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Author Topic: What's new in Antarctica ?  (Read 76919 times)

Gray-Wolf

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Re: What's new in Antarctica ?
« Reply #200 on: November 29, 2016, 02:12:14 PM »
As with ice loss in the Arctic the removal of the 'damping' that the ice provides means swells can impact permafrost cliffs at the shore. In Antarctica the removal of the 'damping' means the ice shelf's come under increased forcing and so fail more often.

With places like Ross removal of the front of the shelf would lead to the rapid collapse of the rear section. Work in the mid noughties showed past 'rapid collapse' events from Ross . I was brought up to believe that East Antarctica was beyond the reach of our warming planet yet since, decade following decade, we learned that we are already seeing impacts in East Antarctica.

If IPO had flipped into its positive state ( and we are not just noting an uptick in solar reaching the Pacific now Chinese pollution is reducing?) then we should expect another 20 years or so of the kind of Sea ice melt we are currently witnessing?

Couple an IPO+ve with the ongoing repair of Ozone over the continent and we should be expecting  rapid changes around the antarctic coasts?
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solartim27

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Re: What's new in Antarctica ?
« Reply #201 on: November 29, 2016, 04:53:09 PM »
Not my discovery, but a melt pond in the Mcmurdo Sound area.
That was the shadow from a cloud.
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magnamentis

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Re: What's new in Antarctica ?
« Reply #202 on: November 29, 2016, 05:44:47 PM »
Not my discovery, but a melt pond in the Mcmurdo Sound area.
That was the shadow from a cloud.

definitely blue water, what's the purpose of that post?

even if it would be gone later on, could be freeze over night hours and snow covered, not saying but i was thinking why one would see this as cloud shadow and that's just one possible explanation should the lake not be visible on a later picture while it's important to have a close look at the time an eventual image without that blue pond was taken, earlier or indeed later than the one attached.

whether it's a pond or a polnya i can't tell because i'm not 100 savvy about terms here, distinguished by size or whether the difference is that a pond could be water ON ice and a polnya just open water withing the ice :-) others know that better.
« Last Edit: November 29, 2016, 05:53:17 PM by magnamentis »
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Tigertown

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Re: What's new in Antarctica ?
« Reply #203 on: November 29, 2016, 06:12:35 PM »
Not my discovery, but a melt pond in the Mcmurdo Sound area.
That was the shadow from a cloud.

I took someone else's word for it. I should have known better.

wehappyfew

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Re: What's new in Antarctica ?
« Reply #204 on: November 29, 2016, 06:21:54 PM »
Definitely shadows from clouds.

In Worldview, toggle the different satellite feeds, like Aqua/MODIS vs Terra/MODIS, and slide the opacity from 0% to 100%. The shadows move as the local time of day changes the sun angle. Observe the shadows of nearby mountains - they can be the exact same dark blue at times (but not always).

The clouds responsible are visible, but just barely (white clouds over white ice).

Observe other cloud shadows over the sloping areas of nearby ice sheets that could never support melt ponds.

I love reading Robert Scribbler, but enthusiasm can, and has, led him to jump to incorrect conclusions. We all do that, but he does it more visibly by blogging so frequently.


Darvince

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Re: What's new in Antarctica ?
« Reply #205 on: November 29, 2016, 06:58:40 PM »
There was definitely a significant amount of melt action though, as you can see the glacier turning much darker blue only between the timespan of the Aqua pass and the Terra pass, as well as it becoming much darker on the 7-2-1 bands between days.

2016-11-25: http://go.nasa.gov/2gFBCAx

2016-11-28: http://go.nasa.gov/2gFySTS

wehappyfew

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Re: What's new in Antarctica ?
« Reply #206 on: November 29, 2016, 07:14:45 PM »
Thank you Darvince.
Nice choice of Base Layers to highlight the white clouds casting shadows on the light blue surface.

Worldview 11-27-16

I see five clouds. Three are casting sharp blue shadows that look like melt ponds, two at the bottom are casting grey shadows - maybe because the surface is different, or maybe the clouds are thinner.


