Tag Archives: antarctica

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I was interested in how long the polynya I blogged about yesterday had existed.

I made a gif of the previous months sea ice data.

The sea ice extent in Pine Island Bay 11 September to 10 October 2016. Data from DMSP SSMI. The development of the polynya can be seen in the development of the dark regions.
The sea ice extent in Pine Island Bay 11 September to 10 October 2016. Data from DMSP SSMI. The development of the polynya can be seen in the growth of the dark regions.

You can see that the polynya in the centre of the picture can be seen from the very beginning. This is forming in front of the Dotson Ice Shelf  - and from the scale bar you can see it is big. This polynya really starts to develop as open water around 5 October 2016.

The coastal polynya on the northern land boundary appear in mid September - and develop throughout the record.

The image below was in my previous post and it shows the three polynya from a MODIS image on 9 October 2016.

The MODIS imagery 9 October 2016 from the TERRA satellite overlain in Google Earth
The MODIS imagery 9 October 2016 from the TERRA satellite overlain in Google Earth

Next diversion will be a area of open water / time plot.

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The Amundsen Sea currently has some very large polynya. In front of the Dotson, Getz and Pine Island ice shelves they are clear in the satellite data.

The sea ice extent along the Antarctic Peninsula 2 October 2016. Data from DMSP SSMI
The sea ice extent along the Antarctic Peninsula 9 October 2016. Data from DMSP SSMI.

polynya is an area of open water in the winter pack ice.

These are likely latent heat polynya, and strong winds are pushing the sea ice away from the coasts to make the open water.  In the open water there will be a lot of sea ice generation. I wouldn't be surprised if the weather that is keeping the sea ice compressed against the Antarctic Peninsula is also responsible for opening them.

Taking the MODIS data from the TERRA satellite and importing that into google earth, the open water shows up as black. At the top of the image in front of Pine Island Glacier the polynya are partially obscured by cloud.

In Google Earth you can measure the area quite easily.

...continue reading

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Mark Brandon, The Open University

You never forget the first time you see an iceberg. The horizon of a ship at sea is a two dimensional space and to see a three dimensional piece of ice appear in the ocean is quite something. But, in truth, the first iceberg you see is likely to be small. Most icebergs that make it far enough north from Antarctica to where they are danger to shipping are sometimes many years old and at the end of their lives. They are small fragments of what once left the continent.

Once in a while, however, a monster breaks free from the edge of Antarctica and drifts away. Tens of kilometres long these bergs can tower perhaps 100 metres above the sea and reach several hundred more below the surface. These are called tabular icebergs – and while it is rare for humans to see something on such a scale they are part of the normal cycle of glacial ice in Antarctica.

A tabular iceberg gets stuck in thin, seasonal sea ice.
Mark Brandon, CC BY-NC-SA

Everyone knows Antarctica is an ice-covered continent, but the ice is not static. To a scientist it is a dynamic environment – it’s just a question of the timescale you are looking at. Snow falls on the continent and over time it has built up layers of ice which flow in glaciers towards the coast.

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Last week I enjoyed an Inaugural lecture by Professor Martin Siegert of Imperial College. Inaugural Lectures are a big deal:

Imperial's Inaugural Lecture series provides a platform to showcase and celebrate the College's new professors. The inaugural lecture provides official recognition and celebration of the academic’s promotion to professor. A number of guests are invited to attend and students, other staff, and the general public may also attend the lecture. Inaugural lectures are preceded by tea and cakes for invited guests and often followed by a drinks reception, buffet or dinner again for invited guests.

Tea and cakes... I love being English.

Martin spoke brilliantly on how Antarctica is changing to an audience of about 150 people. For a crash course in "where we are now" I would say it is a must watch.

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Captain Robert Falcon Scott
Captain Robert Falcon Scott

"England knows Scott as a hero; she has little idea of him as a man. He was certainly the most dominating character in our not uninteresting community: indeed, there is no doubt that he would carry weight in any gathering of human beings. But few who knew him realized how shy and reserved the man was, and it was partly for this reason that he so often laid himself open to misunderstanding.

Add to this that he was sensitive, femininely sensitive, to a degree which might be considered a fault, and it will be clear that leadership to such a man may be almost a martyrdom, and that the confidence so necessary between leader and followers, which must of necessity be based upon mutual knowledge and trust, becomes in itself more difficult. It wanted an understanding man to appreciate Scott quickly; to others knowledge came with experience.

He was not a very strong man physically, and was in his youth a weakly child, at one time not expected to live. But he was well proportioned, with broad shoulders and a good chest, a stronger man than Wilson, weaker than Bowers or Seaman Evans. He suffered from indigestion, and told me at the top of the Beardmore that he never expected to go on during the first stage of the ascent.

Temperamentally he was a weak man, and might very easily have been an irritable autocrat. As it was he had moods and depressions which might last for weeks, and of these there is ample evidence in his diary. The man with the nerves gets things done, but sometimes he has a terrible time in doing them. He cried more easily than any man I have ever known.

What pulled Scott through was character, sheer good grain, which ran over and under and through his weaker self and clamped it together. It would be stupid to say he had all the virtues: he had, for instance, little sense of humour, and he was a bad judge of men. But you have only to read one page of what he wrote towards the end to see something of his sense of justice. For him justice was God. Indeed I think you must read all those pages; and if you have read them once, you will probably read them again. You will not need much imagination to see what manner of man he was.

