Arctic Sea Ice

[Col]

Good grief, it's going into freefall!

http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_prev_L.png
--
Col

Bolton, Lancashire
160m asl

[N_Cook]

Col <reddw...@btinternet.com> wrote in message
news:69adnf0Nw61r4a3N...@bt.com...

Are you taking bets on the minimum of the red curve?

[Dartmoor Will]

"Col" <reddw...@btinternet.com> wrote in message
news:69adnf0Nw61r4a3N...@bt.com...

> Good grief, it's going into freefall!
>
> http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_prev_L.png

It's a snapshot Col, it doesn't mean anything, it's just weather! :-)

Will
--
http://www.lyneside.demon.co.uk/Haytor/automatic/Current_Vantage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
---------------------------------------------

[johnd]

"Col" <reddw...@btinternet.com> wrote in message
news:69adnf0Nw61r4a3N...@bt.com...

> Good grief, it's going into freefall!
>
> http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_prev_L.png

Yes, interesting isn't it, as others have been commenting in a couple of
other similar threads over the past few days. That link that Graham provided
of:

http://www.iup.uni-bremen.de:8084/ssmis/index.html

seems to show the extent fairly well on a polar map (albeit I understand
with suboptimal satellite imagery at present) especially when the png image
is zoomed in and centred. Anyone have any dates as to when the new satellite
will come onstream? Or does it need many months of cross-correlation with
other existing imagery because its data is consiered valid?

The NE passage seems well and truly open now with not even any need for a
diversion towards Alaska to enter the Bering Strait. Shame that the
synoptics seem to be encouraging a stubborn ice block in the McClure Strait
to the north of Banks Island because otherwise the NW passage would appear
to be fully open too.

JGD

[Col]

"N_Cook" <div...@tcp.co.uk> wrote in message
news:k0q5om$lef$1...@dont-email.me...

A new record low looks inevitable, probably significantly
below 4 million square kilometres.

[Stewart Robert Hinsley]

In message <69adnf0Nw61r4a3N...@bt.com>, Col
<reddw...@btinternet.com> writes

>Good grief, it's going into freefall!
>
>http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_prev_L.png

Looking at the graph, it appears to be continuing to retreat at the high
summer rate at a time of year when the retreat would normally be tailing
off.
--
Stewart Robert Hinsley

[Weatherlawyer]

On Aug 19, 6:43 am, "Col" <reddwar...@btinternet.com> wrote:
> Good grief, it's going into freefall!
>
> http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_prev_L.png

You could put that chart on the Unisys archives year for year here: >
http://weather.unisys.com/hurricane/atlantic/index.php

With the obvious exception of 2007 it seems to follow the number of
Atlantic Hurricanes.

Obviously without looking at all the other tropical storms it lacks
focus. But there were two exceptionally large storms in the height of
2007's season:

Hurricane DEAN. 13-23 AUG. Cat 5 and
Hurricane FELIX. 31 AUG - 05 SEP. Cat 5.

A graph of each year it would be clearer.
It gave me an idea for a blog thread though. Now I have to see if any
of it looks likely:

http://my.opera.com/Weatherlawyer/blog/2012/08/19/north-atlantic-tropical-storms-and-arctic-sea-ice

[Alan LeHun]

In article <Jc$dxoGHa...@meden.invalid>, {$news$}@meden.demon.co.uk
says...

> Looking at the graph, it appears to be continuing to retreat at the high
> summer rate at a time of year when the retreat would normally be tailing
> off.
>

If you look at the point right at the start of August, and extrapolate
backwards from there, it has clearly accelerated since then. The fastest
retreat of ice this year was during that first week in August. AFAICT,
the fastest retreat generally occurs during the first week of July.

Indeed, of all the data available in that graph, only the 10-day ave
rate of retreat at the beginning of July 2009 was faster.



--
Alan LeHun

[N_Cook]

Col <reddw...@btinternet.com> wrote in message
news:69adnf0Nw61r4a3N...@bt.com...

dy/dx still constant freefall , I wonder if the representation of that graph
tomorrow will include the 0 to 2 ice extent band

[Alastair McDonald]

"N_Cook" <div...@tcp.co.uk> wrote in message

news:k1fe5j$fl1$1...@dont-email.me...

> Col <reddw...@btinternet.com> wrote in message
> news:69adnf0Nw61r4a3N...@bt.com...
>> Good grief, it's going into freefall!
>>
>> http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_prev_L.png
>> --
>> Col
>

> dy/dx still constant freefall , I wonder if the representation of that
> graph
> tomorrow will include the 0 to 2 ice extent band

The difference between the ice extent this year and the corresponding day in
2007 fell from 775,000 sq km yesterday to 773, 281 sq km today. In other
words, today's dy/dx is less than yesterday. I have copied the IJIS data
into a spreadsheet and that shows if the difference remains unchanged
throughout September the ice extemt will drop to just below 3,500,000 sq km.
No need to extend the axis this year. But today's result may just be a blip.

Cheers, Alastair.

