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Author Topic: What's new in Antarctica ?  (Read 117892 times)

Sleepy

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Re: What's new in Antarctica ?
« Reply #400 on: November 12, 2018, 12:40:31 PM »
Iceberg flux from Antarctica from 1976-2017
https://twitter.com/PixelMnM/status/1061696386897530880
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gerontocrat

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Re: What's new in Antarctica ?
« Reply #401 on: November 12, 2018, 12:45:24 PM »
Iceberg flux from Antarctica from 1976-2017
Is it that the record is more complete in later years or has activity increased?
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Sleepy

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Re: What's new in Antarctica ?
« Reply #402 on: November 12, 2018, 01:32:59 PM »
They don't provide the source in their tweet as you are able to read above, I would suspect it's from Budge an Long though. The Antarctic Iceberg Tracking Database.
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vox_mundi

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Re: What's new in Antarctica ?
« Reply #403 on: November 14, 2018, 05:18:09 PM »
Discovery of High Geothermal Heat at South Pole
https://phys.org/news/2018-11-discovery-high-geothermal-south-pole.html

Scientists have discovered an area near the South Pole where the base of the Antarctic Ice Sheet is melting unexpectedly quickly. Using radar to look through three km of ice, the team found that some of the ice – covering an area that's twice the size of Greater London – appeared to be missing. The results are published this week in the journal Scientific Reports.



... The internal layer draw-down, supported by the highly-reflective bed, points to active and significant basal melting in this region.

... "The process of melting we observe has probably been going on for thousands or maybe even millions of years and isn't directly contributing to ice sheet change. However, in the future the extra water at the ice sheet bed may make this region more sensitive to external factors such as climate change."

Open Source: T. A. Jordan et al. Anomalously high geothermal flux near the South Pole, Scientific Reports (2018).
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

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Sleepy

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Re: What's new in Antarctica ?
« Reply #404 on: November 14, 2018, 09:24:45 PM »
"May" is an understatement.
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Thomas Barlow

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Re: What's new in Antarctica ?
« Reply #405 on: November 15, 2018, 04:02:35 AM »

Bernard

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Re: What's new in Antarctica ?
« Reply #406 on: November 17, 2018, 11:18:20 AM »
"Massive Antarctic iceberg spotted on NASA Operation IceBridge flight"
- NASA.
Before and after.
https://climate.nasa.gov/news/2827/massive-antarctic-iceberg-spotted-on-nasa-operation-icebridge-flight/?fbclid=IwAR3TS86kS9mXrAGJgFr7pBUIMloryjMVT5Vr2cLHH6iR3IbGSZQCVqac2To
Given the color of ice and melt water on the top image in this article, no wonder why this glacier is called PIG  ;D

sidd

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Re: What's new in Antarctica ?
« Reply #407 on: November 19, 2018, 08:46:19 PM »
Bronselaer et al. report on effect of increase ice melt from AIS on climate:

They find:

1)meltwater cools the southern hemisphere sufficiently to delay exceedance of tempertature targets by a decade
2)ITCZ and precip moves north,  enhanced drying of the Southern Hemisphere and reduced drying of the Northern Hemisphere
3)Increased subsea (deeper than 400m) warming aroung AIS increasing basal melt.

Unfortunately it seems CMIP6 does not include the effects discussed.

" The direct contribution from mass loss from the Antarctic Ice Sheet is already included in the IPCC assessments of future sea-level rise, although it is acknowledged to be highly uncertain in the fifth assessment report. However, the effect on climate is not included, and will not be in the upcoming CMIP6 experimental design. Similarly, the effects of meltwater from the Greenland Ice Sheet have so far not been considered, and
could lead to further changes in simulated future climate [Refs. 8,36]."

"Meltwater causes a reduction  in global atmospheric warming, delaying the realization of 1.5 °C and 2 °C warming by more than ten years; it drives a northward shift of the ITCZ, which results in reduced drying over Northern Hemisphere landmasses and enhanced drying in the Southern Hemisphere; and  it causes a large (up to 31%) increase in Antarctic sea-ice formation  relative to the pre-industrial period and an increase in subsurface  ocean warming around the Antarctic coast by a factor of four. Our results suggest that a feedback mechanism is in operation, whereby  the meltwater-induced subsurface warming leads to enhanced melting underneath ice shelves, potentially causing further meltwater-related climate effects. "

I notice Sergienko is an author. I attach fig 4. Paper is at doi: 10.1038/s41586-018-0712-z

coverage at

https://phys.org/news/2018-11-antarctic-atmospheric-sea.html

sidd

wdmn

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Re: What's new in Antarctica ?
« Reply #408 on: December 11, 2018, 02:22:17 AM »
Posted this in the Ice Apocalypse thread, but it belongs here too.

