In Mason's formulation the changes in temperature across the boundary layer can be related to the changes in saturated vapour pressure by the Clausius–Clapeyron relation; the two energy transport terms must be nearly equal but opposite in sign and so this sets the interface temperature of the drop.
According to Mason's theory, fluctuations in temperature within the boundary layer correlate with alterations in saturated vapor pressure via the Clausius–Clapeyron equation; both energy transfer elements should be roughly equivalent yet oppositely signed, thereby defining the interface temperature of the droplet.