Cheers, Alastair.


>
>

[Tudor Hughes]

On Sunday, 19 August 2012 08:56:17 UTC+1, wi...@lyneside.demon.co.uk wrote:
> "Col" <reddw...@btinternet.com> wrote in message news:69adnf0Nw61r4a3N...@bt.com... > Good grief, it's going into freefall! > > http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_prev_L.png It's a snapshot Col, it doesn't mean anything, it's just weather! :-) Will -- http://www.lyneside.demon.co.uk/Haytor/automatic/Current_Vantage_Pro.htm Will Hand (Haytor, Devon, 1017 feet asl) ---------------------------------------------

Just weather? Hmm, are you sure of that? Only 30% according to this:

http://www.bbc.co.uk/news/science-environment-19391211

Tudor Hughes, Warlingham, Surrey.

[Lawrence13]

Well Tudor I hold out hope that most of this is being driven by natural causes but I have to accept the belief that cooling has set in is still yet to be observed. Mind global temps have been pretty much level the last eleven years. Anyway you live way above sea level. As for me I apparently have an altitude problem.

Shhh... don't mention the c term

[Alastair McDonald]

"Alastair McDonald" <a...@abmcdonald.freeserve.co.uk> wrote in message
news:k1fie4$73m$1...@dont-email.me...

> "N_Cook" <div...@tcp.co.uk> wrote in message
> news:k1fe5j$fl1$1...@dont-email.me...
>> Col <reddw...@btinternet.com> wrote in message
>> news:69adnf0Nw61r4a3N...@bt.com...
>>> Good grief, it's going into freefall!
>>>
>>> http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_prev_L.png
>>> --
>>> Col
>>
>> dy/dx still constant freefall , I wonder if the representation of that
>> graph
>> tomorrow will include the 0 to 2 ice extent band

Today it dropped below 4,000,000 sq km for the first time. This is 777, 344
sq km less that is was on the same day in 2007. If it hits a minmum on the
same day this year as it did in 2007 and this difference remains unchanged,
then the extent will be 3,477,187 sq km.

Over the last couple of days it was melting at ~50,000 sq km per day. Before
that it was melting at over ~100,000 sq. km per day. If it melts at that
higher rate for the next 20 days then the axis might well need shifting.

Cheers, Alastair.

[Lawrence13]

Let's face it Alastair all that ice is just a bleedin' nuisance and very slippery.

[Alastair McDonald]

"Lawrence13" <lawre...@sky.com> wrote in message
news:06912f2a-f6d4-4675...@googlegroups.com...

> Let's face it Alastair all that ice is just a bleedin' nuisance and very
> slippery.

A bit like you!

Cheers, Alastair.

[Lawrence13]

Ouch!

[Lawrence13]

On Tuesday, 28 August 2012 19:01:26 UTC+1, Alastair wrote:

Lets face Alastair th ice is clearly a health & Safety risk for all concerned.

[Stewart Robert Hinsley]

In message <k1igut$92g$1...@dont-email.me>, Alastair McDonald
<a...@abmcdonald.freeserve.co.uk> writes

But it obviously won't. The maximum rate of melt occurs in August, and
after than as the amount of sunlight in the Arctic decreases the rate of
melt decreases as well (going negative in mid- to late-September).

The faster rate of melt suggests that a model of the same fall until
minimum as in 2007 is conservative. On the other hand 2007 was an
unusually late minimum, and presumably required weather patterns
delivering heat to the high Arctic.
>
>Cheers, Alastair.
>
>

--
Stewart Robert Hinsley

[N_Cook]

Stewart Robert Hinsley <ste...@meden.demon.co.uk> wrote in message
news:wMvT1oOL...@meden.invalid...

d2y/dx2 still seems to be resolutely <>0 from today's graphical output.
Perhaps there is a tipping point due to the thining as well as area extent.
Then the Coreolis force or something does the rest.

2007 was apparently a severe stormy weather year for break-up, whereas only
one severe storm in the current year , so not equateable.

[Alan LeHun]

In article <wMvT1oOL...@meden.invalid>, ste...@meden.demon.co.uk
says...

> But it obviously won't. The maximum rate of melt occurs in August,

No. AFAICT, it generally happens towards the end of the first week in
July.[1]

Maximum rate this year was at the end of the first week in August. 2007
was also a late year, having it's maximum rate of melt in the first
couple of days in August.

> and
> after than as the amount of sunlight in the Arctic decreases the rate of
> melt decreases as well (going negative in mid- to late-September).
>

[1] Actually I mean the maximum decrease in Ice Extent which isn't quite
the same thing.

--
Alan LeHun

[N_Cook]

Stewart Robert Hinsley <ste...@meden.demon.co.uk> wrote in message
news:wMvT1oOL...@meden.invalid...

Would seem to be heading down to 3 million , more likely than 3.5

[Alastair McDonald]

"N_Cook" <div...@tcp.co.uk> wrote in message

news:k1vl4h$5ai$1...@dont-email.me...

