Knowra Lifting condensation level Lifting condensation level The altitude an unsaturated air parcel reaches as it rises and cools until its relative humidity reaches 100%. Water vapor then begins to condense, often forming cloud droplets.
Adiabatic process : A change in a system’s state without heat entering or leaving it. Rising air cools mainly through expansion without exchanging much heat with its surroundings.
Cloud base : The lowest altitude at which a cloud’s visible elements begin. For clouds formed by rising surface air, the base often lies near the lifting condensation level.
Atmospheric pressure : The force per unit area exerted by the weight of the atmosphere. Pressure decreases as an air parcel rises, shaping its expansion and cooling.
Convective condensation level : The height at which air heated from below, rising without prior lifting, becomes saturated through convection. Unlike the lifting condensation level, it estimates cloud base from surface heating and mixing.
Skew-T log-P diagram : A thermodynamic chart that plots atmospheric temperature and dew point against logarithmic pressure, with temperature axes skewed. A sounding on this chart lets forecasters lift a surface parcel and locate its saturation point.
Dry adiabatic lapse rate : The rate at which unsaturated air cools as it rises, about 9.8°C per kilometer in typical conditions. It governs the parcel’s cooling before it reaches saturation.
Cumulus cloud : A cloud with distinct, often cauliflower-shaped elements, commonly produced by convection. A rising convective parcel can begin forming a cumulus cloud near its condensation level.
Mixing ratio : The mass of water vapor per unit mass of dry air in a sample. Before condensation, a rising parcel’s water-vapor mixing ratio is approximately conserved.
Level of free convection : The altitude above which a lifted air parcel becomes warmer than its environment and rises buoyantly. It marks buoyant acceleration, not the onset of saturation or cloud formation.
Atmospheric sounding : A vertical profile of atmospheric properties measured by instruments carried aloft or remote sensing. Temperature and moisture profiles provide the observations needed to calculate parcel condensation levels.
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