Comments on "instability of the thermohaline circulation with respect to mixed boundary conditions: Is it really a problem for realistic models?"

Abstract

This comment discusses two issues raised by a recent study of the stability of the thermohaline circulation (Tziperman et al.). A numerical problem is pointed out that may have affected the results of the reported calculations. In addition, it is argued that the state transition of the model circulation found in the above study is triggered by a convective instability mechanism, not the advective mechanism discussed by its authors. Should this be the case, then the conclusion of Tziperman et al. that the ocean is close to a stability transition point must be questioned.