GGR214H5 Lecture Notes - Lecture 5: Convective Instability, Radiative Cooling, Advection
Document Summary
Unstable air: a stable layer can become unstable in several ways, the bottom of the layer may be heated. Passing over a warm surface: the top of the layer may be cooled. Advection of colder air: the layer may be lifted. The layer will expand and the top will rise more than the bottom. Especially pronounced if the bottom of the layer is saturated (convective instability) Stable air: temperature decreases weakly with height, strongest stability occurs with inversions, temperature increases with height (elr < 0, turbulence is inhibited. Horizontal movement of air masses pushes warm air upward. Layer of air sinks: e. g, high pressure, or descent down a mountain, heat, moisture and pollutants can be trapped beneath a layer of stable air. Neutral stability: elr layer must be the same as the dalr or thesalr, overcast skies, surface will not be strongly cooled or heated, windy, mixing can produce an elr that is the same as the dalr.
