On 22/01/2017 11:47, JohnD wrote:
Just look at the top of the Wipneus charts - they say 'from NSIDC sea
ice concentration data'.

Re the sea ice forum being moderated, what's the problem? You just need
a standard forum registration, wait a day or two for approval and you
should be in. I don't have any sense that it's any more difficult to
join than any forum that puts the small hurdle of registration at the
entrance. Provided you don't abuse the forum and stick to the rules then
it's as open as any other forum.

So not just sea-ice area and extent but also concentration
https://nsidc.org/cryosphere/seaice/...rminology.html
" Concentration
Concentration is a unitless term that describes the relative amount of
area covered by ice, compared to some reference area. Thus,
concentration describes how much of a 25.0 kilometer by 25.0 kilometer
(15.5 mile by 15.5 mile) box is covered by sea ice. Ice concentration
typically is reported as a percentage (0 to 100 percent ice), a fraction
from 0 to 1, or sometimes in tenths (0/10 to 10/10). Our Sea Ice Index
products show ice concentration as a percentage. A value of 0 means
there is no ice, while a value of 100 means the region is completely
covered by ice. "

Certainly not the y-axis of any Wipneus plots I've seen, despite marked
"from NSIDC sea ice concentration data"