The lapse rate is defined as the negative of the rate of change in an atmospheric variable, usually
temperature, with height observed while moving upwards through an atmosphere. While typically applied to
Earth's atmosphere, the concept can be extended to any gravitationally supported ball of gas.
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The rate of change of an atmospheric variable, usually temperature, with height. A steep lapse rate implies a rapid decrease in temperature with height (a sign of
instability ) and a steepening lapse rate implies that destabilization is occurring. See