And notwithstanding the immense fits of depression which attacked him, Scott was the strongest combination of a strong mind in a strong body that I have ever known. And this because he was so weak! Naturally so peevish, highly strung, irritable, depressed and moody. Practically such a conquest of himself, such vitality, such push and determination, and withal in himself such personal and magnetic charm. He was naturally an idle man, he has told us so;[134] he had been a poor man, and he had a horror of leaving those dependent upon him in difficulties. You may read it over and over again in his last letters and messages.[135]

He will go down to history as the Englishman who conquered the South Pole and who died as fine a death as any man has had the honour to die. His triumphs are many—but the Pole was not by any means the greatest of them. Surely the greatest was that by which he conquered his weaker self, and became the strong leader whom we went to follow and came to love."

Apsley Cherry Garrard wrote that in the Worst Journey in the World.

Captain Scott was a complex man.

I do like Google streetview and often use it if I am going somewhere new to see where I am supposed to be heading. So it's really nice to see it at South Georgia in the South Atlantic.

The landing page has links to various locations, but I particularly like this one of the grave of Sir Ernest Shackleton.

It is a bit clunky as the poor person doing it had to cope with poor weather and moving tourists.

So the gravestone?

Shackletons Gravestone

From the street view you can see that it is quite close to white fence and behind that there is a rocky grass bank. The interesting thing is what is on the back of the gravestone and not in plain view...

The reverse of Shackletons graveA beautiful quote from the poet Robert Browning.

You can see how hard it is to see the quote in this picture.

Shackleton's grave

The cemetery also has a grave from the Falklands War: Petty Officer Felix Artuso. The submarine Sante Fe was attacked and damaged at South Georgia, and it ended up along side at the Whaling Station. Unfortunately PO Artuso was killed after the submarine had been captured. His grave is being photographed in this picture.

Artuso grave

If you look on my photos you will find lots of South Georgia pictures.

It is a truly beautiful and special place.

Everyone likes a wandering albatross (Diomedea exulans), but to see them swoop around icebergs is a special experience. At South Georgia you can watch this sort of thing for hours.

A wandering albatross in front of Icebergs off the coast of South Georgia.
A wandering albatross in front of Icebergs off the coast of South Georgia.

You can download the full resolution image at my flickr page.

But Ruth Mottram reminded me of Coleridge and The Rime of the Ancient Mariner.

tweet

In that poem they did not feel the same way about the albatross. This is memorably captured by the wonderful art of Gustave Doré.

The Albatross by Gustave Doré
The Albatross by Gustave Doré

I like albatross.

The ice fish rediscovered by Doll
Mangé par le chat de l'équipage de la Terror

The cod icefish re-discovered and published in 1904 by Louis Dollo. The original caption says “Mangé par le chat de l'équipage de la Terror” or “Eaten by the Terror’s cat"!

The famous polar ships HMS Erebus and HMS terror had been in the ice long before Franklin took them to their doom in the Northwest Passage. James Clark Ross took them to the Antarctic from 1839-43 on a hugely successful voyage to find the South Magnetic Pole. Ross filled in many blanks on the map and discovered and named many places including Ross Island and Mount Erebus - one of the most spectacular volcanoes yet discovered.

Ross also took civilian experts to describe and write about their discoveries. These civilians produced vast scientific volumes to record their results.

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-- UPDATED 11 June 2014 --

This post got the dreaded TL; DR on Reddit - but at least "they" acknowledged it was useful. Since it takes someone else to pick out the value in your work I offer this tweet from Jason Major.

@JPMajor tweet

- ORIGINAL POST

A significant area of Antarctic glaciological interest is the West Antarctic Ice Sheet (WAIS) and where it discharges into the Amundsen Sea Embayment.

Amundsen Sea Embayment
Amundsen Sea Embayment: Source Wikipedia

It is a research focus (e.g. iSTAR) because it is the region where the glacier ice is melting very rapidly.

A great research article by Dustin Schroeder (The University of Texas at Austin) has just been published in PNAS which presents evidence for the geothermal heat flux beneath the Thwaites Glacier.

Title page of Schroeder et al 2014

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This is the 2012 sea ice extent for both the Arctic and the Antarctic. The day of year and the calendar day are at the bottom.

I chose 2012 only because it is the most recent complete year in this data set.

My reason for making this video is because there have been a couple of huge news stories recently about the West Antarctic Ice Sheet:

On 12 May 2014 we heard that for all intents and purposes the West Antarctic Ice sheet is doomed (here is the primary research which is open access).

Then on 19 May 2014 we were told that Cryosat observations had shown that the loss of ice from Antarctica had increased quite a lot (here is the primary research).

For excellent commentary on these stories you can visit Carbon Brief, or Antarctic glaciers.org.

But whenever there is a big story about the decay of the West Antarctic Ice Sheet - which remember is land based glacial ice, some instantly point to this being not important because sea ice in Antarctica has been at record levels.

People who suggest that the observed decrease in glacial ice is somehow balanced by the observed increase in Antarctic sea ice extent are wrong. The sea ice is generally only a couple of metres thick and it is telling us quite a different climate story.

Over the next few posts I will try and explain why the decrease of Arctic sea ice is not balanced by an increase in Antarctic sea ice extent, and why there is no contradiction in glacial ice at the edge of the Antarctic continent decaying whilst simultaneously the sea ice is  at record extent.

 

[If anyone want the clip, also the Arctic and Antarctic as separate files in various large sizes and formats just send me an email at my work address - you will find a link on the "About me" page. And I will send you a dropbox link. I am a big fan of Creative Commons and Open Educational Resources. ]

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The data is from the US Defense Meteorological Satellite Program (DMSP), and the data is freely accessible from the National Snow and Ice data Centre.