Cabbeling

He reasoned that cabbeling would form a front at the juxtaposition of Warm Deep Water and Shelf Water. Sinking along such a front would thus inhibit the cross shelf flow of shelf water.

To complete this catalog of thermodynamic processes of importance in shallow seas, the phenomenon of cabbeling should be mentioned (from the German ‘Kabbelung’, see Horne et al. (1978), usually pronoun[c]ed in English with the emphasis on the second syllable). Because the equation of state of water is nonlinear, the density of a mixture of two water masses of unequal temperature (and possibly salinity) is greater than the arithmetic average density of the two components. Thus surface mixing of adjacent water masses of differing characteristics generally produces water locally denser than its surroundings, which tends to sink. Sinking motion so generated is referred to as ‘cabbeling’.

This effect is presumably compensated for by cabbelling, or densification on mixing, below the surface, but would be interesting to examine in a numerical model.

When two water parcels with the same mass but different temperature and salinity mix together, the newly generated water parcel may have a density greater than the mean density of the original water parcels. In particular, if the original water parcels have the same density, then the newly formed water parcel may have a density greater than the mean density of the original parcels. As a result, the newly formed water parcel will sink. This process, called cabbeling in oceanography, is due to the nonlinearity of the equation of state of seawater, especially the increase of the thermal expansion coefficient with temperature.