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b_lumenkraft

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Amery Ice Shelf
« on: February 21, 2019, 04:14:14 PM »
Resuming conversation from

New clear Sentinel pics today.

Link >> https://apps.sentinel-hub.com/sentinel-playground/?source=S2&lat=-71.61099038970809&lng=69.23789978027344&zoom=13&preset=CUSTOM&layers=B01,B02,B03&maxcc=20&gain=1.0&gamma=1.0&time=2018-08-01%7C2019-02-21&atmFilter=&showDates=false&evalscript=cmV0dXJuIFtCOEEqMSxCMDMqMSxCMDIqMV0%3D

Indeed the big melt pond is now frozen but with pretty blue cracks visible. I wonder if it's melting again. (pic1)

Upstream the melt ponds are still blue. (pic2)
« Last Edit: March 25, 2022, 09:36:13 AM by oren »

Stephan

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Re: The Amery Ice Shelf Thread
« Reply #1 on: February 21, 2019, 06:07:44 PM »
Thanks for opening this thread. I think Améry should gain more attention than it received so far in this forum.
It is too late just to be concerned about Climate Change

b_lumenkraft

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Re: The Amery Ice Shelf Thread
« Reply #2 on: February 21, 2019, 06:13:25 PM »
Agreed Stephan. :)

Since Neven never opposed i just went for it! ;)

oren

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Re: The Amery Ice Shelf Thread
« Reply #3 on: February 22, 2019, 01:31:57 AM »
Thanks for opening this thread. I think Améry should gain more attention than it received so far in this forum.
+1, although I hope it stays calm and cool and loses attention...

maga

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Re: The Amery Ice Shelf Thread
« Reply #4 on: September 25, 2019, 09:11:07 PM »
Big claving at Amery!

blumenkraft

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Re: The Amery Ice Shelf Thread
« Reply #5 on: September 25, 2019, 09:27:00 PM »
Wow!  :o

Stephan

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Re: The Amery Ice Shelf Thread
« Reply #6 on: September 25, 2019, 10:05:40 PM »
Wow  :o
That is huge, and probably not seen there for a while ?!? [Haven't checked the calving history of this ice shelf]
It is too late just to be concerned about Climate Change

sidd

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Re: The Amery Ice Shelf Thread
« Reply #7 on: September 25, 2019, 11:08:17 PM »
I have been worried about Amery for a while. I have been seein sporadic reports of warm water offshore. The ice profile in that basin is concave upward and the thing is like a dagger pointed into the heart of antarctica.

sidd

oren

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Re: The Amery Ice Shelf Thread
« Reply #8 on: September 26, 2019, 03:46:50 AM »
A quick and dirty Worldview animation shows that the ice shelf forward progress since the year 2000 was less than half of the calve width, so I would say this sets back Amery ~40 years. Hopefully this is cyclical and the next 20 years will see Amery back to its year 2000 position.
If someone has access to older satellite images of the shelf this could be improved.

In addition, this article (linked from Wikipedia) says the following:
Quote
Australians to study giant Antarctic ice cracks
Updated 20 Dec 2006, 7:39am

Hobart scientists are heading to Antarctica to study the cause of enormous cracks forming in the Amery Ice Shelf.

The cracks began forming around a decade ago and are growing at three to five metres a day.

The fractures threatened to break off a 900-square-kilometre piece of the Amery Ice Shelf, which is about the size of Tasmania.

Scientists want to know what is causing these cracks, as the last recorded activity in this part of eastern Antarctica was in the 1960s.

The head of the research, Professor Richard Coleman, says there is not enough evidence to blame global warming.

"It may be in a 50- to 60-year cycle but we would need more data to say whether it's increasing in terms of calving events due to warming of the ice shelf," he said.

Professor Coleman says with the ice already floating, it will not increase ocean levels.

As the new calving is roughly 900 km2 (eyeballing maga's image), this could be the result of a very long process.

IceConcerned

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Re: The Amery Ice Shelf Thread
« Reply #9 on: September 26, 2019, 11:53:44 AM »
The speed of this calving is properly astonishing : I was having  alook from time to ime to the shelf, and the big cracks showed no really active propagation
For example see Sentinel image (from Polarview) on Sept.23 :
https://www.polarview.aq/images/105_S1jpgfull/S1A_IW_GRDH_1SSH_20190923T154447_5F29_S_1.final.jpg

blumenkraft

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Re: The Amery Ice Shelf Thread
« Reply #10 on: September 26, 2019, 07:11:03 PM »
And to make the collection complete, here is the Sentinel radar, 20. vs 25.


