East Queen/Dronning Maud Land
Indian ocean sector
This is an unstable segment of East Antarctica set to appear a lot different in years to come. Located 70°S/ 38°E, Shirase is a mid size glacier near 10km wide occupying an extended deep depression over 200km. It drains a catchment area of 165,000 km2 where ice mass has gained through snowfall in recent decades. Shirase flows at velocity exceeding 2km per year, near 6m per day. One of the fastest flows on the continent. Depths below the floating tongue exceed 1km with warm saline water intrusion from the north. Bottom melt rates may exceed 10m per year. Icebergs can be well beyond 500m thick. Outflow is highly constrained by bathymetry, with a long fracturing frontal tongue prone to colliding into island mass. Relentless force keeps warping through. Fast sea ice generally embraces the bay. Early sea ice break up can be extremely dramatic. Multi-year fast ice can be multiple metres thick. Today it is mostly young.
The tongue is extending roughly about as far north as it has in over 3 decades. The bay was clear of the tongue back to the calving front in Havsbotn Bay in 1988. Sea ice disintegrated in 1997 and 1998 to bring the tongue back down. Sea ice largely broke up a couple of years in the mid 00's and mid 10's without drawing out most of the tongue. In recent years late sea ice break up has tended to be brought to a halt through the onset of freeze. The next time the tongue clears out, the neighbouring gigantic Kaya tongue may be joining a ride alongside much of what remains of the gigantic old tongues of the Riiser-Larsen Peninsula. Large ice mass loss is on the cards, and cards are falling.
The first gif is of EO Browser imagery from 2015 to 2023 displaying the pulling away motion of the peninsula ice intensifying. It seems to be losing its grip. Shallow bathymetry highly constrains ice bergs at the northern tip, largely fencing them in for 40km. They need to go around it or through it like pepper through a grinder. The second gif of Nasa Worldview imagery from 2000 to 2023 focuses on the progression of the shirase tongue extension and sea ice characteristics.
On the 1974 annotated image, the tip of Kaya appears pointing toward the tip of the Shirase tongue and Padda Island. In images from 1989, Kaya appears close against Botnneset Peninsula/Prince Harald Land/ Austhovde rocks. In 2023 it is tending north and it no longer seems to move very slow. 100 years worth of tongue could soon pull away.
1989 peninsula images are flipped horizontal for orientation, and are lifted from this study:
https://www.cambridge.org/core/journals/annals-of-glaciology/article/antarctic-glaciertongue-velocities-from-landsat-images-first-results/98ADAE986007FF2C65FB119A607216EC1973 and 1988 comparison taken from this article:
https://www.sciencedirect.com/science/article/pii/S18739652100003811990/1997/2007 comparison taken from here:
https://www.eorc.jaxa.jp/en/earthview/2007/tp071017.html1974 annoted landsat image is taken from this useful historical resource:
"Satellite Image Atlas of Glaciers of the World ANTARCTICA":
https://pubs.usgs.gov/pp/p1386b/p1386b.pdfThe atlas was more interested in inland meteorite study location and overlooked the peninsula.
Kaya looks understudied. What is known about it? What did it look like?
The sea ice is breaking up right now, before the end of winter. Developing situation.
