... an air parcel rises/descends. The rate at which temperature decreases in a rising, expanding air parcel is called the adiabatic lapse rate. If a rising air parcel remains dry with a relative humidity below 100%,it will decrease in temperature at a rate of about 10C/km. This is known as the dry adiabatic lapse rate. One difference between the dry and saturated adiabatic lapse rates is that whereas the former remains constant the later varies with temperature. This is because saturated adiabatic lapse rate depends upon the amount of heat released by condensation which in turn depends upon the moisture content and therefore the air temperature. Contrast between the environmental lapse rate and the adiabatic lapse rates controls the stability of the atmosphere. There are three types of stability. The first one is absolute stability. Stable atmospheric conditions prevail when the environmental lapse rate is less than the saturated adiabatic rate. ...

See this essay or coursework document in full right now