Does anyone have any idea why February as become so warm recently.
Just looking at some data and it's quite amazing.

Mean temperatures:
1961-90 1988-2005
Dec 3.6c Dec 3.8c +0.2c
Jan 2.8c Jan 3.6c +0.8c
Feb 2.8c Feb 4.1c +1.3c

7 December's have been below the 1961-90 average
since 1988 while January and February have only
managed 7 between them, 4 and 3 respectively.

Just out of interest the 1971-2000 means a
Dec 3.8c
Jan 3.0c
Feb 3.2c

Weston Coyney weather station (North Midlands) 220 metres asl

--
Graham

Yes, I do....
Global Warming, and it's effect on weather patterns, oh, and the melting ice
might have somethign to do with it! lol.

------------------------------------------------------------
"Graham" wrote in message
...
Does anyone have any idea why February as become so warm recently.
Just looking at some data and it's quite amazing.

Mean temperatures:
1961-90 1988-2005
Dec 3.6c Dec 3.8c +0.2c
Jan 2.8c Jan 3.6c +0.8c
Feb 2.8c Feb 4.1c +1.3c

7 December's have been below the 1961-90 average
since 1988 while January and February have only
managed 7 between them, 4 and 3 respectively.

Just out of interest the 1971-2000 means a
Dec 3.8c
Jan 3.0c
Feb 3.2c

Weston Coyney weather station (North Midlands) 220 metres asl

--
Graham

In article ,
"danny (west kent)" writes:
"Graham" wrote in message
...
Does anyone have any idea why February as become so warm recently.
snip
Yes, I do....
Global Warming, and it's effect on weather patterns, oh, and the melting ice
might have somethign to do with it! lol.

But the interesting question is why that should have affected February
so much, when it hardly seems to have affect December at all. We seem
almost to have reached the point now where the period around Christmas
is regularly the coldest of the winter.
--
John Hall
"Hegel was right when he said that we learn from history
that man can never learn anything from history."
George Bernard Shaw (1856-1950)

Yes, I do....
Global Warming, and it's effect on weather patterns, oh, and the melting ice
might have somethign to do with it! lol.

The point I was trying to make was why is the February mean over a
degree warmer when the December mean is almost unchanged from it's
1961-90 average.
--
Graham

"Graham" wrote in message
...

Yes, I do....
Global Warming, and it's effect on weather patterns, oh, and the melting
ice
might have somethign to do with it! lol.

The point I was trying to make was why is the February mean over a
degree warmer when the December mean is almost unchanged from it's
1961-90 average.

I think Danny is correct, it is the Arctic sea ice. The seasonal temperatures
tend
to lag the solar intensity by a couple of months because of the effect of sea
surface temperatures being controlled by the heat capacity of the oceans.

In the past, the formation of ice in the Arctic ocean sealed the heat from
the oceans in and produced a continental type surface where the temperatures
could drop. Now, the lower concentrations of ice mean the seal is not secure
and so Arctic air does not cool to the same extent. These days, the stronger
sun in February means the temperature then exceed those in December
and January.
Here are the ice concentrations for today, three years ago, and six years ago
http://polar.ncep.noaa.gov/seaice/an...h.20050214.gif
http://polar.ncep.noaa.gov/seaice/an...h.20020214.gif
http://polar.ncep.noaa.gov/seaice/an...h.19990212.gif

The darker blue is 95% concentration, the lighter green is 75% conc.

HTH,

Cheers, Alastair.

Alastair McDonald wrote:
"Graham" wrote in message
...

Yes, I do....
Global Warming, and it's effect on weather patterns, oh, and the melting

ice

might have somethign to do with it! lol.


The point I was trying to make was why is the February mean over a
degree warmer when the December mean is almost unchanged from it's
1961-90 average.


I think Danny is correct, it is the Arctic sea ice. The seasonal temperatures
tend
to lag the solar intensity by a couple of months because of the effect of sea
surface temperatures being controlled by the heat capacity of the oceans.

In the past, the formation of ice in the Arctic ocean sealed the heat from
the oceans in and produced a continental type surface where the temperatures
could drop. Now, the lower concentrations of ice mean the seal is not secure
and so Arctic air does not cool to the same extent. These days, the stronger
sun in February means the temperature then exceed those in December
and January.
Here are the ice concentrations for today, three years ago, and six years ago
http://polar.ncep.noaa.gov/seaice/an...h.20050214.gif
http://polar.ncep.noaa.gov/seaice/an...h.20020214.gif
http://polar.ncep.noaa.gov/seaice/an...h.19990212.gif

The darker blue is 95% concentration, the lighter green is 75% conc.


