Rising Air Cools-Sinking Air Warms
8 m/s
494 m/s
502 m/s
502 m/s
494 m/s
Rising Expanding
Sinking Contracting
¥Rising air parcel expands because pressure decreases with altitude
¥Expansion requires that the molecules do work against surrounding air
¥This uses up some of their internal energy which results in their
temperature decreasing
¥Assuming no transfer of heat across parcel walls (adiabatic expansion), cooling rate is
10oC/km
10oC
20oC
no
heat transfer
Ahrens, Fig 5.2
502 m/s