Hi

(You can find graphs on my blog: http://xmetman.wordpress.com/2013/09...last-35-years/)

I have graphed just about every kind of data related to climate and meteorology over the last eighteen months, but for some reason I've never got round to looking for a data set of sea ice extent, and with all the hoo-ha at the moment concerning that and climate change, I thought I would investigate what was going on by downloading the sea ice data made freely available from the National Snow and Ice Data Center in Boulder (thank God for America and its attitude to free data).

Method

Quite a simple parsing of CSV text file, made slightly tricky because the data for the first year or so was not daily but every other day, and the data for the the latest year was in a separate file. I combined both the Arctic data and the Antarctic data into one class to keep everything tidy. The nearly 11,000 lines of data in each file were parsed in less than 0.1 of a second. I plotted two graphs one showing an area chart with the daily values of sea ice extent in 10^6 square kilometres along with a trend line using all the data points. The second graph, a bar chart, displays the change in extent of sea ice in the last 365 days, red indicates less ice (warmer), blue indicates more ice (colder).

Results

The Arctic graphs were how I expected them to look, with a steady decline in sea ice from around 12.5^6 to 10.5^6 square kilometres in the last 35 years a reduction of approximately 16%. I knew that this year Arctic sea ice had been more stubborn to shift by watching the SYNOP observations from northern Canada and Greenland (see this blog). What did surprise me is even though they has been a steady decline in sea ice how volatile the change from season to season is.

The Antarctic graphs were a little surprising too, I did know that there had been a slight increase in sea ice there, and this was borne out by the area chart and the trend line showing a change from around 11.3^6 to 12.0^6 square kilometres, an increase of Antarctic sea ice of approximately 6% in 35 years. The other surprising thing was that for some reason I thought the Antarctic had a great deal more sea ice than the Arctic!

To do

I’ll try and link in this sea ice data set with global surface temperatures and maybe try and find an overlay the projections for future sea ice extent. Let me know if you spot any errors

Bruce.

On Wednesday, September 25, 2013 5:28:10 AM UTC+1, exmetman wrote:
Hi



(You can find graphs on my blog: http://xmetman.wordpress.com/2013/09...last-35-years/)



I have graphed just about every kind of data related to climate and meteorology over the last eighteen months, but for some reason I've never got round to looking for a data set of sea ice extent, and with all the hoo-ha at the moment concerning that and climate change, I thought I would investigate what was going on by downloading the sea ice data made freely available from the National Snow and Ice Data Center in Boulder (thank God for America and its attitude to free data).



Method



Quite a simple parsing of CSV text file, made slightly tricky because the data for the first year or so was not daily but every other day, and the data for the the latest year was in a separate file. I combined both the Arctic data and the Antarctic data into one class to keep everything tidy. The nearly 11,000 lines of data in each file were parsed in less than 0.1 of a second. I plotted two graphs one showing an area chart with the daily values of sea ice extent in 10^6 square kilometres along with a trend line using all the data points. The second graph, a bar chart, displays the change in extent of sea ice in the last 365 days, red indicates less ice (warmer), blue indicates more ice (colder).



Results



The Arctic graphs were how I expected them to look, with a steady decline in sea ice from around 12.5^6 to 10.5^6 square kilometres in the last 35 years a reduction of approximately 16%. I knew that this year Arctic sea ice had been more stubborn to shift by watching the SYNOP observations from northern Canada and Greenland (see this blog). What did surprise me is even though they has been a steady decline in sea ice how volatile the change from season to season is.



The Antarctic graphs were a little surprising too, I did know that there had been a slight increase in sea ice there, and this was borne out by the area chart and the trend line showing a change from around 11.3^6 to 12.0^6 square kilometres, an increase of Antarctic sea ice of approximately 6% in 35 years. The other surprising thing was that for some reason I thought the Antarctic had a great deal more sea ice than the Arctic!



