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Author Topic: Pine Island Glacier (PIG) Calving and Discussion  (Read 738163 times)

Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2950 on: October 20, 2023, 09:52:22 PM »
Three new Icebergs in Pine Island Bay.

Two calvings recently took place at the northeastern edge of PIIS, close to Evan's Knoll.
The new calving fronts are marked with green lines, the new icebergs are marked with a green "*".

See attached picture (size is approx. 16*16 km)
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baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2951 on: October 20, 2023, 10:03:40 PM »
Here is a 12-day Sentinel-1 GIF of the calving in the Northern Shear Margin (NSM).

baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2952 on: October 30, 2023, 03:12:54 PM »
A long-anticipated calving of the SWT:

FredBear

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2953 on: November 09, 2023, 03:50:49 PM »
More calving along the eastern edge today? (Northern shear margin?)(Worldview). Followed by a thin streamer of ice heading north across the bay in a later image
Might be clearer later - & others may have better images.
Update: As Stephan points out the clearer Sentinel images show ice clearing rather than new calving - thanks.
« Last Edit: November 11, 2023, 12:20:46 AM by FredBear »

Stephan

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baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2955 on: November 10, 2023, 05:21:05 PM »
Here is a 2-day GIF showing the movement in the Northern Shear Margin (NSM) is all sea ice and melange.

baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2956 on: November 10, 2023, 07:05:24 PM »
Here is a Sentinal-2 comparison between October 20 and November 9.  Use the top slider.

https://sentinelshare.page.link/5DNx

Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2957 on: November 13, 2023, 09:00:36 PM »
Micro calving at Southern Shear Margin of Pine Island Glacier.

A very clear sentinel picture allows a comparison of details between Oct 20 and Nov 13 of this year.
I want to report on three different observations:
1. Micro calving of two icebergs at the calving front and release of ice mélange close by (greenish circles).
2. Lengthening and deepening of cracks within the Eastern part of SWT (orange lines)
3. Calvings within the "ice mess" of the Southern Shear Margin (SSM) (red squares).

It looks like there is more things to calve and more cracks to develop this melting season.

See attached picture. The dotted blue line roughly divides the two flow directions (lower part NNE, quite slow; upper part WNW, much faster)
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vox_mundi

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2958 on: December 05, 2023, 06:16:42 PM »
Major Antarctic Glacier Passed a Tipping Point In the Last 80 Years, Research Reveals
https://phys.org/news/2023-12-major-antarctic-glacier-years-reveals.html



Researchers have now been able to confirm that Pine Island Glacier underwent a rapid, unstable retreat at some point between the 1940s and 1970s, leading to an irreversible loss of ice over several decades.

Between the 1940s and 1970s the glacier, which was 40km more advanced than its present-day position, detached from a seabed ridge. It underwent a rapid retreat until it temporarily stabilized on a shallow part of the seabed in the late 1980s.

While their study suggests that this accelerated phase of mass loss may now have come to a halt, their results indicate that by the early 1970s the glacier had retreated to a point where it could not recover its original mass and position during colder conditions. This confirms that the glacier's retreat during this period is irreversible, meaning it has passed a tipping point.



The researchers also applied their numerical model to predict the future behavior of the glacier in a separate study and have found that it will again enter periods of rapid retreat unless global warming is kept within limits.

Professor Mattias Green, Professor of Oceanography in the School of Ocean Sciences at Bangor University, said, "The investigation highlights the important interactions between the ocean and the glaciers in Antarctica. The trigger of the historical retreat was possibly an episode of warm ocean water entering the area of Pine Island Glacier, and even when conditions returned to the cold state, the retreat continued. This is quite concerning for the future state of Pine Island Glacier and its neighbors in a warming world.



Brad Reed et al, Recent irreversible retreat phase of Pine Island Glacier, Nature Climate Change (2023).
https://www.nature.com/articles/s41558-023-01887-y
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grixm

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2959 on: December 14, 2023, 10:26:03 PM »
Looks like this piece from the northern sheet next to the PIG is getting ready to calve. Attached is an animation between now and this spring. You can see that the front has already fallen off, but behind, a crack is growing and the whole thing is bulging outwards. And this is actively ongoing, you can tell there was movement even in just the last few weeks.