Stephan

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Re: The Amery Ice Shelf Thread
« Reply #11 on: September 26, 2019, 08:59:10 PM »
Thank you blumenkraft and Oren for these movies.
Compared to PIIS and Thwaites Amery seems to be at least half a tens potency slower.
It is too late just to be concerned about Climate Change

blumenkraft

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Re: The Amery Ice Shelf Thread
« Reply #12 on: September 26, 2019, 09:07:39 PM »
Welcome, Stephan. :)

vox_mundi

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Re: The Amery Ice Shelf Thread
« Reply #13 on: October 01, 2019, 06:34:17 AM »
Giant Iceberg Breaks Off East Antarctica
https://www.theguardian.com/world/2019/oct/01/giant-iceberg-breaks-off-east-antarctica

The tabular iceberg, officially named D-28, separated from the Amery ice shelf on 26 September. The iceberg is 1,636 square kilometres in size, or about 50 x 30km, the Australian Antarctic Division said.

It is the first major calving event on the Amery ice shelf since 1963-64.

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Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

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blumenkraft

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Re: The Amery Ice Shelf Thread
« Reply #14 on: October 01, 2019, 06:47:51 AM »
Actually, it broke off between 24th and 25th, not 26.

Also, the morphing thingy the Guardian did with their GIF is weird. Gives a wrong impression of what happened.

With ASIF you get a timely and correct reporting with accurate GIFs.  :P

sidd

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Re: The Amery Ice Shelf Thread
« Reply #15 on: October 07, 2019, 02:15:38 AM »
Last year, Alley et al. (doi: 10.1016/j.rse.2018.03.025 )  valued antarctic ice shelf vulnerability to hydrofracture. The measure of vulnerability is the fraction of ice saturated firn.

Amery is disquieting, The first figure attached shows the Amery Shelf in panel a (panel b is the Roy Baudouin shelf)

Today ASLR informs of Stokes et al. (doi : 10.1038/s41598-019-50343-5 ) who superpose supraglacial lake images on those vulnerable areas. Amery is even more disquieting. The second figure attached shows Amery in panel b.
The lakes are in black, the grounding lines in red.

sidd



blumenkraft

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Re: The Amery Ice Shelf Thread
« Reply #16 on: February 09, 2020, 07:01:53 PM »
Bit off-topic: Much less pooled water higher up the ice-shelf in this catchment area this year - the lowest big pool in particular is missing!

I noticed the same. I suspected it could have drained. It was very big and must have been very deep. I can't imagine it to freeze solid during one winter.

FredBear

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Re: The Amery Ice Shelf Thread
« Reply #17 on: January 07, 2021, 11:08:02 AM »
Much less "blue" melt water this year on the whole ice shelf so far - probably less than any year since 2002. Amery's biggest melt years  by Jan.7 were 2004-6, 2015, 2019 (on Worldview) with big pools of blue water.

vox_mundi

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Re: The Amery Ice Shelf Thread
« Reply #18 on: June 26, 2021, 07:03:38 AM »
Antarctic Lake Suddenly Disappears
https://phys.org/news/2021-06-antarctic-lake-suddenly.html



A global team of scientists including several from Scripps Institution of Oceanography at the University of California San Diego discovered the sudden demise of a large, deep, ice-covered lake on the surface of an Antarctic ice shelf.

This rare event, chronicled in a study published today in the journal Geophysical Research Letters, occurred during the 2019 Antarctic winter on Amery Ice Shelf in East Antarctica, and it is estimated that 600-750 million cubic meters (21-26 billion cubic feet) of water, about twice the volume of San Diego Bay, were lost to the ocean.

Study authors used images from a radar satellite which can "see" during the polar night to pin the event's timing down to a week or less in June. After drainage, in place of the lake, there was a crater-like depression in the ice shelf surface, covering about eleven square kilometers (4.25 square miles). This surface depression, known as an ice "doline," contained the fractured remains of the ice cover.

The hydrofracture process has been implicated in the collapse of smaller ice shelves in the Antarctic Peninsula, where meltwater forms on the surface of ice shelves during austral summer, but it is not often seen driving through ice as thick as the 1400 meters (4,590 feet) at this location on Amery Ice Shelf.

