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Author Topic: PIG has calved  (Read 160586 times)

AbruptSLR

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Re: PIG has calved
« Reply #650 on: February 04, 2017, 06:10:52 PM »
Here is a gif from Jan 5 (?) to Feb 1 of the rift in the SW Tributary glacier next to PIG from

Thanks for this nice gif sequence highlighting the opening of the rift in the SW Tributary ice shelf.  The attached image shows a Sentinel 2 image from Feb 2 2017 of both the PIIS and the SW Tributary ice shelf, to which I have added a segmented yellow line indicating the approximate location of where I am concerned that the next upstream crack will occur in the PIIS as the rift in the SW Tributary ice shelf continues to open.  If I am correct, the opening of such an upstream crack would cause a major calving event along the location of the current crack in the PIIS.
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Wipneus

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Re: PIG has calved
« Reply #651 on: February 15, 2017, 08:47:54 AM »
The recent calving is the subject of Nasa's Earth Observatory Image of the Day

Glacial “Aftershock” Spawns Antarctic Iceberg

The discussion mentions: ‘rapid fire’ calving

Jim Hunt

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Re: PIG has calved
« Reply #652 on: February 15, 2017, 01:10:38 PM »
The recent calving is the subject of Nasa's Earth Observatory Image of the Day

In addition NASA's first reference is to this very forum.

Well done SolarTim, Wipneus et al.!
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oren

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Re: PIG has calved
« Reply #653 on: February 15, 2017, 02:16:01 PM »
I actually missed the ASIF reference at first. Nice!

DrTskoul

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Re: PIG has calved
« Reply #654 on: February 15, 2017, 03:23:31 PM »
Testament to the superb scientific discovery and analysis work done at AIF!!
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solartim27

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Re: PIG has calved
« Reply #655 on: April 17, 2017, 09:58:51 PM »
Thinking more about the lateral compression, it seems that there is a compression from the opposite side, a bit further down. This pushed the calving face to the river right, after passing Evans Knoll.

I suspect, but can't prove, that this deformation force increases the backpressure on the rest of the glacier, as it forces the visible bend to the river right.

I suspect that this deformation was part of the reason the calving broke off the way it did (first the river right, the the river left last, as it was in compression for the longest). I think this may be a protective factor, decreasing the chance of a large calving soon. I hope.

I worry about the rate of decline once the calving front passes those lateral pinning points.  That's when it'll really start flying. :(

A is the compression force due to Evans Knoll, B is the one on the opposite, causing the flexion around Evans Knoll.

I was surprised that PIG didn't go this summer, but it still looks like it can go at any time, as we are seeing increasing amounts of minor calving at the notches to either side of PIG. 

I believe the compression from the SW Trib described above is keeping it penned in.  There is a good image on that post, worth going back to review.
Click to animate and zoom in for a closer look. Dates are 23 Mar to 16 Apr.

http://www.polarview.aq/images/105_S1jpgfull/S1A_EW_GRDM_1SSH_20170416T042746_5C37_S_1.final.jpg

S1A_EW_GRDM_1SSH_20170323T042745_D14E_S_1.final.jpg
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solartim27

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Re: PIG has calved
« Reply #656 on: April 22, 2017, 07:32:41 AM »
Here is a quick look over the past year.  See anything disturbing?  Click to animate.
(Tried a smaller version, 1 MB, it works!)(Oh well, I'm going to bed.  Here are the 2 pics, go full screen and toggle between them to your hearts content.  I was looking at the rifts between PIG and the Trib)

http://www.polarview.aq/images/105_S1jpgfull/S1A_EW_GRDM_1SSH_20170420T035503_D89B_S_1.final.jpg  (38 MB)

S1A_EW_GRDM_1SSH_20160331T045150_542F_S_1.final.jpg  (35 MB)

« Last Edit: April 22, 2017, 07:47:03 AM by solartim27 »
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Darvince

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Re: PIG has calved
« Reply #657 on: April 22, 2017, 07:35:16 AM »
Forum software decided to not animate it for some reason, just to let you know.

oren

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Re: PIG has calved
« Reply #658 on: April 22, 2017, 08:42:12 AM »
Forum software decided to not animate it for some reason, just to let you know.
It's probably too large. If you limit to 700 pixel width it should work.
Edit: the last one works.

solartim27

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Re: PIG has calved
« Reply #659 on: May 03, 2017, 03:39:22 AM »
Looks like the rift has made it to the notch at the top of the screen (to me).  Maybe it'll go with the next full moon?  Click to animate, (1.6 MB).
Apr 20 to May 2

http://www.polarview.aq/images/105_S1jpgfull/S1A_EW_GRDM_1SSH_20170502T035504_E082_S_1.final.jpg (40 MB)

S1A_EW_GRDM_1SSH_20170420T035503_D89B_S_1.final.jpg (40 MB)
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Wipneus

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Re: PIG has calved
« Reply #660 on: May 07, 2017, 10:08:58 AM »
The pixel noise in these Sentinel radar images make it hard to be sure. But it looks as some more opening/deepening at the ends of the crack.

nukefix

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Re: PIG has calved
« Reply #661 on: May 07, 2017, 05:02:28 PM »
The pixel noise in these Sentinel radar images make it hard to be sure. But it looks as some more opening/deepening at the ends of the crack.
Yes, if there's coherence InSAR would be the way to see the progress for sure.