In soc.history.medieval Soren Larsen wrote:
Paul J Gans wrote:
In soc.history.medieval Zimri

But if you want to investigate world-wide temperatures I'd
think that tree ring data is one way to go.


You'll need world wide tree ring samples going back enough.

Good luck with the project.

It is needed for historical and archaeological reasons as well

World wide is about impossible to get, as you know. But we
do have it back even further than that for some of Europe
and North America, and possibly other places.

If there was a really cold spell world wide in the 6th
century, it will show up there.

In other words what we have is a possibility of *disproving*
the hypotheses even if we can't *prove* it.


--
--- Paul J. Gans

Paul J Gans wrote:

In soc.history.medieval Zimri wrote:
This question is primarily for sci.geo.meteorology; I'm x-posting to
soc.history.ancient and .medieval because the answer is for their sake.

It's a common meme among us Late Antiquity fans that there was a vast global
chill in 535 CE, which threw at least Europe into the Dark Age. This was
popularised by David Keys in "Catastrophe" in 2000, and its claims are still
cited in scholarly journals; for instance Hirschfeld in "THE CRISIS OF THE
SIXTH CENTURY" (pdf:
http://www.rhodes.aegean.gr/maa_jour...CHFELD_s06.pdf)
and several post-2000 articles cited therein (esp. McCormick). I'm concerned
with Europe right now, primarily Lombardy and Merovingian France, so I'll
restrict this post to that region.

Hirschfeld tells me that the Po River flooded in 540 CE. David Keys did not
employ particularly deep meteorological expertise in "Catastrophe"; from the
book, I got the impression that if it was anomalous then it could be blamed
on the global chill. To his credit, Keys did not list the Po flood among the
calamities stemming from the 535 CE sunless year.

What causes the floods, to my limited understanding, is humid air running
into the basin of the Po; specifically, into the southern Alps. Presumably
that air would come in from the southwest. So what we are looking for is a
large low-pressure system far off in the Atlantic to the northwest of the
Alps. (Cyclones of this sort, up here in the Northern Hemisphere, spin
anticlockwise around the "eye".)

The seemingly obvious culprit would be the famed North Atlantic Oscillation,
"NAO". Meteorologists measure, in winter, the relative barometric pressure
between the Azores (west of Europe) and Iceland (northwest). When the index
is "positive", it follows that there is lower pressure in Iceland than in
the Azores. When it is VERY positive then there is a cyclone in the north
Atlantic, pulling moist and warmer air off the Canary Islands and into
southern France. When this stuff hits the Alps, depending on how cold it was
there before it hits, it precipitates out and floods the Po. (Do I have this
right so far?)

The NAO index oscillates between positive and negative. Some say it does
this over a span of slightly less than 10 years. In general, over the last
32 years it has been positive 25 times and negative 7. Either way, the NAO
is not caused by, e.g., the sunspot cycle.

The next step would be to ascertain what creates cyclones in Iceland, of all
places. But since I am on the subject of the late 530s, which as mentioned
above Keys blames on a vast global cooling...

1. What happens when Iceland suffers an anomalous downturn in its
temperature? I seem to remember from high school that cold fluids, water
excepted, are less dense than hot ones. Could a deep chill in Iceland
suffice to lower its air pressure, to the extent of creating a low pressure
system / high NAO index?

You've got it backwards. Cool air is *more* dense than warm air.

2. Perhaps Krakatoa could erupt; perhaps Santorini or Vesuvius. Iceland has
enough volcanoes of its own. Any of these could increase "cloud" cover
locally; or, some other factor might boost actual clouds over Iceland.
However it happens: does cloud cover over Iceland affect its air pressure,
directly or through chilling it? What happens when the whole Northern
Hemisphere is clouded?

That depends. Clouds reflect sunlight back to outer space.
Thus widespread clouding over a period of time is cooling.

On the other hand, clouds also reflect heat from the earth
back to the earth, which means that at night clouds keep
the surface of the earth warmer.

if the body is close enough to the sun to absorb significant Infra red.




But if you want to investigate world-wide temperatures I'd
think that tree ring data is one way to go.

--
--- Paul J. Gans

"Zimri" wrote in message
. net...
This question is primarily for sci.geo.meteorology; I'm x-posting to
soc.history.ancient and .medieval because the answer is for their sake.

