The influence of water vapor fluctuations on turbulent fluxes

The influence of water vapor fluctuations on vertical turbulent fluxes is examined. It is shown that effects on density and, consequently, buoyancy are insignificant. However, because specific heat of air is a function of specific humidity, these fluctuations are found to influence sensible heat flux significantly. The critical parameter is the Bowen ratio, and a formulation relating the heat flux assuming dry air to the true value is given. The implications of this analysis to flux-gradient relationships in the surface layer are commented on.