The purpose of this Investigation is to use Stüve diagrams to illustrate the rates at which rising (and sinking) parcels of air cool (and warm). When rising air is subsaturated, it cools at the "dry adiabatic lapse rate" which is 9.8 C/km. The dry adiabatic lapse rate lines on a Stüve diagram are the solid green diagonal lines. The point that represents conditions in a "dry" volume of air rises parallel to the dry adiabatic lapse rate line to illustrate the temperature of the rising dry air at any level in the atmosphere. On the other hand, when rising air is saturated, it cools at the "moist adiabatic lapse rate of 6 C/km. The moist adiabatic lapse rate lines on a Stüve diagram are the dashed blue curved lines. The point that represents conditions in a "moist" or saturated volume of air rises parallel to the moist adiabatic lapse rate line to illustrate the temperature of the rising saturated air at any level in the atmosphere. Note that all sinking air warms at the dry adiabatic rate because, as soon as the volume warms by compressional warming, it becomes subsaturated.

• published: 17 Oct 2013
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