ATOC 1050 Lecture 7: Lecture 7 2:7:17
11 Feb 2017
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Document Summary
An air parcel is an imaginary volume of air that acts independently of its surroundings. There is no heat exchange between the parcel and its surroundings. Additionally, we will assume no mixing of air between the parcel and the surroundings. Adiabatic process: temp changes that occur without adding or subtracting heat, temp change is due to the compression or expansion of air, when air is compressed it warms and when air expands it cools. As an air parcel rises through the atmosphere, it reaches areas of lower and lower pressure. As pressure decreases, parcel expands and cools adiabatically. Conversely, as an air parcel descends in the atmosphere it experiences higher presses, compresses and warms adiabatically. The rate of cooling/warming for dry air parcel is 10 degrees c for every 1,000 m of ascent/descent. This is known as the dry adiabatic lapse rate. If parcel rises high enough, it will eventually cool to its dew point and begin process of condensation.
