Alastair McDonald wrote:
"Graham P Davis" wrote in message
...



Although I tried to pour cold water on your suggestion of breaks in the
main area of Arctic ice a few weeks ago, Alastair, I've seen that there
was indeed broken ice running NE from Svalbard. What puzzled me was the
perfect curvature of the breaks, with the inner curve running through
87N 90E and ending at 83N 180. As the roughly parallel bands ended in
the (then) open water to the north of Svalbard, I suspect that there was
icebreaker activity in the area. I've seen evidence of this in
previous years but only during the summer.


I wonder if it was a tidal effect? They seem to play a big role in polar
ice, but it is something I know nothing about :-(


I'm not sure, but it could be a boundary between different ocean
currents. However, the curves look a bit too artificial to me. Not so
artificial as a few years ago when there were a series of parallel
straight lines covering a square of a hundred or so miles per side. The
first two lines were joined at one end by a semi-circle, the second and
third by another at the opposite end, and so on so as to make a single,
continuous track. Up until I'd seen that, I hadn't realized that
icebreaker tracks could be seen on the AMSR pictures.


I'm also puzzled by some grey areas of ice which are interpreted as low
concentrations. For example, the fast ice to the east of the Lena delta
is consistently grey, but with some whiter strips. This ice has been
immobile for the winter and, given its location, must be several feet
thick. Could it be that the ice is just a bit mucky?


There is concern that the Asian Brown Cloud is altering the albedo of
the Arctic ice. I have also heard that the push by the British government
to encourage diesel vehicles has also contributed :-) The white lines
could be resent pressure ridges exposing cleaner ice.

This area being fast ice, I would have expected that any pressure ridges
would have been formed at the beginning of the winter. Perhaps they've
collected fresh snow, whereas the flatter surface of the rest of the ice
is swept clear of snow? This is bordering on quesswork on my part.
Bordering?

Cheers,

Graham