Weatherlawyer wrote:

The Artist Formerly Known As Your Highness wrote:
On 23 Feb 2006 15:44:32 -0800, "Weatherlawyer"
wrote:

The Artist Formerly Known As Your Highness wrote:
On 23 Feb 2006 10:40:08 -0800, "Tony"

Could anyone please tell me why the air rotates around a low pressure
anti-clockwise and around a high pressure clockwise in the northern
hemishpere given that they are both subject to the same coriolis force
direction.

Try http://tinyurl.com/f3ytg for a succinct explanation.

That just shows a couple of diagrammes, it doesn't explain their
chirality. It can't-when you consider that in the North Atlantic, the
lower latitude storms move east to west and the higher latitude ones
move west to east.

Platitudes don't cut it. Try again. This time take account of the fact
that there is no "force" in the Coriolis Effect and that the winds in
the cyclones are immensely powerful and only come out to play when
there is calm weather.

Read it again, and comprehend it this time. It's not that difficult.

From the above link:
Cyclones and Anticyclones

Cyclones are areas of low pressure. Cyclones usually exhibit nearly
circular isobars. If isobars are oblong or elongate with the lowest
pressure near the center we call them troughs.

As air enters an area of low pressure from all directions, the Coriolis
effect bends the direction of the wind to the right of its path. This
creates a counterclockwise rotation around the low and convergence
near the center of the system. As the air collides near the center it
is forced aloft where divergence takes air away from the center of the
system. The upper-level divergence is necessary for the system to be
maintained as an area of low pressure.

Without the divergence, the system would fill with air and the
horizontal pressure differences would be equalized causing the system
to dissipate. Anticyclones are areas of high pressure that exhibit
nearly circular isobars. If isobars are oblong or elongate with the
highest pressure near the center we call them ridges.

For high pressure areas, air descends toward the surface due to
convergence aloft. As the air nears the surface it is forced outward
(divergence) from the center. The Coriolis effect bends the air to the
right of its path creating a clockwise rotation around the high.

*******

I had the impression that the OP wanted an explanation of why the above
occurs. Perhaps we can ignore some of the more prosaic errros in the
explanation and just cover the bit he wanted an answer to?

Why do cyclones exhibit the form of chirality we know and accept
without question?

Then we can get onto the subject of how much force there is in the
Coriolis effect and how it is more likely to heighten the chiral effect
(when horizontal winds do quite the opposite.)

*******

As it happens; it is the process of one layer of material falling or
rising through the other that causes rotation. Care to explain the
physics?

********

Hi

Thanks for some of the answers. But having had a look at some of the
links it still doesn't seem to answer my question. The diagrams show
air entering a low pressure at the area of convergence and being bent
to the left to creat the anti-clockwise rotation. This would seem to go
aginst the whole idea of the coriolis force and its affect on moving
fluids in the northern hemisphere.

Take it easy

Tony