Further to that thread initiated by James Brown on the 22nd, I have made
some measurements of the temperature around this feature and other apparent
breaks (leads) in the Arctic ice. What appears on an IR image as breaks to
open water or blocks of ice surrounded by water can be misleading. The
temperature of the 'dark' areas comes out at -10 to -15C, with the whiter
blocks or expanses of ice at around -35C to -40C. The Arctic ice is floating
on water, and is subject to stress by currents, swell waves permeating from
the other Oceans, and wind effects. The cracked eggshell appearance seems to
be where breaks or tears in the ice sheet occur as a result of these
stresses, and are probably the site of liquid water pushing through and
quickly freezing on the surface. I have been unable to find any of these
cracks or leads with a temperature higher than -5C, (averaged over 1km
pixels).

--
Bernard Burton
Wokingham, Berkshire, UK.

Satellite images at:
www.btinternet.com/~wokingham.weather/wwp.html