wxman007
(Meteorologist)
Fri May 31 2002 04:24 PM
Re: Question for the Meteorologists out there...

Not really, but I'll try to explain...

Because the surface of the earth is NOT uniform (i.e. it varies in altitude) we use pressure readings at the surface. However, above the surface of the earth, we use CONSTANT PRESSURE levels instead....that is what is meant by the 925, 850 etc. It is algebraicly more convienient to use constant pressure instead of altitude. So when you see the term 500mb height (or any other pressure level) it means that that is the height (in dekameters or meters) at which the air pressure reaches 500mb....it's the opposite of sea level pressure.

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