absolute instability

absolute instability

[′ab·sə‚lüt ‚in·stə′bil·ə·dē]
(meteorology)
The state of a column of air in the atmosphere when it has a superadiabatic lapse rate of temperature, that is, greater than the dry-adiabatic lapse rate. Also known as autoconvective instability; mechanical instability.

absolute instability

absolute instabilityclick for a larger image
As it relates to meteorology, the state of a layer of air within the atmosphere in which a parcel of air, if given an upward push, will move away from its initial level without further outside force being applied. It is that condition in which the observed lapse rate is more than the dry and saturated adiabatic lapse rates. A mass of dry air in this case will rise until it becomes saturated and will still continue to rise, as the observed lapse rate is still greater. See also dry adiabatic lapse rate and saturated adiabatic lapse rate.