Alastair McDonald wrote in message
...

"N_Cook" wrote in message
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It would be nice to know the reason for the revisions - say different
satellite over-passes and so different sun-angles.

I had always assumed that it took time to count all those pixels
accurately
:-) but your suggestions make more sense.

They always seem to revise the difference between consecutive days
downwards, which may give a clue to what is going on.

Cheers, Alastair.




Every day seems to be 7 paces forward and then next day 6 paces back.
I can see that with different sat passes and different traverses and
different sun angles , then sea ice cliffs could be included as surface area
in some passes and not other passes and broken ice appearing as solid in
some passes. Then an average taken , but why the implied 7 figure accuracy.