Support the Arctic Sea Ice Forum and Blog

Author Topic: What's new in Antarctica ?  (Read 179468 times)

Sleepy

  • Nilas ice
  • Posts: 1202
  • Retired, again...
    • View Profile
  • Liked: 126
  • Likes Given: 0
Re: What's new in Antarctica ?
« Reply #400 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.
Omnia mirari, etiam tritissima.
-
Science is a jealous mistress and takes little account of a man's feelings.

vox_mundi

  • Nilas ice
  • Posts: 1752
    • View Profile
  • Liked: 737
  • Likes Given: 116
Re: What's new in Antarctica ?
« Reply #401 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

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

Sleepy

  • Nilas ice
  • Posts: 1202
  • Retired, again...
    • View Profile
  • Liked: 126
  • Likes Given: 0
Re: What's new in Antarctica ?
« Reply #402 on: November 14, 2018, 09:24:45 PM »
"May" is an understatement.
Omnia mirari, etiam tritissima.
-
Science is a jealous mistress and takes little account of a man's feelings.

Thomas Barlow

  • Frazil ice
  • Posts: 103
    • View Profile
  • Liked: 25
  • Likes Given: 22
Re: What's new in Antarctica ?
« Reply #403 on: November 15, 2018, 04:02:35 AM »

Bernard

  • Frazil ice
  • Posts: 105
    • View Profile
  • Liked: 14
  • Likes Given: 10
Re: What's new in Antarctica ?
« Reply #404 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

  • Young ice
  • Posts: 4985
    • View Profile
  • Liked: 387
  • Likes Given: 0
Re: What's new in Antarctica ?
« Reply #405 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

  • Frazil ice
  • Posts: 359
    • View Profile
  • Liked: 73
  • Likes Given: 49
Re: What's new in Antarctica ?
« Reply #406 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

  • First-year ice
  • Posts: 6813
    • View Profile
  • Liked: 1709
  • Likes Given: 22
Re: What's new in Antarctica ?
« Reply #407 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!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

vox_mundi

  • Nilas ice
  • Posts: 1752
    • View Profile
  • Liked: 737
  • Likes Given: 116
Re: What's new in Antarctica ?
« Reply #408 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

vox_mundi

  • Nilas ice
  • Posts: 1752
    • View Profile
  • Liked: 737
  • Likes Given: 116
Re: What's new in Antarctica ?
« Reply #409 on: December 31, 2018, 08:12:31 PM »
Science Team Drills Into Mercer Subglacial Lake
https://salsa-antarctica.org/2018/12/28/3578/
https://earther.gizmodo.com/scientists-just-melted-a-hole-through-3-500-feet-of-ice-1831329404



After four days of troubleshooting components that sustained wear and tear from sitting through two winters on ice, the Subglacial Antarctic Lakes Scientific Access (SALSA) Drill Team began drilling the main borehole on the evening of December 23rd and reached the lake faster than expected at 10:30pm on December 26th with a borehole depth of 1084 meters. The drill team then reamed (smoothed and widened) the borehole so that instruments can be sent down.



The only other subglacial lake humans have drilled into—nearby Lake Whillans, sampled in 2013—demonstrated that these extreme environments can play host to diverse microbial life. Naturally, scientists are stoked to see what they’ll find lurking in Lake Mercer’s icy waters.

Now that the lake is open, the real fun has begun. The SALSA team is deploying a suite of instruments to study the lake, including a CTD (Conductivity, Temperature, Depth) probe that will assess temperature and provide details on the structure of the water column, and a remotely operated vehicle to take similar measurements away from the borehole and capture 4k video. Researchers will collect samples of water and microbial DNA, as well as ice from the top of the lake and sediment from the bottom.
« Last Edit: December 31, 2018, 08:27:31 PM 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

Juan C. García

  • Nilas ice
  • Posts: 1532
    • View Profile
  • Liked: 545
  • Likes Given: 517
Re: What's new in Antarctica ?
« Reply #410 on: January 14, 2019, 09:52:44 PM »
Quote
Ice loss from Antarctica has sextupled since the 1970s, new research finds

An alarming study shows massive East Antarctic ice sheet already is a significant contributor to sea-level rise
https://www.washingtonpost.com/energy-environment/2019/01/14/ice-loss-antarctica-has-sextupled-since-s-new-research-finds/?utm_term=.1ef083fa3e2b

Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

wdmn

  • Frazil ice
  • Posts: 359
    • View Profile
  • Liked: 73
  • Likes Given: 49
Re: What's new in Antarctica ?
« Reply #411 on: January 14, 2019, 11:53:09 PM »
"Every 360 billion tonnes = 1 mm of sea level rise."

