Monthly Archives: February 2017

I noticed yesterday that a polynya had formed in front of the Ronne Ice Shelf over the last 2 weeks.

Screengrab from NASA Worldview 17 February 2017
Screengrab from NASA Worldview 17 February 2017

In that image it is about 27,000 kmin area.

I mapped the opening of the polynya from MODIS imagery over the last two weeks. There is cloud in the images but the opening of the polynya is fairly clear.

Formation of the Ronne Polynya 30 January to 14 February 2017.
Formation of the Ronne Polynya 30 January to 14 February 2017.

On 31 January 2017 there is no open water, but then over the 16 day period it opens to the ~27,000 kmin area. If you're eagle eyed you can see that there is thin frazil ice forming in the open water in front of the ice shelf at the end of the sequence.

So what caused it?

...continue reading

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Watching the sea ice extent this summer in Antarctica has been a bit surprising. The Antarctic sea ice extent has been tracking at record lows virtually the whole austral summer. We are very close now to the expected sea ice minimum, and this is where we are:

Antarctic sea ice extent 12 Feb 2017 & diff from mean 1989-93 on same day. Blues imply more ice and reds imply less compared with the mean.
Antarctic sea ice extent 12 Feb 2017 & diff from mean 1989-93 on same day. Blues imply more ice and reds imply less compared with the mean.

On the left is the sea ice extent from the DMSP satellite 12 February 2017, and on the right the difference between the mean sea ice extent on 12 Feb over the period 1989-93 and 12 Feb 2017. I chose this time period as the cycle has been generally quite stable from year to year.

The current sea ice extent is:

Antarctic sea ice extent. Downloaded from NSIDC 14 February 2017.
Antarctic sea ice extent. Downloaded from NSIDC 14 February 2017.

It's clear the sea ice over the summer 2016-17 is showing historic lows. But it's also clear from the sea ice extent above that there is little sea ice left to melt out before the summer turns. Where the sea ice remains - mainly in the Weddell Sea and along the coast of Wilkes Land it is clearly densely packed. If the winds change and the remaining sea ice is decompressed then the extent may fall some more.

This is an animation of the Antarctic sea ice extent from 1 January 2017 to 12 February 2017:

The Antarctic sea ice extent 1 January to 12 February 2017. Data from DMSP SMMI
The Antarctic sea ice extent 1 January to 12 February 2017. Data from DMSP SMMI

And finally the difference between the mean sea ice extent by day for the 5-year period 1989-1993 minus the concentration from 1 Jan to 12 Feb 2017. Blue shades imply an increased sea ice extent compared with a 5-year mean, and reds imply a decreased sea ice extent.

The difference between the mean sea ice extent by day for the 5-year period 1989-1993 minus the concentration from 1 Jan to 12 Feb 2017. Blue shades imply an increased sea ice extent compared with a 5-year mean, and reds imply a decreased sea ice extent.
The difference between the mean sea ice extent by day for the 5-year period 1989-1993 minus the concentration from 1 Jan to 12 Feb 2017. Blue shades imply an increased sea ice extent compared with a 5-year mean, and reds imply a decreased sea ice extent.

Not long until the Antarctic sea ice minimum.

The Metropolitan Museum of Art has made more than a third of a million images both public domain and searchable online. This is one of my current favourites:

An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford and painted in 1871.

An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871
An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871

If you look really closely you can see it is a steam assisted ship.

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

I really like the colours in the sea ice in the foreground. It's hard not to see that when you are in the sea ice.

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

And let's not forget the ice bear in the foreground.

 

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

The caption on the Met page makes clear they were hunting this bear:

In 1861 the marine painter William Bradford made the first of his eight expeditions to the Arctic. This painting, based on photographs and sketches produced during his final trip, in 1869, shows the artist’s steamer, Panther, plying its way through the summer ice along the northern coast of Greenland. Panther was one of numerous vessels engaged in the search for the Northwest Passage between the Atlantic and Pacific Oceans. According to Bradford’s journal, the ship’s crew had decided to hunt the polar bear seen in the foreground, “anxious to possess so fine a skin,” but the bear made a parting glance over its shoulder before heading for the water, managing to escape its pursuers.

But it is art for sure.

There is no way you could get an iceberg with this sort of freeboard close to the shore...

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

And I love the detail of a wrecked ship mast on the left.

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

There is a long history of romantic artists balancing the struggle of man against the icy wastes. My all time favourite in that category is Landseer's Man Proposes, God Disposes.

Man Proposes, God Disposes by Edward Landseer 1864.
Man Proposes, God Disposes by Edward Landseer 1864.

Thanks Metropolitan museum for putting it online.