> As the name suggests this circulation is driven almost entirely by changes in temperature and salinity
This is one of these 'facts' that are often repeated, but are actually false, and it's simple to explain why. Aside from mixing within the ocean interior, all processes that affect the density of water (e.g. evaporation, precipitation, and sea-ice formation) occur at the surface. As a result, whilst it's possible to form dense waters at the surface of the ocean (which can sink), there is no process that can reduce the density of the resulting deep waters, and thereby bring them back to the surface. In other words, it is energetically impossible for the 'thermohaline circulation' to be driven by changes in temperature and salinity.
In actual fact, the more-accurately-named meridional overturning circulation is chiefly driven by a combination of winds in the Southern Ocean, and interior mixing (e.g. Gnanadesikan (1999), Johnson et al. (2007)). The formation of dense water masses is a necessary condition to have strong overturning, but it isn't the driver.
Chlorophilia t1_is1o5bf wrote
Reply to comment by [deleted] in Does the salinity of ocean water increase as depth increases? by rhinotomus
> As the name suggests this circulation is driven almost entirely by changes in temperature and salinity
This is one of these 'facts' that are often repeated, but are actually false, and it's simple to explain why. Aside from mixing within the ocean interior, all processes that affect the density of water (e.g. evaporation, precipitation, and sea-ice formation) occur at the surface. As a result, whilst it's possible to form dense waters at the surface of the ocean (which can sink), there is no process that can reduce the density of the resulting deep waters, and thereby bring them back to the surface. In other words, it is energetically impossible for the 'thermohaline circulation' to be driven by changes in temperature and salinity.
In actual fact, the more-accurately-named meridional overturning circulation is chiefly driven by a combination of winds in the Southern Ocean, and interior mixing (e.g. Gnanadesikan (1999), Johnson et al. (2007)). The formation of dense water masses is a necessary condition to have strong overturning, but it isn't the driver.