More Glaciers in East Antarctica Are Waking Up https://www.nasa.gov/feature/goddard/2018/more-glaciers-in-antarctica-are-waking-up

Quote
East Antarctica has the potential to reshape coastlines around the world through sea level rise, but scientists have long considered it more stable than its neighbor, West Antarctica. Now, new detailed NASA maps of ice velocity and elevation show that a group of glaciers spanning one-eighth of East Antarctica’s coast have begun to lose ice over the past decade, hinting at widespread changes in the ocean.

gerontocrat

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Re: What's new in Antarctica ?
« Reply #409 on: December 11, 2018, 12:12:52 PM »
Bronselaer et al. report on effect of increase ice melt from AIS on climate:

"Meltwater causes a reduction  in global atmospheric warming, delaying the realization of 1.5 °C and 2 °C warming by more than ten years; it drives a northward shift of the ITCZ, which results in reduced drying over Northern Hemisphere landmasses and enhanced drying in the Southern Hemisphere; and  it causes a large (up to 31%) increase in Antarctic sea-ice formation
sidd

All the scientists say increased melt from the AIS will cause / is causing an increase in Antarctic sea ice extent. Up to 2014 the data supported this. Since then the data does not. I posted this on the Antarctic Sea Ice extent thread. At this moment in time the sea ice in Antarctic is falling to bits.

Quote from: AbruptSLR

Quote
This defined layering of temperatures is exactly what is happening now around the Antarctic.

"The reason for the layering is that global warming in parts of Antarctica is causing land-based ice to melt, adding massive amounts of freshwater to the ocean surface," said ARC Centre of Excellence for Climate System Science researcher Prof Matthew England an author of the paper.
"At the same time as the surface is cooling, the deeper ocean is warming, which has already accelerated the decline of glaciers on Pine Island and Totten. It appears global warming is replicating conditions that, in the past, triggered significant shifts in the stability of the Antarctic ice sheet.""

There is a consistent narrative -

AGW is causing land-based ice to melt faster, adding massive additional amounts of freshwater to the ocean surface.

You would think that cold surface water (also low salinity with a higher freezing temperature) would encourage sea ice freeze as winter approaches and discourage sea ice melt as summer commences. Since 1979 up to recently, there has been a slow but measurable increase in Antarctic sea ice extent (maximum extent in 2014). Hypothesis confirmed ?

BUT since then the opposite. Antarctic sea ice extent is in decline, not just at max and min but during the melt season. Temporary aberration? Or is something  extra going on?


ps :Found this post from Jim Pettit on an old Antarctic Thread

https://forum.arctic-sea-ice.net/index.php/topic,178.msg2754.html#msg2754

Quote
New paper explains the recent growth of Antarctic sea ice.
« on: March 31, 2013, 10:20:40 PM »

Nature Geoscience published a new study online today that I found very interesting. It sheds some more light on the reasons behind the seemingly paradoxical growth of Antarctic sea ice (Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion) From the abstract:

"Changes in sea ice significantly modulate climate change because of its high reflective and strong insulating nature. In contrast to Arctic sea ice, sea ice surrounding Antarctica has expanded, with record extent in 2010. This ice expansion has previously been attributed to dynamical atmospheric changes that induce atmospheric cooling. Here we show that accelerated basal melting of Antarctic ice shelves is likely to have contributed significantly to sea-ice expansion. Specifically, we present observations indicating that melt water from Antarctica’s ice shelves accumulates in a cool and fresh surface layer that shields the surface ocean from the warmer deeper waters that are melting the ice shelves. Simulating these processes in a coupled climate model we find that cool and fresh surface water from ice-shelf melt indeed leads to expanding sea ice in austral autumn and winter. This powerful negative feedback counteracts Southern Hemispheric atmospheric warming. Although changes in atmospheric dynamics most likely govern regional sea-ice trends, our analyses indicate that the overall sea-ice trend is dominated by increased ice-shelf melt. We suggest that cool sea surface temperatures around Antarctica could offset projected snowfall increases in Antarctica, with implications for estimates of future sea-level rise.
"Para a Causa do Povo a Luta Continua!"
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vox_mundi

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Re: What's new in Antarctica ?
« Reply #410 on: December 13, 2018, 03:18:58 AM »
Two Technicians Die at U.S. Research Station In Antarctica
https://mobile.reuters.com/article/amp/idUSKBN1OC02G

Two technicians performing maintenance at a U.S. research station in Antarctica died on Wednesday while working on a building that houses a generator for a nearby radio transmitter, the National Science Foundation (NSF) said.

The pair, both employed by Virginia-based subcontractor, PAE , which provides logistical support to the NSF-managed McMurdo Station in Antarctica, were found unconscious on the floor of the building after a helicopter pilot flying over the area saw what appeared to be smoke coming from the structure and landed to investigate.

The two technicians had been working on a fire-suppression system at McMurdo station on Ross Island,

Arlington, Virginia-based Pacific Architects and Engineers (PAE) is a subcontractor to Leidos, which bills itself as the prime contractor for the National Science Foundation's US Antarctic Program.
« Last Edit: December 13, 2018, 03:39:35 AM by vox_mundi »
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

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