>
> Would seem to be heading down to 3 million , more likely than 3.5
>

The data from the IJIS/JAXA site I have been using
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
now has the current level of ice 900,000 sq km less that this day in 2007
which would give a minimum of ~ 3,335,000 sq km on the 24th September if
that offset with the 2007 extent is maintained. The offset has increased
from 777, 344 sq km on the 28th August five days ago. So if the offset
continues to increases by 100,000 sq km per five days, then by 24th August
the offset with 2007 could be 400,000 sq km more. So < 3,000,000 sq km
does seems feasible but unlikely.

Cheers, Alastair.

[haaark]

On Sep 2, 5:10 pm, "Alastair McDonald"
<a...@abmcdonald.freeserve.co.uk> wrote:
> "N_Cook" <dive...@tcp.co.uk> wrote in message

>
> news:k1vl4h$5ai$1...@dont-email.me...
>
>
>
> > Would seem to be heading down to 3 million , more likely than 3.5
>

> The data from the IJIS/JAXA site I have been usinghttp://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

> now has the current level of ice 900,000 sq km less that this day in 2007
> which would give a minimum of ~ 3,335,000 sq km on the 24th September if
> that offset with the 2007 extent is maintained. The offset has increased
> from 777, 344 sq km on the 28th August five days ago. So if the offset
> continues to increases by 100,000 sq km per five days, then by 24th August
> the offset with 2007 could be 400,000 sq km more. So < 3,000,000 sq km
> does seems feasible but unlikely.
>
> Cheers, Alastair.

There was a lot of talk on this very site in May that this would be a
record low year. How right we were! Looks like the NW passage is open
at last.

[N_Cook]

was there a storm in the last day?
biggest daily drop in the last 2 weeks

[N_Cook]

N_Cook <div...@tcp.co.uk> wrote in message

news:k2768k$fjr$1...@dont-email.me...

> was there a storm in the last day?
> biggest daily drop in the last 2 weeks
>
>

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" ?

[Alastair McDonald]

"N_Cook" <div...@tcp.co.uk> wrote in message

news:k29qql$dhc$1...@dont-email.me...

> 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" ?

JAXA quite often revise their readings later in the day, but they don't seem
to be updating their front page. Earlier it was showing "The latest value :
3,628,125 km2 (September 5, 2012)" yet they had .

Anyway, at the moment it is showing that there was a big drop yesterday of
67,000 sq km and the extent is currently running at 833,000 sq km less than
2007.

Cheers, Alastair.

[Alastair McDonald]

"N_Cook" <div...@tcp.co.uk> wrote in message

news:k29qql$dhc$1...@dont-email.me...

> 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.

[N_Cook]

Alastair McDonald <a...@abmcdonald.freeserve.co.uk> wrote in message

news:k2cgls$d1b$1...@dont-email.me...

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

[Weatherlawyer]

On Sep 7, 11:10 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> Alastair McDonald <a...@abmcdonald.freeserve.co.uk> wrote in message
>
> news:k2cgls$d1b$1...@dont-email.me...
>
>
>
>
>
>
>
>
>
>
>

> > "N_Cook" <dive...@tcp.co.uk> wrote in message

Probably the region is now gaining newsworthiness and so a satellite
has been adjusted accordingly?

Or someone has been appointed to Chief Ice Measurer in the Department
of Ididntknowyoucared.

[Alastair McDonald]

"N_Cook" <div...@tcp.co.uk> wrote in message

news:k2ch6v$frt$1...@dont-email.me...

>
> 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.

[N_Cook]

Alastair McDonald <a...@abmcdonald.freeserve.co.uk> wrote in message

news:k2cgls$d1b$1...@dont-email.me...

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 remelt to the previous amounts.

I have a thing about specious accuracy
If the latest published daily value is likely to be revised significantly
then it should , in a sense be flaggged , by entering a figure such
as -3600000 (implying between 3500000 and 3700000 ) and not specious 6th
decimal place accuracy of 3601875

[John Hall]

In article <k2cie4$m2h$1...@dont-email.me>,

N_Cook <div...@tcp.co.uk> 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

[N_Cook]

John Hall <nospam...@jhall.co.uk> wrote in message
news:W+nuW3GU...@jhall.demon.co.uk.invalid...

mindslip , re-freeze

[N_Cook]

Alastair McDonald <a...@abmcdonald.freeserve.co.uk> wrote in message

news:k2cicq$lt5$1...@dont-email.me...

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.

[Alastair McDonald]

"N_Cook" <div...@tcp.co.uk> wrote in message

news:k2hoi9$q4r$1...@dont-email.me...

>
> 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/NOAA/G02135/north/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.

[Weatherlawyer]

On Sep 7, 11:31 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> Alastair McDonald <a...@abmcdonald.freeserve.co.uk> wrote in message
>
> news:k2cgls$d1b$1...@dont-email.me...
>
>
>
>
>
>
>
>
>
>
>

> > "N_Cook" <dive...@tcp.co.uk> wrote in message

> 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.