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Author Topic: What's new in Antarctica ?  (Read 76944 times)

Laurent

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Re: What's new in Antarctica ?
« Reply #150 on: July 06, 2016, 09:42:24 PM »
Australian Uranium Mining Is Polluting Antarctica Some 6,000 Miles Away
http://www.huffingtonpost.co.uk/entry/australian-uranium-mining-is-polluting-antarctica-some-6000-miles-away_uk_577b8d4ee4b073366f0fb3e5?edition=uk

Scientists have discovered that uranium mining in Australia is polluting the Antarctic, despite being 6,000 nautical miles away from each other.

The damning news comes just a few days after research showed that the enormous ozone hole over Antarctica had in fact started to heal as a result of human action.

solartim27

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Re: What's new in Antarctica ?
« Reply #151 on: July 10, 2016, 01:15:44 AM »
Avoiding the news here in the US, catching up on podcasts I heard this.  15 days left to listen to the stream.
http://www.bbc.co.uk/programmes/p03yptx1
Oldest Antarctic Ice Found
The Science Hour
The importance of analysing the trapped past atmospheres contained in bubbles in ice cores is invaluable to our understanding of our climate. Until now, ice cores drilled in Antarctica only go back to 800,000 years old. But geologists exploring a little known valley, high up in the Trans-Antarctic Mountain chain, have discovered ice that is more than a million years old. And they did not have to use expensive drills to get it, just a shovel! The ice was under a thin layer of debris, pushed up from the deep.


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Adam Ash

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Re: What's new in Antarctica ?
« Reply #152 on: July 14, 2016, 11:15:32 AM »
Has anybody estimated what the effect on sea level rise will be from the resulting isostatic rebound? 

Assuming it all rebounds to near or above present-day sea level, that displacement would add several metres more to the current maximum estimated sea level rise.  Both Antarctica and Greenland have massive ice overburden on top of land held below sea level which will no doubt rise (and hence displace ocean) when the load is removed.

Laurent

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Re: What's new in Antarctica ?
« Reply #153 on: July 14, 2016, 11:40:58 AM »
What some centimetres of that plate would do to sea level... https://en.wikipedia.org/wiki/Antarctic_Plate 11% of earth surface ?...

folke_kelm

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Re: What's new in Antarctica ?
« Reply #154 on: July 14, 2016, 02:54:43 PM »
Adam Ash,

Since isostatic rebound is a question of geology i may answer because just that is my profession.
You have always  to consider that isostatic rebound is a complex movement of the plate and its surroundings. While Antarctica itself is depressed into the deeper layers, this material is squeezed aside and lifts up the surrounding plates without ice cap.
Due to the fact that Antarctica is surrounded by oceanic crust  this crust will sink as a reaction of the isostatic rebound of Antarctica. This will counteract a potential sea level rise due to a rebounding antarctic plate.


AbruptSLR

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Re: What's new in Antarctica ?
« Reply #155 on: July 14, 2016, 08:05:32 PM »
Has anybody estimated what the effect on sea level rise will be from the resulting isostatic rebound? 

Assuming it all rebounds to near or above present-day sea level, that displacement would add several metres more to the current maximum estimated sea level rise.  Both Antarctica and Greenland have massive ice overburden on top of land held below sea level which will no doubt rise (and hence displace ocean) when the load is removed.


The following reference indicates that after GIA correction the Amundsen Sea sector is contributing more to SLR than model GRACE measurements indicate, possibly by as much as 40%:

An investigation of Glacial Isostatic Adjustment over the Amundsen Sea sector, West Antarctica
by: A. Groh; H. Ewert, M. Scheinert, M. Fritsche, A. Rülke, A. Richter, R. Rosenau, R. Dietrich
http://dx.doi.org/10.1016/j.gloplacha.2012.08.001

Abstract
The present study focuses on the Amundsen Sea sector which is the most dynamical region of the Antarctic Ice Sheet (AIS). Based on basin estimates of mass changes observed by the Gravity Recovery and Climate Experiment (GRACE) and volume changes observed by the Ice, Cloud and Land Elevation Satellite (ICESat), the mean mass change induced by Glacial Isostatic Adjustment (GIA) is derived. This mean GIA-induced mass change is found to be 34.1 ± 11.9 Gt/yr, which is significantly larger than the predictions of current GIA models. We show that the corresponding mean elevation change of 23.3 ± 7.7 mm/yr in the Amundsen Sea sector is in good agreement with the uplift rates obtained from observations at three GPS sites. Utilising ICESat observations, the observed uplift rates were corrected for elastic deformations due to present-day ice-mass changes. Based on the GRACE-derived mass change estimate and the inferred GIA correction, we inferred a present-day ice-mass loss of − 98.9 ± 13.7 Gt/yr for the Amundsen Sea sector. This is equivalent to a global eustatic sea-level rise of 0.27 ± 0.04 mm/yr. Compared to the results relying on GIA model predictions, this corresponds to an increase of the ice-mass loss or sea-level rise, respectively, of about 40%.
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sidd

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Re: What's new in Antarctica ?
« Reply #156 on: July 14, 2016, 09:41:33 PM »
Nice paper on CDW melt on Antarctic Peninsula, showing melt of southern glaciers due to warming at depth.

