In article ,
N_Cook writes:
I wonder if 2012/13 winter will be like the 2007/8 a winter and full remelt
or whether 2013 spring will start with a much lower ice area because of
failure to fully remelt to the previous amounts.

When you say "remelt" do you mean "refreeze"? If not, then I'm
struggling to understand that.
--
John Hall

"The beatings will continue until morale improves."
Attributed to the Commander of Japan's Submarine Forces in WW2

John Hall wrote in message
...
In article ,
N_Cook writes:
I wonder if 2012/13 winter will be like the 2007/8 a winter and full
remelt
or whether 2013 spring will start with a much lower ice area because of
failure to fully remelt to the previous amounts.

When you say "remelt" do you mean "refreeze"? If not, then I'm
struggling to understand that.
--
John Hall

"The beatings will continue until morale improves."
Attributed to the Commander of Japan's Submarine Forces in WW2

mindslip , re-freeze

Alastair McDonald wrote in message
...

"N_Cook" wrote in message
...


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.

"N_Cook" wrote in message
...


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.


New result are now available with yesterday's figure going up from
3,595,781 to 3,674,844 and today's figure given as 3,593,750, a new
record. But today has still another twelve hours to go so the value
they quote for that is unlikely to remain true.

I think that you are taking these values too seriously. They are only best
estimates using a satellite designed to measure wind speeds, now that the
original satellite has packed up. The values they are publishing are only
the results of their calculations, not a true value for the ice extent, if
such actually exists! Across at NSIDC, http://nsidc.org/arcticseaicenews/ ,
the data they use:
ftp://sidads.colorado.edu/DATASETS/N...th/daily/data/ gives
values of 3,488340 and 3,576,350 for Thursday and Friday compared with
3,676,406 and 3,664,531 from JAXA.

Near the botom of their web page JAXA do say :

"In general, sea-ice extent is defined as a temporal average of several days
(e.g., five days) in order to eliminate calculation errors due to a lack of
data (e.g., for traditional microwave sensors such as SMMR and SSM/I).
However, we adopt the average of latest two days (day:N & day:N-1) to
achieve rapid data release. Only for the processing of WindSat data (Oct. 4,
2011 to the present) the data of the day before yesterday (day:N-2) is also
sometimes used to fill data gaps." and "... SIC data could have errors of
10% at most ..."

Using the JAXA data and my algorithm, it now seems unlikely that their
value will drop below 3,500,000 sq km THIS year.

Cheers, Alastair.

On Sep 7, 11:31*am, "N_Cook" wrote:
Alastair McDonald wrote in message

...











"N_Cook" wrote in message
...

Ah, the hand of man rather than the hand of big-G
the last 2 entries for the csv table for 05 sept
04,3726563
05,3628125

changed to
04,3726563
05,3681094
06,3614219

on the 6 Sept, the AWG-brigade put its oar in ?
Where is the footnote relating to such "revisions" ?

I think I have now worked out what is going on.

Today the figures have changed to:

04, 3726563
05, 3681094
06, 3676406
07, 3601875

In other words, yesterday's (06,) figures have been revised when today's
provisional figure was entered. The change between 05, and 06, was
only -4,688 sq km and at present the change betwween 06 and 07 is -74,531
sq
km but this will probably be revised down. So the difference between 2007
and 2012 will most likely settle at around 800,000 sq km i.e. an extent of
between 3,400,000 and 3,500,000 sq km.

There is an page on the BBC web site about the melting sea ice posted this
morning:
http://www.bbc.co.uk/news/world-europe-19508906

Cheers, Alastair.

This is a probable tipping-point
"If the ice is thinner there is more light penetrating and that light can
heat the water."
I wonder if 2012/13 winter will be like the 2007/8 a winter and full remelt
or whether 2013 spring will start with a much lower ice area because of
failure to fully refreeze to the previous amounts.

Wouldn't a surface of fresh water tend to freeze more quickly than the
more usual brine?

It doesn't have to cope with a lading of salt to start with, therefore
will remain on the surface all winter. It's just that business of
reaching 4 degrees C.

I wonder how it will react to warmer brine at depth.