<P> A formal definition from the Glossary of Meteorology is: </P> <Dl> <Dd> The decrease of an atmospheric variable with height, the variable being temperature unless otherwise specified . </Dd> </Dl> <Dd> The decrease of an atmospheric variable with height, the variable being temperature unless otherwise specified . </Dd> <P> In general, a lapse rate is the negative of the rate of temperature change with altitude change, thus: </P>

A lapse rate of celsius degrees per 1000 meters