Tealight

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Re: What's new in Antarctica ?
« Reply #207 on: November 29, 2016, 07:23:20 PM »
As solartim27 and wehappyfew said its definitely a shadow of a cloud on blue ice. However there are some smaller melt ponds scattered over the glacier.

I attached a S2A image of the region (180 degrees rotated compared to Worldview)

Tigertown

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Re: What's new in Antarctica ?
« Reply #208 on: November 29, 2016, 07:31:21 PM »
Definitely shadows from clouds.

In Worldview, toggle the different satellite feeds, like Aqua/MODIS vs Terra/MODIS, and slide the opacity from 0% to 100%. The shadows move as the local time of day changes the sun angle. Observe the shadows of nearby mountains - they can be the exact same dark blue at times (but not always).

The clouds responsible are visible, but just barely (white clouds over white ice).

Observe other cloud shadows over the sloping areas of nearby ice sheets that could never support melt ponds.

I love reading Robert Scribbler, but enthusiasm can, and has, led him to jump to incorrect conclusions. We all do that, but he does it more visibly by blogging so frequently.
Thanks. I tried that and see that it both moves and changes shape.

AbruptSLR

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Re: What's new in Antarctica ?
« Reply #209 on: December 04, 2016, 05:11:43 AM »
The linked article is entitled: "Why is a blue cloud appearing over Antarctica?"

http://www.csmonitor.com/Science/2016/1203/Why-is-a-blue-cloud-appearing-over-Antarctica

Extract: "Noctilucent, or night-glowing, clouds appear over the South Pole each year. This year they arrived much earlier than usual, puzzling scientists.

The noctilucent clouds provide clues to the mesosphere's "connections to other parts of the atmosphere, weather, and climate," she wrote. They are summer phenomena, appearing above the Arctic in July and August and above the Antarctic in November and December."
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magnamentis

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Re: What's new in Antarctica ?
« Reply #210 on: December 04, 2016, 08:51:10 PM »
would be interesting to find out how many tripple century drops have ever occurred in the antarctic or anywhere else?
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Tigertown

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Re: What's new in Antarctica ?
« Reply #211 on: December 04, 2016, 10:21:37 PM »
would be interesting to find out how many tripple century drops have ever occurred in the antarctic or anywhere else?

I don't where to get the raw numbers with JAXA, but just looking at the graph, I don't see anything close to that. Off the top of my head,I think it may be a record. NSIDC I believe recently posted a drop of about 284k.

diablobanquisa

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Re: What's new in Antarctica ?
« Reply #212 on: December 05, 2016, 12:23:55 AM »
JAXA data is available here: https://ads.nipr.ac.jp/vishop/#/extent (just select "Antarctic" and click on "Download...")

In December, most years have at least one tripple century drop.
There are also a few years with quadruple century drops, and even a fivefold century drop in December 1993.



Gray-Wolf

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Re: What's new in Antarctica ?
« Reply #213 on: December 07, 2016, 05:41:20 PM »
https://www.theguardian.com/world/2016/dec/07/british-antarctic-research-station-crack-ice

Looks like the B.A.S. are not taking any chances this summer?

With the ice already withdrawn in Weddell

https://worldview.earthdata.nasa.gov/?p=antarctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&t=2016-10-02&z=3&v=-775296,1355648,-600448,1437312

will swells waggle that chasm fully across the shelf this summer? And what of the full moon in 7 days? that'll give quite a bit of a 'lift' along that central end of the chasm....
« Last Edit: December 13, 2016, 05:29:55 PM by Gray-Wolf »
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Tigertown

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Re: What's new in Antarctica ?
« Reply #214 on: December 12, 2016, 11:04:26 PM »

Tigertown

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Re: What's new in Antarctica ?
« Reply #215 on: December 16, 2016, 01:49:18 AM »

jai mitchell

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Re: What's new in Antarctica ?
« Reply #216 on: December 16, 2016, 08:20:13 PM »
https://www.washingtonpost.com/news/energy-environment/wp/2016/12/16/warm-ocean-water-is-slamming-into-and-melting-the-biggest-glacier-in-east-antarctica

