1. What is CCL?
CCL (Convective Condensation Level) is the height of cloud bases resulting from air rising from the surface due to positive buoyancy alone. The units given are a pressure level.
2. How is CCL determined?
Note the surface dewpoint. Parallel a mixing ratio line through the dewpoint until it intersects the temperature sounding. The intersection on the temperature sounding is the pressure level of the CCL.
3. Operational significance of CCL:
VERSUS LCL: The CCL will be greater in height than the LCL since the surface must warm to an adequate temperature first before a parcel will rise due to positive buoyancy alone. Warming the surface decreases the RH and thus requires the parcel to rise higher before condensation will occur.
Height of cloud bases: Cumulus clouds that form in the afternoon due to daytime heating are often the result of air rising from the surface up to the CCL from positive buoyancy. The drier the PBL, the higher the cloud bases will be.