Editing Troposphere (section)

====Environment====
The environmental lapse rate (<math>dT/dz</math>), at which temperature decreases with altitude, usually is unequal to the adiabatic lapse rate (<math>dS/dz \ne 0</math>). If the upper air is warmer than predicted by the adiabatic lapse rate (<math>dS/dz > 0</math>), then a rising and expanding parcel of air will arrive at the new altitude at a lower temperature than the surrounding air. In which case, the air parcel is denser than the surrounding air, and so falls back to its original altitude as an air mass that is stable against being lifted. If the upper air is cooler than predicted by the adiabatic lapse rate, then, when the air parcel rises to a new altitude, the air mass will have a higher temperature and a lower density than the surrounding air and will continue to accelerate and rise.<ref name="DLA"/><ref name="LL"/>