EAPS 10200 Lecture Notes - Lecture 5: Fluid Parcel, Orographic Lift
20 Oct 2017
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Document Summary
Atmospheric stability helps explain the varying sizes of clouds and the different amounts and duration of precipitation. We have seen how a cool parcel of air sinks because of density. Cool sinking air is called stable air because it doesn"t tend to do much except sit on the surface. However, if the parcel of air is warmer then its surroundings it will rise until it reaches an altitude where the temperature is the same as the surroundings. Earlier we discussed the adiabatic cooling rate. This is the rate at which a rising parcel of air cools do to its expansion. This cooling rate is about 10 c per 1,000 m of rise however, there is another cooling rate called the environmental lapse rate. This is simply the temperature of the air at a certain altitude and is about 5 c 1,000 m.