To do



I’ll try and link in this sea ice data set with global surface temperatures and maybe try and find an overlay the projections for future sea ice extent. Let me know if you spot any errors



Bruce.

You could just have gone to "Cryosphere Today" Bruce, though you obviously enjoy manipulating the data.

On Wednesday, 25 September 2013 06:23:27 UTC+1, Dawlish wrote:
On Wednesday, September 25, 2013 5:28:10 AM UTC+1, exmetman wrote:

Hi







(You can find graphs on my blog: http://xmetman.wordpress.com/2013/09...last-35-years/)







I have graphed just about every kind of data related to climate and meteorology over the last eighteen months, but for some reason I've never got round to looking for a data set of sea ice extent, and with all the hoo-ha at the moment concerning that and climate change, I thought I would investigate what was going on by downloading the sea ice data made freely available from the National Snow and Ice Data Center in Boulder (thank God for America and its attitude to free data).







Method







Quite a simple parsing of CSV text file, made slightly tricky because the data for the first year or so was not daily but every other day, and the data for the the latest year was in a separate file. I combined both the Arctic data and the Antarctic data into one class to keep everything tidy. The nearly 11,000 lines of data in each file were parsed in less than 0.1 of a second. I plotted two graphs one showing an area chart with the daily values of sea ice extent in 10^6 square kilometres along with a trend line using all the data points. The second graph, a bar chart, displays the change in extent of sea ice in the last 365 days, red indicates less ice (warmer), blue indicates more ice (colder).







Results







The Arctic graphs were how I expected them to look, with a steady decline in sea ice from around 12.5^6 to 10.5^6 square kilometres in the last 35 years a reduction of approximately 16%. I knew that this year Arctic sea ice had been more stubborn to shift by watching the SYNOP observations from northern Canada and Greenland (see this blog). What did surprise me is even though they has been a steady decline in sea ice how volatile the change from season to season is.







The Antarctic graphs were a little surprising too, I did know that there had been a slight increase in sea ice there, and this was borne out by the area chart and the trend line showing a change from around 11.3^6 to 12.0^6 square kilometres, an increase of Antarctic sea ice of approximately 6% in 35 years. The other surprising thing was that for some reason I thought the Antarctic had a great deal more sea ice than the Arctic!







To do







I’ll try and link in this sea ice data set with global surface temperatures and maybe try and find an overlay the projections for future sea ice extent. Let me know if you spot any errors







Bruce.



You could just have gone to "Cryosphere Today" Bruce, though you obviously enjoy manipulating the data.

so Cryosphere me a river or graph.

"exmetman" wrote in message
...

Results

The Arctic graphs were how I expected them to look, with a steady decline in
sea ice from around 12.5^6 to 10.5^6 square kilometres in the last 35 years
a reduction of approximately 16%. I knew that this year Arctic sea ice had
been more stubborn to shift by watching the SYNOP observations from northern
Canada and Greenland (see this blog). What did surprise me is even though
they has been a steady decline in sea ice how volatile the change from
season to season is.

The Antarctic graphs were a little surprising too, I did know that there had
been a slight increase in sea ice there, and this was borne out by the area
chart and the trend line showing a change from around 11.3^6 to 12.0^6
square kilometres, an increase of Antarctic sea ice of approximately 6% in
35 years. The other surprising thing was that for some reason I thought the
Antarctic had a great deal more sea ice than the Arctic!

================================================== ==========

I think you may be missing a point about changes to sea ice. In the Northern
Hemisphere the trend in winter ice is much less than the annual average and
the trend in summer ice is much greater. See:
http://arctic.atmos.uiuc.edu/cryosph....1900-2010.png

I suspect the opposite is the case in the Southern Hemisphere.

The reason that the extent of the winter Arctic sea ice has remained fairly
constant is that there is a positive feedback controlling it. The more sea
ice there is, the colder the air can get and the further the sea ice can
spread out. So after a big summer melt when the winter ice reforms
it does so slowly, bet when it catches up then it spreads out to the same
area as before.