DOI: 10.1126/science.aae0017

 I attach fig 1.

AbruptSLR

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Re: What's new in Antarctica ?
« Reply #157 on: July 29, 2016, 07:44:44 PM »
The atmospheric CO₂ concentration has now passed the 400ppm mark:

http://www.envirotech-online.com/news/environmental-laboratory/7/breaking_news/antarctic_carbon_dioxide_concentration_hits_440ppm_for_first_time_in_four_million_years/39743/

Extract: "On May 23rd, the continent of Antarctica finally surpassed the 400PPM mark, making it the last region on Earth to succumb to our relentless pollution of the atmosphere. It’s the first time that the continent has witnessed such high levels of CO2 in at least four million years."
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FishOutofWater

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Re: What's new in Antarctica ?
« Reply #158 on: July 30, 2016, 07:46:16 PM »
Remember that isostatic rebound is a slow process that is still going on from the last glacial period more than 10,000 years ago.

AbruptSLR

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Re: What's new in Antarctica ?
« Reply #159 on: August 02, 2016, 03:30:18 AM »
Remember that isostatic rebound is a slow process that is still going on from the last glacial period more than 10,000 years ago.

You should remember from school, that isostatic rebound from current ice mass loss is associated with two processes, with the first due to elastic rebound (related you Young's Modulus) which happens immediately after the ice mass is lost (only the second process is slow due to magma migration).
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AbruptSLR

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Re: What's new in Antarctica ?
« Reply #160 on: August 09, 2016, 12:18:53 AM »
The Polar Meteorology Group has some interesting research going on:

http://bpcrc.osu.edu/groups/polar-meteorology-group
http://polarmet.osu.edu/

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sidd

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Re: What's new in Antarctica ?
« Reply #161 on: August 09, 2016, 05:36:12 AM »
bprc.osu.edu is the Byrd Polar research centre, one of my favorite places. The great Lonnie Thompson, his wife Ellen-Mosely who is a formidable researcher also, Ian Howat, Leonid Polyak and many others. Mercer was from there also, more recently Box and Enderlin who have moved on.

In misty days of yore, I stole ... borrowed ... equipment and facilities from and supplied some to them as well. They have accumulated one of the largest ice core archives under the Thompsons and many others.

Nice place. Check em out on the web, or if you are in Columbus, in person. They frequently have talks which are always worth attending, most are streamed on the net.

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FishOutofWater

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Re: What's new in Antarctica ?
« Reply #162 on: August 09, 2016, 02:56:17 PM »
Large volumes of magma are not moving around eastern Canada and Scandinavia.

Isostatic adjustment occurs by mantle creep. At the high temperatures of the upper mantle the rock undergoes plastic deformation. Because the effective viscosity of solid ultramafic rock is very high, isostatic adjustment is very slow.

http://gji.oxfordjournals.org/content/157/3/1297.full

AbruptSLR

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Re: What's new in Antarctica ?
« Reply #163 on: August 09, 2016, 06:35:24 PM »
Large volumes of magma are not moving around eastern Canada and Scandinavia.

Isostatic adjustment occurs by mantle creep. At the high temperatures of the upper mantle the rock undergoes plastic deformation. Because the effective viscosity of solid ultramafic rock is very high, isostatic adjustment is very slow.

http://gji.oxfordjournals.org/content/157/3/1297.full


FishOutofWater,
Thanks for the useful/relevant information about isostatic rebound in Northern Latitudes; however, as the following re-posted information indicates the tectonic behavior in the WAIS is more complex as the mantle below the Byrd Subglacial Basin (BSB) and Marie Byrd Land has magma with very low viscosity, as discussed in the two re-posted Replies from the Antarctic Tectonic thread (also the rate of ice mass loss from the BSB is exceptionally high).