Repeat orbits of ICESat-2 on the exact ground tracks before and after the lake drainage revealed the vertical scale of the disruption. The ice surface fell as much as 80 meters (260 feet) in the doline cavity, even though the loss of the water load made the floating ice shelf lighter and ocean pressure caused it to flex upwards, with the lake's immediate surroundings rising as much as 36 meters (118 feet).

The team also used surface elevation maps generated by the Polar Geospatial Center (PGC) at the University of Minnesota to show that the disruption modified the regional landscape across 60 square kilometers (23 square miles).

The uplift of the lake created a new lake out of a shallow arm of the original one. During the next melt season this lake filled within a few days at more than a million cubic meters per day and overflowed into the doline cavity. When ICESat-2 crossed the doline again a few days later, the team was able to measure a meltwater channel 20 meters (65 feet) wide, freshly cut into the doline, detecting the water surface at three meters depth, and photons scattered from the stream bed a further three meters below.

The amount of water lost to the ocean was calculated using the volume of the cavity and the extent of uplift. While Amery Ice Shelf does have many melt-lakes and streams in austral summer, the amount of water lost when the lake drained was many times the annual meltwater input to it.

"This abrupt event was apparently the culmination of decades of melt-water accumulation and storage beneath that insulating lid of ice," said co-author Jonathan Kingslake, professor at Lamont Doherty Earth Observatory at Columbia University, who aided in the measuring of the surface meltwater.

The future of the newly formed doline is uncertain. It may accumulate meltwater again or drain to the ocean more frequently. It appears that the fissure reopened briefly in the 2020 melt season. It is certain that scientists will now be watching.

Roland C. Warner et al, Rapid formation of an ice doline on Amery Ice Shelf, East Antarctica, Geophysical Research Letters (2021).
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL091095
There are 3 classes of people: those who see. Those who see when they are shown. Those who do not see

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

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oren

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Re: The Amery Ice Shelf Thread
« Reply #19 on: June 26, 2021, 11:00:28 AM »
Amazing.


FredBear

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Re: The Amery Ice Shelf Thread
« Reply #21 on: January 28, 2022, 05:50:01 AM »
The lack of melt ponds on the Amery Ice Shelf can be seen in the posts from reply 16 - due to the draining of a massive ice-covered melt lake in the middle of winter down through 1.4km of ice in 2019, which also disrupted the surface of the shelf over an area of 60 sq km.

Although many of the old melt pools are missing from the shelf (because of the disruption of old drainage patterns?), blue melt & pools are still quite evident in the grounded area surrounding the shelf at this time.

FredBear

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Re: The Amery Ice Shelf Thread
« Reply #22 on: February 25, 2022, 12:11:57 AM »
Blue signs of melt have continued round the fringe of the Amery Ice Shelf but little on the shelf this year again (now freezing from mid-February).
Fast-ice had been keeping the open sea away from the left hand front of the shelf but recently this has broken away and eventually turned to "mush", adding a little to the fast-ice on the right hand side which has been disappearing in a similar fashion this year.
The old section of the front of the tongue is therefore more exposed now and has had old cracks to the left which have been growing for many years    .     .     .

IceConcerned

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Re: The Amery Ice Shelf Thread
« Reply #23 on: March 09, 2022, 12:25:00 PM »
On the Eastern side of Amery IS, one glacier is close to losing its floating tongue and generate quite a big iceberg. It is besoming more obvious even on the low-res images currently available. I guess it will stay there for a moment, even after calving, either staying grounded or blocked by D23 acting as a cork.
About D23, it has shed some ice cubes in the past months (full line), and seems about to repeat that feat (dotted lines). Nothing to change its situation radically however

FredBear

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Re: The Amery Ice Shelf Thread
« Reply #24 on: March 09, 2022, 02:03:18 PM »
(On Worldview in 2003) D23 was breaking from the glacier in a similar manner to the new 'berg and it has been moving forward and fraying ever since!  (Glacial pace!!)
This year more fast ice has broken away from the fronts of D23 and the Amery tongue leaving them more exposed than last year - but previously in many years there has been less fast ice remaining.
The big crack in the Amery Shelf (would be above D23 in the image) has widened in the last year - but each year there are deeper cracks that appear in it during the melt season. One day (& it could be in winter?) the next big calving from Amery will occur and the landscape will change    .    .   .

gerontocrat

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Re: Amery Ice Shelf
« Reply #25 on: July 03, 2022, 03:30:45 PM »
This article - open access, discusses the impact of warm surface waters on ice shelves using the Lambert Glacier–Amery Ice Shelf (AIS) and Prydz Bay in 2017 as a case-study.