This has, IMHO, led scientists into a misleading complacency regarding
the loss od Arctic sea ice. They have concentrated on the annual trend,
roughly half the summer trend, and not realised that the summer ice loss is
more important because the strength of a chain is in its weakest link.

Cheers, Alastair.

On 25/09/2013 05:28, exmetman wrote:
Hi

(You can find graphs on my blog: http://xmetman.wordpress.com/2013/09...last-35-years/)

I have graphed just about every kind of data related to climate and meteorology over the last eighteen months, but for some reason I've never got round to looking for a data set of sea ice extent, and with all the hoo-ha at the moment concerning that and climate change, I thought I would investigate what was going on by downloading the sea ice data made freely available from the National Snow and Ice Data Center in Boulder (thank God for America and its attitude to free data).

Method

Quite a simple parsing of CSV text file, made slightly tricky because the data for the first year or so was not daily but every other day, and the data for the the latest year was in a separate file. I combined both the Arctic data and the Antarctic data into one class to keep everything tidy. The nearly 11,000 lines of data in each file were parsed in less than 0.1 of a second. I plotted two graphs one showing an area chart with the daily values of sea ice extent in 10^6 square kilometres along with a trend line using all the data points. The second graph, a bar chart, displays the change in extent of sea ice in the last 365 days, red indicates less ice (warmer), blue indicates more ice (colder).

Results

The Arctic graphs were how I expected them to look, with a steady decline in sea ice from around 12.5^6 to 10.5^6 square kilometres in the last 35 years a reduction of approximately 16%. I knew that this year Arctic sea ice had been more stubborn to shift by watching the SYNOP observations from northern Canada and Greenland (see this blog). What did surprise me is even though they has been a steady decline in sea ice how volatile the change from season to season is.

The Antarctic graphs were a little surprising too, I did know that there had been a slight increase in sea ice there, and this was borne out by the area chart and the trend line showing a change from around 11.3^6 to 12.0^6 square kilometres, an increase of Antarctic sea ice of approximately 6% in 35 years. The other surprising thing was that for some reason I thought the Antarctic had a great deal more sea ice than the Arctic!

To do

I’ll try and link in this sea ice data set with global surface temperatures and maybe try and find an overlay the projections for future sea ice extent. Let me know if you spot any errors

Bruce.


What we lose on the arctic, we gain on the antarctic. Swings and
roundabouts.

On Wed, 25 Sep 2013 11:05:36 +0100
Joe Egginton wrote:

On 25/09/2013 05:28, exmetman wrote:

Results

The Arctic graphs were how I expected them to look, with a steady
decline in sea ice from around 12.5^6 to 10.5^6 square kilometres
in the last 35 years a reduction of approximately 16%. I knew that
this year Arctic sea ice had been more stubborn to shift by
watching the SYNOP observations from northern Canada and Greenland
(see this blog). What did surprise me is even though they has been
a steady decline in sea ice how volatile the change from season to
season is.

The Antarctic graphs were a little surprising too, I did know that
there had been a slight increase in sea ice there, and this was
borne out by the area chart and the trend line showing a change
from around 11.3^6 to 12.0^6 square kilometres, an increase of
Antarctic sea ice of approximately 6% in 35 years. The other
surprising thing was that for some reason I thought the Antarctic
had a great deal more sea ice than the Arctic!



What we lose on the arctic, we gain on the antarctic. Swings and
roundabouts.

So, according to your maths, 2.0^6 = 0.7^6.

Apart from dodgy maths, you are also ignoring the fact that there is
also a net loss of ice in the Antarctic when the land ice is included.
Ice is being lost in both locations.