Best,
ASLR

The following abstract comes from the International Glacial Society Proceeding 65 at the following link:

http://www.igsoc.org/symposia/2014/chamonix/proceedings/procsfiles/procabstracts_65.htm

It is particularly interesting that Wilson et al 2014 indicate that the magma beneath Marie Byrd Land has very low viscosity:

70A1149
The POLENET-ANET integrated GPS and seismology approach to understanding glacial isostatic adjustment and ice mass change in Antarctica

Terry WILSON, Michael BEVIS, Stephanie KONFAL, Richard ASTER, Julien CHAPUT, David HEESZEL, Douglas WIENS, Sridhar ANANDAKRISHNAN, Ian DALZIEL, Audrey HUERTA, Eric KENDRICK
Corresponding author: Terry Wilson
Corresponding author e-mail: wilson.43@osu.edu

Abstract: "The POLENET-ANET project is simultaneously resolving crustal motions, measured by GPS, and Earth structure and rheological properties, mapped by seismology. Measured vertical and horizontal crustal motion patterns are not explained by extant glacial isostatic adjustment (GIA) models. These models have ice histories dominated by ice loss following the Last Glacial Maximum (LGM) and rely on 1-D Earth models, with rheological properties varying only radially. Seismological results from POLENET-ANET are revealing significant complexity in lateral variation in Earth properties. For example, crustal thickness variations occur not only across the East-West Antarctic boundary, but also between crustal blocks within West Antarctica. Modeling of mantle viscosity based on shear wave velocities shows a sharp lateral gradient from high to low viscosity in the Ross Embayment, a much more gradual gradient in the Weddell Embayment, and very low viscosities below Marie Byrd Land and the Amundsen Sea Embayment (ASE). Remarkable vertical and horizontal bedrock crustal motion velocity magnitudes, directions and patterns correlate spatially, in many aspects, with Earth property variations mapped by seismology. Within the ASE, extremely high upward velocities are flanked by subsiding regions – neither predicted by GIA models. Given the thin crust and low mantle viscosity, it is likely that this is not an LGM signal, which would have already relaxed, and uplift due to the elastic response to modern ice mass change clearly is important. As in other regions where rapid GIA-induced uplift has been measured, the crustal velocities in the Amundsen Embayment may also record a viscoelastic response to ice loss on decadal–centennial timescales. Along the East-West Antarctic boundary in the Ross Embayment, GIA-induced horizontal crustal motions are toward rather than away from the principal ice load center, correlating spatially with the strong lateral gradient in mantle viscosity. In the Weddell Embayment region, where crustal thickness is intermediate between East and West Antarctica and mantle viscosity values are moderate, crustal motions show the best match with predictions of GIA models. It is clear that lateral variations in Earth properties fundamentally control the isostatic response to ice mass changes in Antarctica. Ongoing integrated seismic-GPS studies are critical to developing the next generation of GIA models."

Also see:
The following linked reference cites evidence of low upper mantle velocities inland of the Amundsen Sea.  Such low-velocity zones indicate the presence of a significant degree of partial melting, and thus to potential for rapid rebound when ice mass is lost from the Byrd Subglacial Basin:

Natalie J. Accardo, Douglas A. Wiens, Stephen Hernandez, Richard C. Aster, Andrew Nyblade, Audrey Huerta, Sridhar Anandakrishnan, Terry Wilson, David S. Heeszel and Ian W. D. Dalziel, (2014), "Upper mantle seismic anisotropy beneath the West Antarctic Rift System and surrounding region from shear wave splitting analysis", Geophys. J. Int. (2014) doi: 10.1093/gji/ggu117

http://gji.oxfordjournals.org/content/early/2014/05/21/gji.ggu117.abstract

Abstract: "We constrain azimuthal anisotropy in the West Antarctic upper mantle using shear wave splitting parameters obtained from teleseismic SKS, SKKS and PKS phases recorded at 37 broad-band seismometres deployed by the POLENET/ANET project. We use an eigenvalue technique to linearize the rotated and shifted shear wave horizontal particle motions and determine the fast direction and delay time for each arrival. High-quality measurements are stacked to determine the best fitting splitting parameters for each station. Overall, fast anisotropic directions are oriented at large angles to the direction of Antarctic absolute plate motion in both hotspot and no-net-rotation frameworks, showing that the anisotropy does not result from shear due to plate motion over the mantle. Further, the West Antarctic directions are substantially different from those of East Antarctica, indicating that anisotropy across the continent reflects multiple mantle regimes. We suggest that the observed anisotropy along the central Transantarctic Mountains (TAM) and adjacent West Antarctic Rift System (WARS), one of the largest zones of extended continental crust on Earth, results from asthenospheric mantle strain associated with the final pulse of western WARS extension in the late Miocene. Strong and consistent anisotropy throughout the WARS indicate fast axes subparallel to the inferred extension direction, a result unlike reports from the East African rift system and rifts within the Basin and Range, which show much greater variation. We contend that ductile shearing rather than magmatic intrusion may have been the controlling mechanism for accumulation and retention of such coherent, widespread anisotropic fabric. Splitting beneath the Marie Byrd Land Dome (MBL) is weaker than that observed elsewhere within the WARS, but shows a consistent fast direction, possibly representative of anisotropy that has been ‘frozen-in’ to remnant thicker lithosphere. Fast directions observed inland from the Amundsen Sea appear to be radial to the dome and may indicate radial horizontal mantle flow associated with an MBL plume head and low upper mantle velocities in this region, or alternatively to lithospheric features associated with the complex Cenozoic tectonics at the far-eastern end of the WARS."
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FishOutofWater

