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Author Topic: Sea Ice in Amundsen Sea / Pine Island Bay  (Read 493 times)

Stephan

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Sea Ice in Amundsen Sea / Pine Island Bay
« on: September 29, 2019, 05:32:03 PM »
I start this topic to discuss the different patterns of sea ice and its melting during austral summer which should be separated from Thwaites Glacier / Pine Island Glacier calving events (see the individual threads).
I compared the last for years (see attached pictures from EOSDIS Worldview), which differ widely in extent and structure of the sea ice. I chose clear days, so all pictures are from around end September, but not at the same date. In this time of the year the changes from day to day can be relevant.
2016 saw in general a low sea ice cover in that area, 2017 had the closest ice cover. All pictures show the SE→NW flow of the ice.
It is too late just to be concerned about Climate Change

blumenkraft

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Re: Sea Ice in Amundsen Sea / Pine Island Bay
« Reply #1 on: September 29, 2019, 06:01:29 PM »
My bet is on Circumpolar Deep Water upwellings.

Quote
Glaciological and oceanographic observations coupled with numerical models show that warm Circumpolar Deep Water (CDW) upwelling onto the West Antarctic continental shelf causes melting of the undersides of floating ice shelves. Because these ice shelves buttress glaciers feeding into them, their ocean-induced thinning is driving Antarctic ice-sheet loss today.

Link >> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5510715/

Quote
One day, near the southern edge of Pine Island Glacier Ice Shelf, the researchers directly observed the strength of the melting process as they watched frigid,  seawater appear to boil on the surface like a kettle on the stove. To Jacobs, it suggested that deep water, buoyed by added fresh glacial melt, was rising to the surface in a process called upwelling. Jacobs had never witnessed upwelling first hand, but colleagues had described something similar in the fjords of Greenland, where summer runoff and melting glacier fronts can also drive buoyant plumes to the sea surface

Link >> https://www.earth.columbia.edu/articles/view/2815

Quote
The ice, the ocean and the atmosphere are all intrinsically linked, and in Antarctica we now see how complex changes in atmospheric circulation, driven by climate change and the ozone hole, are changing ocean circulation. Increased upwelling of warm, salty Circumpolar Deep Water is melting away the base of the ice shelves and the grounding lines of some of the largest, most vulnerable glaciers and ice streams in Antarctica, resulting in rapid, far-reaching and irreversible changes.

Link >> http://www.antarcticglaciers.org/glaciers-and-climate/ice-ocean-interactions/changes-circumpolar-deep-water/
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Stephan

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Re: Sea Ice in Amundsen Sea / Pine Island Bay
« Reply #2 on: November 01, 2019, 06:54:51 PM »
I will add some pictures from time to time to compare 2019 with earlier years.
This year the sea ice seems to be much more fragile than last year. I attach the photos from EOSDIS Oct 30, 2019 (upper) and Oct 30, 2018 (lower). Unfortunately there was no day without clouds, but I think you can get an idea of the difference of this year compared with last year.

PS: The orange circled iceberg is one of the remainders of last year's calving.
It is too late just to be concerned about Climate Change