It's a common meme among us Late Antiquity fans that there was a vast
global chill in 535 CE, which threw at least Europe into the Dark Age.
This was popularised by David Keys in "Catastrophe" in 2000, and its
claims are still cited in scholarly journals; for instance Hirschfeld in
"THE CRISIS OF THE SIXTH CENTURY" (pdf:
http://www.rhodes.aegean.gr/maa_jour...CHFELD_s06.pdf)
and several post-2000 articles cited therein (esp. McCormick). I'm
concerned with Europe right now, primarily Lombardy and Merovingian
France, so I'll restrict this post to that region.

Hirschfeld tells me that the Po River flooded in 540 CE. David Keys did
not employ particularly deep meteorological expertise in "Catastrophe";
from the book, I got the impression that if it was anomalous then it could
be blamed on the global chill. To his credit, Keys did not list the Po
flood among the calamities stemming from the 535 CE sunless year.

What causes the floods, to my limited understanding, is humid air running
into the basin of the Po; specifically, into the southern Alps. Presumably
that air would come in from the southwest. So what we are looking for is a
large low-pressure system far off in the Atlantic to the northwest of the
Alps. (Cyclones of this sort, up here in the Northern Hemisphere, spin
anticlockwise around the "eye".)

The seemingly obvious culprit would be the famed North Atlantic
Oscillation, "NAO". Meteorologists measure, in winter, the relative
barometric pressure between the Azores (west of Europe) and Iceland
(northwest). When the index is "positive", it follows that there is lower
pressure in Iceland than in the Azores. When it is VERY positive then
there is a cyclone in the north Atlantic, pulling moist and warmer air off
the Canary Islands and into southern France. When this stuff hits the
Alps, depending on how cold it was there before it hits, it precipitates
out and floods the Po. (Do I have this right so far?)

The NAO index oscillates between positive and negative. Some say it does
this over a span of slightly less than 10 years. In general, over the last
32 years it has been positive 25 times and negative 7. Either way, the NAO
is not caused by, e.g., the sunspot cycle.

The next step would be to ascertain what creates cyclones in Iceland, of
all places. But since I am on the subject of the late 530s, which as
mentioned above Keys blames on a vast global cooling...

1. What happens when Iceland suffers an anomalous downturn in its
temperature? I seem to remember from high school that cold fluids, water
excepted, are less dense than hot ones. Could a deep chill in Iceland
suffice to lower its air pressure, to the extent of creating a low
pressure system / high NAO index?

Air is a gas

Cold air is denser that warm air. That gets you a high cool air high
pressure zone. A low is warm air or at least warmer than the high.

Water is fuild/liquid but nothing else acts exactly like it does.

Cooling warm water causes it to contract until near the freezing point at
which time it starts to expand. Salt concentration will change both the
density and freezing point so you need to do some serious reading.



2. Perhaps Krakatoa could erupt; perhaps Santorini or Vesuvius. Iceland
has enough volcanoes of its own. Any of these could increase "cloud" cover
locally; or, some other factor might boost actual clouds over Iceland.
However it happens: does cloud cover over Iceland affect its air pressure,
directly or through chilling it? What happens when the whole Northern
Hemisphere is clouded?

Depends but usually cloud cover cools the surface.


Thank you in advance
--
zimriel sbc dot
at global net
.
http://pages.sbcglobal.net/zimriel/
*new improved shorter .sig*

On Fri, 26 Jan 2007 23:09:27 -0600, "deowll"
wrote:


---- snip -----

1. What happens when Iceland suffers an anomalous downturn in its
temperature? I seem to remember from high school that cold fluids, water
excepted, are less dense than hot ones. Could a deep chill in Iceland
suffice to lower its air pressure, to the extent of creating a low
pressure system / high NAO index?

Air is a gas

Cold air is denser that warm air. That gets you a high cool air high
pressure zone. A low is warm air or at least warmer than the high.

Water is fuild/liquid but nothing else acts exactly like it does.

Cooling warm water causes it to contract until near the freezing point at
which time it starts to expand. Salt concentration will change both the
density and freezing point so you need to do some serious reading.



2. Perhaps Krakatoa could erupt; perhaps Santorini or Vesuvius. Iceland
has enough volcanoes of its own. Any of these could increase "cloud" cover
locally; or, some other factor might boost actual clouds over Iceland.
However it happens: does cloud cover over Iceland affect its air pressure,
directly or through chilling it? What happens when the whole Northern
Hemisphere is clouded?

