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Author Topic: Pine Island Glacier (PIG) Calving and Discussion  (Read 738063 times)

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1450 on: January 12, 2020, 01:13:18 PM »
Damit, it's Sentinel day and it's cloudy over the PIG. :(

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1451 on: January 14, 2020, 03:20:36 PM »
meh -.-

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1452 on: January 14, 2020, 04:48:08 PM »
Blumenkraft, this morning Polar View was working and is currently working (at least this morning I saved the images).

But there was nothing to report and therefore no post.

attached two zoom :
one relative to the PIIS from the low resolution image (S1A_EW_GRDM_1SDH_20200114)
one relative to the Cork from the high resolution image (S1B_IW_GRDH_1SSH_20200114)

There's no need to be in a hurry, it can break at any time or not, the Cork, transformed into a "Ball", will be rolling along the SIS and in a month's time will still be in this situation. ;)

Translated with www.DeepL.com/Translator (free version)

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1453 on: January 14, 2020, 04:57:59 PM »
There's no need to be in a hurry

It's not only that i'm impatient, i also hate it when stuff doesn't work as expected.  ;)

RoxTheGeologist

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1454 on: January 14, 2020, 06:50:10 PM »

Seriously. I check this thread every day. it's a real (ice) cliff hanger.

grixm

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1455 on: January 14, 2020, 10:28:17 PM »
What's going on here? Clouds? Or several mini-calvings?


baking

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Tammukka

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1457 on: January 15, 2020, 11:40:34 AM »
There is new pic from today, in polar view. No calving yet. BTW how can I post images?

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1458 on: January 15, 2020, 07:57:27 PM »
Todays SAR shows, nothing happened.

...

oren

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1459 on: January 15, 2020, 09:17:12 PM »
Thanks for the zoomed out animation over multiple frames. Makes it easier to understand the big picture.
Watching it a few times, it's clear the width of the big crack at its western side (nearer to the cork) has increased significantly over the last week.

Tammukka

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1460 on: January 16, 2020, 05:11:04 PM »
Thanks for animation also. It make all the difference when looking these pics. I think I can see some widening on crack when I look at one point in animation. But Im not sure. There is new satelite image from today, but nothing new. Maybe if it its aded to animation. I still cant put images from my computer here. Only from web. Can you help with that?
« Last Edit: January 16, 2020, 08:15:31 PM by Janne Hietalahti »

Tor Bejnar

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1461 on: January 17, 2020, 12:29:45 AM »
Janne,
I sent you a Private Message (PM) (re posting images).  And welcome to the ASIF!
« Last Edit: January 17, 2020, 05:52:22 PM by Tor Bejnar »
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

crandles

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1462 on: January 17, 2020, 01:21:08 AM »
So what will it be?

1. R2 crack widens allowing ice into that crack which reduces pressure resisting the cork twisting further, so large calving can pass the cork.

2. Cork to twist a little more so large calving can pass the cork (without ice needing to enter crack).

3. Another small calving near cork so large calving can pass the cork.

4. Cork small calving/split/disintegration such that large calving can pass the cork/push parts of cork out.

5. Cork doesn't matter, it is when there is wide enough rifts to shear off calving at Northern end?

6. Something else?

Surely not much longer?

wdmn

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1463 on: January 17, 2020, 02:28:37 AM »
I have no opinion.

But imagine somewhere out there, there's some sort of equivalent to the cork just holding this whole beautiful, terrible universe together?

Praise the cork!
F#ck the cork!

KiwiGriff

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1464 on: January 17, 2020, 03:18:16 AM »
Cork this for a lark.
It is done put a cork in it.
Cork and be damned.

I see cracks appearing either side of the date in that Gif
Trick of the light or are they new  ?
Animals can be driven crazy by placing too many in too small a pen. Homo sapiens is the only animal that voluntarily does this to himself.
Notebooks of Lazarus Long.
Robert Heinlein.

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1465 on: January 17, 2020, 03:58:00 AM »
Crandles,

South side:
The compression effort between the Cork and the future Iceberg is decreasing and will soon be null which will lead in any case to the release of the Iceberg on the south side (hypothesis 2).
It could be that the southern edge of the iceberg will crumble beforehand (hypothesis 3): if this becomes more difficult as the pressure decreases, it must be taken into account that it must not be in good condition.
The Cork itself should not break (I thus retain less probable hypothesis 4).
The widening of R2 is upstream of the Cork-Iceberg junction and for me it does not change the terms of the problem (so I do not retain hypothesis 1)
I would like to add two other hypotheses for completeness:
Crumbling of the eastern edge of the future Iceberg SWT-SIS which is one of the points of support of the Cork. This side took a big knock during the compression by the plug with the formation of many fractures parallel to the compression stress. Now the compression tends to decrease, but also to change direction, which, taking into account the existing fractures, could lead to its crumbling: to be taken into account (hypothesis 6).
The iceberg is now weakened and could break north of the point of contact with the cork (hypothesis 7).

