- Level of free convection
The level of free convection (LFC) is the altitude in the atmosphere where the
temperatureof the environment decreases faster than the moist adiabatic lapse rateof a saturated air parcelat the same level.
The usual way of finding the LFC is to lift a parcel from a lower level along the
dry adiabatic lapse rateuntil it crosses the mixing ratio line of the parcel: this is the lifted condensation level(LCL). From there on, follow the moist adiabatic lapse rateuntil the temperature of the parcel reaches the air mass temperature, at the equilibrium level(EL). If the temperature of the parcel along the moist adiabat is warmer than the environment on further lift, one has found the LFC.
Since the volume of the parcel is larger than the surrounding air after LFC by the
ideal gas law(PV = nRT), it is less dense and becomes buoyant rising until its temperature (in E) crosses back the airmass one. If the airmass has one or many LFC, it is potentially unstable and may lead to convective clouds like cumulusand thunderstorms.
Free convective layer
* [http://www.theweatherprediction.com/habyhints/309/ SKEW-T: A LOOK AT LFC]
* [http://amsglossary.allenpress.com/glossary/search?id=level-of-free-convection1 Level of free convection (LFC)] (Glossary of Meteorology)
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