Depends but usually cloud cover cools the surface.

You can't apply simplistic analyses like these to weather or climate.
Barometric lows tend to be associated with lower temperatures than
barometric highs. There are all kinds of reasons for this including
the respective latitudes of highs and lows. See
http://ess.geology.ufl.edu/ess/Notes...tmosphere.html
But then you have to take into account such things as Bernoulli's
theorem http://130.64.87.22/ldaps/htdocs/physics/bernoulli.html
whereby wind speed and air pressure are interchangeable, the gas laws
http://en.wikipedia.org/wiki/Gas_laws whereby pressure, temperature
and volume are related. You absolutely MUST NOT forget the question of
the latent heat of water http://en.wikipedia.org/wiki/Latent_heat
which materially affects the temperature of the atmosphere according
to whether water is being evaporated or condensing (rain). Then when
you think you've got a handle on it you discover that in a realworld
dynamic system you can get sharp cahges in atmospheric state to
another and then you learn about the adiabatic lapse rate - see
http://en.wikipedia.org/wiki/Adiabatic_lapse_rate

Before you have got partway through any of this you will begin to
realise that the problem is far too complex for analysis in the manner
you are attempting. :-)



Eric Stevens

"Zimri"
It's a common meme among us Late Antiquity fans that there was a vast
global chill in 535 CE, which threw at least Europe into the Dark Age.
This was popularised by David Keys in "Catastrophe" in 2000, and its
claims are still cited in scholarly journals; for instance Hirschfeld in
"THE CRISIS OF THE SIXTH CENTURY" (pdf:
http://www.rhodes.aegean.gr/maa_jour...CHFELD_s06.pdf)
and several post-2000 articles cited therein (esp. McCormick). I'm
concerned with Europe right now, primarily Lombardy and Merovingian
France, so I'll restrict this post to that region.

Hirschfeld tells me that the Po River flooded in 540 CE.
....
1. What happens when Iceland suffers an anomalous downturn in its
temperature? I seem to remember from high school that cold fluids, water
excepted, are less dense than hot ones. Could a deep chill in Iceland
suffice to lower its air pressure, to the extent of creating a low
pressure system / high NAO index?

"deowll" wrote in message
...
Air is a gas

Cold air is denser that warm air. That gets you a high cool air high
pressure zone. A low is warm air or at least warmer than the high.

Thanks, but after reading McCormick last weekend (which I should have done
before posting) I have realised that Hirschfeld misquoted him about as badly
as I've ever seen one published author misquote another. McCormick cites
Procopius "Wars" 6.28.3-6: the Po did not flood in winter 539/40; it dried
up, and returned to its proper state later.

A Po river drought is associated with the NAO Azores:Iceland negative index.
What you are saying about cold air being denser sounds like it might result
in a high pressure system over more northerly areas. Like Iceland versus the
Azores.

deowll
Water is fuild/liquid but nothing else acts exactly like it does.

Cooling warm water causes it to contract until near the freezing point at
which time it starts to expand. Salt concentration will change both the
density and freezing point

On that topic, suppose that, in the Arctic as elsewhere, summer simply fails
to arrive in 535 CE. Allow a few years for the region to collect snow and
then to warm up again. Then in summer 539, fresh water is injected into the
North Atlantic. Might this also affect the weather in Iceland that winter?

deowll
so you need to do some serious reading.

I've been doing that ...

--
zimriel sbc dot
at global net
..
http://pages.sbcglobal.net/zimriel/
*new improved shorter .sig*

deowll wrote:

"Zimri" wrote in message
. net...
This question is primarily for sci.geo.meteorology; I'm x-posting to
soc.history.ancient and .medieval because the answer is for their sake.

It's a common meme among us Late Antiquity fans that there was a vast
global chill in 535 CE, which threw at least Europe into the Dark Age.
This was popularised by David Keys in "Catastrophe" in 2000, and its
claims are still cited in scholarly journals; for instance Hirschfeld in
"THE CRISIS OF THE SIXTH CENTURY" (pdf:
http://www.rhodes.aegean.gr/maa_jour...CHFELD_s06.pdf)
and several post-2000 articles cited therein (esp. McCormick). I'm
concerned with Europe right now, primarily Lombardy and Merovingian
France, so I'll restrict this post to that region.

