2. Parameters

Temperature/Levels » Virtual Temperature (Tv) Definition

Definition: Virtual Temperature

The virtual temperature (Tv) is the temperature at which dry air would have the same density as the moist air, at a given pressure. In other words, two air samples with the same virtual temperature have the same density, regardless of their actual temperature or relative humidity.

Scale with 2 air parcels on it. On left, t=27, td=24, and tv=30. On right, t=29, td=5, and tv=30. The 2 parcels balance.

Because water vapor is less dense than dry air and warm air is less dense than cool air, the virtual temperature is always greater than or equal to the actual temperature.

Note because the saturation mixing ratio increases exponentially with temperature (roughly doubling with every increase of about 10°C), the virtual temperature correction becomes increasingly important for higher dewpoints.