The density temperature and the dry and wet virtual adiabats.
A density temperature is introduced to represent virtual temperature and potential temperature on thermodynamic diagrams. This study reviews how the dry and wet virtual adiabats can be used to represent stability and air parcel density for unsaturated and cloudy air, and present formulae and tabulations.
Betts, A.K., and J. Bartlo, 1991: The density temperature and the dry and wet virtual adiabats. Mon. Wea. Rev., 119, 169-175.