Scientists at institutions in the United States and Australia on Friday published a set of unprecedented ocean observations near the largest glacier of the largest ice sheet in the world: Totten glacier, East Antarctica. And the result was a troubling confirmation of what scientists already feared — Totten is melting from below.


see: http://advances.sciencemag.org/content/2/12/e1601610
Ocean heat drives rapid basal melt of the Totten Ice Shelf

    Stephen Rich Rintou et al.

Observations from the Totten calving front confirm that (0.22 ± 0.07) × 106 m3 s−1 of warm water enters the cavity through a newly discovered deep channel.


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AbruptSLR

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Re: What's new in Antarctica ?
« Reply #217 on: December 20, 2016, 10:16:22 AM »
The linked article discusses how right now the Australian research vessel the "Aurora Australis" is traveling to East Antarctica to gather more/new data on the stability of marine glaciers (including Totten):

http://mashable.com/2016/12/19/east-antarctica-totten-glacier-melt-climate/#hmoYBXlpksqo
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solartim27

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Re: What's new in Antarctica ?
« Reply #218 on: December 20, 2016, 06:13:13 PM »
I saw this little video clip, and couldn't help but wonder about all the yellowish gunk on the bottom of the ice.  Anyone have any thoughts?
The bow of the NG/Linblad Explorer slides through the seasonal sea ice on the Antarctic Peninsula.
https://www.instagram.com/p/BOOVgZujbuL/
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Tigertown

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Re: What's new in Antarctica ?
« Reply #219 on: December 20, 2016, 07:13:13 PM »
Phytoplankton. Recently discovered under Arctic ice, now looks to be under Antarctic ice also. The water is relatively warm just below the surface.

georged

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Re: What's new in Antarctica ?
« Reply #220 on: December 21, 2016, 04:04:40 AM »
Antarctic under-ice phytoplankton has been well known for a while. It was a fairly established subject when my housemate was doing her PhD on it in 2006.

Tigertown

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Re: What's new in Antarctica ?
« Reply #221 on: December 21, 2016, 06:19:31 AM »
Just looking into news of the warmer than usual circumpolar current that is melting away at the Totten Ice Shelf and possibly making a cavity  at the entrance of an under-water canyon about 1200 meters or less down. This is a big concern because of a retrograde inland that would channel the warm water under the glacier. The basin there contains a huge volume of ice. I am learning as I go on this, so maybe others can add details. I do have some temp and salinity charts for the area of concern.

sidd

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Re: What's new in Antarctica ?
« Reply #222 on: December 21, 2016, 06:44:42 AM »
Ice at depth melts easier, i seem to recall that at 1000m ice melts at -1.2C, which is around 2.5C colder than water temp at that depth from the chart above.

Tigertown

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Re: What's new in Antarctica ?
« Reply #223 on: December 21, 2016, 06:53:52 AM »
Ice at depth melts easier, i seem to recall that at 1000m ice melts at -1.2C, which is around 2.5C colder than water temp at that depth from the chart above.
Allowing another  -1.8 for salinity would make that about a 4.3oC differential.

sidd

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Re: What's new in Antarctica ?
« Reply #224 on: December 21, 2016, 10:48:56 PM »
The salinity effect is irrelevant, since the phenoenon under discussion is the met of glacial ice derived from fresh water. If we were speaking of melting saline ice or freezing saline water the argument might hold. But we are speaking of melt of fresh ice.