Doesn't exactly sound frightening.

sidd

  • Young ice
  • Posts: 4985
    • View Profile
  • Liked: 387
  • Likes Given: 0
Re: What's new in Antarctica ?
« Reply #412 on: January 15, 2019, 01:20:48 AM »
The paper referred to in the Post article is open access.

doi:10.1073/pnas.1812883116

sidd

Sebastian Jones

  • Frazil ice
  • Posts: 314
    • View Profile
  • Liked: 52
  • Likes Given: 40
Re: What's new in Antarctica ?
« Reply #413 on: January 15, 2019, 06:13:16 AM »
"Every 360 billion tonnes = 1 mm of sea level rise."

Doesn't exactly sound frightening.

Unless the rate of loss keeps doubling every 6 years or so.....

Gray-Wolf

  • Grease ice
  • Posts: 795
    • View Profile
  • Liked: 49
  • Likes Given: 152
Re: What's new in Antarctica ?
« Reply #414 on: January 15, 2019, 10:17:26 AM »
Agreed Sebastian , it is the time period of doubling as things do start to move pretty quick a few 'doublings' down the line!

But this misses the point that this has been the 'Drip,Drip' losses prior to the start of 'Ice cliff Fracturing' denudation which will see mass losses shoot up overnight!
KOYAANISQATSI

ko.yaa.nis.katsi (from the Hopi language), n. 1. crazy life. 2. life in turmoil. 3. life disintegrating. 4. life out of balance. 5. a state of life that calls for another way of living.
 
VIRESCIT VULNERE VIRTUS

wdmn

  • Frazil ice
  • Posts: 359
    • View Profile
  • Liked: 73
  • Likes Given: 49
Re: What's new in Antarctica ?
« Reply #415 on: January 15, 2019, 04:30:05 PM »
Let's assume the amount doubles every 6 years.

In the 30 years from 2017 to 2047 the cumulative melt would be 44.8mm or 4.48 cm, or 1.76 inches.

In the 60 years from 2017 to 2077 the cumulative melt would be 716.8mm or 71.6 cm, or 28.2 inches, or 2 feet 4.2 inches.

So from 2017 to 2047 sea levels would rise (from Antarctica alone) 1.76 inches, and from 2047 to 2077 sea levels would rise 2 feet 2.44 inches. That's quite a dynamic second 30 years.

This would require the collapse of the WAIS beginning around mid-century.

Stephan

  • Grease ice
  • Posts: 803
    • View Profile
  • Liked: 271
  • Likes Given: 141
Re: What's new in Antarctica ?
« Reply #416 on: January 15, 2019, 08:26:56 PM »
Thank you for doing this calculation. :)
It is too late just to be concerned about Climate Change

Sebastian Jones

  • Frazil ice
  • Posts: 314
    • View Profile
  • Liked: 52
  • Likes Given: 40
Re: What's new in Antarctica ?
« Reply #417 on: January 17, 2019, 07:34:41 AM »
Thank you for doing this calculation. :)
Yes, and it lines up neatly with ASLR's projection that the WAIS will start to disintegrate in the 2050s.

Adam Ash

  • Frazil ice
  • Posts: 306
    • View Profile
    • The 100 metre line
  • Liked: 8
  • Likes Given: 20
Re: What's new in Antarctica ?
« Reply #418 on: January 17, 2019, 10:17:57 AM »
But isn’t the big fear the Great Discontinuity, where a whole lot of ice areas begin similtaneous sudden collapse?  Put two ice cubes in a box. Does one melt first then the other?  No. There is a thermal link which sees both melt at similar rates.  Doesn’t out atmospheric and oceanic circulation provide that same linkage, ensuring that most land-fast ice approaches the point of strucural failure at about the same time? 

mitch

  • New ice
  • Posts: 87
    • View Profile
  • Liked: 16
  • Likes Given: 0
Re: What's new in Antarctica ?
« Reply #419 on: January 17, 2019, 04:56:24 PM »
"...But isn’t the big fear the Great Discontinuity, where a whole lot of ice areas begin similtaneous sudden collapse?  ..."