North side:
For the moment is more solid, but once it's yielded to the south it shouldn't last long (a month?). Hypothesis 5 for me is therefore not an alternative to the other hypotheses, but complements them.
But while waiting for the north side the iceberg could start to crumble (hypothesis8).

Open questions:
* North side: how will the breakage occur: will we keep the side of the shelf attached to the pinning point or will we lose a piece of it, which would move the pinning point back?
* Once the Pinning Point is detached from the future Iceberg, will it stay in place at least temporarily or will it also calve immediately allowing the dense ice mixture upstream to calve quickly?
* Will R3 continue to widen and expand creating the conditions for further calving or, once the south side of the Iceberg is free, will it temporarily stabilize?

 Conclusions : we don't have many positive elements ...

Translated with www.DeepL.com/Translator (free version)

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1466 on: January 17, 2020, 05:10:30 AM »
Thanks for animation also.

Welcome, Janne. :)

And welcome to the forum also!

Tammukka

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1467 on: January 17, 2020, 09:19:44 AM »
No news since yesterday, thanks to Neven I can now post the pictures. I circled the point were you might see some widening. Here is 16.1 image included.

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1468 on: January 17, 2020, 10:32:29 AM »
This is the cork zoomed in, from end of 2017 to today, monthly increments.

Click to play

Any time now...

Tor Bejnar

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1469 on: January 17, 2020, 05:57:01 PM »
The "cork" looks like a crushable re-forming (smaller and smaller) set of ball bearings.  Great GIF, B_.
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1470 on: January 17, 2020, 06:03:28 PM »
Thanks, Tor.

And nice description. ;)

oren

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1471 on: January 17, 2020, 08:20:02 PM »
Honestly it looks like it's already calved and is not attached in any way to the rest of the ice shelf. Just held by a bit of side pressure.

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1472 on: January 17, 2020, 09:41:57 PM »
Oren,
there are only 600m and they only hold because there are only compressive forces, but for the moment there has been no separation between the Cork and the future Iceberg (the image is from 06/01, but the Sentinel1 images of the following days don't seem to show anything else), the two are still attached. This can break at any time, but for me it can't be said that he has already calved (virtually maybe, but not really).
Plus there's no detachment on the north side yet.

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grixm

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1473 on: January 17, 2020, 10:22:04 PM »
I'm also of the impression that the cork means nothing. Maybe there is still a connection or friction, but it looks completely dwarfed by the strength that comes from the connection on the northern side.

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1474 on: January 17, 2020, 10:54:24 PM »
Grimx,
There was and still is no friction, but a compression to be absorbed to allow the advancement of both: Future Iceberg and Cork: it was physical, to advance it was necessary to compress (reduce the cumulated length of the Future Iceberg and Cork). In a certain sense this is the principle of the keystones.
That's what made it possible to hold. As soon as the pressure stops (and it is decreasing) and/or shear forces appear, both will immediately detach.
It is not the north side that the south side holds together... 

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blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1475 on: January 18, 2020, 06:24:53 AM »

grixm

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1476 on: January 18, 2020, 08:14:53 AM »
Grimx,
There was and still is no friction, but a compression to be absorbed to allow the advancement of both: Future Iceberg and Cork: it was physical, to advance it was necessary to compress (reduce the cumulated length of the Future Iceberg and Cork). In a certain sense this is the principle of the keystones.
That's what made it possible to hold. As soon as the pressure stops (and it is decreasing) and/or shear forces appear, both will immediately detach.
It is not the north side that the south side holds together... 

Translated with www.DeepL.com/Translator (free version)

Where is this pressure coming from? The shelf seems to move perpendicular to the cork, not towards it. And it looks to be in a position where if the shelf does push towards it, it would not hold back at all, it would just rotate away effortlessly and yield.

crandles

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1477 on: January 18, 2020, 12:48:50 PM »
Where is this pressure coming from? The shelf seems to move perpendicular to the cork, not towards it. And it looks to be in a position where if the shelf does push towards it, it would not hold back at all, it would just rotate away effortlessly and yield.

This is how I interpret it. The compression pressure increases until we get to the narrowest pinch point which I have tried to indicate below. Basically calving and cork are too wide to fit through the gap but we are now nearly at the pinch point.

This shows the pressure will soon start decreasing but not quite there yet. However I am not sure my perpendicular and direction of travel are perfect.

Southernmost point in direction perpendicular to travel is nearly at the narrowest point. Also just a little more rotation by cork and direction of travel for calving will be free. Or maybe a combination of these.

The southern pinch point has been slowly deforming to make the gap wider. While ahead of the northern pinchpoint there have been calvings which I think are indicative of this compression stress.
« Last Edit: January 18, 2020, 01:01:09 PM by crandles »

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1478 on: January 18, 2020, 03:16:00 PM »
I tried to be as precise as possible, for this reason I used the images of 06/01 and 18/01 (the two most recent homogeneous images).
I used the same colors as Crandle.
We can see that the movement tends to be perpendiculous at the Cork and that on the 18th we're not far from 90°, but not yet...