Tigertown

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Re: What's new in Antarctica ?
« Reply #225 on: December 22, 2016, 01:02:16 AM »
The area under attack from the warm water has a current flowing against it. So it is a steady flow of salt water, not stationary,so it doesn't cool like saltwater melting ice normally would. Wouldn't this make the salt more effective than normal?

georged

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Re: What's new in Antarctica ?
« Reply #226 on: December 22, 2016, 02:13:10 AM »
Just looking into news of the warmer than usual circumpolar current that is melting away at the Totten Ice Shelf and possibly making a cavity  at the entrance of an under-water canyon about 1200 meters or less down. This is a big concern because of a retrograde inland that would channel the warm water under the glacier. The basin there contains a huge volume of ice. I am learning as I go on this, so maybe others can add details. I do have some temp and salinity charts for the area of concern.


It's my understanding that this depression is due to glacial weight? In any case, it is over 2700m deep at the grounding line. This is a phenomenal deep surface.

http://imagecache.jpl.nasa.gov/images/640x350/earth20150316b-16-640x350.jpg

Tigertown

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Re: What's new in Antarctica ?
« Reply #227 on: December 22, 2016, 02:20:06 AM »
Thanks georged. Hope you don't mind if I go ahead and post that image, as it is very helpful in understanding the situation better.

sidd

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Re: What's new in Antarctica ?
« Reply #228 on: December 22, 2016, 05:40:34 AM »
Re: saltwater current more effective than fresh at melting fresh ice

call the current velocity v, current density rho, specific heat Cp, the area exposed to the current A, and the temperature drop of the current dT     

in order of magnitude terms the heat extracted from the current Q available for ice melt  is

Q=rho*Cp*A*v*dT
 
(This neglects melt efflux mixed into the impinging current, roughness, turbulence and a whole bunch of things. But to order of magnitude, is ok)

Both rho and Cp are functions of salinity (and pressure and temperature ...) From the difference in the term rho*Cp between fresh water and water and sea water (at the relevant pressure and temperature ...)  we can calculate the difference in heat delivered. I leave this as an excercise for the reader, but i think it is a few percent.

sidd

Tigertown

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Re: What's new in Antarctica ?
« Reply #229 on: December 22, 2016, 06:11:13 AM »
Thanks sidd. From what I understand it is a very strong current right now. Looking forward to any additional info that anyone comes across about this in the near future.

johnm33

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Re: What's new in Antarctica ?
« Reply #230 on: December 22, 2016, 01:43:44 PM »
Thanks for that image g+Tt, I'm going to keep an eye on hy-com for an outburst of fresh water thereabouts.

charles_oil

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Re: What's new in Antarctica ?
« Reply #231 on: December 26, 2016, 11:30:25 AM »
Huffington article and video about seafloor life in Antarctica - and the possible effects of CO2 changes.

http://www.huffingtonpost.co.uk/entry/rare-video-of-the-antarctic-seafloor-reveals-stunning-landscape_uk_585ab317e4b0d590e44ca05c?icid=maing-grid7%7Cmain5%7Cdl1%7Csec3_lnk1%26pLid%3D1285279572_uk

When you think of the seafloor in Antarctica you would be forgiven for thinking that it’s probably a barren wasteland, covered by vast swathes of ice in freezing cold temperatures.

While those last two points are accurate, an Australian Antarctic Division underwater research robot has captured a rare glimpse into the astonishing diversity that actually exists in this remotest of landscapes.

Rather than being a lifeless all-consuming mass of grey it seems Antarctica’s seafloor is brimming not only with life, but some dazzling colours too.

AbruptSLR

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Re: What's new in Antarctica ?
« Reply #232 on: December 30, 2016, 12:09:56 AM »
The linked article is entitled: "Satellite spots massive object hidden under the frozen wastes of Antarctica", and indicates that there may be a large asteroid impact crater buried beneath the ice in Wilkes Land.

http://www.news.com.au/technology/science/satellite-spots-massive-object-hidden-under-the-frozen-wastes-of-antarctica/news-story/dfdc58ee88bde178ceb611782185f39a

Extract: "The Sun reports the huge and mysterious “anomaly” is thought to be lurking beneath the frozen wastes of an area called Wilkes Land.

It stretches for a distance of 151 miles across and has a maximum depth of about 848 metres.
Some researchers believe it is the remains of a truly massive asteroid which was more than twice the size of the Chicxulub space rock which wiped out the dinosaurs.

