GEOG 1290 Lecture Notes - Lecture 17: Lapse Rate, Dew Point, Buoyancy
29 Nov 2014
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Document Summary
Adiabatic principle: the physical principle that a gas cools as it expands and warms as it compressed. Caused by change in pressure not heat in or out. Atmospheric pressure decreases with altitude: as a parcel of air rises pressure on parcel decreases, air expands and cool, as parcel of air descends pressure on parcel increases and air is compressed and warms. Adiabatic cooling they rise: large masses of air can be cooled to the dew point only by expanding as, when air rises, pressure decreases and it expands and cools adiabatically. Lifting condensation level: altitude at which rising air cools and reaches 100% relative humidity and condensation begins. Saturated (wet) adiabatic lapse rate (sar: rate of cooling: occurs above the lcl, release of latent heat, 6 degrees celsius per km. Adiabatic lapse rate applies to mass of moving air up/down through atmosphere: dar (10c per km) and sar (6c per km)