While it is of significant concern about how fast sea level might rise, the other big fear is that we start something that will continue for centuries and has a large net sea level increase.  Best estimates for Pliocene sea level, the last time CO2 was around 400 ppm,  are around 20 m higher than modern. 

Stephan

  • Grease ice
  • Posts: 803
    • View Profile
  • Liked: 271
  • Likes Given: 141
Re: What's new in Antarctica ?
« Reply #420 on: January 17, 2019, 07:52:09 PM »
"...But isn’t the big fear the Great Discontinuity, where a whole lot of ice areas begin similtaneous sudden collapse?  ..."

While it is of significant concern about how fast sea level might rise, the other big fear is that we start something that will continue for centuries and has a large net sea level increase.  Best estimates for Pliocene sea level, the last time CO2 was around 400 ppm,  are around 20 m higher than modern...
...which would cause probably one billion refugees who will look for another place to live and who can not be sent back to their original countries/areas because these will be then completely inundated.
It is too late just to be concerned about Climate Change

b_lumenkraft

  • Guest
Re: What's new in Antarctica ?
« Reply #421 on: January 18, 2019, 09:38:51 AM »
Can someone tell me what is happening here in the Amery Ice Shelf?

Huge water ponds are forming despite the low temperatures (well below zero) on a white underground (low heat absorbing). Is this water coming from the mountains around?


sidd

  • Young ice
  • Posts: 4985
    • View Profile
  • Liked: 387
  • Likes Given: 0
Re: What's new in Antarctica ?
« Reply #422 on: January 18, 2019, 10:06:09 AM »
I think those ponds have formed in years past, they are meltwater possibly from foehn winds.

Amery is one i watch closely. The thing is a dagger pointed into the heart of Antarctica. The danger is in the bed. The ice behind it has concave profile in elevation view as i have posted before, which has significance.

https://forum.arctic-sea-ice.net/index.php/topic,263.msg40975.html#msg40975

Amery disturbs me. When that shelf breaks up ...

sidd
« Last Edit: January 18, 2019, 10:13:35 AM by sidd »

b_lumenkraft

  • Guest
Re: What's new in Antarctica ?
« Reply #423 on: January 18, 2019, 10:41:18 AM »
I think those ponds have formed in years past, they are meltwater possibly from foehn winds.

Amery is one i watch closely. The thing is a dagger pointed into the heart of Antarctica. The danger is in the bed. The ice behind it has concave profile in elevation view as i have posted before, which has significance.

https://forum.arctic-sea-ice.net/index.php/topic,263.msg40975.html#msg40975

Amery disturbs me. When that shelf breaks up ...

sidd

Thanks for your answer Sidd. Down the rabbit-hole i go... ;)


FredBear

  • Frazil ice
  • Posts: 124
    • View Profile
  • Liked: 17
  • Likes Given: 30
Re: What's new in Antarctica ?
« Reply #425 on: January 18, 2019, 12:50:58 PM »
Amery often grows large melt pools in January, with blue tints to the surrounding slopes (but snow reduces these signs, often starting by about Feb. 10?).
The most melt was visible in 2004-6, 2015, 2017 and this year, so is quite variable.
The front of the glacier has been advancing with no major calving for years.

b_lumenkraft

  • Guest
Re: What's new in Antarctica ?
« Reply #426 on: January 18, 2019, 02:15:54 PM »
Thank you FredBear,

i've seen the ponds in recent years as you pointed out, but this year they seem to grow at a higher rate (?). I've also seen one article mentioning it was very big in 1988. I've also seen them getting brighter over time in recent years. The blue tint fades which i interpret as freezing again (at least on the surface).

I'm failing in finding an article that tells me how this is happening. I would like to know the physics behind this because in freezing temperatures at a high albedo (fresh)water should not just melt, right?

b_lumenkraft

  • Guest
Re: What's new in Antarctica ?
« Reply #427 on: January 18, 2019, 02:21:35 PM »
On the other hand i find a lot of info about how this is an implication for how the ice sheet might behave in the future.

Tealight

  • Frazil ice
  • Posts: 431
    • View Profile
    • CryosphereComputing
  • Liked: 133
  • Likes Given: 14
Re: What's new in Antarctica ?
« Reply #428 on: January 18, 2019, 07:58:39 PM »
I'm failing in finding an article that tells me how this is happening. I would like to know the physics behind this because in freezing temperatures at a high albedo (fresh)water should not just melt, right?

Melting snow and ice below freezing is nothing extraordinary at molecular level.