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Re: What's new in Antarctica ?
« Reply #164 on: August 09, 2016, 08:19:28 PM »
Very interesting papers about rebound in Antarctica. If rebound can happen quickly there because of large scale magma movement towards the region of ice loss then the whole process of deglaciation and sea level rise may speed up. It's a good problem for folks testing numerical models.

Then there's the possibility of increased volcanic activity caused by decompression melting of upper mantle and lower crustal rock.

I had no idea that Antarctica had rapid rebound. Low silica magmas have low viscosity so we can guess that the magma composition is basaltic to ultramafic.  Hmmm....

Thanks. There's a lot to think about.

AbruptSLR

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Re: What's new in Antarctica ?
« Reply #165 on: August 09, 2016, 09:08:54 PM »
Very interesting papers about rebound in Antarctica. If rebound can happen quickly there because of large scale magma movement towards the region of ice loss then the whole process of deglaciation and sea level rise may speed up. It's a good problem for folks testing numerical models.

Then there's the possibility of increased volcanic activity caused by decompression melting of upper mantle and lower crustal rock.

I had no idea that Antarctica had rapid rebound. Low silica magmas have low viscosity so we can guess that the magma composition is basaltic to ultramafic.  Hmmm....

Thanks. There's a lot to think about.


The linked thread on Antarctic Tectonics addresses many of the issues that you raise:

http://forum.arctic-sea-ice.net/index.php/topic,393.0.html
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AbruptSLR

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Re: What's new in Antarctica ?
« Reply #166 on: August 24, 2016, 11:36:35 PM »
The linked article discusses how one Antarctic ice core was obtained & transported to the USA:

http://arstechnica.com/science/2016/08/from-the-south-pole-to-the-science-section-how-ice-becomes-knowledge/

Extract: "The newest specimen in the Antarctic collection is the US-National-Science-Foundation-funded South Pole ice (SPICE) core, a 1,750-meter-long stick of ice drilled just a few kilometers from the permanent Amundsen-Scott South Pole Station. Obtaining it took two two-month campaigns.
One of the most distinctive aspects of this core is that it will contain a record of extremely trace gases. University of Washington researcher TJ Fudge explained to Ars, “If we’re thinking about carbon dioxide, that’s measured in parts per million. If we’re thinking about methane, that’s measured in parts per billion. This core is going to be good for measuring COS [carbonyl sulfide]; that’s measured in parts per trillion.”
“The reason this is a good site for it is that it has a unique combination of being very cold, because it’s so far [south] at the pole, yet it has a relatively high snowfall because it gets moisture [traveling] from the West Antarctic side over to the East Antarctic side,” he continued. Higher snowfall means thicker annual layers of ice, so you can make measurements at higher resolution—even if you need a fair number of trapped bubbles of gas to make your delicate measurement. Since the South Pole is so isolated even by Antarctic standards, the ice contains little in the way of impurities that make measuring trace chemicals difficult.