There's also the older but still growing crack further inward that could lead to an even larger calving some day.

Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2960 on: December 26, 2023, 08:48:14 PM »
Calving at South West Tributary (SWT).

The actual EOSDIS shows that the western tip of this glacier has calved (circled in yellowish green). It has been connected so far at two points (red arrows) and blocked SWT like a cork. Now the ice has lost both connections which will further destabilize SWT. I marked all cracks that have widened or expanded in comparison to Dec 13 with blue lines.

See attached picture, N is up, size is approx. 12*16 km.
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Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2961 on: January 31, 2024, 04:12:20 PM »
Micro calving at SWT.

Yesterday a small nose of ice broke off the northeasternmost tip of Southwest Tributary (SWT), circled in orange. This part has been under pressure for a while now from the icebergs coming out of the south shear margin, flowing parallel to the PIIS. Its flow direction is almost orthogonal to that of SWT.
More calvings in this area to be expected in the near future.
See attached picture. N is up.
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baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2962 on: February 09, 2024, 03:31:51 PM »
Small calving today at the front of PIG.

Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2963 on: February 13, 2024, 09:40:58 PM »
Recent observations at SWT.

The latest Sentinel picture of SWT is very clear.
Compared to January 4 following developments have occurred:
Four micro-calvings of grounded icebergs and tips of the SWT (red squares)
New cracks (green lines) have appeared.
In general the disintegration continues, movement is visible if you compare the two pictures from Jan 04 with Feb 13 in the "compare mode".

See attached picture. N is up. Double click to enlarge it.
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grixm

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2964 on: February 29, 2024, 01:13:30 PM »
SWT calving

baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2965 on: February 29, 2024, 02:56:13 PM »
A 2-day low-res GIF showing a calving from the front of the SWT.

Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2966 on: February 29, 2024, 07:09:27 PM »
Thank you for the animation. This was long awaited and might open further calvings of icebergs from the Southern Shear Margin.
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Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2967 on: March 01, 2024, 08:04:04 PM »
Micro calving at Northern Shear Margin (NSM).

Sentinel shows a little missing piece of ice opposite to PIG (circled in red). The area is approx. 1 km². See attached picture. N is up.
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iwantatr8

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2968 on: March 02, 2024, 08:33:49 AM »
Hello Folks,

In an item of historical interest PIG was used to help define the speed of crack propogation through the glacier. This is expected to lead to a new model for ice break up.

https://phys.org/news/2024-02-mph-glacier-fracture-reveal-physics.html

some nice images of the 2012/3 breakup.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023AV001023

sidd

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2969 on: March 02, 2024, 11:10:06 PM »
Yes, that is a nice paper and i believe it was posted in another thread, but it really deserves mention here.

sidd

baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2970 on: March 19, 2024, 02:11:45 PM »
2-day low-res GIF showing a calving in the Northern Shear Margin (NSM) of Pine Island Glacier.

baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2971 on: March 25, 2024, 07:24:33 PM »
1-day GIF from Worldview showing a calving from the Melange at the Southern Shear Margin (SSM) near the Southwest Tributary (SWT.)

Stephan

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2972 on: March 25, 2024, 10:44:08 PM »
This was really long awaited. I think there is more to come before the sea freezes over. Thanks for sharing.
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Phil.

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2973 on: March 26, 2024, 02:48:19 AM »
Yes, it's at the convergence of those two flows which you showed in this earlier image:
https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=429.0;attach=399421;image

baking

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Re: Pine Island Glacier (PIG) Calving and Discussion
« Reply #2974 on: March 26, 2024, 03:00:18 PM »
12-day high-res GIF of yesterday's calving of the Melange in the Southern Shear Margin (SSM) near the Southwest Tributary (SWT.)