Melting snow and ice is all about breaking bonds between water molecules. At 0°C and standard atmospheric pressure the individual molecules move or vibrate so much around that existing bonds break and not enough new bonds can form. Temperature is just a description of the average movement of the molecules. Some move faster and some move slower than the average. During noon the slopes of the Amery ice shelf get to around -5°C so not very far off from 0°C. Depending on the slope angle the surface also get's blasted with 700-1000W/m2 (during noon)  of electromagnetic radiation from the sun which further increases the movement of molecules.

Albedo is just an average of reflected vs absorbed energy for all molecules in an area. A single molecule doesn't have an albedo value. Either it get's hit and absorbs the photon's energy (followed by a quick re-release of the energy with a lower energy photon) or the photon misses the molecule.

On a macro level snow can get down to an albedo of 50%, meaning it absorbs 300-500W/m2 while only losing maybe 100-200W/m2 to the below freezing air.


b_lumenkraft

  • Guest
Re: What's new in Antarctica ?
« Reply #429 on: January 18, 2019, 08:12:39 PM »
Thank you so much Tealight!

Yeah, makes sense. Looks like until now i haven't understood the albedo effect correctly. Need to read up on that.  ;D

vox_mundi

  • Nilas ice
  • Posts: 1752
    • View Profile
  • Liked: 737
  • Likes Given: 116
Re: What's new in Antarctica ?
« Reply #430 on: January 18, 2019, 09:32:38 PM »
Report: Evidence of Life Found in Lake Deep Beneath Antarctic Ice
https://gizmodo.com/report-evidence-of-life-found-in-lake-deep-beneath-ant-1831870240

Scientists have found the bodies of tardigrades, algae, diatoms, and small crustaceans in a body of water buried beneath over a kilometer of Antarctic ice, according to a news report from Nature.

The results come from the Subglacial Antarctic Lakes Scientific Access (SALSA) project, which had previously announced that it would explore the water, called Lake Mercer, with a 60-centimeter-wide drill.

The carcasses originated from either 10,000 or 120,000 years ago during warming periods, after which ice smothered the lake again, according to Nature. It’s unclear how the life, particularly the land-dwelling, microscopic tardigrade and a certain fungus, got down there. But it’s thought that they subsisted on bacteria in the water.

The expert confirmed that the organisms looked like they’d been dead for thousands of years and that they were similar to ones found in some of Antarctica’s glacier-free regions
“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

steve s

  • New ice
  • Posts: 75
    • View Profile
  • Liked: 4
  • Likes Given: 5
Re: What's new in Antarctica ?
« Reply #431 on: January 19, 2019, 05:17:27 AM »
There is another factor in the formation of melt ponds: snow absorbs near infrared better than visible frequencies, but both penetrate the surface. Thus, even if the surface is kept below freezing, the temperature just below the surface can reach freezing with melting beginning there. That melting darkens the snow and changes the albedo. Then a broader spectrum is absorbed, increasing the melt, as discussed by Tealight.

b_lumenkraft

  • Guest
Re: What's new in Antarctica ?
« Reply #432 on: January 19, 2019, 06:56:35 AM »
Thank you Steve,

that's interesting! Didn't know about infrared getting absorbed better.

vox_mundi

  • Nilas ice
  • Posts: 1752
    • View Profile
  • Liked: 737
  • Likes Given: 116
Re: What's new in Antarctica ?
« Reply #433 on: January 22, 2019, 05:37:19 PM »
Antarctic Krill Population Contracts Southward as Polar Oceans Warm
https://phys.org/news/2019-01-antarctic-krill-population-southward-polar.html

Quote


Important krill habitats are under threat from climate change, and this latest research – published today (21st January 2019) in Nature Climate Change – has found that their distribution has contracted towards the Antarctic continent. This has major implications for the ecosystems that depend on krill.

"These northern waters have warmed and conditions throughout the Scotia Sea have become more hostile, with stronger winds, warmer weather and less ice. This is bad news for young krill."

https://www.nature.com/articles/s41558-018-0370-z

“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

gerontocrat

  • First-year ice
  • Posts: 6813
    • View Profile
  • Liked: 1709
  • Likes Given: 22
Re: What's new in Antarctica ?
« Reply #434 on: January 22, 2019, 06:58:53 PM »
Antarctic Krill Population Contracts Southward as Polar Oceans Warm
https://phys.org/news/2019-01-antarctic-krill-population-southward-polar.html


Important krill habitats are under threat from climate change, and this latest research – published today (21st January 2019) in Nature Climate Change – has found that their distribution has contracted towards the Antarctic continent. This has major implications for the ecosystems that depend on krill.

