Tag Archives: South Georgia

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This is a MODIS image from 2004, but it's too good not to post here.

Iceberg A38 at South Georgia 12 April 2004
Iceberg A38 at South Georgia 12 April 2004

I'm giving a talk tonight for the South Georgia Association called Giant Icebergs and South Georgia, so I'm wandering through a lot of these images at the moment.

South Georgia is a small island approximately 190 x 30 km within the Antarctic Circumpolar Current in the South Atlantic. It has a continental shelf that extends more than 50 km from the coast with average depth ~200 m, although there are deeper submarine canyons.

A38 is about 300 Gt in mass, so it's really significant. The work I was doing on this was picked up in 2010 by the BBC in a story called Giant icebergs head to watery end at island graveyard.

On 26th September 2016 the MODIS sensor on The TERRA satellite captured this beautiful image of South Georgia, with Iceberg A66 drifting past.

Iceberg A66 passing South Georgia captured in a MODIS image on the 26 September 2016.
Iceberg A66 passing South Georgia captured in a MODIS image on the 26 September 2016. The image is available on a KML file on the MODIS Websites.

The iceberg A66 is about 15 km at it's widest point in this image.

We can do a bit simple maths. Estimate the iceberg has a 200 m thickness and it is triangular in shape with a base of ~4 km.

the volume =  0.5 x 15 km x 4 km x 0.2 km = 6 km3.

So the relatively small A66 contains of 6000 gigtons of water. It's a lot. But it's not a lot.

Icebergs get their reference number depending on where they originate from. This one has an identifier "A" which means it came from the sector 0° to 90°W - that's the Bellingshausen and Weddell Sea region. You can track icebergs like this both visually - like in in the image above - or using something called a Scatterometer. A scatterometer can measure the winds over the ocean, and because the winds change over the ice one can track the icebergs. Prof David Long at Brigham Young University provides an excellent database of Antarctic iceberg data based on that idea (this is their research paper on how they do that).

If we look at the location data from the ASCAT sensor you can see that A66 is at the tip of the Antarctic Peninsula - but this data is only from this year. I will have to dig a little deeper. A job for later.

The track of Iceberg A66 from the BYU database
The track of Iceberg A66 from the BYU database

Once the icebergs reach the edge of the Weddell Sea they get to South Georgia very quickly. I did write about that in a paper in the OU database Physical oceanography in the Scotia Sea during the CCAMLR 2000 survey, austral summer 2000.

And some of these icebergs (although not A66) ground at South Georgia and ultimately can affect the ecosystem. Jon Amos wrote about some work I did at a San Francisco conference  in 2010 about that - it's still available on the BBC website: Giant icebergs head to watery end at island graveyard.

Giant icebergs head to watery end at island graveyard
Giant icebergs head to watery end at island graveyard. By Jon Amos

Overall A66 is nothing special, this is not an unusual observation.

It is a beautiful image though.

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.

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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.