On the rate of ice formation in water cooled by a more saline sublayer

A less saline water mass (of salinity S₁) at its freezing temperature (T_1f) is superposed on a more saline water mass (of salinity S₂) of a temperature T₂ T_1f. Both water masses have temperatures lower than their respective temperatures for maximal density, thus 0 < S₁ <S₂ < 24.7%. As heat diffuses much faster than salt there will be thermal convection in the two water masses. Heat is transferred down into the lower layer and ice forms in the upper layer. The present paper shows that in the actual parameter range (R_ρ » 10) the heat exchange between the layers is controlled by the molecular processes in the pycnocline and not by the properties of the induced thermal convection in the homogeneous layers. A theory that predicts some experimental results on the growth-rate of ice quite well is developed.