"These northern waters have warmed and conditions throughout the Scotia Sea have become more hostile, with stronger winds, warmer weather and less ice. This is bad news for young krill."

Worth quoting from the Puerto Rico insect decline

Quote
......Lister calls these impacts a “bottom-up trophic cascade”, in which the knock-on effects of the insect collapse surge up through the food chain.

“I don’t think most people have a systems view of the natural world,” he said. “But it’s all connected and when the invertebrates are declining the entire food web is going to suffer and degrade. It is a system-wide effect.”
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

vox_mundi

  • Nilas ice
  • Posts: 1752
    • View Profile
  • Liked: 737
  • Likes Given: 116
Re: What's new in Antarctica ?
« Reply #435 on: January 28, 2019, 03:19:25 AM »
Antarctic Team 'Upbeat' About Hope of Finding Shackleton's Ship
https://www.theguardian.com/world/2019/jan/27/antarctic-expedition-upbeat-about-hope-of-finding-shackletons-ship-endurance-weddell-sea

Quote
Antarctic explorers are to break their way through 75 miles of sea ice in an effort to reach the final resting place of Sir Ernest Shackleton’s ship, the Endurance, which sank to the bottom of the Weddell Sea in November 1915.

Expedition leaders believe they have the best chance yet to find the wreckage of the lost vessel, which became trapped in sea ice for 10 months and eventually went down in two miles of water after the crushing forces of the surrounding ice breached its hull.

... “Just getting to the wreck site will be an exciting challenge,” Shears said. “We will need to break through about 120km of dense, thick pack ice, up to 2-3 metres thick.



Scientists on the SA Agulhas II have spent the past two weeks collecting samples and surveying the area around the Larsen C ice shelf, where a trillion-tonne iceberg, A68, four times the size of Greater London, calved in July 2017. 
“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

Neven

  • Administrator
  • First-year ice
  • *****
  • Posts: 7209
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 732
  • Likes Given: 477
Re: What's new in Antarctica ?
« Reply #436 on: January 28, 2019, 10:14:52 AM »
What a waste of resources, but I guess this is what makes us human.  :)
Il faut comparer, comparer, comparer, et cultiver notre jardin

FredBear

  • Frazil ice
  • Posts: 124
    • View Profile
  • Liked: 17
  • Likes Given: 30
Re: What's new in Antarctica ?
« Reply #437 on: January 28, 2019, 10:21:39 AM »
Antarctic Krill Population Contracts Southward as Polar Oceans Warm
https://phys.org/news/2019-01-antarctic-krill-population-southward-polar.html


Important krill habitats are under threat from climate change, and this latest research – published today (21st January 2019) in Nature Climate Change – has found that their distribution has contracted towards the Antarctic continent. This has major implications for the ecosystems that depend on krill.

"These northern waters have warmed and conditions throughout the Scotia Sea have become more hostile, with stronger winds, warmer weather and less ice. This is bad news for young krill."

Worth quoting from the Puerto Rico insect decline

Quote
......Lister calls these impacts a “bottom-up trophic cascade”, in which the knock-on effects of the insect collapse surge up through the food chain.

“I don’t think most people have a systems view of the natural world,” he said. “But it’s all connected and when the invertebrates are declining the entire food web is going to suffer and degrade. It is a system-wide effect.”
Closer to home - there were always some flies going round central light fittings at home when I was a kid, now - none! We did not see them disappear   .   .   . :o

Thomas Barlow

  • Frazil ice
  • Posts: 103
    • View Profile
  • Liked: 25
  • Likes Given: 22
Re: What's new in Antarctica ?
« Reply #438 on: February 01, 2019, 08:17:26 PM »
""Huge cavity in Antarctic glacier signals rapid decay""
By Carol Rasmussen,
NASA's Earth Science News Team

https://climate.nasa.gov/news/2838/huge-cavity-in-antarctic-glacier-signals-rapid-decay/?fbclid=IwAR31b4aaHlwm9kgutE6nZCW0dcTDVQeOmfhTGb7Yj3imh03WnGnKsvXfTQI

Juan C. García

  • Nilas ice
  • Posts: 1532
    • View Profile
  • Liked: 545
  • Likes Given: 517
Re: What's new in Antarctica ?
« Reply #439 on: February 07, 2019, 09:28:24 PM »
More of the same…
(Could be in several topics, but maybe this one is the best).

