Factors for Cloud Heights
My son Jared ask me these questions after looking
at the flat bottoms of our storm clouds. What determines the lower
altitude of rain cloud? Is there a formula to calculate the bottom
position of the clouds?
The bottom of a cloud occurs at the elevation where the
air becomes saturated with water. This is called the
lifting condensation level. The air is cooled to this point
either by lifting of a layer of air (yielding a stratus cloud
layer) or by a upwards moving convective plume (yielding
individual cumulus clouds).
Equations to determine the bottom of a cloud are beyond the
scope of this web site. However, data from a radiosonde sounding
can be used to determine the height at which the air temperature
in a parcel of air would be cooled to the dew point temperature
(where saturation would occur), as a rough estimate of the height
at which a cloud would occur.
David R. Cook
Atmospheric Physics and Chemistry Section
Environmental Research Division
Argonne National Laboratory
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Update: June 2012