ANT-3451 Lecture Notes - Lecture 1: Fluid Parcel, Cool Air, Lapse Rate
Document Summary
Stability and cloud development: atmospheric stability. Dry adiabatic cooling: as long as the relative humidity is less than 100% the rate of adiabatic cooling or warming remains constant. Dry adiabatic rate: 10 degrees c heating or cooling for every 1000m (1 kilometer) of change in elevation. The atmosphere is stable when the di erence in temp between the surface air and the air aloft is relatively small. Atmosphere stabilizes as air aloft warms or the surface air cools. Absolute instability: when the environmental lapse rate is greater than the dry adiabatic rate: buoyant force: when air parcel in an unstable atmosphere has an upward directed force acting on it. The warmer the air parcel compared to it"s surroundings, the greater the buoyant force and the faster it rises. Conditional instability occurs when the environmental lapse rate is between the moist adiabatic rate and the dry adiabatic rate: the atmosphere is ordinarily in a state of conditional instability.