More likely that the lighter green is cloud cover. These charts are OK
for finding the main edge of the ice but concentrations within the
ice-field should be taken with a large amount of brine. Simply looking
at the animated sequence shows these areas of lower concentrations
moving quickly over the ice. Similar areas of "ice" can be seen speeding
over the oceans.

The AMSR images at http://www.seaice.de/ also suffer from this problem.
Some of the dark areas within the ice-pack are cloud rather than areas
of more broken ice. Similarly, some breaks in the ice may be masked by
cloud. Examination of a sequence of images is still necessary to get a
true picture of the ice conditions.

Graham

"Graham P Davis" wrote in message
...


More likely that the lighter green is cloud cover. These charts are OK
for finding the main edge of the ice but concentrations within the
ice-field should be taken with a large amount of brine. Simply looking
at the animated sequence shows these areas of lower concentrations
moving quickly over the ice. Similar areas of "ice" can be seen speeding
over the oceans.

The AMSR images at http://www.seaice.de/ also suffer from this problem.
Some of the dark areas within the ice-pack are cloud rather than areas
of more broken ice. Similarly, some breaks in the ice may be masked by
cloud. Examination of a sequence of images is still necessary to get a
true picture of the ice conditions.

I would agree that clouds can affect these maps but, as you say, the clouds
move quickly and the light green features have been persistent for periods
much longer than that. Moreover, a smaller similar feature was persistent
during February in 2003. My interpretation is that the Arctic Ocean is
warming and the ice is no longer as thick as it has been in the past. This
makes it more vulnerable to the formation of leads and polynas.

The clouds would contribute to the darker features rather than the lighter
features because both ice and cloud reflect solar radiation.

But Sod's law has struck, and the light green areas have disappeared today!
If they reappear tomorrow, then I think it will be fair to blame their
disappearance on cloud, rather than their existence. See;
http://www.abmcdonald.freeserve.co.uk/north.htm

If you look at the map to which you referred I think it is clear that
the ice is thinning right up to the pole. See
http://iup.physik.uni-bremen.de:8084..._AMSRE_nic.png

Cheers, Alastair.

This change by which December is now colder than February (and about
the same as January) is most striking, for
a) It goes against everything the textbooks say regarding a maritime
climate, where the effect of sea temps should put off the coldest
weather till after the solstice
and
b) It means that if we take the year as a whole, the temperature graph
is not symmetrical. By this I mean that the *same time-lag still occurs
in summer*, with August significantly warmer than June. So the warmest
and coldest periods (on average) are not 6 months apart. How could
sea-ice changes explain this?

Edmund

Edmund Lewis wrote:
This change by which December is now colder than February (and about
the same as January) is most striking, for
a) It goes against everything the textbooks say regarding a maritime
climate, where the effect of sea temps should put off the coldest
weather till after the solstice
and
b) It means that if we take the year as a whole, the temperature graph
is not symmetrical. By this I mean that the *same time-lag still occurs
in summer*, with August significantly warmer than June. So the warmest
and coldest periods (on average) are not 6 months apart. How could
sea-ice changes explain this?

Edmund


My perception is that the peak of summer is end-July and start-August,
so I would hope August would be warmer than June. I would normally
expect January to be the coldest month (not this year!), so I never
thought of symmetry. I have not of course read the text book.

My perception is based on my recollection over the years btw ... no
supporting data. The pattern in the UK seems much the same as in IT.

--
Gianna Stefani

www.buchan-meteo.org.uk

"Edmund Lewis" wrote in message
oups.com...
This change by which December is now colder than February (and about
the same as January) is most striking, for
a) It goes against everything the textbooks say regarding a maritime
climate, where the effect of sea temps should put off the coldest
weather after the solstice

The coldest period is still January, which is after the solstice.

and
b) It means that if we take the year as a whole, the temperature graph
is not symmetrical. By this I mean that the *same time-lag still occurs
in summer*, with August significantly warmer than June. So the warmest
and coldest periods (on average) are not 6 months apart. How could
sea-ice changes explain this?

It is partly due to the sea ice which has not melted by June, that makes
August warmer. The ice has a nonlinear effect because of its latent heat
and that can upset any symmetry.

We could well see a very warm July this year if the ice melts faster than
ususal, and it is not cloudy.

Cheers, Alastair.