The compression effort, in the past months, has had several effects and, to limit myself to the future Iceberg:
* mini-calving at the joint
* opening of the longitudinal fractures (parallel to the calving front) in the Iceberg
* in the north it probably delayed the opening of fractures parallel to the flow due to the shearing, which may cause more damage to the pinning point (in the static or semi-static shelf in front of the pinning point) which may move the pinning point upstream (which is not good at all)

I also suspect that the action of the Cork it is for something in the very fast opening of the R3 (which is not good at all)

crandles

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1479 on: January 18, 2020, 04:25:41 PM »
Thanks for that Paolo, much better than my effort.

With 12 days between those images, it looks to me that if the movement continues at the same rate then green line will become perpendicular in about 24 days. So it seems unlikely that cork could continue to provide much resistance for more than about 24 days. (Could of course happen earlier with small calvings/splits/increased speed etc.) Slowing the movement might make it longer but there is so nearly enough room now whereas previous a high rate of squeeze was needed to make the progress it has, so slowdown now doesn't seem likely. Perhaps this is what Paola is referring to when he said "As soon as the pressure stops (and it is decreasing)"?

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1480 on: January 19, 2020, 04:27:05 AM »
Previously!

27 frames, monthly increments, click to play.
« Last Edit: January 19, 2020, 08:32:18 AM by blumenkraft »

Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1481 on: January 19, 2020, 08:25:19 AM »
Thank you for the animation. It is clearly visible that each of the major calvings happens further upstream than before. The next calving will also be at the highest position ever - independently from when it will happen exactly.
Even the speeding up of PIIS-MIS can't make up for this.
It is too late just to be concerned about Climate Change

Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1482 on: January 19, 2020, 02:18:33 PM »
We should also be aware of the fact that - to my knowledge - the cork is the last solid connection between SWT/SIS on the SW side and the Main Ice Shelf (MIS) of PIIS on the NE side. If this connection is lost, the next solid connection between MIS and SIS is far upstream SE of the "zone of destruction" with hundreds of flosting icebergs. I wonder whether the increasing speed of the MIS will also lead to an extension of the "zone of destruction" further upstream, because the differences in flow speed between MIS and SIS are so huge.
It is too late just to be concerned about Climate Change

baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1483 on: January 19, 2020, 02:33:05 PM »
When If this connection is lost . . .
FTFY

Tammukka

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1484 on: January 20, 2020, 07:22:35 AM »
No news here. 19.1 image here Included.

Tammukka

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1485 on: January 20, 2020, 02:10:24 PM »
New Image from today, still now news.

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1486 on: January 20, 2020, 04:48:15 PM »
North side: R2 and R0 new expansions, now R0 is ahead of R1 and R2 is almost at the same level as R1.

R0, R1, R2, R3 : composite calving  ::)

In this weird calving, and if everything in the north started with R0 ?
 :o

and if everything started with North ?!?
 :o :o


« Last Edit: January 20, 2020, 05:05:42 PM by paolo »

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1487 on: January 20, 2020, 05:28:42 PM »
Maybe! I feel like we see more dynamic changes in the north at the moment. The cork can rotate a little longer. It may act as a natural suspension, holding back the pressure in the south-west.

Something has to give ... any time now.

Tammukka

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1488 on: January 20, 2020, 06:18:12 PM »
Here is new real clear image from south.

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1489 on: January 21, 2020, 11:22:20 AM »
Mini calving.

This is 20. vs 21.

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1490 on: January 22, 2020, 01:05:53 PM »
Good news!

Today is Sentinel day, and for what i can see it will be cloud-free. \o/

grixm

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1491 on: January 22, 2020, 02:06:12 PM »
How can one see the schedule for the sentinel sats?

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1492 on: January 22, 2020, 02:16:17 PM »
Grixm,
The satellite travels in the same orbit every 10 days.

And that's why, to create animations, you have to use images with multiple intervals of 10 days!

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1493 on: January 22, 2020, 02:17:09 PM »
https://sentinel.esa.int/web/sentinel/missions/sentinel-2/acquisition-plans

But you don't need that, actually. There is a repeating pattern, every 10 days for some days (the 2nd, and 7th for the PIG. Moving on the calendar when the month has 31 days of course).

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1494 on: January 22, 2020, 02:21:39 PM »
Blumenkraft,

currently the 2nd and 6th  ;)

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1495 on: January 22, 2020, 02:40:46 PM »
Ah, right. Thanks for the correction, Paolo.

But the blumencrack region is also scheduled for 07th. ;)

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1496 on: January 22, 2020, 08:58:59 PM »
Some zoom:
- Cork NE side (Join with the future iceberg)
- A possible joint between R1 and R2 (which could stop the extension of R2)
- Extension R2
- Extension R3

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1497 on: January 22, 2020, 09:10:45 PM »
and the overall rift context

paolo

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1498 on: January 22, 2020, 09:25:20 PM »
and one last zoom on the north side

blumenkraft

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #1499 on: January 22, 2020, 09:28:19 PM »
I surely didn't expect R3 to grow this direction.

Here is a zoomed out comparison of 23.12. (latest valid cloud-free date) vs. today.

Click to play