Hirschfeld tells me that the Po River flooded in 540 CE. David Keys did
not employ particularly deep meteorological expertise in "Catastrophe";
from the book, I got the impression that if it was anomalous then it could
be blamed on the global chill. To his credit, Keys did not list the Po
flood among the calamities stemming from the 535 CE sunless year.

What causes the floods, to my limited understanding, is humid air running
into the basin of the Po; specifically, into the southern Alps. Presumably
that air would come in from the southwest. So what we are looking for is a
large low-pressure system far off in the Atlantic to the northwest of the
Alps. (Cyclones of this sort, up here in the Northern Hemisphere, spin
anticlockwise around the "eye".)

The seemingly obvious culprit would be the famed North Atlantic
Oscillation, "NAO". Meteorologists measure, in winter, the relative
barometric pressure between the Azores (west of Europe) and Iceland
(northwest). When the index is "positive", it follows that there is lower
pressure in Iceland than in the Azores. When it is VERY positive then
there is a cyclone in the north Atlantic, pulling moist and warmer air off
the Canary Islands and into southern France. When this stuff hits the
Alps, depending on how cold it was there before it hits, it precipitates
out and floods the Po. (Do I have this right so far?)

The NAO index oscillates between positive and negative. Some say it does
this over a span of slightly less than 10 years. In general, over the last
32 years it has been positive 25 times and negative 7. Either way, the NAO
is not caused by, e.g., the sunspot cycle.

The next step would be to ascertain what creates cyclones in Iceland, of
all places. But since I am on the subject of the late 530s, which as
mentioned above Keys blames on a vast global cooling...

1. What happens when Iceland suffers an anomalous downturn in its
temperature? I seem to remember from high school that cold fluids, water
excepted, are less dense than hot ones. Could a deep chill in Iceland
suffice to lower its air pressure, to the extent of creating a low
pressure system / high NAO index?

Air is a gas

Cold air is denser that warm air. That gets you a high cool air high
pressure zone. A low is warm air or at least warmer than the high.

Water is fuild/liquid but nothing else acts exactly like it does.


except for other fluids and gases!
you need to go back to school - Bernouli?






Cooling warm water causes it to contract until near the freezing point at
which time it starts to expand. Salt concentration will change both the
density and freezing point so you need to do some serious reading.


2. Perhaps Krakatoa could erupt; perhaps Santorini or Vesuvius. Iceland
has enough volcanoes of its own. Any of these could increase "cloud" cover
locally; or, some other factor might boost actual clouds over Iceland.
However it happens: does cloud cover over Iceland affect its air pressure,
directly or through chilling it? What happens when the whole Northern
Hemisphere is clouded?

Depends but usually cloud cover cools the surface.


Thank you in advance
--
zimriel sbc dot
at global net
.
http://pages.sbcglobal.net/zimriel/
*new improved shorter .sig*

Zimri wrote:

"Zimri"
It's a common meme among us Late Antiquity fans that there was a vast
global chill in 535 CE, which threw at least Europe into the Dark Age.
This was popularised by David Keys in "Catastrophe" in 2000, and its
claims are still cited in scholarly journals; for instance Hirschfeld in
"THE CRISIS OF THE SIXTH CENTURY" (pdf:
http://www.rhodes.aegean.gr/maa_jour...CHFELD_s06.pdf)
and several post-2000 articles cited therein (esp. McCormick). I'm
concerned with Europe right now, primarily Lombardy and Merovingian
France, so I'll restrict this post to that region.

Hirschfeld tells me that the Po River flooded in 540 CE.
...
1. What happens when Iceland suffers an anomalous downturn in its
temperature? I seem to remember from high school that cold fluids, water
excepted, are less dense than hot ones. Could a deep chill in Iceland
suffice to lower its air pressure, to the extent of creating a low
pressure system / high NAO index?

"deowll" wrote in message
...
Air is a gas

Cold air is denser that warm air. That gets you a high cool air high
pressure zone. A low is warm air or at least warmer than the high.

Thanks, but after reading McCormick last weekend (which I should have done
before posting) I have realised that Hirschfeld misquoted him about as badly
as I've ever seen one published author misquote another. McCormick cites
Procopius "Wars" 6.28.3-6: the Po did not flood in winter 539/40; it dried
up, and returned to its proper state later.

