This post is quite long but stay with it. It shows how large some of the heat exchanges going on in the polar oceans can be.
The picture above shows an iceberg through mist rising from the sea.
It is pretty, but it is also showing is a vast heat flux of hundreds of watts per m2 from the ocean to the atmosphere...
I have talked before on this blog about how the sea ice moves, and how the International Arctic Buoy Programme provide some lovely movies of the buoy tracks which show this. I also pointed to Eric Larsen's video of the ice moving too.
But what does this ice movement mean for the climate?
As the ice moves it fractures, and the cracks extend over wide areas. These cracks are responsible for the "water sky" I talked about previously.
From the scale bar on the bottom left you can see that the open water is ~18 km wide, and the lead is more than 100 km long. More than enough to get a ship through!