Today’s Earth looks a lot like it did 115,000 years ago. All we’re missing is massive sea level rise.

https://www.washingtonpost.com/climate-environment/2019/02/06/todays-earth-looks-lot-like-it-did-years-ago-all-were-missing-is-massive-sea-level-rise/?utm_term=.229f575f196e&wpisrc=nl_green&wpmm=1
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Stephan

  • Grease ice
  • Posts: 803
    • View Profile
  • Liked: 271
  • Likes Given: 141
Re: What's new in Antarctica ?
« Reply #440 on: February 07, 2019, 10:14:45 PM »
Thanks for sharing!
And another 'Like' earned
It is too late just to be concerned about Climate Change

FredBear

  • Frazil ice
  • Posts: 124
    • View Profile
  • Liked: 17
  • Likes Given: 30
Re: What's new in Antarctica ?
« Reply #441 on: February 12, 2019, 11:22:47 PM »
A few islands near the northern tip of the antarctic peninsular lose snow cover - while the rest remain white - why?. In the 2001 image it looks as if sea ice is still surrounding the greenish island. It does not look as if the loss of Larsen B ice shelf has changed anything. Snow beginning to re-appear in the 2019-02-12 pic. Images cut from arctic.io

magnamentis

  • Guest
Re: What's new in Antarctica ?
« Reply #442 on: February 13, 2019, 01:15:41 AM »
A few islands near the northern tip of the antarctic peninsular lose snow cover - while the rest remain white - why?.

Elevation above sea-level as well as coastline topography may play a role among other factors ?

sidd

  • Young ice
  • Posts: 4985
    • View Profile
  • Liked: 387
  • Likes Given: 0
Re: What's new in Antarctica ?
« Reply #443 on: February 13, 2019, 07:03:41 AM »
There is a paper in cryosphere discuss by levermann and feldman based on a reductionist scaling approach. They find that Thwaites is more unstable than PIG, and i agree there, but think the method is too sanguine about Amery.

Open, read all about it:

https://www.the-cryosphere-discuss.net/tc-2018-252/

I attach fig a1, because that depiction is one that i yearned for, but i have been too lazy to make myself. Really brings it home when you see that big red blotch of 3Km high ice behind Totten ... and it's all Volume Above Flotation.

sidd

vox_mundi

  • Nilas ice
  • Posts: 1752
    • View Profile
  • Liked: 737
  • Likes Given: 116
Re: What's new in Antarctica ?
« Reply #444 on: February 13, 2019, 05:02:37 PM »
Ice Shelves Buckle Under Weight of Meltwater Lakes
https://cires.colorado.edu/news/ice-shelves-buckle-under-weight-meltwater-lakes



For the first time, a research team co-led by CIRES-based scientists, has directly observed an Antarctic ice shelf bending under the weight of ponding meltwater on top, a phenomenon that may have triggered the 2002 collapse of the Larsen B ice shelf. And ice shelf flexure could potentially impact other vulnerable ice shelves, causing them to break up, quickening the discharge of ice into the ocean and contributing to global sea level rise

Meltwater lakes can contain water weighing fifty thousand to two million tons each, and that pushes downward on the ice, creating an indent. If the lake drains, this indent pops back up. If the resultant stress is large enough, the ice surrounding the lake basin weakens, and may start to break, the researchers predict.



And climate models predict that there will be more melting across more ice shelves over the next few decades, leading to an increase in the occurrence of meltwater lakes,” added Willis.

These observations are important because they help us better understand the triggers of ice shelf break up, which leads to sea level rise,” said Banwell. “Our results can be used to improve models to better predict which ice shelves are more vulnerable and are most susceptible to collapse.