I don't think this study has been noted in the ASIF so far.

They suggest their results can be applied to the Antarctic ice shelves in general.

Of interest also is that this year (2022) the February minimum sea ice area and extent in the Indian Ocean region was at a record low - even lower than in 2017. See graoph & map attached. Was there a similar effect to 2017 on melting of the ice shelf?

https://www.nature.com/articles/s43247-022-00456-z
Warm surface waters increase Antarctic ice shelf melt and delay dense water formation
Quote
Abstract
Melting ice shelves around Antarctica control the massive input of freshwater into the ocean and play an intricate role in global heat redistribution. The Amery Ice Shelf regulates wintertime sea-ice growth and dense shelf water formation. We investigated the role of warm Antarctic Surface Water in ice shelf melting and its impact on dense shelf water.

Here we show that the coastal ocean in summer 2016/17 was almost sea-ice free, leading to higher surface water temperatures. The glacial meltwater fraction in surface water was the highest on record, hypothesised to be attributable to anomalous ice shelf melting. The excess heat and freshwater in early 2017 delayed the seasonal evolution of dense shelf water. Focused on ice shelf melting at depth, the importance and impacts of warming surface waters has been overlooked. In a warming climate, increased surface water heating will reduce coastal sea-ice production and potentially Antarctic Bottom Water formation.

Introduction
The Antarctic margin and continental shelf globally impact the heat, freshwater, and carbon cycles through the global thermohaline circulation1. Acceleration of continental ice mass loss, initiated through the melting of ice shelves by oceanic heat, will additionally lead to a rise in global mean sea level2,3,4. Excess glacial meltwater input alters stratification that can induce a change in the ventilation of Antarctic Bottom Water5,6,7, the densest watermass in the global ocean. The variability in coastal stratification can also change air-sea exchange of carbon-dioxide and biological productivity8,9. Antarctic shelf waters vary regionally depending the interaction of key physical processes such as buoyancy loss through sea water freezing, heat supply by warm water intrusion, and freshwater discharge from continental ice10,11. Antarctic Bottom Water broadly forms from Dense Shelf Water (DSW)12,13 that originates from sea-ice production and brine rejection in polynyas around the Antarctic coast14.

The second largest polynya, as defined by the area of sea-ice production14, is the Cape Darnley Polynya (CDP, Fig. 1a). The CDP is located immediately west of a large continental embayment called Prydz Bay (PB; Fig. 1a), into which flows the Lambert Glacier–Amery Ice Shelf (AIS), the largest glacier–ice-shelf system in East Antarctica15. Ocean circulation in this embayment is characterized by the clockwise Prydz Bay Gyre associated with westward coastal current, which transports warm modified Circumpolar Deep Water shoreward16,17. Downstream and upstream of the AIS are the Mackenzie and Barrier Polynyas, which provide substantial brine rejection and DSW formation18. Traditionally, the AIS has been regarded as a cold cavity system, with its glacial melting mainly driven by DSW as the Deep Mode and to a lesser extent by modified Circumpolar Deep Water as the Intermediate Mode19,20, out of the typical three overturning circulation regimes in sub-ice-shelf cavity21,22.


a Distribution of sea surface temperature (SST)26 anomaly in February 2017. Active polynyas (climatological sea ice production above 10 m yr−1 51) are shown in blue. Model-based melt rate anomaly in 2017 (relative to the 1979–2019 climatology) is shown for the Amery Ice Shelf and Publications Ice Shelf.
b, e, h Vertical profiles of potential temperature from summer hydrography b in the Cape Darnley Polynya (CDP), e at the shelf break off CDP, and h in front of Amery Ice Shelf. Red solid line denotes the station average in February 2017 shown by red dots in a, and the gray solid line denotes the station average in February during 2010–2020 shown by all dots in a, respectively. Profiles are first averaged for each year, and then averaged for all years. Gray error bar indicates the standard deviation of the multiple years.
c, f Vertical profiles of oxygen isotope ratio and d, g profiles of glacial meltwater fraction (c, d) off CDP and (f, g) at the shelf break off CDP. The upper-bound and lower-bound of the meltwater fraction in d, g were derived from the oxygen isotope endmember of iceberg and ice-core, respectively, and the solid line denotes their average.


