Totten Glacier Discussion

[FredBear]

Some early ice losses from a tongue just west of 120E in Wilkes Land on Worldview today?

[Stephan]

Well spotted, FredBear.
I am not familiar with the name of the glacier that is affected. This post (and FredBear's post) should go into a new thread.
A calving took place on Oct 10 at that ice shelf. It has a size of 7*34 km.
The remainders are circled in green on the second picture.
First picture is from Oct 02, second is from Oct 27. Size of the pictures are roughly 100*65 km, N is down right.

[gerontocrat]

Ice sheet mass loss in the Wilkes Basin since 2002 is the 4th highest in the 25 Antarctic basins  according to the GRACE/GRACE-FO data as analysed by GFZ. (the 3 highest are in in the West Antarctic Ice Sheet)

Also sea ice in the West Pacific Region (that includes the Wilkes Basin coast) is currently the lowest on this day in the 44 year satellite record. (Graph attached).

So much for the ice fortress of East Antarctica?

[oren]

I'm having trouble locating it, on my mobile.
Could it be Frost?

[FredBear]

Looks like Totten, a little above 120 E line & flowing from behind the bulge.
These maps are very useful, thanks.

[oren]

It's thanks to the thread you started (which I've now made sticky).

[paolo]

On the occasion of the recent calving (see posts in the thread "Antarctic Ice Sheet") I start this new thread
I remind you that the Totten Glacier is likely to be the sick one in East Antarctica and that it would be important to follow it

Here you will find an animation related to this calving that I think dates from October 09 (in the Sentinel1 EW image (low resolution) of 08 the calving has not yet taken place and that of 10 is after it)

All the images of the animation: maps and satellite images, are loaded on QGIS (I used Quantarctica as base)
Standard information added :
> latitude and longitude
> front and grounding lines provided by :
>> MEaSUREs Antarctic boundaries (in green; with data for the years 2007/2009)
>> USNIC_Antarctic Ice Shelf Data (yellow; from early 2019)
>> SCAR_ADD-Antarctic Digital Database (v7.3; orange; from early 2020)
And, not visible (overwritten by v7.3 as there has been no update in this sector)
>> SCAR_ADD-Antarctic Digital Database (v7.4; in red; from early 2021)
>> SCAR_ADD-Antarctic Digital Database (v7.5; in purple; from early 2022)

The images in the animation are :
> the PGC Antarctic map,
> the composite image of
>> the "Cape Peremennyy to Totten Glacier (Aviation Map)" map from AADC
>> the Sentinel1 IW image (high resolution) of 03/10/2022 (before calving)
> a first zoom (factor 4) of this same image
> a later zoom (factor 4) of the Sentinel1 IW image of 03/10/2022
> the Sentinel1 IW image of 15/10/2022 (after calving)
> Sentinel1 IW image of 27/10/2022
> Sentinel1 IW image of 13/10/2022 to which I have added information

This calving in itself is not extraordinary, but the last two years' calvings have significantly reduced the Tongue and the front has regressed significantly.

Large images (2000x1500) click to animate and click again to enlarge completely.

[oren]

Paolo thanks for starting this thread and for the animation which places the location within context and clearly shows the calving.
I took the liberty of moving the posts from the other thread here, they are bumped above the original post as sorting is by date.

[Stephan]

Thank you Paolo for starting this thread and thank you Oren to move the Totten Glacier related postings into this new thread.

[FredBear]

Not a lot has changed on the visible front to this glacier since the break-out reported in late October. Surface flow away from the glacier has tended to clear ice from the "active" front but the area is still protected more generally by surrounding pack ice at the moment.
Icebergs breaking off from Totten do not accumulate into long lasting "rafts" as appear at Thwaites but may help reinforce the local pack ice?

Totten is worth watching for changes as this area is suspected of being attacked by melt from deeper warm waters which could lead to rapid calving.

[kassy]

Antarctic helicopter mission helps confirm Totten Glacier melting from below due to warm water


In short: A helicopter expedition has helped scientists confirm warm water is melting the Totten Glacier from below.

By dropping probes from a helicopter into cracks in the ice, a research team was able to measure temperature and salinity in previously inaccessible areas in East Antarctica.

The researchers say helicopter-based measurements are better than ships because helicopter operations are "insensitive to sea ice conditions", faster and more manoeuvrable than ships and "cheaper to operate than an icebreaker".

What's next? The research, conducted in 2019 but only just published, will help researchers fill in the "bigger picture" of the pathways and mechanisms of warm water inflow.

...

Over six days, a helicopter crew dropped dozens of probes into cracks — ranging from 15 metres to over half a kilometre — in the ice.

The probes measured the temperature and salinity of the water down to a depth of 1,000 metres.

After sinking to the seabed, they transmitted data back to the helicopter.

...

The data confirmed a long-held theory: warm water — between 0.5 and 1 degrees Celsius — had entered a large and previously unsampled depth under the continental shelf region.

...

https://www.abc.net.au/news/2023-09-13/antarctic-sea-ice-probes-dropped-from-helicopter-totten-glacier/102844512

Helicopter-Based Ocean Observations Capture Broad Ocean Heat Intrusions Toward the Totten Ice Shelf
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL097864

[Often Distant]

I attach a few up to date animations. The first one spans 2015 to 2023, one image per year, focusing mainly on Totten Glacier. The region sits near the margin of the Antarctic circle. Surrounding bathymetry is shallow, constraining many icebergs many years, which can be unsettling for sea ice as well as aiding its formation. Sea ice can remain fasted for multiple years. High winds can smash it through the grinders. To the west of Totten, open seas tore away much of the tongue of Williamson Glacier in 2021. Williamson flows down the land mass Law Dome from near 1km high. Totten occupies a trough in excess of 1km deep for hundreds of kilometres, and drains a basin that mostly sits grounded well below sea level. A narrower trough near 2km deep continues around the other side of Law Dome, where Vanderford Glacier is seen having recently calved.

The second gif is further east. It switches between 2017 to 2023, and 2015 to 2023. Moscow University Ice Shelf (MUIS) comes in at the left, and Porpoise Bay is to the right releasing sprays of icebergs into the churners. MUIS occupies a similar trough to Totten near 1km deep, though has lower inflow, outflow and elevation. Discharge highly constrained.

The third gif has a longer duration and is spectacular like ice on fire. Extremely interesting to watch as it captures quite a lot. One of the hottest animations yet. A sense the world is burning seems somehow portrayed. Fly over times are similar throughout. Sun angles change through the seasons, highlighting differing features at differing altitudes and elevations. It begins in 2015 and follows the sea ice and iceberg dynamics through the initial freezing season, before Totten comes into view and focus switches to various lighting dynamics through melt seasons to current and better captures the break up of Williamson Glacier.