Not seen it that cold at Vostok before -85.4°c
--
Keith (Southend)

'Weather Home & Abroad'
http://www.southendweather.net

That is cold, however the record is something like -89. I have noticed this
year, what appears to me anyway, to be more extensive ice around Antarctica
than recent years.

Shaun Pudwell.


"Keith (Southend)" wrote in message
...
Not seen it that cold at Vostok before -85.4°c
--
Keith (Southend)

'Weather Home & Abroad'
http://www.southendweather.net

A carbon dioxide frost?
Seems to be below the freezing point of CO2 - but perhaps sea level
pressure would be required?
Alex.

"Shaun Pudwell" wrote in message
...
That is cold, however the record is something like -89. I have noticed
this
year, what appears to me anyway, to be more extensive ice around
Antarctica
than recent years.

Shaun Pudwell.


"Keith (Southend)" wrote in message
...
Not seen it that cold at Vostok before -85.4°c
--
Keith (Southend)

'Weather Home & Abroad'
http://www.southendweather.net

Alex Stephens Jr wrote:
A carbon dioxide frost?
Seems to be below the freezing point of CO2 - but perhaps sea level
pressure would be required?
Alex.


The partial pressure of CO2 at sea level is about 0.35 mb, so the
temperature needed at sea level for CO2 to freeze out would be about
-143°C, at which temperature CO2 has this vapour pressure.

Tudor Hughes, Warlingham, Surrey.

"Shaun Pudwell" wrote in message
...
That is cold, however the record is something like -89. I have noticed this
year, what appears to me anyway, to be more extensive ice around Antarctica
than recent years.

You can compare the Antarctic sea-ice at my site;
http://www.abmcdonald.freeserve.co.uk/south.htm

There doesn't seem much difference over the last six years as far as I can
see.

Cheers, Alastair.

Looking at those charts, there does seem to be a markedly high and low
season for the ice. Mid-September being the high point, and mid March being
the low point, with the reduction being from Sept-March. Would this be due
to the reversal of seasons in the Southern Hemisphere? This got me thinking,
the earth is tilted, as we all know, but because Antarctica is near a pole,
does this mean it is less affected by seasons? And, at the true poles, would
this mean there would be no change in seasons at all, as they are directly
on the ends of the earth so to speak.

Mike

Alastair, just looking through the charts further, could you tell me what
the coating of the British Isles is on the 7th Apr 2005. The key seems to
point towards it being 16-21% ice.

Cheers,

Mike

"Michael Di Bernardo" wrote in
message . uk...
Looking at those charts, there does seem to be a markedly high and low
season for the ice. Mid-September being the high point, and mid March being
the low point, with the reduction being from Sept-March. Would this be due
to the reversal of seasons in the Southern Hemisphere?

Yes, here are the corresponding maps for the Arctic ice;
http://www.abmcdonald.freeserve.co.uk/north.htm

It is at its minimum around today, which you can check by flicking forward and
backwards by a day or two around this date for previous years.

This got me thinking,
the earth is tilted, as we all know, but because Antarctica is near a pole,
does this mean it is less affected by seasons? And, at the true poles, would
this mean there would be no change in seasons at all, as they are directly
on the ends of the earth so to speak.

If you were to take a daily average you would be correct, because at the
pole the day and night take all year! However, the long night allows a lot
of cooling and the long day would make the surface very hot if was not for
the snow and ice. Fresh snow reflects up to 90% of the sunshine, and
hence Antarctica remains fairly cold during the summer.

The Arctic is different because the sea ice is over the pole, and it melts
during the summer exposing the ocean which warms. In the Arctic, the
temperature sticks near 0C because the melting ice keeps the sea
surface temperature at zero. But the multi-year ice is retreating due to
global warming, and this year's minimum is a record.

Eventually, one summer it will melt completely, and the Arctic ocean will
warm enough from the continual sun to prevent the winter ice from
reforming. The subsequent effect on the climate of the Northern
Hemisphere where most of the world's crops are grown is going to be
catastrophic!

Cheers, Alastair.

"Michael Di Bernardo" wrote in
message . ..
Alastair, just looking through the charts further, could you tell me what
the coating of the British Isles is on the 7th Apr 2005. The key seems to
point towards it being 16-21% ice.

The maps are produced using satellite data and applying algorithms to deduce
the ice coverage. False readings are given by coasts and by clouds. I suspect
what you are seeing there is a combination of both over the Irish Sea. In the
Arctic I think you will see areas of high concentration which appear to sweep
across the ocean. I think that they are caused by clouds.

I do not do any processing of the data. The maps are made by Bob Grumbine who
works for NOAA, the US Met Office. I copy them without any "added value."

HTH,

Cheers, Alastair.

In article ,
Michael Di Bernardo
writes:
Looking at those charts, there does seem to be a markedly high and low
season for the ice. Mid-September being the high point, and mid March being
the low point, with the reduction being from Sept-March. Would this be due
to the reversal of seasons in the Southern Hemisphere?

Yes.

This got me thinking,
the earth is tilted, as we all know, but because Antarctica is near a pole,
does this mean it is less affected by seasons? And, at the true poles, would
this mean there would be no change in seasons at all, as they are directly
on the ends of the earth so to speak.

You have it the wrong way round. Seasons tend to be least well-defined
near the equator, because that is where the hours of daylight and the
maximum daily elevation of the sun above the horizon vary the least.

At the Poles, you are going from six months of darkness in winter to 6
months of daylight in summer, which naturally has a big effect. However
the maximum elevation of the sun is never very great (never above about
23 degrees), which means that even in summer it's not going to get very
warm (though if all the ice was ever to melt it would be substantially
warmer in summer than it gets now).
--
John Hall "Hard work often pays off after time, but laziness always
pays off now." Anon