lapse rate
Noun
Meaning
lapse rate (plural lapse rates)
(meteorology) The rate of change in an atmospheric variable, especially temperature, with increase of height.
Examples
Additionally, the insurance program has a low 3.5% lapse rate of the 1.7 million members and their families who are insured.
A rise from sea level into the upper regions of the atmosphere causes the temperature to decrease (see adiabatic lapse rate ).
As the air rises, the temperature drops (following the lapse rate ), causing the relative humidity (RH) to rise.
If, on the contrary, the upper air is cooler than predicted by the adiabatic lapse rate, then when the air parcel rises to its new height it will have a higher temperature and a lower density than its surroundings, and will continue to accelerate upward.
The dry adiabatic lapse rate accounts for the effect of the expansion of dry air as it rises in the atmosphere and wet adibatic lapse rates includes the effect of the condensation of water vapor on the lapse rate.
The environmental lapse rate (the actual rate at which temperature drops with height, ) is not usually equal to the adiabatic lapse rate (or correspondingly, ).