If this explanation is true, it could mean this killer asteroid caused the Permian — Triassic extinction event which killed 96 per cent of Earth’s sea creatures and up to 70 per cent of the vertebrate organisms living on land."
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Tealight

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Re: What's new in Antarctica ?
« Reply #233 on: January 14, 2017, 08:02:26 PM »
Iceberg B31 (calved in November 2013, from Pine Island Glacier) was mostly visible for a few days. It appears to stay in the same position, but it spins at around 50 degrees per day or a full rotation in 7 days. The edges are around 10km from the rotation center so they move at 9km/day linear speed. Does this greatly increase the melt rate?

http://go.nasa.gov/2iseuFX

solartim27

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Re: What's new in Antarctica ?
« Reply #234 on: January 14, 2017, 09:39:39 PM »
I saw two nice bits on research stations in Antarctica with lots of nice pictures.

How Antarctic bases went from wooden huts to sci-fi chic:
http://www.bbc.co.uk/news/magazine-38574003

The incredible 'mad max' journey across Antarctica: Stunning satellite image reveals gruelling trek to resupply Earth's most remote research station
 Gruelling 10 day traverse is to reach Concordia, a giant two towered research station in Antarctica
The 'caravans' carry up to 300 tonnes of fuel, food and heavy equipment in 300 m-long convoys
http://www.dailymail.co.uk/sciencetech/article-4114796/The-incredible-mad-max-journey-Antarctica-Stunning-satellite-image-reveals-gruelling-trek-resupply-Earth-s-remote-research-stations.html
« Last Edit: January 14, 2017, 09:54:41 PM by solartim27 »
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iwantatr8

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Re: What's new in Antarctica ?
« Reply #235 on: January 20, 2017, 01:46:15 PM »
This looks like it might be a very useful resource for monitoring antartica data.

http://quantarctica.npolar.no/

but it's a bit big!


Laurent

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Re: What's new in Antarctica ?
« Reply #236 on: February 13, 2017, 08:32:10 PM »
http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2888.html
Enhanced weathering and CO2 drawdown caused by latest Eocene strengthening of the Atlantic meridional overturning circulation

Abstract

On timescales significantly greater than 105 years, atmospheric pCO2 is controlled by the rate of mantle outgassing relative to the set-point of the silicate weathering feedback. The weathering set-point has been shown to depend on the distribution and characteristics of rocks exposed at the Earth’s surface, vegetation types and topography. Here we argue that large-scale climate impacts caused by changes in ocean circulation can also modify the weathering set-point and show evidence suggesting that this played a role in the establishment of the Antarctic ice sheet at the Eocene–Oligocene boundary. In our simulations, tectonic deepening of the Drake Passage causes freshening and stratification of the Southern Ocean, strengthening the Atlantic meridional overturning circulation and consequently raising temperatures and intensifying rainfall over land. These simulated changes are consistent with late Eocene tectonic reconstructions that show Drake Passage deepening, and with sediment records that reveal Southern Ocean stratification, the emergence of North Atlantic Deep Water, and a hemispherically asymmetric temperature change. These factors would have driven intensified silicate weathering and can thereby explain the drawdown of carbon dioxide that has been linked with Antarctic ice sheet growth. We suggest that this mechanism illustrates another way in which ocean–atmosphere climate dynamics can introduce nonlinear threshold behaviour through interaction with the geologic carbon cycle.


solartim27

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Re: What's new in Antarctica ?
« Reply #237 on: February 13, 2017, 10:57:21 PM »
Just a fun gif of an iceberg wreacking havoc.  I believe it is B15AA.
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bairgon

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Re: What's new in Antarctica ?
« Reply #239 on: February 26, 2017, 07:35:07 AM »
Enderby Land has a chunk of ice approx 50km x 150km floating away. In gif is an animation from 10.2 to 25.2 2017.