Open Access: Direct measurements of ice-shelf flexure caused by surface meltwater ponding and drainage
https://www.nature.com/articles/s41467-019-08522-5
“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

Tealight

  • Frazil ice
  • Posts: 431
    • View Profile
    • CryosphereComputing
  • Liked: 133
  • Likes Given: 14
Re: What's new in Antarctica ?
« Reply #445 on: February 13, 2019, 11:20:42 PM »
A few islands near the northern tip of the antarctic peninsular lose snow cover - while the rest remain white - why?. In the 2001 image it looks as if sea ice is still surrounding the greenish island. It does not look as if the loss of Larsen B ice shelf has changed anything. Snow beginning to re-appear in the 2019-02-12 pic. Images cut from arctic.io

The islands are east of the Antarctic Peninsular, which means they are sheltered from the wet westerly winds and receive little snow fall compared to islands west of the peninsular. They are also in a good position to receive warm and dry from Foehn wind. Together with the fairly northern latitude is enough to keep the low elevation coastal regions from getting glaciated and become snow free in summer. But since they are so close to Antarctica snow can fall any time of the year. It really depends on the weather.

b_lumenkraft

  • Guest
Re: What's new in Antarctica ?
« Reply #446 on: February 14, 2019, 02:21:03 PM »
Dropping a camera down a 650m-deep hole drilled in the Filchner Ice Shelf to study how the Antarctic will respond to warming global temperatures [Video]

Link >> https://gfycat.com/linearearlygiraffe

vox_mundi

  • Nilas ice
  • Posts: 1752
    • View Profile
  • Liked: 737
  • Likes Given: 116
Re: What's new in Antarctica ?
« Reply #447 on: February 15, 2019, 06:16:31 PM »
Search for Shackleton's Lost Endurance Ship Called Off
https://www.bbc.com/news/science-environment-47227657

The attempt this week to find Sir Ernest Shackleton's missing ship, the Endurance, has ended - without success.

A UK-led expedition to the Weddell Sea sent a sub to the ocean floor to look for the sunken polar yacht, but this robot was itself lost in the process.

The team has now withdrawn from the area because of deteriorating weather and sea-ice conditions.

Quote
... "Like Shackleton before us, who described the graveyard of Endurance as 'the worst portion of the worst sea in the world,' our well laid plans were overcome by the rapidly moving ice and what Shackleton called 'the evil conditions of the Weddell Sea,'"

“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

b_lumenkraft

  • Guest
Re: What's new in Antarctica ?
« Reply #448 on: February 15, 2019, 06:21:39 PM »
Damn! :-\

vox_mundi

  • Nilas ice
  • Posts: 1752
    • View Profile
  • Liked: 737
  • Likes Given: 116
Re: What's new in Antarctica ?
« Reply #449 on: February 16, 2019, 06:53:17 PM »
More Trophic Cascade Collapse ...

Tiny Invertebrates Spell Big Trouble for Southern Ocean Fish
https://phys.org/news/2019-02-nutritious-diet-southern-ocean-fish.html

Like collapsing ice shelves, the surge of barrel-bodied salps in the Southern Ocean tells us that other life forms in Antarctica and its surrounding waters are in decline. Blooms of a gelatinous plankton, known as salp, have been identified in waters south of 60°S, in the Indian Sector of the Southern Ocean, by researcher Paige Kelly

... "In the Southern Ocean, waters south of 60°S are typically full of Antarctic krill, which are a crucial food source for mammals and fish," says Paige, a Ph.D. student at the Institute for Marine and Antarctic Studies and Antarctic Climate and Ecosystems Cooperative Research Centre.

"The presence of salps so far south means that these mammals and fish might have to eat salps instead of krill. And this could have serious consequences for the ecosystem."

The consumption of these East Antarctic salps—which contain less than one third of the calories and protein of krill—could change the weight, reproduction and behaviour of commercially fished species that prefer to feed on krill.

When salps are abundant, Antarctic krill are scarce. Krill are a keystone species here. Everything eats them directly or indirectly. Penguins, baleen whales, seals, seabirds and fish, even krill eat krill. No krill, no Antarctica.

Since the 1970s krill populations have dropped by as much as 70 per cent in their most critical habitat, the southwest Atlantic sector of the Southern Ocean. Krill, especially juveniles, depend on sea ice subsurface matrix of brine channels and crevices, a microcosm of life where innumerable plankton live, feed and hide from predators. Summer krill abundance is correlated with the extent of the previous winter's sea ice.



-------------------------------

Dutch Scientists Probing Mystery of Mass Bird Deaths
https://phys.org/news/2019-02-dutch-scientists-probing-mystery-mass.html

... Why, for example, are only guillemots dying all along the Dutch coastline? Leopold said he has received no similar reports from Belgium or Germany. "They are pretty robust birds," he said, but now, dead birds are washing up "in their thousands"

"That's pointing out that there is something wrong at sea, and that's alarming."
“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