Implications for future Antarctic surface water
We have demonstrated the excess heat can accelerate the summer melt of ice shelves and delay dense shelf water formation. The beginning of 2017 was a warm summer in PB and the CDP that was likely attributable to the ocean/ice-albedo feedback. In fact, the sea-ice extent in the preceding spring was the minimum across the 40-year record on the circumpolar scale37,38 and contributed to an albedo decrease on a global scale39. The sea-ice extent minimum coincided with anomalously warm Antarctic Surface Water surrounding most of Antarctica40,41. Future predictions of the Southern Ocean indicate a broad loss of sea-ice cover in association with global warming42,43. The series of anomalous phenomena in the 2016/17 season is categorized as just one extraordinary mode at the moment, but the situation delineated in this study could be the new normal in the near future (Fig. 5).



Together with the anomalous surface heating, the excessive glacial meltwater flux induced by warm Antarctic Surface Water can delay dense water formation, suggesting a potential impact on subsequent Antarctic Bottom Water formation. Given the likely increase in open-water/ice-free periods and corresponding surface ocean heat storage around the Antarctic coastline in response to global warming, there will be an step-increase in the importance and impact of Shallow Mode ice shelf melting44. The summer heat storage in the Antarctic coastal ocean will thus be of increasing relevance to project both global meridional overturning circulation and sea level rise.
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FredBear

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Re: Amery Ice Shelf
« Reply #26 on: October 28, 2022, 12:15:14 PM »
Latest images from Worldview seem to show ice missing (calving?) from western parts of the ice shelf.

Stephan

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Re: Amery Ice Shelf
« Reply #27 on: October 28, 2022, 10:17:45 PM »
Yes, a calving has recently taken place.
A chunk of ice (28 * 18 km) has calved on October 15.
See attached pictures (roughly 250 * 150 km, N is approx. to the right side).
It is too late just to be concerned about Climate Change

FredBear

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Re: Amery Ice Shelf
« Reply #28 on: January 21, 2023, 01:53:46 AM »
Amery Ice Shelf Update.
The iceberg calved in October has been given the number D32 and is proceeding westwards towards the Weddell Sea (like D28?).
The Worldview image of Amery from 19.01.2023 appears to have more cracks near the front of the eastern side of the shelf - some may just be last year's fast ice breaking off but others might be preparation for the next big calving?
Although the surrounding banks around the ice shelf have some blue "melt" colours there has been much less sign of melt ponds on the shelf since the wet-looking 2019-20 summer season. (The big pond drained during the 2019 winter season.)
« Last Edit: January 21, 2023, 02:02:51 AM by FredBear »

FredBear

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Re: Amery Ice Shelf
« Reply #29 on: January 31, 2023, 09:37:55 AM »
More 1st year fast ice has flaked off the east side of Amery, the cracks grinning through the clouds in the shelf above are looking clearer?
« Last Edit: January 31, 2023, 09:56:33 AM by FredBear »

FredBear

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Re: Amery Ice Shelf
« Reply #30 on: February 06, 2023, 09:21:27 PM »
Any radar pictures looking through the clouds at the moment?

Edit
Thanks Paolo, could not see through the clouds but the Amery visible edge looked a bit wide - thought it might be worth checking?
« Last Edit: February 07, 2023, 12:33:16 AM by FredBear »

paolo

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Re: Amery Ice Shelf
« Reply #31 on: February 06, 2023, 09:53:32 PM »
FredBear,

I've looked around and there's nothing to report.

PS: Why don't you use Sentinel Hub EO Browser ?

gerontocrat

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Re: Amery Ice Shelf
« Reply #32 on: March 25, 2023, 11:24:55 PM »
Another less than encouraging science paper - Eric Rignot one of the authors.
Those contributors on the ASIF who understand all this stuff are likely to find this paper really useful.

Lazy me just accepts the conclusions, which seems to be that current models may greatly underestimate the potential for accelerated glacial mass loss as ocean temperatures at grounding zones increase.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL102430
Grounding Zone of Amery Ice Shelf, Antarctica, From Differential Synthetic-Aperture Radar Interferometry
Hanning Chen, Eric Rignot, Bernd Scheuchl, Shivani Ehrenfeucht
First published: 17 March 2023 https://doi.org/10.1029/2022GL102430
Quote
Abstract
We employ a time series of Sentinel-1 differential radar interferometry data from 2018 to detect the variability in grounding line position of the Fisher, Mellor, and Lambert glaciers, which drain about 47 billion tons of ice per year from East Antarctica.

