ENVIRSC 1C03 Lecture Notes - Lecture 8: Fluid Parcel, Buoyancy, Dew Point
3 Sep 2018
School
Department
Course
Professor
Document Summary
Adiabatic process: if a parcel of air expands and cools/compresses and warms with no interchange of heat with its surroundings. At the earth"s surface, a parcel of air has the same temperature and pressure as the air surrounding it. Lower pressure outside the air parcel allows the air molecules inside the parcel to push the parcel walls outward, therefore expanding the parcel. Because there is no other source of energy source available, air molecules inside must use some of their own energy to expand the air parcel. This results in slower speeds and a lower parcel temperature. Higher pressure squeezes the parcel back into its original volume. Squeezing increases the average speed of the air molecules and the parcel temperature therefore rises. As an air parcel rises and expands, it cools. As an air parcel sinks and contracts, it warms.
