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A mechanistic model of isopycnal diffusion in the ocean

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A two-dimensional (xz) box ocean model, is formulated to examine the mechanistic role of isopycnal diffusion (i.e. diffusion along a constant density surface) as compared to that of horizontal/vertical diffusion. A large-scale surface temperature anomaly forces a steady solution. The presence of isopycnal diffusion substantially increases the vertical penetration in the steady state: the vertical heat flux is increased by an order of magnitude in some locations. The time scale of the transient response is also modified, and the nature of this response is scale dependent. It is thus not possible in general to reproduce the transient response with isopycnal diffusion by adjusting diffusitives in a lateral diffusion formulation. Implications of the results to climate modelling are considered.

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Lin, C.A. A mechanistic model of isopycnal diffusion in the ocean. Climate Dynamics 2, 165–171 (1988). https://doi.org/10.1007/BF01053473

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  • Steady State
  • Heat Flux
  • Surface Temperature
  • Mechanistic Model
  • Density Surface