"The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. \"Vertical momentum diffusivity\" means the vertical component of the diffusivity of momentum due to motion which is not resolved on the grid scale of the model. Convective mixing in the ocean is somtimes modelled as an enhanced diffusivity." . . . "Climate and Forecast (CF)" . . "ocean vertical momentum diffusivity due to convection" . .