A Po river drought is associated with the NAO Azores:Iceland negative index.
What you are saying about cold air being denser sounds like it might result
in a high pressure system over more northerly areas. Like Iceland versus the
Azores.

deowll
Water is fuild/liquid but nothing else acts exactly like it does.

Cooling warm water causes it to contract until near the freezing point at
which time it starts to expand. Salt concentration will change both the
density and freezing point

On that topic, suppose that, in the Arctic as elsewhere, summer simply fails
to arrive in 535 CE. Allow a few years for the region to collect snow and
then to warm up again. Then in summer 539, fresh water is injected into the
North Atlantic. Might this also affect the weather in Iceland that winter?


and Betelgeuse .............. ah forget it!





deowll
so you need to do some serious reading.

I've been doing that ...

--
zimriel sbc dot
at global net
.
http://pages.sbcglobal.net/zimriel/
*new improved shorter .sig*

"Computers Suck" wrote in message
...


deowll wrote:

"Zimri" wrote in message
. net...
This question is primarily for sci.geo.meteorology; I'm x-posting to
soc.history.ancient and .medieval because the answer is for their sake.

It's a common meme among us Late Antiquity fans that there was a vast
global chill in 535 CE, which threw at least Europe into the Dark Age.
This was popularised by David Keys in "Catastrophe" in 2000, and its
claims are still cited in scholarly journals; for instance Hirschfeld
in
"THE CRISIS OF THE SIXTH CENTURY" (pdf:
http://www.rhodes.aegean.gr/maa_jour...CHFELD_s06.pdf)
and several post-2000 articles cited therein (esp. McCormick). I'm
concerned with Europe right now, primarily Lombardy and Merovingian
France, so I'll restrict this post to that region.

Hirschfeld tells me that the Po River flooded in 540 CE. David Keys did
not employ particularly deep meteorological expertise in "Catastrophe";
from the book, I got the impression that if it was anomalous then it
could
be blamed on the global chill. To his credit, Keys did not list the Po
flood among the calamities stemming from the 535 CE sunless year.

What causes the floods, to my limited understanding, is humid air
running
into the basin of the Po; specifically, into the southern Alps.
Presumably
that air would come in from the southwest. So what we are looking for
is a
large low-pressure system far off in the Atlantic to the northwest of
the
Alps. (Cyclones of this sort, up here in the Northern Hemisphere, spin
anticlockwise around the "eye".)

The seemingly obvious culprit would be the famed North Atlantic
Oscillation, "NAO". Meteorologists measure, in winter, the relative
barometric pressure between the Azores (west of Europe) and Iceland
(northwest). When the index is "positive", it follows that there is
lower
pressure in Iceland than in the Azores. When it is VERY positive then
there is a cyclone in the north Atlantic, pulling moist and warmer air
off
the Canary Islands and into southern France. When this stuff hits the
Alps, depending on how cold it was there before it hits, it
precipitates
out and floods the Po. (Do I have this right so far?)

The NAO index oscillates between positive and negative. Some say it
does
this over a span of slightly less than 10 years. In general, over the
last
32 years it has been positive 25 times and negative 7. Either way, the
NAO
is not caused by, e.g., the sunspot cycle.

The next step would be to ascertain what creates cyclones in Iceland,
of
all places. But since I am on the subject of the late 530s, which as
mentioned above Keys blames on a vast global cooling...

1. What happens when Iceland suffers an anomalous downturn in its
temperature? I seem to remember from high school that cold fluids,
water
excepted, are less dense than hot ones. Could a deep chill in Iceland
suffice to lower its air pressure, to the extent of creating a low
pressure system / high NAO index?

Air is a gas

Cold air is denser that warm air. That gets you a high cool air high
pressure zone. A low is warm air or at least warmer than the high.

Water is fuild/liquid but nothing else acts exactly like it does.


except for other fluids and gases!
you need to go back to school - Bernouli?

I do pretty often. Cool air still sinks and hot air still rises.







Cooling warm water causes it to contract until near the freezing point at
which time it starts to expand. Salt concentration will change both the
density and freezing point so you need to do some serious reading.


2. Perhaps Krakatoa could erupt; perhaps Santorini or Vesuvius. Iceland
has enough volcanoes of its own. Any of these could increase "cloud"
cover
locally; or, some other factor might boost actual clouds over Iceland.
However it happens: does cloud cover over Iceland affect its air
pressure,
directly or through chilling it? What happens when the whole Northern
Hemisphere is clouded?