The other key piece of information is the evidence of volcanic eruptions marked by sulfate (and occasionally ash) in the core. “What’s nice about the South Pole,” Erich Osterberg said, “is that we’ve got this southern polar vortex—you can almost think about it like this big drain in the atmosphere, or this big whirlpool—and all the [volcanic material] that’s up in the stratosphere gets funneled down and focused into the middle of Antarctica. So at the South Pole, we think that we will get to see a more clean picture of what’s happening for volcanic eruptions around the world.”
That’s interesting in its own right, as large eruptions have short-term impacts on climate worth studying. But it’s also extremely useful for nailing down the timeline of the ice core. The fallout from an eruption will show up in that year’s ice in many cores, so this provides a firm marker you can use to tie all the timelines together. That adds an independent check on your annual layer count, and at depths in the core where annual layers become too thin to pick apart, it sets known points to work between.
“That’s a big part of what we’re doing, because the whole science community that is gonna use this ice core, they need that timescale. All the science is really constrained by how good the timescale is,” Osterberg said. “If we want to do analyses, or start to understand what’s forcing the climate, how the climate is responding, if you don’t know exactly when these [things] are happening you can’t compare to other records, you can’t compare to other ice cores, you can’t compare to the records from the ocean telling us what the ocean is doing.”
Once ages are assigned to every point along the ice core, the rest of the science can begin. That includes examining the temperatures recorded by isotopes of oxygen and hydrogen, as well as greenhouse gas concentrations. But the South Pole ice core will make other, more distinct contributions.
First, it will provide pristine records of trace gases like carbonyl sulfide [COS], carbon monoxide, and methyl chloride. “The thing about COS, unlike CO2, is that it isn’t respired by plants,” TJ Fudge said. “It’s taken up by plants, but it isn’t respired by plants. So looking at changes in COS through time has the potential to tell us about global biological production—essentially, what are the plant life changes that occur through these climate changes?”
Carbon monoxide plays a significant role in the network of reactions that eats up gases like methane (converting it to CO2), but we don’t understand the natural sources of carbon monoxide nearly as well as we do other gases. Getting a long-term record of carbon monoxide behavior will help put its recent behavior in context, allowing scientists to better tease apart human impacts. And methyl chloride helps researchers finger the sources responsible for changes in methane concentrations. It’s also one of the compounds that naturally destroys ozone, so changes in methyl chloride shift the balance of ozone chemistry.

As it happens, there is also a record of phytoplankton growth trapped in this ice core. Phytoplankton produce dimethyl sulfide, an organic sulfur compound that drifts into the atmosphere where it contributes to cloud formation. Some of that dimethyl sulfide ends up in the Antarctic ice in the form of methanesulfonic acid (MSA). So when phytoplankton productivity goes up, the amount of MSA in the South Pole ice core should show it.
“So we’re actually able to look at both of those hypotheses. Do we see evidence that there would be more biological activity? And do we see evidence that just the winds themselves may have increased mixing and changed CO2?” Osterberg said.
There’s plenty more, like using an isotope of beryllium to track historic solar activity or an isotope of krypton to investigate local atmospheric pressure variability. "
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budmantis

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Re: What's new in Antarctica ?
« Reply #167 on: August 25, 2016, 02:25:27 AM »
Enjoyed reading your post ASLR. I'd be curious to know how many years this ice core will span.

AbruptSLR

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Re: What's new in Antarctica ?
« Reply #168 on: August 25, 2016, 02:51:19 AM »
Enjoyed reading your post ASLR. I'd be curious to know how many years this ice core will span.


It spans well over the past 40,000 years, and you can read about all the details about the SPICE program at the following link:

http://spicecore.org/
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budmantis

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Re: What's new in Antarctica ?
« Reply #169 on: August 25, 2016, 03:06:15 AM »
Thanks!

Gray-Wolf

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Re: What's new in Antarctica ?
« Reply #170 on: September 03, 2016, 09:42:51 PM »
Couple of days of big drops in extent? First of the spring storms?
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AbruptSLR

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Re: What's new in Antarctica ?
« Reply #171 on: September 04, 2016, 12:10:18 AM »
Couple of days of big drops in extent? First of the spring storms?

The linked article indicates that storm-force winds have flipped winter to summer conditions in West Antarctica:

https://robertscribbler.com/2016/09/02/warm-storm-force-winds-blowing-up-from-the-equator-change-west-antarctic-winter-to-summer/

Extract: "Warm, Storm-Force Winds Blowing From the Equator Flip West Antarctic Winter to Summer"

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Re: What's new in Antarctica ?
« Reply #172 on: September 15, 2016, 06:26:39 PM »
Extract: "Warm, Storm-Force Winds Blowing From the Equator Flip West Antarctic Winter to Summer"

I'll say.  Looks like southern winter maximum came about 3 weeks early.....around August 22nd or so.  And then the ice extent has made an initial sharp move lower since then.

Looks like the earliest max in quite a while.....
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Re: What's new in Antarctica ?
« Reply #173 on: September 18, 2016, 12:27:30 PM »
Extract: "Warm, Storm-Force Winds Blowing From the Equator Flip West Antarctic Winter to Summer"

I'll say.  Looks like southern winter maximum came about 3 weeks early.....around August 22nd or so.  And then the ice extent has made an initial sharp move lower since then.

