On Tuesday, 31 July 2018 11:53:14 UTC+1, JGD wrote:
On 31/07/2018 11:36, Alastair wrote:

There is a chart he
http://web.nersc.no/WebData/arctic-r...1_ice_area.png
which shows ice area rather than extent. The ice there is not on a
minimum for time of year. Not sure why.


Simply because ice area and ice extent are different measures and they
never agree exactly. See eg:

http://nsidc.org/arcticseaicenews/faq/#area_extent

The chart corresponding to the area rather than the extent referred to
above is:

https://sites.google.com/site/arctis...a_byyear_b.png

(which really could do with some editing to clarify the colours - there
are now just too many superimposed lines).

The area chart shows this year as the most ice over the last few years whereas the extent chart is showing the least ice cover the last few years. It is this contrast that I find curious.