Depends but usually cloud cover cools the surface.


Thank you in advance
--
zimriel sbc dot
at global net
.
http://pages.sbcglobal.net/zimriel/
*new improved shorter .sig*

On Sun, 4 Feb 2007 15:46:38 -0600, "deowll"
wrote:


"Computers Suck" wrote in message
...


deowll wrote:

"Zimri" wrote in message
. net...
This question is primarily for sci.geo.meteorology; I'm x-posting to
soc.history.ancient and .medieval because the answer is for their sake.

It's a common meme among us Late Antiquity fans that there was a vast
global chill in 535 CE, which threw at least Europe into the Dark Age.
This was popularised by David Keys in "Catastrophe" in 2000, and its
claims are still cited in scholarly journals; for instance Hirschfeld
in
"THE CRISIS OF THE SIXTH CENTURY" (pdf:
http://www.rhodes.aegean.gr/maa_jour...CHFELD_s06.pdf)
and several post-2000 articles cited therein (esp. McCormick). I'm
concerned with Europe right now, primarily Lombardy and Merovingian
France, so I'll restrict this post to that region.

Hirschfeld tells me that the Po River flooded in 540 CE. David Keys did
not employ particularly deep meteorological expertise in "Catastrophe";
from the book, I got the impression that if it was anomalous then it
could
be blamed on the global chill. To his credit, Keys did not list the Po
flood among the calamities stemming from the 535 CE sunless year.

What causes the floods, to my limited understanding, is humid air
running
into the basin of the Po; specifically, into the southern Alps.
Presumably
that air would come in from the southwest. So what we are looking for
is a
large low-pressure system far off in the Atlantic to the northwest of
the
Alps. (Cyclones of this sort, up here in the Northern Hemisphere, spin
anticlockwise around the "eye".)

The seemingly obvious culprit would be the famed North Atlantic
Oscillation, "NAO". Meteorologists measure, in winter, the relative
barometric pressure between the Azores (west of Europe) and Iceland
(northwest). When the index is "positive", it follows that there is
lower
pressure in Iceland than in the Azores. When it is VERY positive then
there is a cyclone in the north Atlantic, pulling moist and warmer air
off
the Canary Islands and into southern France. When this stuff hits the
Alps, depending on how cold it was there before it hits, it
precipitates
out and floods the Po. (Do I have this right so far?)

The NAO index oscillates between positive and negative. Some say it
does
this over a span of slightly less than 10 years. In general, over the
last
32 years it has been positive 25 times and negative 7. Either way, the
NAO
is not caused by, e.g., the sunspot cycle.

The next step would be to ascertain what creates cyclones in Iceland,
of
all places. But since I am on the subject of the late 530s, which as
mentioned above Keys blames on a vast global cooling...

1. What happens when Iceland suffers an anomalous downturn in its
temperature? I seem to remember from high school that cold fluids,
water
excepted, are less dense than hot ones. Could a deep chill in Iceland
suffice to lower its air pressure, to the extent of creating a low
pressure system / high NAO index?

Air is a gas

Cold air is denser that warm air. That gets you a high cool air high
pressure zone. A low is warm air or at least warmer than the high.

Water is fuild/liquid but nothing else acts exactly like it does.


except for other fluids and gases!
you need to go back to school - Bernouli?

I do pretty often. Cool air still sinks and hot air still rises.

Not always. That's why we get temperature inversions:

http://www.epa.gov/apti/course422/ce1.html
http://www.virtual-lakes.co.uk/photoderLatinversion.htm







Cooling warm water causes it to contract until near the freezing point at
which time it starts to expand. Salt concentration will change both the
density and freezing point so you need to do some serious reading.


2. Perhaps Krakatoa could erupt; perhaps Santorini or Vesuvius. Iceland
has enough volcanoes of its own. Any of these could increase "cloud"
cover
locally; or, some other factor might boost actual clouds over Iceland.
However it happens: does cloud cover over Iceland affect its air
pressure,
directly or through chilling it? What happens when the whole Northern
Hemisphere is clouded?

Depends but usually cloud cover cools the surface.


Thank you in advance
--
zimriel sbc dot
at global net
.
http://pages.sbcglobal.net/zimriel/
*new improved shorter .sig*






Eric Stevens