Looks like the earliest max in quite a while.....

Have a look at the NSIDC extent graph for 2015. there was a similar, but smaller decline at this time, but then a steep increase from day 269 to 277
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abc australia article about antarctic sea ice plunge
« Reply #174 on: September 21, 2016, 12:28:44 PM »
Anecdotal thinning shelves near Mawson and Davis in Antarctica:

http://www.abc.net.au/news/2016-09-21/sea-ice-record-retreat-has-antarctic-experts-worried/7865732

"Often the first voyage of the season is quite challenging getting close to Davis [station] so from a long way out we'll encounter ice some [160 to 320 kilometres] and that can be hard to get through," he said.

"With any luck that ability to get closer to the station will be easier.

"But it could be we don't have good enough ice beside the station in which to park the ship and unload our cargo onto the ice."

He said equipment may have to be dismantled and flown in to bases like Davis.

"We can use our helicopters to get our equipment and people onshore if the ice isn't good enough to drive on, however obviously we can't get our heavy equipment to shore in that case," Mr Clifton said.

Earlier this week a vehicle travelling outside Mawson station broke through a thin section of sea ice, but no one was hurt.


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Re: What's new in Antarctica ?
« Reply #175 on: October 25, 2016, 07:17:01 PM »
Colorized version of the film of Scott's expedition:
http://boingboing.net/2016/10/25/colorized-film-and-photos-of-a.html
In 1912, Herbert Ponting captured remarkable film and images of Captain Robert Falcon Scott's ill-fated Terra Nova Expedition. Amateurs and pros have all worked to restore and colorize Ponting's work.

Via the preservationists at BFI:

    The Great White Silence is one of the jewels in the crown of the BFI National Archive fully justifying this stunning tinted and toned restoration with new score by electronic musician Simon Fisher Turner. The official film record of the British Expedition of 1910-13 led by Scott was reworked by photographer Herbert Ponting to tell the tragic tale but It is the beauty of the images of Antarctica’s frozen landscapes in this film that linger.

Bonus: Interesting mini-doc on how they chose the scoring:  (viewable on website, includes quite a few bits of the movie)
The film also shows the "making-of" reverse of Ponting's stunning still, colorized by Imgurian ktrcoyote http://imgur.com/06LqCsG:
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solartim27

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Re: What's new in Antarctica ?
« Reply #176 on: October 25, 2016, 11:36:30 PM »
I am sad to report the death of researcher Gordon Hamilton this weekend in an accident while working in Antarctica.

http://www.pri.org/stories/2016-10-25/us-climate-scientist-killed-antarctica-accident

http://www.nytimes.com/2016/10/25/science/gordon-hamilton.html?smid=tw-nytimesscience&smtyp=cur&_r=0
The helicopter hovered 30 feet above a fjord in Greenland, a thrumming red speck of human ingenuity in a vast wilderness of rock and ice.

Gordon Hamilton leaned out the right side at a crazy angle, dropping a scientific instrument into the water below. He wore a seatbelt for safety, but he looked as if he might break free at any moment and plunge into the icy water.

He must have seen the worried look on my face, and he shot me a big grin. That moment, that smile: That is how I will always remember him, a man willing to court danger to do the job he loved.

Gordon Stuart Hamilton, 50, a glaciologist at the University of Maine, was killed over the weekend on a scientific expedition to Antarctica. He was surveying a trail to find the crevasses that can make working on glacial ice so dangerous, and his snowmobile plunged into one of them.


http://www.nytimes.com/2016/10/25/science/gordon-hamilton-climate-scientist-dies-accident-antarctica.html?action=click&contentCollection=Science&module=RelatedCoverage&region=Marginalia&pgtype=article
Gordon Hamilton, a prominent climate scientist who studied glaciers and their impact on sea levels in a warming climate, died on Saturday in Antarctica when the snowmobile he was riding plunged into a 100-foot-deep crevasse. He was 50.

The National Science Foundation, which was funding his research, reported the death. The episode is under investigation, officials said.

Dr. Hamilton died on White Island in the continent’s Ross Archipelago, according to the University of Maine, in Orono, where he was an associate research professor in the glaciology group at the Climate Change Institute.
...
When not in the field, he taught undergraduate and graduate students at the University of Maine. He was also involved in statewide initiatives aimed at high school-age children.

Before joining the university’s Climate Change Institute as an assistant research professor in 2000, Dr. Hamilton worked at the Byrd Polar and Climate Research Center at Ohio State University and at the Norwegian Polar Institute, according to the National Science Foundation.

