I can understand why low pressure cells are deeper in winter - greater
temperature contrast, but what mechanism causes winter high pressure
cells to have higher central values than summer ones?
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)

On Dec 13, 8:59�am, Paul Hyett wrote:
I can understand why low pressure cells are deeper in winter - greater
temperature contrast, but what mechanism causes winter high pressure
cells to have higher central values than summer ones?
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)

Its partly a case of what goes up must come down. The large amount of
rising air needed for a deep low descends somewhere to form an intense
high. Also the intense radiational cooling over the continents in
winter adds to the effect through the extra density of the cold
boundary layer air.

Dick Lovett
Charlbury

On Dec 13, 8:59 am, Paul Hyett wrote:
I can understand why low pressure cells are deeper in winter - greater
temperature contrast, but what mechanism causes winter high pressure
cells to have higher central values than summer ones?

Short answer is that cold air is denser. So total column density is
larger. Clear skies of a high with limited hours of winter insolation
tend to allow the nights to be colder and self reinforcing. The sun is
very low in the sky this time of year.

It is a very cold frosty day with bright azure blue sky and golden
sunshine up here in N Yorks today.

Regards,
Martin Brown

On Dec 13, 9:52 am, Dick Lovett wrote:
On Dec 13, 8:59�am, Paul Hyett wrote:

I can understand why low pressure cells are deeper in winter - greater
temperature contrast, but what mechanism causes winter high pressure
cells to have higher central values than summer ones?
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)

Its partly a case of what goes up must come down. The large amount of
rising air needed for a deep low descends somewhere to form an intense
high. Also the intense radiational cooling over the continents in
winter adds to the effect through the extra density of the cold
boundary layer air.

Sort of knock the theory about low pressure raising so many inches of
North Sea into a cocked hat doesn't it?

All it's got to do is cool down to affect all that hot air. So why
doesn't it strap all that high pressure instead of raising a tide?

Does it even suck in the right direction?

On Dec 13, 8:59 am, Paul Hyett wrote:

I can understand why low pressure cells are deeper in winter - greater
temperature contrast

So what causes greater temperature differences?

In article
,
Weatherlawyer writes:
On Dec 13, 8:59 am, Paul Hyett wrote:

I can understand why low pressure cells are deeper in winter - greater
temperature contrast

So what causes greater temperature differences?


The temperature at the Equator doesn't change much throughout the year,
as the sun at local noon is always within 23 degrees or so of the
vertical, and the length of time between sunrise and sunset doesn't
change much either. But close to the Pole you have almost six months
with no sun, so naturally there is a large difference in temperature
between winter and summer. That produces a much greater temperature
difference between Polar and Equatorial regions in winter than in
summer.
--
John Hall
"Honest criticism is hard to take,
particularly from a relative, a friend,
an acquaintance, or a stranger." Franklin P Jones

In uk.sci.weather on Thu, 13 Dec 2007, Dick Lovett
wrote :
On Dec 13, 8:590 I can understand why low pressure cells are deeper in winter - greater
temperature contrast, but what mechanism causes winter high pressure
cells to have higher central values than summer ones?
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)

Its partly a case of what goes up must come down. The large amount of
rising air needed for a deep low descends somewhere to form an intense
high. Also the intense radiational cooling over the continents in
winter adds to the effect through the extra density of the cold
boundary layer air.

OK, that makes sense.
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)