That area suffered significant melting in April 2016, so the ice there is only one year old:


solartim27

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Re: What's new in Antarctica ?
« Reply #240 on: February 26, 2017, 07:25:33 PM »
Just saw this 2015 documentary on Claude Lorius, "Antarctica  Ice and Sky"  Lots of great historical video and  information on doing the initial research.

http://imdb.com/rg/an_share/title/title/tt4466550/
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dingojoe

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Re: What's new in Antarctica ?
« Reply #241 on: February 26, 2017, 10:03:39 PM »
Enderby Land has a chunk of ice approx 50km x 150km floating away. In gif is an animation from 10.2 to 25.2 2017.

That area suffered significant melting in April 2016, so the ice there is only one year old:

We've talked about that area on various threads, but it would have never occurred to me to look at April time frame for fast ice breakdown.

bairgon

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Re: What's new in Antarctica ?
« Reply #242 on: February 27, 2017, 05:44:31 PM »
Looking at the Weddell Sea, I've noticed that the ice has consistently been moving north from the shore for the last month or so. Hope the gif works; otherwise click.

New ice is forming in the gap. Also interesting to see the grounded iceberg which is perhaps helping to anchor the sea ice, but to little effect in this sequence.

Link: https://worldview.earthdata.nasa.gov/?p=antarctic&l=MODIS_Terra_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),Coastlines&t=2017-02-27&z=3&v=-1769401.1403176677,742212.6312051003,-786361.1403176677,1246532.6312051003&ab=off

Red

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Re: What's new in Antarctica ?
« Reply #243 on: February 27, 2017, 09:34:17 PM »
Enderby Land has a chunk of ice approx 50km x 150km floating away. In gif is an animation from 10.2 to 25.2 2017.

That area suffered significant melting in April 2016, so the ice there is only one year old:

We've talked about that area on various threads, but it would have never occurred to me to look at April time frame for fast ice breakdown.
If you go back through the Aprils to '13 you'll see that '16 was the first year that most of the bay opens. So a lot of that was MYI that let go last year. This melt season if you look at Ludzow-Holm Bay, the left side started to open against the mainland back in early December. This was melt out in MYI ice that existed at least back to '13, (thats as far as I know how to get to). Comparing various areas of East Antarctica's satellite records for the years from '13 to '16 it appears that every year there is a little more MYI goes missing by April. The area just in front of the Shirase toe has taken quite a hit this year compared to last. There are some icebergs coming free that haven't been loose in years. A little more MYI being lost consistently every year for the past four is not the end of days but, it would seem to indicate an increase in energy arriving at the surface during melt season year over year.

Neven

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Re: What's new in Antarctica ?
« Reply #244 on: March 27, 2017, 09:00:59 PM »
Here's a comment Hyperion made in the wrong thread:

Thanks slow wing. Especially for pointing out my elderly muddleheaded mixuped mismemoring of the enthalpy of vapourisation figure. How embarrassing to under calculate a figure by some 500 times. ::)
 And you Jai. Wish I had more time right now to read those papers. Very busy day unfortunately.  These worldwide changes to the circulation patterns we are used to seem to be happening almost hour by hour right now. It does seem like, particularly in the polar regions the tropopause has lifted suddenly and dramatically as predicted by some models and proposed as necessary for single cell circulation regimes in past equable climates. As for whether I'm a magnitude out in those estimated flow rates? As an engineer you tend to go "how bad could it get? What is the level of safety we need built in to handle it?" the precautionary principle with a mind to the future is the mindset. Not scientific understatement, with no credibility placed on any data but the solidly studied and proven historic data. And so I think it is possibly the best introduction we currently have, to what to expect in the late Arctic summer to observe whats going on down south here right now. That TPW fist that was heading for the Antarctic peninsula is now there. 15kg/sqm of water aboard and suddenly the whole peninsula is hotter by 6-10 degC. Up to 6 above freezing in places. The one heading for Ross, south of NZ is packing 30kg/sqm and came from mainly over Australia.  The Fist from the Indian Ocean Tropics is packing 45kg/sqm and just about to pass the Kerguellens at 52 sth and ram East Antarctica.
The huge 930hpa low taking up the whole space between Australia and Antarctica is the scariest mother I've ever seen, and looks capable of grabbing the whole of the Pacific Tropical airmass and squeezing all of it out on Antarctica. Especially as it comes across and meshes with the Anticyclone taking up nearly all the cental south pacific. Also absurdly large.
No I don't think its usual for the whole of the south Pacific trades to be turned from the tropics and sprayed on Antarctica Tigertown. It happened two weeks ago. There's even some of the Trades from Nth of the equator being pulled into the flow that just hit the Antarctic Peninsula, and the big puddle that just grazed our New Zealand east coast that's setting itself up to be shot south from between those two Flywheels.
Your Nth Atlantic Storm is looking serious. Its very tall, above 30km. Reckon its going to do much the same with the atlantic Tropical Air. We seem to have transitioned to a primarily Ferral cell circulation mode. The angular momentum of Polewards air is being stored in the jets, and retrieved by the high altitude equator wise backflows IMHO.