He is survived by his wife, Fiona, and two children, Martin and Calum.
« Last Edit: October 25, 2016, 11:48:32 PM by solartim27 »
FNORD

Sleepy

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Re: What's new in Antarctica ?
« Reply #177 on: October 26, 2016, 06:45:36 AM »
Thanks solartim, not one single line about Hamilton here.

Tigertown

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Re: What's new in Antarctica ?
« Reply #178 on: October 27, 2016, 05:52:02 AM »

jai mitchell

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Re: What's new in Antarctica ?
« Reply #179 on: October 27, 2016, 07:24:06 PM »
here is the article and a very very important graphic, note the elevation changes per year.

article here:  http://www.nature.com/articles/ncomms13243

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Tigertown

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Re: What's new in Antarctica ?
« Reply #180 on: October 27, 2016, 08:12:37 PM »
Just read that Smith's, Pine Island, and Thwaites Glaciers are all on retro-grade slopes away from the grounding lines.When warm water circulates under the ice shelf, it gets under the ice and flows downhill inland, melting away at these from underneath.

AbruptSLR

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Re: What's new in Antarctica ?
« Reply #181 on: October 28, 2016, 05:48:30 PM »
The linked article is entitled: "Space Weather from a Southern Point of View".  It indicates that Antarctic provides a unique vantage point for viewing near-Earth space:

https://eos.org/project-updates/space-weather-from-a-southern-point-of-view?utm_source=eos&utm_medium=email&utm_campaign=EosBuzz102816

Extract: "A recently completed instrument array in Antarctica provides a more complete understanding of the near-Earth space environment."
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AbruptSLR

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Re: What's new in Antarctica ?
« Reply #182 on: October 30, 2016, 11:55:15 PM »
The linked reference is entitled: "Resonance vibrations of the Ross Ice Shelf and observations of persistent atmospheric waves":

Oleg A. Godin & Nikolay A. Zabotin (10 October 2016), "Resonance vibrations of the Ross Ice Shelf and observations of persistent atmospheric waves", JGR Space Physics, DOI: 10.1002/2016JA023226


http://onlinelibrary.wiley.com/doi/10.1002/2016JA023226/abstract

Abstract: "Recently reported lidar observations have revealed a persistent wave activity in the Antarctic middle and upper atmosphere that has no counterpart in observations at midlatitude and low-latitude locations. The unusual wave activity suggests a geographically specific source of atmospheric waves with periods of 3–10 h. Here we investigate theoretically the hypothesis that the unusual atmospheric wave activity in Antarctica is generated by the fundamental and low-order modes of vibrations of the Ross Ice Shelf (RIS). Simple models are developed to describe basic physical properties of resonant vibrations of large ice shelves and their coupling to the atmosphere. Dispersion relation of the long surface waves, which propagate in the floating ice sheet and are responsible for its low-order resonances, is found to be similar to the dispersion relation of infragravity waves in the ice-free ocean. The phase speed of the surface waves and the resonant frequencies determine the periods and wave vectors of atmospheric waves that are generated by the RIS resonant oscillations. The altitude-dependent vertical wavelengths and the periods of the acoustic-gravity waves in the atmosphere are shown to be sensitive to the physical parameters of the RIS, which can be difficult to measure by other means. Predicted properties of the atmospheric waves prove to be in a remarkable agreement with the key features of the observed persistent wave activity."

See also the associate article entitled: "Weird 'Gravity' Waves Above Antarctica Caused by Ice Vibrations":

http://www.livescience.com/56686-ice-vibrations-cause-weird-waves-above-antarctica.html
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Sigmetnow

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Re: What's new in Antarctica ?
« Reply #183 on: November 03, 2016, 12:30:35 PM »
Photos from this year's NASA Operation IceBridge mission over Antarctica.
http://www.nbcnews.com/slideshow/fly-over-country-stunning-aerial-views-antarctica-n676866
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AbruptSLR

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Re: What's new in Antarctica ?
« Reply #184 on: November 05, 2016, 04:41:24 PM »
Photos from this year's NASA Operation IceBridge mission over Antarctica.
http://www.nbcnews.com/slideshow/fly-over-country-stunning-aerial-views-antarctica-n676866


Also the linked website offers some more stunning photos of Antarctica from NASA's IceBridge flights:

http://news.nationalgeographic.com/2016/11/nasa-ice-bridge/

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Re: What's new in Antarctica ?
« Reply #185 on: November 14, 2016, 02:42:49 PM »
http://www.nature.com/articles/ncomms13243

Getting twitchy about this now. I had been keeping up to the travels of warmed bottom waters as they broke through the circumpolars ( whist they were being augmented by the Ozone hole ) and headed around the continent finally reaching Ross in 2012.

