level of free convection

level of free convection

[′lev·əl əv ‚frē kən′vek·shən]

(meteorology)

The level at which a parcel of air lifted dry and adiabatically until saturated, and lifted saturated and adiabatically thereafter, would first become warmer than its surroundings in a conditionally unstable atmosphere. Abbreviated LFC.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

level of free convection

If a dry mass of air is lifted from A to B adiabatically it will tend to come down from its position B to position A. However, if it becomes saturated at B and rises to C, it will continue to rise.

The level at which a parcel of air lifted dry adiabatically becomes saturated. It would then rise moist adiabatically and being warmer than the surrounding atmosphere would continue to rise in a conditionally unstable atmosphere. The dry adiabatic lapse rate is the rate of decrease of temperature with the height of a parcel of dry air lifted adiabatically. It is equal to 3°C/5.4°F per 1000 ft (9.767°C/km). ELR is the environmental lapse rate (i.e., the actual rate of decrease of temperature in the atmosphere).
 

An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved