Lifted Condensation Level - Relation With CCL

Relation With CCL

The convective condensation level (CCL) results when strong surface heating causes buoyant lifting of surface air and subsequent mixing of the planetary boundary layer, so that the layer near the surface ends up with a dry adiabatic lapse rate. As the mixing becomes deeper, it will get to the point where the LCL of an air parcel starting at the surface is at the top of the mixed region. When this occurs, then any further solar heating of the surface will cause a cloud to form topping the well-mixed boundary layer, and the level at which this occurs is called the CCL. If the boundary layer starts off with a stable temperature profile (that is, with a lapse rate less than the dry adiabatic lapse rate), then the CCL will be higher than the LCL. In nature, the actual cloud base is often initially somewhere between the LCL and the CCL. If a thunderstorm forms, then as it grows and matures, processes such as increased saturation at lower levels from precipitation and lower surface pressure usually lead to a lowering of the cloud base.

Finally, the LCL can also be considered in relation to the level of free convection (LFC). A smaller difference between the LCL and LFC (LCL-LFC) is conducive to the rapid formation of thunderstorms. One reason for this is that a parcel requires less work and time to pass through the layer of convective inhibition (CIN) to reach its level of free convection (LFC), after which deep, moist convection ensues and air parcels buoyantly rise in the positive area of a sounding, accumulating convective available potential energy (CAPE) until reaching the equilibrium level (EL).