Overstability analysis on salt-fingers convection with parabolic temperature and salinity profiles

This paper explores the influence of parabolic profiles of temperature and salinity, as might arise due to local evaporation or warming disturbance, on the marginal stability problem in a salt-fingering regime. From the results of this article, the governing equations obtained for stationary onset of salt-fingers convection of a gravity gradient due to local disturbance in parabolic temperature and salinity profiles are similar to those obtained by the small-gap Taylor–Couette problem. Detailed relationships between the effective Rayleigh number ( R ˜ c ) , the critical wave number ( a c ) and the couple disturbed local depth under the stationary stability analysis are also shown in this work. The result of overstability analysis shows that the oscillatory motion of salt-fingers convection will be triggered under a certain definite characteristic frequency. In overstability, it provoke restoring forces so strong as to overshoot the corresponding position on the other side of equilibrium for case of coupled disturbance in the upper layer of ocean.