Now the Ozone hole is showing some recovery and the Pacific forcings supposedly reversed in 2014 meaning the losses, noted above, will now rapidly increase.
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Tigertown

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Re: What's new in Antarctica ?
« Reply #186 on: November 14, 2016, 06:28:10 PM »
I have been reading for a while now about the crack in Larson C ,but this is the newest info that I can find.

www.climatecentral.org/news/rift-speeds-up-across-antarctic-ice-shelf-20752

Anyone runs across any updates, please share, as this will be a huge iceberg, when it breaks off.

Sleepy

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Re: What's new in Antarctica ?
« Reply #187 on: November 14, 2016, 06:46:49 PM »
Tigertown, there's a dedicated thread on Larsen C here:
http://forum.arctic-sea-ice.net/index.php/topic,1175.0.html

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Re: What's new in Antarctica ?
« Reply #188 on: November 14, 2016, 08:46:55 PM »
Tigertown, there's a dedicated thread on Larsen C here:
http://forum.arctic-sea-ice.net/index.php/topic,1175.0.html


Thanks. I will follow henceforth.

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Re: What's new in Antarctica ?
« Reply #189 on: November 16, 2016, 03:54:07 AM »

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Re: What's new in Antarctica ?
« Reply #190 on: November 16, 2016, 06:56:27 AM »
That was a good article.  Here's a gif of the area above Larsen B from Nov 10 to 15.  Looking pretty blue.  Remarkable how fast the sea ice can scurry away.
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Re: What's new in Antarctica ?
« Reply #191 on: November 17, 2016, 09:37:40 PM »

Andre

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Re: What's new in Antarctica ?
« Reply #192 on: November 19, 2016, 04:20:15 AM »
Not sure if this has been posted already:

RIMS 2016: Sea Level Rise Will Be Worse and Come Sooner
http://www.insurancejournal.com/news/national/2016/04/12/405089.htm

Abstract:
"Think sea level rise will be moderate and something we can all plan for? Think again.

Sea levels could rise by much more than originally anticipated, and much faster, according to new data being collected by scientists studying the melting West Antarctic ice sheet – a massive sheet the size of Mexico."

Tigertown

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Re: What's new in Antarctica ?
« Reply #193 on: November 19, 2016, 04:31:45 AM »
Good article, but failed to mention the geothermal activity under the W. Antarctica ice sheet. That could move the calendar up a bit.

oren

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Re: What's new in Antarctica ?
« Reply #194 on: November 19, 2016, 02:06:00 PM »
This talk has been mentioned before (note this is from April) but I believe the article itself was not. I wonder when these OMG findings might be made public.

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Re: What's new in Antarctica ?
« Reply #195 on: November 21, 2016, 01:04:01 AM »
The "OMG findings" were her personal opinion (as per corrective e-mail to Eric Holtaus earlier this year). Worst case is 1m by 2050 atm (per the Hansen paper), which would cause plenty of issues on its own.

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Re: What's new in Antarctica ?
« Reply #196 on: November 23, 2016, 09:55:05 PM »
New article on the BBC news service:

Huge glacier retreat triggered in 1940s
By Jonathan Amos
BBC Science Correspondent

http://www.bbc.com/news/science-environment-38079838

The melting Antarctic glacier that now contributes more to sea-level rise than any other ice stream on the planet began its big decline in the 1940s.
This is when warm ocean water likely first got under Pine Island Glacier (PIG) to loosen the secure footing it had enjoyed up until that point.
Researchers figured out the timing by dating the sediments beneath the PIG.
It puts the glacier’s current changes in their proper historical context, the scientists tell Nature magazine.

## When you go to the BBC article - and click on the ....tell Nature Magazine part, it takes you to the article in full (but un-downloadable).

Tigertown

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Re: What's new in Antarctica ?
« Reply #197 on: November 29, 2016, 12:07:22 AM »
Not my discovery, but a melt pond in the Mcmurdo Sound area.


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Re: What's new in Antarctica ?
« Reply #198 on: November 29, 2016, 10:44:13 AM »
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Buddy

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Re: What's new in Antarctica ?
« Reply #199 on: November 29, 2016, 12:42:16 PM »
More news on P.I.G. (and its upcoming collapse?)

Day by day.....week by week....and month by month, mother earth is screaming at us, and many are turning a blind eye.

Next 1 - 5 years should certainly provide some scientific excitement in Antarctica as the sea ice most likely continues its melting march.

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