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.
A 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.
I noticed in a blog post last week that there was a finger of open water extending down the Western Weddell Sea. I've carried on watching this open water in the MODIS satellite data. Whilst it's been opening and closing, there is a lot of open water. It's clearly a major sea ice generating factory at the moment.
The open water is clear in the lower resolution passive microwave sea ice data too.
If you look at some model output there are air temperatures above this open water of between -10° to about -25°C.
What is really good is if you look at the temperature anomaly (i.e. the departure from the average with a 1979-2000 baseline), it is very warm over the Weddell Sea.
I think the reason it is warmer is because the Weddell Sea pack ice is looser this year. So (as you can see in the picture above) there is lots of open water. The atmosphere is being warmed by the ocean as the sea ice is being generated.
I think the Weddell Sea pack ice is more mobile this winter. This is also telling us something about the difference between sea ice extent and sea ice thickness. The sea ice extent is large and easy to measure in the Antarctic - but we don't know how thick it is.
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.
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.