Comment on two papers by Canuto and Dubovikov

The above papers by Canuto and Dubovikov claim that present oceanographic models ignore an important term in the mean buoyancy and tracer equations, but previously published work shows this is not the case. Canuto and Dubovikov also argue that this same “missing” term in the mean buoyancy equation leads to extra diapycnal advection across mean isopycnals which should be included in the energetic considerations of the mean diapycnal advection-diffusion balance in the deep ocean. We show that this is incorrect; the relevant mean diapycnal advection (“upwelling”) is caused by small scale mixing processes (and various processes due to the non-linear nature of the equation of state) but is not caused by the four so-called “mesoscale-adiabatic” terms identified by Canuto and Dubovikov.