--
Graham P Davis, Bracknell, Berks.
'In wine there is wisdom, in beer there is freedom, in water there is
bacteria.' - Benjamin Franklin

On 25/09/13 11:52, Graham P Davis wrote:
On Wed, 25 Sep 2013 11:05:36 +0100
Joe wrote:

On 25/09/2013 05:28, exmetman wrote:

Results

The Arctic graphs were how I expected them to look, with a steady
decline in sea ice from around 12.5^6 to 10.5^6 square kilometres
in the last 35 years a reduction of approximately 16%. I knew that
this year Arctic sea ice had been more stubborn to shift by
watching the SYNOP observations from northern Canada and Greenland
(see this blog). What did surprise me is even though they has been
a steady decline in sea ice how volatile the change from season to
season is.

The Antarctic graphs were a little surprising too, I did know that
there had been a slight increase in sea ice there, and this was
borne out by the area chart and the trend line showing a change
from around 11.3^6 to 12.0^6 square kilometres, an increase of
Antarctic sea ice of approximately 6% in 35 years. The other
surprising thing was that for some reason I thought the Antarctic
had a great deal more sea ice than the Arctic!



What we lose on the arctic, we gain on the antarctic. Swings and
roundabouts.

So, according to your maths, 2.0^6 = 0.7^6.

Apart from dodgy maths, you are also ignoring the fact that there is
also a net loss of ice in the Antarctic when the land ice is included.
Ice is being lost in both locations.



Presumably the loss of land ice would lead to a freshening of the
Southern Ocean which would make it easier for sea ice to form?
Alternatively, the warming trend in the Southern Ocean is compensated
for by an increase in the freezing point of the ocean?

On Wednesday, 25 September 2013 20:40:25 UTC+1, Adam Lea wrote:
On 25/09/13 11:52, Graham P Davis wrote:

On Wed, 25 Sep 2013 11:05:36 +0100

Joe wrote:



On 25/09/2013 05:28, exmetman wrote:



Results



The Arctic graphs were how I expected them to look, with a steady

decline in sea ice from around 12.5^6 to 10.5^6 square kilometres

in the last 35 years a reduction of approximately 16%. I knew that

this year Arctic sea ice had been more stubborn to shift by

watching the SYNOP observations from northern Canada and Greenland

(see this blog). What did surprise me is even though they has been

a steady decline in sea ice how volatile the change from season to

season is.



The Antarctic graphs were a little surprising too, I did know that

there had been a slight increase in sea ice there, and this was

borne out by the area chart and the trend line showing a change

from around 11.3^6 to 12.0^6 square kilometres, an increase of

Antarctic sea ice of approximately 6% in 35 years. The other

surprising thing was that for some reason I thought the Antarctic

had a great deal more sea ice than the Arctic!







What we lose on the arctic, we gain on the antarctic. Swings and

roundabouts.



So, according to your maths, 2.0^6 = 0.7^6.



Apart from dodgy maths, you are also ignoring the fact that there is

also a net loss of ice in the Antarctic when the land ice is included.

Ice is being lost in both locations.







Presumably the loss of land ice would lead to a freshening of the

Southern Ocean which would make it easier for sea ice to form?

Alternatively, the warming trend in the Southern Ocean is compensated

for by an increase in the freezing point of the ocean?

People go on with this myth of loss of land ice. It's rubbish even on the coast the average temperature is below freezing. Its a sorry excuse to explain the growing sea ice which is defying all logic and growing because Antarctica is warmed by .5 degrees Celsius.

Does anyone actually believe that?

On Wed, 25 Sep 2013 20:40:25 +0100
Adam Lea wrote:

On 25/09/13 11:52, Graham P Davis wrote:
On Wed, 25 Sep 2013 11:05:36 +0100
Joe wrote:

On 25/09/2013 05:28, exmetman wrote:

Results

The Arctic graphs were how I expected them to look, with a steady
decline in sea ice from around 12.5^6 to 10.5^6 square kilometres
in the last 35 years a reduction of approximately 16%. I knew that
this year Arctic sea ice had been more stubborn to shift by
watching the SYNOP observations from northern Canada and Greenland
(see this blog). What did surprise me is even though they has been
a steady decline in sea ice how volatile the change from season to
season is.

