” she said, citing similar occurrences on ice shelves in Antarctica. ...
I'm surprised this is "typical"! Why would ice shelves have a mid-glacial river bed at which rifts start or end? (I'm confused, unless she's referring to chevron cracks that form semi-parallel relatively short cracks when a somewhat brittle material [like a glacier or ice shelf or cheese or clay] is stretched.) 

I wonder if there might be a longitudinal weakness (crack) that runs under the mid-glacier river bed, with the left side of the glacier moving slightly faster than the right side, providing a triple-point.  (Pure speculation!)


I will want to watch this new rift, and see if it connects with other known cracks or the sides of the glacier.

I'm of course also watching what appears to be a completed rift around the right end of the glacier (see my previously post (March 14, 2017), above).
« Last Edit: April 30, 2017, 06:39:40 AM by Tor Bejnar »
Arctic ice is healthy for children and other living things.

Tealight

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #462 on: May 01, 2017, 12:33:33 AM »
For a change here are some non-cracking news.

The terminus of Petermann Glacier is mostly blown snow free and left behind blue ice. It looks like several melt lakes survived the winter and appear in a deeper blue. I would really like to know how deep they are and how thick the ice cover is.

DrTskoul

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #463 on: May 01, 2017, 04:33:16 AM »
Neat!!
“You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird... So let's look at the bird and see what it's doing -- that's what counts.”
― Richard P. Feynman

sidd

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #464 on: May 01, 2017, 06:16:23 AM »
Very nice pictures.  Are they draining off the edge as in the Bell paper ? doi:10.1038/nature22048

I commented on that paper here :

https://forum.arctic-sea-ice.net/index.php/topic,622.msg111095.html#msg111095

Ifso that is a stabilizer.

sidd

Tealight

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #465 on: May 01, 2017, 11:13:44 AM »
Very nice pictures.  Are they draining off the edge as in the Bell paper ? doi:10.1038/nature22048
...

Most of the lakes are on the part that is about to calve and probably don't have and any effect on stability.


I've been thinking about that new crevasse (rift, crack) that appears to 'start' at the longitudinal trough (river bed, "feature") that runs down the middle of Petermann Glacier. (screen shot from the 2nd link above) 
... Brunt points out that the rift currently appears to end at a feature running down the center of the glacier. “That’s pretty typical,” she said, citing similar occurrences on ice shelves in Antarctica. ...
I'm surprised this is "typical"! Why would ice shelves have a mid-glacial river bed at which rifts start or end? (I'm confused, unless she's referring to chevron cracks that form semi-parallel relatively short cracks when a somewhat brittle material [like a glacier or ice shelf or cheese or clay] is stretched.) 

I'm not sure there is something as typical rifts/cracks. If something is typical then a glacier flows fasted in the middle, where the ocean is deepest and the lowest friction occurs. Because of the higher speed, the centre of the glacier detaches (cracks) from the main glacier before the sides do. But Petermann Gletscher is squeezed through a small fjord and the edges constantly grind along the rock. If the ice gets struck then cracks develop from the sides.

By the way the centre crack already cut through the main drainage channel. Not good for any rafting fan.

TerryM

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Re: Petermann Gletscher / Petermann Fjord / North West Greenland
« Reply #466 on: May 03, 2017, 02:51:34 AM »
Tor
You might want to explore
https://icyseas.org/




I thing you will find many of your questions about the underside of Petermann answered.


Terry