We observe kilometer-scale tidal migration, two orders of magnitude larger than expected for ice flowing over a hard bed. The migration is not in phase with changes in oceanic tide. In two estuaries underlaid by subglacial channels, we observe two states of migration that switch on and off over time scales of several weeks. The range of vertical motion reveals a water column thickness of 2–20 cm. Such intrusions of seawater over wide grounding zones are not accounted for in physical models. Including them will add vigorous melting of grounded ice that will enhance the sensitivity of glaciers to ocean warming and increase projections of mass loss.

Key Points
The zone of tidal variability of Amery Ice Shelf grounding line (GL) is two orders of magnitude wider than expected from hydrostatic equilibrium

We detect GL migration uncorrelated with tide up to 15 km upstream, along subglacial troughs, with 2–20 cm thick water intrusions

Seawater intrusion in estuaries has high potential for melting ice in grounding zone and enhance sensitivity of glaciers to ocean warming

Plain Language Summary
Grounding lines (GLs) are assumed to migrate back and forth with changes in oceanic tides based on hydrostatic equilibrium, which induces horizontal migration in the range of a few 100 m, similar to the spatial resolution of ice sheet models. Differential radar interferometry data from the Sentinel-1 mission, however, reveals that for the Fisher, Mellor, and Lambert glaciers, the migration is two orders of magnitude larger. Such widespread intrusions of seawater will melt grounded ice and affect the regime of basal friction of glaciers and their stability.

Physical models in charge of projecting sea level rise assume a fixed GL, with zero melt. We report regions of enhanced migration (10–15 km) along estuaries underlaid by subglacial channels where water gets trapped for several weeks before draining out. These irregular, widespread interactions between ice and seawater will have a strong impact on glacier evolution and projections if implemented in physical models.
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sidd

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Re: Amery Ice Shelf
« Reply #33 on: March 26, 2023, 07:35:49 AM »
I think i saw a preprint on this a bit ago as well, thanks for the link to the published version. As i have said before, Amery worries me.

sidd

Stephan

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Re: Amery Ice Shelf
« Reply #34 on: March 26, 2023, 07:39:16 PM »
Thanks gero for finding this important and interesting work.
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Re: Amery Ice Shelf
« Reply #35 on: August 31, 2023, 02:08:19 PM »
The first gif spans worldview imagery from 2000-present focusing on the eastern rift, icebergs, glaciers and sea ice characteristics near the end of melting seasons. The large central iceberg at the start of the gif, is also visible in imagery from 1989, having some time previously calved from Polar Record Glacier, which is the largest of the group of comparatively small glaciers to the immediate east of Amery Ice Shelf along the Ingrid Christensen Coast, collectively known as the Publications Ice Shelf. In the dark of 2013, the big old iceberg broke apart rather suddenly in collision with iceberg D23, which calved in the early 00's from Polar Times Glacier. The icebergs along with the expanding tongues, have assisted in general fast sea ice coverage in the shallow corner of Prydz Bay. The rift in Amery keeps widening and D23 keeps shrinking, creating potential the ocean can soon get further in to clear out more rift melange.

The second gif runs from 2015-present of sentinel hub images roughly 6 months apart showing rift progression in more detail. Sea ice is generally near invisible to the camera, though thick multi-year sea ice can be seen remaining in place the entire duration. The consistent swap in sun angle creates an interesting 3D simulation effect highlighting persistent features in the rift. The rift has met up with an existing deep widening crevasse close to the buttressing point where it starts getting a lot deeper underneath the shelf.
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FredBear

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Re: Amery Ice Shelf
« Reply #36 on: January 27, 2024, 01:53:04 PM »
The big fracture in the main shelf above D23 still seems to be widening and the fractures at the sea-ward end of D23 have adjusted themselves recently (on Worldview). Glacial action!

(One day we will see another huge calving like D28, which is currently sailing north of South Georgia and fraying at the edges 4+ years after calving.)
« Last Edit: January 29, 2024, 12:27:26 PM by FredBear »

FredBear

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Re: Amery Ice Shelf
« Reply #37 on: February 15, 2024, 02:49:15 PM »
"Small(?)" calving from the front centre of the ice shelf (Worldview) - still waiting for the big one.