AVIA102 Lecture Notes - Lecture 1: Adiabatic Process, Cloud Condensation Nuclei, Cumulonimbus Cloud
Document Summary
Sky condition: the sky is divided into eight segments called oktas, clear: no clouds, few: 2 oktas or less covered by clouds, scattered: 3 4 oktas covered, broken: 5 7 oktas covered, overcast: 8/8 oktas covered. Cloud formation: clouds formed when water vapour in the air condense into water droplets. Warm air masses form dense, thick clouds: adiabatic expansion. Cooling due to expansion brought about by lifting. One of the most common causes of cloud formation: clouds also form if the air is super saturated and can no longer hold the moisture resulting in condensation, stable air horizontal sheets of air is formed. Orographic lift: air flowing against a range of mountains is forced upward by the terrain which greatly increases its speed and lowers the pressure at the top. Convection: as warm air rises during the day, cold air from above is pulled down and then heated and then rises resulting in a cycle.