The Antarctic graphs were a little surprising too, I did know that
there had been a slight increase in sea ice there, and this was
borne out by the area chart and the trend line showing a change
from around 11.3^6 to 12.0^6 square kilometres, an increase of
Antarctic sea ice of approximately 6% in 35 years. The other
surprising thing was that for some reason I thought the Antarctic
had a great deal more sea ice than the Arctic!



What we lose on the arctic, we gain on the antarctic. Swings and
roundabouts.

So, according to your maths, 2.0^6 = 0.7^6.

Apart from dodgy maths, you are also ignoring the fact that there is
also a net loss of ice in the Antarctic when the land ice is
included. Ice is being lost in both locations.


Presumably the loss of land ice would lead to a freshening of the
Southern Ocean which would make it easier for sea ice to form?
Alternatively, the warming trend in the Southern Ocean is compensated
for by an increase in the freezing point of the ocean?

Several years ago, I suggested the idea that increased melting of the
land ice would have cooled the ocean and also lowered the salinity,
thus making formation of ice more likely. Whether that is the main
cause or whether the changing wind patterns have more to do with it I've
no idea, but I did wonder just over a dozen years ago why the southern
ocean was continually colder than normal. I'm afraid it took me a while
to realise that it could be due to the melting of the ice cap.

--
Graham P Davis, Bracknell, Berks.
'In wine there is wisdom, in beer there is freedom, in water there is
bacteria.' - Benjamin Franklin

On Wednesday, 25 September 2013 23:06:28 UTC+1, Graham P Davis wrote:
On Wed, 25 Sep 2013 20:40:25 +0100

Adam Lea wrote:



On 25/09/13 11:52, Graham P Davis wrote:

On Wed, 25 Sep 2013 11:05:36 +0100

Joe wrote:



On 25/09/2013 05:28, exmetman wrote:



Results



The Arctic graphs were how I expected them to look, with a steady

decline in sea ice from around 12.5^6 to 10.5^6 square kilometres

in the last 35 years a reduction of approximately 16%. I knew that

this year Arctic sea ice had been more stubborn to shift by

watching the SYNOP observations from northern Canada and Greenland

(see this blog). What did surprise me is even though they has been

a steady decline in sea ice how volatile the change from season to

season is.



The Antarctic graphs were a little surprising too, I did know that

there had been a slight increase in sea ice there, and this was

borne out by the area chart and the trend line showing a change

from around 11.3^6 to 12.0^6 square kilometres, an increase of

Antarctic sea ice of approximately 6% in 35 years. The other

surprising thing was that for some reason I thought the Antarctic

had a great deal more sea ice than the Arctic!







What we lose on the arctic, we gain on the antarctic. Swings and

roundabouts.



So, according to your maths, 2.0^6 = 0.7^6.



Apart from dodgy maths, you are also ignoring the fact that there is

also a net loss of ice in the Antarctic when the land ice is

included. Ice is being lost in both locations.





Presumably the loss of land ice would lead to a freshening of the

Southern Ocean which would make it easier for sea ice to form?

Alternatively, the warming trend in the Southern Ocean is compensated

for by an increase in the freezing point of the ocean?



Several years ago, I suggested the idea that increased melting of the

land ice would have cooled the ocean and also lowered the salinity,

thus making formation of ice more likely. Whether that is the main

cause or whether the changing wind patterns have more to do with it I've

no idea, but I did wonder just over a dozen years ago why the southern

ocean was continually colder than normal. I'm afraid it took me a while

to realise that it could be due to the melting of the ice cap.



--

Graham P Davis, Bracknell, Berks.

'In wine there is wisdom, in beer there is freedom, in water there is

bacteria.' - Benjamin Franklin

Okay

So is there evidence that the oceans around Antarctica have cooled?

Also where is this evidence of melting land ice. If that were true then there would have been a noticeable increase in sea ice around Greenland.

Sorry Graham but its rubbish of the lowest order.