On 20/02/17 16:55, Crusader wrote:
On Tuesday, 14 February 2017 14:48:05 UTC, N_Cook wrote:
The Antarctic sea-ice new record extent stood at 2.287 million sq
km yesterday and likely to be still dropping for a week or so. 27
Feb 1997 previous satellite era record of 2.290 million sq km using
the NSIDC algorithm and output at
http://nsidc.org/arcticseaicenews/ch...sea-ice-graph/


new record confirmed here
https://www.scientificamerican.com/a...at-both-poles/


some background here
https://forum.arctic-sea-ice.net/ind...,1759.450.html

It is no great surprise given that when the Austral winter was in
full force, there was a dearth of much warmer water further south in
the Pacific because of El Nino. This warmer mass of water was then
distributed around the southern ocean easily over the summer (aiding
melting at the surface/ice shelf margins) due to there being no land
mass to divert it, like there would be in the northern hemisphere.

I was stationed in the South Atlantic for another couple of El Nino
years and we observed that exact occurrence back then too.

The only difference to nowadays was that back then, most of the ice
extent was measured by ship reports and manual readings where as now,
we rely on satellites which cannot see the ice through cloud...of
which there is a massive amount over the Antarctic and Arctic for a
lot of the summer months. So there is an awful lot of "interploation"
that goes on to produce the current stats. I personally do not find
that particularly scientific, though the main reason for it is cost
and efficiency I suppose.

Hope this is useful for someone.


I'm not sure what you mean when you say that cloud cover is a current
problem for satellite imagery of ice. It was certainly a problem back in
the '60s when I was producing ice charts. It was a slog ploughing
through days of satellite photos to sort out what was ice and what was
cloud. However, this was largely resolved near the end of that decade
when we started getting weekly minimum-brightness pictures from the
States. This was pretty basic technology which involved a computer doing
the job automatically for a week of pictures that I'd been doing by hand.

--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
Web-site: http://www.scarlet-jade.com/
Never approach a bull from the front, a horse from the rear,
or an idiot from any direction! [Irish proverb]