Feature of thermohaline circulation in two-layer conceptual model based on energy constraint

The assertion that the thermohaline circulation(THC)is driven and sustained by mechanical energy has been increasingly accepted.The simplest conceptual model describing the THC is the Stommel two-box model.Given the vertical stratification in the real ocean,layered models were designed and used.In this research,using a two-layer conceptual model based on energy constraint,we studied basic features of thermal-mode and saline-mode circulations.We focused on the effects of freshwater flux and mixing energy on the intensity and multiple equilibrium states of the THC.The results show that more important than affecting the THC intensity,both the decrease of freshwater flux and increase of mixing energy can lead to an"abrupt transition"in the THC from a stable saline to a stable thermal mode,which further develops the THC energy theory.