wirelessguru1 Wrote:
-------------------------------------------------------
> > Nowhere does it say anything about the
> fluctuation of
> > Earths magnetic field affecting the climate.
>
> So, how are low pressure zones made?



From A. Miller. 1976. Meteorology (3rd ed). Columbus, OH: Charles Merrill

“Consider the north-south cross sections of the atmosphere illustrated in Figure 3.3 If the temperature does not vary in the horizontal at any level [part (a) of the figure], the density at any height will be equal everywhere; thus the equal-pressure surfaces (isobars) and the equal-density surfaces will be straight and horizontal. But if the air to the south is warmer than it is in the north [Figure 3.3 (b)], the density at any level will increase from south to north. The less dense, warm air in the south will rise while the denser, cold air in the north sinks.
Near the surface, the pressure surfaces will slope upward toward the colder, denser air of the north. However, the north-south slope of the isobars will decrease with altitude above the surface until eventually the slope will be reversed. This is because the vertical pressure gradient in cold air is greater than it is in warm air. Since pressure measures the weight per unit area, the change in pressure experienced in 1000-foot ascent, will depend on the weight of the 1000-foot column of air of unit area. If the air in the layer is dense, the pressure drop will be greater than if the air is not so dense. At any particular pressure, the density depends on the temperature (Charles law); warm air is less dense than cold air.
Therefore, although the horizontal flow is always from high to low pressure, near the surface this means north to south (cold to warm) motion, while aloft it will be just the opposite. The closed circuit formed by the moving parcels of air is a thermal circulation. Note that it looks very much like the pattern of motion that occurs in a pan of water that is being heated at one point.
In summary, there are two rather large “basic” forces acting on the atmosphere—pressure gradient and gravity. The latter is directed entirely in the vertical , while the former has a very small component directed in t he horizontal. Even though each of the two forces acting in the vertical is much greater than in the horizontal, this does not mean that vertical motion is much stronger than that in the horizontal, remember it is the net or unbalanced force that determines acceleration, and the two vertical forces are almost always very nearly equal and oppositely directed. Actually, except in small circulation cells such as those in a thunderstorm, the vertical air velocity is normally only a tenth or a hundredth of the horizontal velocity.”

BOM- Thus the air is warmer near the Equator and thus less dense and rises; the air at the poles is colder and denser. This sets up a circular motion of the air Equator to Pole at higher altitude and Pole to Equator at the surface. This would be simple except that the earth is spinning and that creates a lot of complications in the weather. The basic point, however is that high and low pressure areas have to do with the temperature of the air and nothing whatever to do with the earth’s magnetic field.


>
> Why are so many tornados around thunder storms?
>
> > By talking about increased seismic activity.
>
> > Singeling out some earthquakes when
> discussing this
> > is like talking about the weather of the day
> when
> > climate change is being discussed. Then
> again, you've
> > done that in the previous threads....
>
> Come on, I was just singeling out the LARGEST
> one(s)!
>
> > If someone claims that human beings have
> increased in
> > height over the millenia, would a short
> person that
> > you pass by in the street be evidence that
> the claim is
> > wrong?
>
> Of course not! LOL
>
> > How about the evidence of how these things
> affect
> > what is being discussed here?
>
> Look Tommi, electricity and therefore magnetism,
> since they are both related, have always been an
> integral part of the weather! Example, thunder
> storms, lightening, coliding fronts, etc...

The following from a NASA site
[ksnn.larc.nasa.gov]

“When cold air moves in and meets warm moist air, the warm air rises rapidly, forming anvil shaped cumulonimbus clouds or thunderstorm clouds! During the thunderstorm, water droplets and ice crystals in the clouds bump together and break up as they rub against each other in strong currents of air. As a result, static electrical charges can develop in the clouds.


The positive electrical charges in the cloud concentrate at the top, while the negative electrical charges are at the bottom. When the charge at the base of the cloud reaches a certain strength, electrical energy is released and passes through the air to another point that has an opposite charge. This release of energy is called a leader stroke and can travel along a path from the cloud to the ground or from the cloud to another cloud. No one is sure why lightning bolts usually follow a zigzag path as they move. The main stroke will travel back up to the cloud and produce a flash of lightning and also heat the air, causing it to expand quickly and produce the sound we hear as thunder.”


BOM- Thus the source of electric charge in clouds that leads to thunder and lightning is not the earth’s magnetic field.

Just because there is a relationship that electric currents produce magnetic fields and that conversely moving magnetic fields produce electric currents does not mean that all electricity is somehow related to magnetic fields and vice versa.



>
> So, are you trying to "suggest" here that changes
> in Earth magnetism have no affect/effect on the
> weather changes!?
>
> -wirelessguru1
>
Please cite *Quote* evidence that they do.

Bernard

p.s. The latest *Scientific American* has an interesting article on the causes of the earth's magnetic poes and their reversals.G. A. Glatzmeir and P. Olson. 2005. "probing the Geodynamo," *Scientific American*292 (#4, April):51-57.



Edited 1 time(s). Last edit at 03/18/2005 05:56PM by bernard.