https://earth.nullschool.net/#current/wind/isobaric/1000hPa/overlay=total_precipitable_water/azimuthal_equidistant=159.15,-58.94,371
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DrTskoul

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Re: What's new in Antarctica ?
« Reply #245 on: March 30, 2017, 12:21:04 AM »
Scientists highlight Antarctic ice upheaval in response to prehistoric climate change

The research, led by palaeoclimatologist Dr Diederik Liebrand as part of an International Ocean Discovery Program collaboration, suggests that 20 to 30 million years ago the Antarctic periodically gained and lost huge ice caps – equivalent to the entire modern-day East Antarctic Ice Sheet.

Dr Liebrand said: "Our research shows that even slow, naturally forced climate change is capable of driving rapid large-scale changes in ice volume in Antarctica – and therefore global sea levels.

"This is of particular interest to scientists because humans are now the main agents of climate change, and the rates of change today are much faster than those that occurred millions of years ago during the interval that we studied.

"Increasingly we are understanding that the Antarctic ice cap is not some enduring monolithic block but a much more slippery ephemeral beast – and the implications of that realisation for the future of Antarctic ice sheets in a very rapidly warming world have not escaped us."

The scientists examined oxygen isotopes in fossilised micro-organisms – found in a drill core of marine sediments taken from a water depth of 2.5km in the South Atlantic – to reach their findings, published this week in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).


Evolution of the early Antarctic ice ages, PNAS,
www.pnas.org/cgi/doi/10.1073/pnas.1615440114

Provided by: University of Southampton
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wili

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Re: What's new in Antarctica ?
« Reply #246 on: April 03, 2017, 02:46:36 AM »
This isn't new (sorry if it's already been posted here), and it's not exclusively relevant to the Antarctic, but it's a nice concise summary of the major feedbacks that affect ice sheet melt.

http://www.bitsofscience.org/sea-level-rise-ice-sheet-dynamics-melting-feedbacks-acceleration-7295/#more-7295

(Thanks to chilyb at PeakOilForums for the link)
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FredBear

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Re: What's new in Antarctica ?
« Reply #247 on: April 03, 2017, 01:14:41 PM »
On arctic io :-  Some ice in old Larsen B area broke away 18/03/2017, lot more looks as if it may have melt-water from 29th? Bit late in the season but might be katabatic winds, other ice breaking off and blowing east further south (sea ice n. end of Larsen C, 28/03?)  .   .   .   

sidd

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Re: What's new in Antarctica ?
« Reply #248 on: April 07, 2017, 07:53:31 AM »

sidd

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Re: What's new in Antarctica ?
« Reply #249 on: April 11, 2017, 11:17:07 PM »
Landsat-8 derived surface velocities for 2014 and 2015 with a detailed comparison to previous estimates at doi:10.5194/tc-2017-34

Many pretty pictures. Worries in the Wilkes Basin. Open access. Read all about it at

 http://www.the-cryosphere-discuss.net/tc-2017-34/