References

Ocean Science

Ocean Sci.

1812-0792

Copernicus Publications

Göttingen, Germany

10.5194/os-10-127-2014

The instability of diffusive convection and its implication for the thermohaline staircases in the deep Arctic Ocean

Zhou

S.-Q.

¹ Qu

¹ ² Lu

Y.-Z.

¹ ² Song

X.-L.

¹ ²

State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, 164 West Xingang Road, Haizhu District, Guangzhou 510301, China

University of Chinese Academy of Sciences, Beijing, 100049, China

24 02 2014

10 1 127 134

2014

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In the present study, the classical description of diffusive convection is updated to interpret the instability of diffusive interfaces and the dynamical evolution of the bottom layer in the deep Arctic Ocean. In the new consideration of convective instability, both the background salinity stratification and rotation are involved. The critical Rayleigh number of diffusive convection is found to vary from 103 to 1011 in the deep Arctic Ocean as well as in other oceans and lakes. In such a wide range of conditions, the interface-induced thermal Rayleigh number is shown to be consistent with the critical Rayleigh number of diffusive convection. In most regions, background salinity stratification is found to be the main hindrance to the occurrence of convecting layers. With the new parameterization, it is predicted that the maximum thickness of the bottom layer is 1051 m in the deep Arctic Ocean, which is close to the observed value of 929 m. The evolution time of the bottom layer is predicted to be ~ 100 yr, which is on the same order as that based on 14C isolation age estimation.

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